Older adults experience better affective well-being in solitude: The moderating role of goal for conflict de-escalation.

Older adults report greater affective well-being in solitude than younger adults, but prior findings are based on correlational designs. We aim to examine age differences in affective well-being in solitude using an experimental design and to examine conflict de-escalation as a potential mechanism. In Study 1, 207 participants were randomly assigned to either a solitude or a social interaction condition. In Study 2, 128 participants were randomly assigned to one of four conditions: solitude-escalation, solitude-de-escalation, interaction-escalation, and interaction de-escalation. After a 15-min solitude or social interaction period, they reported their affective experiences. In Study 1, older (vs. younger) adults reported more positive affect overall. This age-related difference was greater in the solitude (vs. social interaction) condition; older adults reported less negative affect than younger adults in the solitude, but not the social interaction, condition. In Study 2, older (vs. younger) participants reported more high-arousal positive affect in the solitude-escalation condition. This difference was not significant in conflict de-escalation conditions. Our studies provide causal evidence of the relationship between solitude and affective well-being and advance our understanding of motivations that explain why older adults maintain better affective well-being in solitude.

Age differences in the experience of everyday happiness: The role of thinking about the future.

Happiness can be experienced differently in young as compared to older adulthood, possibly due to shifts in temporal focus and differences in preferences for high- versus low-arousal affective states. The current project aimed to replicate initial evidence on age-related differences in the experience of happiness by investigating the positive affective correlates of everyday happiness; we further explored the role of thinking about the future in moderating such associations. We used daily life assessments from 257 participants (Mage = 48.3, SDage = 24.6; 68% female; 77% Asian [East Asian, South Asian, and Southeast Asian]; 73% postsecondary educated), combining four data sets collected at two locations (Vancouver, Canada; Hong Kong) with different age samples (older and younger adults). Participants provided up to 30 repeated daily life assessments of momentary affective states and thoughts about the future, over 10 days. Results replicate previous findings by showing that happiness was more strongly associated with low-arousal positive affect and more weakly associated with high-arousal positive affect among older compared to younger adults. Engagement in thinking about the future was higher among younger compared to older adults in general, but its role in moderating the association between happiness and positive affect varying in arousal levels was confounded by the age moderation. Separate analyses conducted for each age group indicate different roles of everyday thinking about the future in shaping happiness experiences for different age groups. Age and future thinking-related contours of happiness are discussed in the context of emotional aging theories. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Everyday Pain in Middle and Later Life: Associations with Daily and Momentary Present-Moment Awareness as One Key Facet of Mindfulness.

This study investigated everyday associations between one key facet of mindfulness (allocating attention to the present moment) and pain. In Study 1, 89 community-dwelling adults (33-88 years; Mage = 68.6) who had experienced a stroke provided 14 daily end-of-day present-moment awareness and pain ratings. In Study 2, 100 adults (50-85 years; Mage = 67.0 years) provided momentary present-moment awareness and pain ratings three times daily for 10 days. Multi-level models showed that higher trait present-moment awareness was linked with lower overall pain (both studies). In Study 1, participants reported less pain on days on which they indicated higher present-moment awareness. In Study 2, only individuals with no post-secondary education reported less pain in moments when they indicated higher present-moment awareness. Findings add to previous research using global retrospective pain measures by showing that present-moment awareness might correlate with reduced pain experiences, assessed close in time to when they occur.

Hot Instantaneous Temperature and Affect: Meaningful Activities as a Buffer for Older Adults With Low Socioeconomic Status.

Background and Objectives: Extremely hot temperature affects psychological well-being negatively, especially for older adults with lower socioeconomic status (SES). The objectives of this study are to examine: (a) the impact of hot instantaneous temperature on older adults' emotional well-being and (b) whether meaningful engagement could reduce the above impact, particularly for those of lower SES. Research Design and Methods: We conducted a quantitative time-sampling study during hot-weather months (May-September) in 2021 and 2022. The sample comprises 344 participants aged 60 years or older (Mage = 67.15, SDage = 5.26) living in urban areas of Hong Kong, where hot days (daily maximum temperature ≥33°C) accounted for 23% of the study days. Participants reported positive and negative affect, and engagement in meaningful activities, three times a day over a 10-day period, and wore sensors that tracked the instantaneous temperature of their immediate environment. Multilevel modeling was employed to examine the impacts on affect from temperature, SES, and meaningful activity engagement. Results: Hotter instantaneous temperature predicted greater momentary negative affect and less positive affect immediately afterwards. Meaningful engagement significantly buffered against the affective impacts of hotter temperature, and this buffering effect was more salient among older adults of lower SES. Discussion and implications: This study highlights the role of meaningful engagement in reducing the impact of hotter instantaneous temperature on older adults' emotional well-being, particularly for those of lower SES. Meaningful activity engagement may be capitalized on, as a strategy, to reduce climate-related social inequality.

