Daily Contacts Research Articles

Contrastive Analysis of Tabe Politeness Speech Acts in Bugis and Sumimasen in Japanese (Pragmatic Study)

This research investigates the level of politeness exhibited by Tabe in Bugis and Sumimasen in Japanese. The researchers do a contrastive analysis to examine the differences and similarities between Tabe in Bugis and Sumimasen in Japanese, which encompasses the act of begging and the pragmatic aspect of politeness. This research uses a contrastive descriptive qualitative methodology, in which the data consists of elaborate qualitative information rather than numerical values. This data is examined by using two distinct approaches, specifically descriptive and contrastive data analysis. The findings of this investigation in the term "tabe" holds significant symbolism in Bugis language and culture, serving as a means to kindly and respectfully request permission. By strategic use of "tabe" in appropriate circumstances, individuals can demonstrate profound gratitude and courtesy towards others, enhance social connections, and uphold societal harmony. Likewise, the use of "sumimasen" in Japan underscores cultural principles that emphasize courtesy, modesty, and social concord. The word is employed in several contexts to apologise, request assistance, or convey appreciation, and serves to sustain positive relationships and prevent conflict in daily contacts.

Multiple factors shape social contacts in dairy cows

Cattle develop preferential relationships with other individuals in the herd. These social interactions between individuals have a significant impact on both animal welfare and production. Given the relevance of social behaviour in dairy cattle, scientific studies have focused on understanding social interactions among cattle. These may also be influenced by individual area preferences, particularly when animals are housed in confined spaces. Therefore, investigating the relationship between individual area preferences and social interactions is essential for understanding social behaviour in dairy cattle. Real-time location systems provide the opportunity to monitor individual area preferences and social contacts at the same time. This study aims to assess the impact of dairy cows' area preferences on their daily social contacts and to determine the potential implications of overlooking individual area preferences in social behaviour studies. The individual position of the lactating cows was automatically collected once per second for two months on a Swedish commercial farm housing dairy cows inside a free-stall barn. The location data of 243 lactating cows was used to construct the social networks and to estimate the similarity of the area utilisation distributions between these individuals. The effect of utilisation distribution similarity in social networks was investigated by applying separable temporal exponential random graph mixed models. The role of different cow characteristics in the similarity of the utilisation distributions was assessed through a linear mixed model. Our analyses stressed the importance of similarity of area preference, parity, kindergarten effect, and filial relatedness in shaping daily social contacts in dairy cattle. The kindergarten effect refers to the effect on cow behaviour of being grouped together in the early stages of their lives. Similarity of area preference was influenced by the kindergarten effect and relatedness by pedigree, which favoured interactions between these individuals. The described approach allowed to disassociate the area preference from the social contacts between cows, providing more accurate results of the importance of the cow’s characteristics on their social behaviour.

Relationship between anhedonia, biological rhythms, functioning and depression severity in patients with bipolar disorder.

The purpose of this study was to examine relationship between anhedonia, disruption of biological rhythms, functioning and depression severity in patients with bipolar disorder (BD). The sample included 58 patients with bipolar depression aged 18-65 years. The participants were assessed using the following scales: Dimensional Anhedonia Rating Scale (DARS), Snaith-Hamilton Pleasure Scale (SHAPS), Quick Inventory of Depressive Symptomatology- self-report (QIDS-SR), Biological Rhythms Interview of Assessment in Neuropsychiatry (BRIAN), Functioning Assessment Short Test (FAST). Correlations between the variables were calculated. We built linear regression models with FAST or QIDS-SR as a dependent variable. Mediation analysis was performed. Statistically significant correlations were observed between the included variables. Biological rhythms dysregulation and anhedonia were independent predictors of the level of functioning or depression severity. Mediation analysis demonstrated statistically significant mediation of the relationship between anhedonia and depression severity/functioning by the BRIAN score. We demonstrated for the first time the interactions between anhedonia, dysregulation of biological rhythms and functioning/depression severity in patients with BD. Reward deficits by causing disruption of rhythm of daily activities and social contacts may result in more difficulties in functioning and higher intensity of depressive symptoms.