The perks of doing housework: Longitudinal associations with survival and underlying mechanisms.

BACKGROUND: Although the majority of existing literature has suggested positive effects of housework on older adults' health and survival rate, the underlying mechanisms of such effects remain unclear. To address potential mechanisms, the present study examined the association between older adults' housework engagement and days of survival across 14 years and tested three potential mediation pathways in this association. METHODS: Four thousand Hong Kong older adults (50% female; aged between 65 and 98 years) participated in a longitudinal study in which they reported initial housework engagement and health status across three domains (cognitive functioning, physical health, and mental health) at the baseline, and the numbers of days they survived over the subsequent 14-year period were recorded. Linear regression, Cox proportional hazard, and parallel mediation analyses were performed to examine the relationship between housework engagement and days survived, and the mediating effects of these three health factors. RESULTS: The results showed a positive association between housework engagement and days survived after controlling for demographic variables (age, sex, education, marital status, subjective social status, and living alone). Physical health and mental health, but not cognitive functioning, partially mediated the relationship between housework engagement and days survived. The findings suggest that doing housework may contribute to longer survival by improving older adults' physical and mental health. CONCLUSION: The current study confirms positive relations of housework with health and mortality among Hong Kong older adults. As the first study examining the relationships and mediation pathways between doing housework and survival in later life, the findings advance our understanding of the mechanisms underlying the positive association between housework and mortality and provide insights for future daily-life health-promotion interventions for older adults.

The differential roles of chronic and transient loneliness in daily prosocial behavior.

Loneliness is a recognized risk factor for morbidity and mortality across the adult life span including old age. Loneliness is a negative emotional experience that has been associated with social isolation, but loneliness may also be adaptive to the extent that it signals a need to socially reengage. To reconcile these seemingly contradictory findings, we unpack the timing of the underlying processes by distinguishing between transient and chronic loneliness in shaping prosocial behaviors. Using 10 days of electronic daily life assessments from 100 middle-aged and older adults (Mage = 67.0 years; 64.0% women), findings indicate that chronic loneliness moderates time-varying associations between transient loneliness and prosocial behavior. Simple slope results point to individual differences in daily loneliness-prosocial action associations. Specifically, adults high in chronic loneliness, but not those low in chronic loneliness, showed decreased prosocial behaviors on days with elevated transient loneliness. Findings suggest that chronic loneliness may elicit maladaptive responses to transient loneliness by hampering the use of opportunities to engage in prosocial behavior. Exploratory analyses point to fear of evaluation as a potential mechanism that is associated with increased loneliness and reduced prosocial behavior. Findings highlight the differential roles of transient and chronic loneliness in shaping prosocial activities in midlife and older adulthood, thereby providing a more nuanced picture as well as potential avenues for intervention. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Attitudes Toward Aging: A Glance Back at Research Developments Over the Past 75 Years.

With global aging, it is crucial to understand how older adults and the process of aging are viewed by members of society. These attitudes can often influence how older adults are treated. Since the Journal of Gerontology was founded, we have gained increasing insights into attitudes toward aging, with several notable research developments, including clearer conceptualization of different types of aging attitudes (e.g., life-domain-specific attitudes and self-perceptions of aging), a wider variety of measurements, better understanding of how different social determinants shape aging attitudes, and more sophisticated investigations of cultural variance and invariance in aging attitudes. In this article, we highlight these major shifts in the field of aging attitudes in the past 75 years, discuss the contributions of these developments, and point to potential future directions.

Choosing Solitude: Age Differences in Situational and Affective Correlates of Solitude-Seeking in Midlife and Older Adulthood.