Social support as perceived, provided and needed by family-members of migrants with type 2 diabetes – a qualitative study

BackgroundSocial support provided by a family member has been found to have a buffering effect on distress and is associated with better diabetes self-care. This study explores the meaning of social support, as described by close family members of foreign-born people living with type 2 diabetes (PWDM) in Sweden. It also explores the support provided by family members, and the support they need to be able to support the PWDM.MethodsQualitative explorative study, semi-structured interviews for data collection. Qualitative content analysis based on a theoretical framework on social support. Purposive sample of 13 family members, 18–52-years-old, born in countries in the Middle East, Africa, and Russia.ResultsThe meaning of support was described as social and emotional. Most participants described a stressful situation; feelings of sadness/worry about the risk of the PWDM developing complications added to a strained life situation from which one could not opt out. Frequent daily contacts in a family network were evident, particularly by children trained as healthcare professionals. Caring for a family member was considered a filial piety, but it was also a chance to reciprocate. The support provided was mainly informational (e.g., reminders about nutritional intake), but it was also instrumental/practical (administering medicines, helping with economy/logistics, planning/cooking meals, basic care) and emotional (sharing meals, thoughts, and activities). The support the family members needed was getting first-hand information by attending the physician visits, being able to book appointments themselves at suitable times, and preventing the withholding of important information about the PWDM. They also desired an open telephone-line, oral and written information, particularly on diet.ConclusionsTo family-members, supporting the PWDM was normal and a filial piety. Support provided and needed was not only informational but also instrumental/practical and emotional. In diabetes care, addressing foreign-born individuals, diabetes education needs to be developed, also including family members. Informational material, particularly on diet, and improved access to healthcare and information about the healthcare system have the potential to increase family members’ control over the situation and prevent a negative trajectory in caregiving with perceived demands causing high levels of stress.

Social contact patterns during the early COVID-19 pandemic in Norway: insights from a panel study, April to September 2020

BackgroundDuring the COVID-19 pandemic, many countries adopted social distance measures and lockdowns of varying strictness. Social contact patterns are essential in driving the spread of respiratory infections, and country-specific measurements are needed. This study aimed to gain insights into changes in social contacts and behaviour during the early pandemic phase in Norway.MethodsWe conducted an online panel study among a nationally representative sample of Norwegian adults by age and gender. The panel study included six data collections waves between April and September 2020, and 2017 survey data from a random sample of the Norwegian population (including children < 18 years old) were used as baseline. The market research company Ipsos was responsible for carrying out the 2020 surveys. We calculated mean daily contacts, and estimated age-stratified contact matrices during the study period employing imputation of child-to-child contacts. We used the next-generation method to assess the relative reduction of R0 and compared the results to reproduction numbers estimated for Norway during the 2020 study period.ResultsOver the six waves in 2020, 5 938 observations/responses were registered from 1 718 individuals who reported data on 22 074 contacts. The mean daily number of contacts among adults varied between 3.2 (95%CI 3.0-3.4) to 3.9 (95%CI 3.6–4.2) across the data collection waves, representing a 67–73% decline compared to pre-pandemic levels (baseline). Fewer contacts in the community setting largely drove the reduction; the drop was most prominent among younger adults. Despite gradual easing of social distance measures during the survey period, the estimated population contact matrices remained relatively stable and displayed more inter-age group mixing than at baseline. Contacts within households and the community outside schools and workplaces contributed most to social encounters. Using the next-generation method R0 was found to be roughly 25% of pre-pandemic levels during the study period, suggesting controlled transmission.ConclusionSocial contacts declined significantly in the months following the March 2020 lockdown, aligning with implementation of stringent social distancing measures. These findings contribute valuable empirical information into the social behaviour in Norway during the early pandemic, which can be used to enhance policy-relevant models for addressing future crises when mitigation measures might be implemented.

English for Business Communication: An in Depth Analysis

The English language has a more significant role in our daily contacts in both national and international contexts. The English language has been deeply ingrained in every part of our life due to its global qualities. Outstanding chances for an individual are associated with proficiency in the English language. The productive and effective operation of business and communication is greatly dependent on the English language. Due to the English language, multinational firms are able to conduct business all over the world. In order to thrive as a businessman with a global profile, one needs to improve their communication skills in English. English communication abilities that are both effective in spoken and written form are essential for business. The idea of Business English has changed significantly in recent years due to a number of developments, such as improvements in genre theory and the amalgamation of English for Business Purposes and Business Communication that have been motivated by the realization that there is a gap to be filled between the academic world and the global business world. This pioneering review, which draws on developments in the analysis of business discourses, particularly in applied genre analysis, revisits the frameworks now implemented in English for Business Purposes and Business Communication (or, more broadly, Professional Communication). The design of English for Business Communication (EBC) programs is thus suggested to be based on the combination of the two techniques. The research report includes an in-depth evaluation of numerous relevant published works.

A cross-sectional study of the relationship between daily social contact features and the prevalence of common mental disorders in Taiwan, 2000-2015.

The aim of this study was to examine the influence of daily contact features on the prevalence of common mental disorders (CMDs) in Taiwan from 2000 to 2015. Data from the Taiwan Social Change Survey for 2000, 2005, 2010, and 2015 were used to examine the relationship between the number and level of familiarity with daily social contacts with the probable CMDs (determined by score of ≥ 3 on a 12-item Chinese Health Questionnaire). Descriptive statistics and multivariable logistic regression analyses were used to assess the association. Among the 7,841 respondents, the prevalence of probable CMDs increased from 18.28% in 2000 to 21.29% in 2015. Multivariable analysis showed that respondents with more daily social contacts were less likely to have probable CMDs in the four observed years adjusting for sociodemographic characteristics and physical health limitations on daily activities in the past two weeks. A negative relationship between probable CMDs and level of familiarity with daily contacts was found in 2000 (OR = 0.67, 95% CI-0.48-0.94) and 2005 (OR = 0.70, 95% CI-0.53-0.93). Findings from our study suggest the development of culturally tailored programs/interventions through features of daily social contacts may reduce the prevalence of CMDs in Taiwan.

FUNCTIONAL LIMITATIONS, LIVING ARRANGEMENT, DAILY SOCIAL CONTACTS, AND LONELINESS IN LATE LIFE

Abstract Older adults with functional limitations are at a greater risk of social isolation and loneliness, largely due to difficulties in mobility and compromised social contacts. Lack of social contact throughout the day may contribute to loneliness among older adults with functional limitations, and these associations may differ by living arrangements. This study examined associations between functional limitations, living alone, daily social contacts, and loneliness throughout the day. Community-dwelling older adults aged 65 + (N = 310, Mage = 73.96) from the Daily Experiences and Well-being Study completed a measure of functional limitations in a baseline interview. Then, in ecological momentary assessments (EMA), they reported social contacts and loneliness every 3 hours for 5 to 6 days. Multilevel models revealed a significant interaction between functional limitations and social contacts on loneliness, such that people with higher levels of functional limitations felt less lonely if they had more social contacts in the prior 3 hours, but not for those with lower levels of functional limitations. The three-way interaction between functional limitations, living alone, and loneliness revealed that more social contacts were associated with reduced loneliness only among individuals with functional limitations and who lived with others. Individuals with functional limitations who lived alone had higher levels of loneliness than those with functional limitations who lived with others. The findings emphasize the vulnerability in social isolation of older adults with functional limitations, especially those who live alone. Yet this vulnerable group may also benefit more from adequate daily social contacts.

Social contact patterns among employees in U.S. long-term care facilities during the COVID-19 pandemic, December 2020 to June 2021

ObjectiveWe measured contact patterns using social contact diaries for 157 U.S. long-term care facility employees from December 2020 - June 2021. These data are crucial for analyzing mathematical transmission models and for informing healthcare setting infection control policy.ResultsThe median number of daily contacts was 10 (IQR 8–11). Household contacts were more likely partially masked than fully masked, more likely to involve physical contact, and longer in duration compared to facility contacts.

Quantifying social contact patterns in Minnesota during stay-at-home social distancing order

SARS-CoV-2 is primarily transmitted through person-to-person contacts. It is important to collect information on age-specific contact patterns because SARS-CoV-2 susceptibility, transmission, and morbidity vary by age. To reduce the risk of infection, social distancing measures have been implemented. Social contact data, which identify who has contact with whom especially by age and place are needed to identify high-risk groups and serve to inform the design of non-pharmaceutical interventions. We estimated and used negative binomial regression to compare the number of daily contacts during the first round (April–May 2020) of the Minnesota Social Contact Study, based on respondent’s age, gender, race/ethnicity, region, and other demographic characteristics. We used information on the age and location of contacts to generate age-structured contact matrices. Finally, we compared the age-structured contact matrices during the stay-at-home order to pre-pandemic matrices. During the state-wide stay-home order, the mean daily number of contacts was 5.7. We found significant variation in contacts by age, gender, race, and region. Adults between 40 and 50 years had the highest number of contacts. The way race/ethnicity was coded influenced patterns between groups. Respondents living in Black households (which includes many White respondents living in inter-racial households with black family members) had 2.7 more contacts than respondents in White households; we did not find this same pattern when we focused on individual’s reported race/ethnicity. Asian or Pacific Islander respondents or in API households had approximately the same number of contacts as respondents in White households. Respondents in Hispanic households had approximately two fewer contacts compared to White households, likewise Hispanic respondents had three fewer contacts than White respondents. Most contacts were with other individuals in the same age group. Compared to the pre-pandemic period, the biggest declines occurred in contacts between children, and contacts between those over 60 with those below 60.