OBJECTIVES: Despite a basic need for social connection, individuals across the adult lifespan sometimes seek solitude-a phenomenon that is not well understood. This study examined situational and affective correlates of solitude-seeking and how they may differ between middle-aged and older adults. METHOD: One hundred community-dwelling adults aged 50-85 years (64% female, 56% East Asian, 36% European, 8% other) completed approximately 30 electronic daily life assessments over 10 days regarding their current location, affect, activities, and current and desired social context. RESULTS: Solitude was common; 86% of solitude instances happened by individuals' own choosing. When desiring solitude, older adults were more likely to be at home and less likely to be outdoors, compared to other locations. Middle-aged adults showed no such solitude-location associations. Among middle-aged adults, desire for solitude was associated with decreased positive affect. Older adults experienced no such dip in affect. DISCUSSION: Findings suggest that compared to middle-aged adults, older adults are more likely to go to locations that match their desired social context, and also that solitude-seeking has more positive ramifications for older adults. Findings are discussed in the context of age differences in activities, social preferences, and emotion regulation.

Solitude in context: On the role of culture, immigration, and acculturation in the experience of time to oneself.

Older adults spend much time in solitude (without social interaction), putting them at risk of loneliness, especially if aging outside their country of origin (e.g., Chinese immigrants to Canada). Yet, cultural contextual factors that may reduce loneliness in moments of solitude are poorly understood. This study sought to disentangle the roles of culture, immigration, and acculturation in solitude-loneliness associations across two countries. Community-dwelling adults aged 51-85 in Vancouver (N = 58 East Asian, N = 37 European/North American) and in Hong Kong (N = 56 East/Southeast Asian) completed approximately 30 ecological momentary assessments over 10 days on their current affect and social situations. Participants in Vancouver spent more time in solitude, desired solitude more, and felt less lonely overall than those in Hong Kong. Multilevel models revealed that moments of solitude felt lonelier than moments spent in social interaction, but only for individuals less acculturated to their host culture or not concurrently desiring solitude. Associations held regardless of host culture, cultural heritage, or immigration status. Findings suggest that solitude need not feel lonely if it happens by choice and if individuals feel connected with their host culture, for both immigrant older adults and those aging in their birth country.

Everyday solitude, affective experiences, and well-being in old age: the role of culture versus immigration.

Objectives: Being alone is often equated with loneliness. Yet, recent findings suggest that the objective state of being alone (i.e. solitude) can have both positive and negative connotations. The present research aimed to examine (1) affective experience in daily solitude; and (2) the association between everyday affect in solitude and well-being. We examined the distinct roles of culture and immigration in moderating these associations. Method: Using up to 35 daily life assessments of momentary affect, solitude, and emotional well-being in two samples (Canada and China), the study compared older adults who aged in place (local Caucasians in Vancouver , Canada and local Hong Kong Chinese in Hong Kong, China) and older adults of different cultural heritages who immigrated to Canada (immigrated Caucasians and immigrated East Asians). Results: We found that older adults of East Asian heritage experienced more positive and less negative affect when alone than did Caucasians. Reporting positive affect in solitude was more positively associated with well-being in older adults who had immigrated to Canada as compared to those who had aged in place. Conclusions:These findings speak to the unique effects of culture and immigration on the affective correlates of solitude and their associations with well-being in old age.

By myself and liking it? Predictors of distinct types of solitude experiences in daily life.

OBJECTIVE: Solitude is a ubiquitous experience, often confused with loneliness, yet sometimes sought out in daily life. This study aimed to identify distinct types of solitude experiences from everyday affect/thought patterns and to examine how and for whom solitude is experienced positively versus negatively. METHOD: One hundred community-dwelling adults aged 50-85 years (64% female; 56% East Asian, 36% European, 8% other/mixed heritage) and 50 students aged 18-28 years (92% female; 42% East Asian, 22% European, 36% other/mixed) each completed approximately 30 daily life assessments over 10 days on their current and desired social situation, thoughts, and affect. RESULTS: Multilevel latent profile analysis identified two types of everyday solitude: one characterized by negative affect and effortful thought (negative solitude experiences) and one characterized by calm and the near absence of negative affect/effortful thought (positive solitude experiences). Individual differences in social self-efficacy and desire for solitude were associated with everyday positive solitude propensity; trait self-rumination and self-reflection were associated with everyday negative solitude propensity. CONCLUSIONS: This study provides a new framework for conceptualizing everyday solitude. It identifies specific affect/thought patterns that characterize distinct solitude experience clusters, and it links these clusters with well-established individual differences. We discuss key traits associated with thriving in solitude.

Social relationship quality buffers negative affective correlates of everyday solitude in an adult lifespan and an older adult sample.

Aging takes place in a social context but older adults also spend a significant amount of their time alone. Solitude (the objective state of being alone and without social interaction) has been associated with negative experiences but also with specific benefits. We examine the importance of social relationships for time-varying associations between affective experiences and solitude. Using repeated daily life assessments from an adult life span sample (Study 1, N = 183, age: 20-81 years) and an older adult sample (Study 2, N = 97, age: 50-85 years), we examined the moderating role of social relationship quality on within-person solitude-affect associations. Data were analyzed using multilevel models controlling for gender, age, overall amount of time in solitude, retirement status, marital status, education, and current work activity. Higher relationship quality was associated with higher average affective well-being. Compared to being with others, participants reported lower levels of high-arousal positive affect (PA) during solitude in both studies. In Study 1, solitude was also associated with higher levels of low-arousal negative affect (NA) and higher levels of low-arousal PA compared to when with others. Across both studies, individuals with higher quality relationships reported lesser increases in low-arousal NA when in solitude, as compared to individuals with lower quality relationships. Findings highlight that solitude is experienced less negatively for individuals embedded in a context of higher quality social relationships. Thus, preservation and promotion of social resources in older adulthood may be important to ward off potential negative ramifications of spending a significant amount of time alone. (PsycINFO Database Record

How We Experience Being Alone: Age Differences in Affective and Biological Correlates of Momentary Solitude.

BACKGROUND: Spending time alone constitutes a ubiquitous part of our everyday lives. As we get older, alone time increases. Less is known, however, about age differences in the experience of spending time alone (momentary solitude). OBJECTIVES: We examined time-varying associations between momentary solitude, affect quality, and two hypothalamic-pituitary-adrenal axis activity markers [salivary cortisol; dehydroepiandrosterone sulfate (DHEAs)] to better understand the affective and biological correlates of momentary solitude across the adult life span. METHOD: A total of 185 adults aged 20-81 years (mean age = 49 years, 51% female, 74% Caucasian) completed questionnaires on momentary solitude (alone vs. not alone) and current affect on a handheld device, and provided concurrent saliva samples up to seven times a day for 10 consecutive days. Data were analyzed using multilevel models, controlling for the overall amount of time participants spent alone during the study (overall solitude). RESULTS: Greater overall solitude was associated with decreased average high arousal positive affect and increased average cortisol and DHEAs levels. Momentary solitude was associated with reduced high arousal positive affect, increased low arousal positive affect, and increased low arousal negative affect. Age by momentary solitude interactions indicate that greater age was associated with increased high arousal positive affect and reduced low arousal negative affect during momentary solitude. Furthermore, momentary solitude was associated with increased cortisol and DHEAs. With greater age, the association between momentary solitude and cortisol weakened. CONCLUSION: Consistent with the negative connotations to loneliness and objective social isolation, greater overall solitude was associated with negative affective and biological correlates. Spending a large overall amount of time alone in old age might thus have negative ramifications for health and well-being. Momentary solitude, in contrast, can be a double-edged sword as evidenced by both positive and negative well-being implications. Importantly, greater age is linked to more favorable affective and biological correlates of momentary solitude. The momentary state of spending time alone is thus an experience that is not necessarily negative and that may improve with aging.

Neuroticism and Extraversion Magnify Discrepancies Between Retrospective and Concurrent Affect Reports.

OBJECTIVE: Although research often relies on retrospective affect self-reports, little is known about personality's role in retrospective reports and how these converge or deviate from affect reported in the moment. This micro-longitudinal study examines personality (Neuroticism, Extraversion) and emotional salience (peak and recent affect) associations with retrospective-momentary affect report discrepancies over different time frames. METHOD: Participants were 179 adults aged 20-78 (M = 48.7 years; 73.7% Caucasian/White) who each provided up to 60 concurrent affect reports over 10 days, then retrospectively reported overall intensity of each affective state after 1 day and again after 1-2 months. RESULTS: Multilevel models revealed that individuals retrospectively overreported or underreported various affective states, exhibiting peak associations for high arousal positive and negative affect, recency associations for low arousal positive affect, and distinct personality profiles that strengthened over time. Individuals high in both Extraversion and Neuroticism exaggerated high arousal positive and negative affect and underreported low arousal positive affect, high Extraversion/low Neuroticism individuals exaggerated high arousal positive affect and underreported low arousal positive affect, and low Extraversion/high Neuroticism individuals exaggerated high and low arousal negative affect. CONCLUSIONS: This study is the first to identify arousal-specific retrospective affect report discrepancies over time and suggests retrospective reports also reflect personality differences in affective self-knowledge.

Osmoregulatory thirst in mice lacking the transient receptor potential vanilloid type 1 (TRPV1) and/or type 4 (TRPV4) receptor.

Recent studies suggest the ability of the central nervous system to detect changes in osmolality is mediated by products of the genes encoding the transient receptor potential vanilloid-1 (TRPV1) or vanilloid-4 (TRPV4) channel. The purpose of the present study was to determine whether deletion of TRPV1 and/or TRPV4 channels altered thirst responses to cellular dehydration in mice. Injection of 0.5 or 1.0 M NaCl produced dose-dependent increases in cumulative water intakes of wild-type (WT), TRPV1-/-, TRPV4-/-, and TRPV1-/-V4-/- mice. However, there were no differences in cumulative water intakes between WT versus any other strain despite similar increases in plasma electrolytes and osmolality. Similar results were observed after injection of hypertonic mannitol. This was a consistent finding regardless of the injection route (intraperitoneal vs. subcutaneous) or timed access to water (delayed vs. immediate). There were also no differences in cumulative intakes across strains after injection of 0.15 M NaCl or during a time-controlled period (no injection). Chronic hypernatremia produced by sole access to 2% NaCl for 48 h also produced similar increases in water intake across strains. In a final set of experiments, subcutaneous injection of 0.5 M NaCl produced similar increases in the number of Fos-positive nuclei within the organum vasculosum of the lamina terminalis and median preoptic nucleus across strains but significantly smaller number in the subfornical organ of WT versus TRPV1-/-V4-/- mice. Collectively, these findings suggest that TRPV1 and/or TRPV4 channels are not the primary mechanism by which the central nervous system responds to cellular dehydration during hypernatremia or hyperosmolality to increase thirst.

Dietary salt intake exaggerates sympathetic reflexes and increases blood pressure variability in normotensive rats.

Previous studies have reported that chronic increases in dietary salt intake enhance sympathetic nerve activity and arterial blood pressure (ABP) responses evoked from brain stem nuclei of normotensive, salt-resistant rats. The purpose of the present study was to determine whether this sensitization results in exaggerated sympathetic nerve activity and ABP responses during activation of various cardiovascular reflexes and also increases ABP variability. Male Sprague-Dawley rats were fed 0.1% NaCl chow (low), 0.5% NaCl chow (medium), 4.0% NaCl chow (high) for 14 to 17 days. Then, the animals were prepared for recordings of lumbar, renal, and splanchnic sympathetic nerve activity and ABP. The level of dietary salt intake directly correlated with the magnitude of sympathetic nerve activity and ABP responses to electrical stimulation of sciatic afferents or intracerebroventricular infusion of 0.6 mol/L or 1.0 mol/L NaCl. Similarly, there was a direct correlation between the level of dietary salt intake and the sympathoinhibitory responses produced by acute volume expansion and stimulation of the aortic depressor nerve or cervical vagal afferents. In contrast, dietary salt intake did not affect the sympathetic and ABP responses to chemoreflex activation produced by hypoxia or hypercapnia. Chronic lesion of the anteroventral third ventricle region eliminated the ability of dietary salt intake to modulate these cardiovascular reflexes. Finally, rats chronically instrumented with telemetry units indicate that increased dietary salt intake elevated blood pressure variability but not mean ABP. These findings indicate that dietary salt intake works through the forebrain hypothalamus to modulate various centrally mediated cardiovascular reflexes and increase blood pressure variability.

Spousal neuroticism moderates everyday problem--wellbeing associations in older couples.

OBJECTIVE: Marriage partners exert a special influence on each other's health and wellbeing, potentially even more so in old age, when social networks shrink and spouses become ever more important resources for dealing with everyday problems. This study extends past research by examining associations between spousal levels of neuroticism, a key trait tied to wellbeing and health, and everyday fluctuations in positive affect (PA) and negative affect (NA), physical symptoms, and responses to everyday problems. METHODS: Forty-nine wives and 49 husbands aged 60-83 years (M marriage duration = 42.5 years) provided independent neuroticism self-reports. Spouses then simultaneously reported their PA and NA, physical health symptoms, and everyday problems 3 times daily for 9 days (up to 27 daily life assessments in total) using handheld computers. RESULTS: Hierarchical linear models replicate past research by linking higher individual neuroticism with lower overall PA, higher overall NA, and more severe overall physical symptoms. Interestingly, although individual neuroticism did not affect associations between everyday problems and affect and physical symptoms, spousal neuroticism did moderate these relationships. Individuals with spouses higher in neuroticism (compared with those with spouses lower in neuroticism) reported less pronounced elevations in NA and physical symptoms, and less pronounced reductions in PA, when number of problems was greater, even when controlling for partner presence and various individual- and couple-level covariates. CONCLUSIONS: Findings are discussed in the context of evolutionary psychology and suggest that spousal neuroticism may serve adaptive functions by increasing vigilance and preparing older spouses to deal with everyday problems.

Medical student participation in a surgical outpatient clinic: a randomized controlled trial.

BACKGROUND: To determine the patient, doctor and student perceptions with different styles of student participation in a surgical outpatient clinic. METHODS: A randomized controlled trial was conducted in surgical outpatients. Participants included patients scheduled to see one of four specialist general surgeons, the surgeons themselves and third-year medical students undertaking their general surgery rotation at the Geelong Hospital. A total of 151 consultations were randomized to one of three consultation styles between August 2011 and August 2012. (i) 'No Student', consultation without a student being present, (ii) 'Student with Doctor', consultation where the student accompanied the doctor throughout the consultation and (iii) 'Student before Doctor', consultation where the student interviewed the patient before the doctor and examined the patient in the doctor's presence. Participants' perceptions and experience of each of the consultations was assessed in the form of written questionnaires. RESULTS: There was no difference in overall patient satisfaction with different styles of student participation (P = 0.080). Students showed a clear preference for the 'Student before Doctor' consultation style (P = 0.023). There were no differences in consultation outcomes from the doctor's perspective (P = 0.88), except time (P < 0.0001). CONCLUSION: This study supports a style of consultation where students are actively involved in patient care as it has no adverse effects on patient satisfaction and it is the preferred participation style from the student's perspective. Doctors do not feel that active student involvement interferes with their ability to deliver healthcare except that it prolongs consultation time.

Understanding the drive to escort: a cross-sectional analysis examining parental attitudes towards children's school travel and independent mobility.

BACKGROUND: The declining prevalence of Active School Transportation (AST) has been accompanied by a decrease in independent mobility internationally. The objective of this study was to compare family demographics and AST related perceptions of parents who let their children walk unescorted to/from school to those parents who escort (walk and drive) their children to/from school. By comparing these groups, insight was gained into how we may encourage greater AST and independent mobility in youth living in the Greater Toronto and Hamilton Area, Canada. METHODS: This study involved a cross-sectional design, using data from a self-reported questionnaire (n =1,016) that examined parental perceptions and attitudes regarding AST. A multinomial logistic regression analysis was used to explore the differences between households where children travelled independently to school or were escorted. RESULTS: Findings revealed that unescorted children were: significantly older, the families spoke predominantly English at home, more likely to live within one kilometer from school, and their parents agreed to a greater extent that they chose to reside in the current neighborhood in order for their child to walk to/from school. The parents of the escorted children worried significantly more about strangers and bullies approaching their child as well as the traffic volume around school. CONCLUSIONS: From both a policy and research perspective, this study highlights the value of distinguishing between mode (i.e., walking or driving) and travel independence. For policy, our findings highlight the need for planning decisions about the siting of elementary schools to include considerations of the impact of catchment size on how children get to/from school. Given the importance of age, distance, and safety issues as significant correlates of independent mobility, research and practice should focus on the development and sustainability of non-infrastructure programs that alleviate parental safety concerns.