THE CULTURE OF EVERYDAY LIFE: TRENDS OF CHANGE

Society is the most dynamic structure of being. Determining the direction of its changes is the way to success in planning and implementing any social initiatives and projects. Everyday life is an area where changes underlie many social changes that determine the dynamics of social development. Identifying trends in the culture of everyday life opens up opportunities for scientific planning of the development of society, improving the quality of life and meeting the needs of individuals, that underlines the main relevance of the study. The main purpose of the study is to identify trends in the changing culture of everyday life at the present stage of the development of Russian society. The dialectical method and the system-structural approach allowed us to determine how people's daily communication has changed due to the introduction of information technologies and digitalization into life, how the "visual turn" determines people's interests and their daily contacts, how following the social stratification of Russian society associated with the country's transition to the capitalist path of development, the daily life of people has become diverse. Social groups that differ in the way and style of everyday life have been formed. All of these phenomena have prospects for further development and act as major trends in changing the culture of everyday life, and the scientific novelty and value of the study consists in their identification, analysis and a systematization. The practical significance of this article is seen in the use of its results in the context of the organization of both everyday events and in the planning of further transformations of Russian society, taking into account the changes occurring in the culture of everyday life: digitalization, visualization, the formation of diverse styles of behavior and lifestyles. The use of a historical approach and the reliance on sociological material from VTSIOM made it possible to show that the newly emerged trends exist on a par with the cultural traditions of Russians, with their interest in reading, visiting theaters, exhibitions, museums, which also constitute an important part of their lives. Thus, innovations in the culture of everyday life are combined with traditions of everyday life-such a conclusion derives from this study.

Social contact patterns during the COVID-19 pandemic in 21 European countries – evidence from a two-year study

BackgroundMost countries have enacted some restrictions to reduce social contacts to slow down disease transmission during the COVID-19 pandemic. For nearly two years, individuals likely also adopted new behaviours to avoid pathogen exposure based on personal circumstances. We aimed to understand the way in which different factors affect social contacts – a critical step to improving future pandemic responses.MethodsThe analysis was based on repeated cross-sectional contact survey data collected in a standardized international study from 21 European countries between March 2020 and March 2022. We calculated the mean daily contacts reported using a clustered bootstrap by country and by settings (at home, at work, or in other settings). Where data were available, contact rates during the study period were compared with rates recorded prior to the pandemic. We fitted censored individual-level generalized additive mixed models to examine the effects of various factors on the number of social contacts.ResultsThe survey recorded 463,336 observations from 96,456 participants. In all countries where comparison data were available, contact rates over the previous two years were substantially lower than those seen prior to the pandemic (approximately from over 10 to < 5), predominantly due to fewer contacts outside the home. Government restrictions imposed immediate effect on contacts, and these effects lingered after the restrictions were lifted. Across countries, the relationships between national policy, individual perceptions, or personal circumstances determining contacts varied.ConclusionsOur study, coordinated at the regional level, provides important insights into the understanding of the factors associated with social contacts to support future infectious disease outbreak responses.

Homelessness and primary care: Problems and solutions

As the housing circumstances of a person or family become uncertain, they often encounter a variety of people and services before losing their home. Each point of contact can be an opportunity to identify or prevent homelessness. They might have a social worker, attend addiction services, visit a food bank, or contact their GP. GP practices are embedded in local communities, and with many daily patient contacts primary care has potential to connect those at risk with appropriate services before a crisis point.

Policy evaluation using model over-fitting: the Nordic case.

The interest of this article is to better understand the effects of different public policy alternatives to handle the COVID-19 pandemic. In this work we use the susceptible, infected, recovered (SIR) model to find which of these policies have an actual impact on the dynamic of the spread. Starting with raw data on the number of deceased people in a country, we over-fit our SIR model to find the times at which the main parameters, the number of daily contacts and the probability of contagion, require adjustments. For each , we go to historic records to find policies and social events that could explain these changes. This approach helps to evaluate events through the eyes of the popular epidemiological SIR model, and to find insights that are hard to recognize in a standard econometric model.

Home treatment for substance use disorder - Hospitalisation addictologique à domicile (HAAD)

In Switzerland, substance use disorders (SUD) are responsible for individual suffering and major economic costs. Especially the co-occurrence of SUD with other psychiatric disorders often leads to a revolving door effect and high emergency room attendance. For other severe psychiatric disorders outreach offers have been established, including home treatment (HT). Research has detected several advantages of HT, while noting that this form of treatment is not suitable for SUDs. We implemented an HT module especially for individuals suffering from SUD, called "Hospitalisation addictologique à domicile (HAAD)" which is carried out by a multidisciplinary team and realized in the same way and at the same frequency as in the hospital, but it takes place at home and aims at maintaining the patients in their daily activities and social contacts.

Estimating Changes in Contact Patterns in China Over the First Year of the COVID-19 Pandemic: Implications for SARS-CoV-2 Spread - Four Cities, China, 2020.

Previous studies have demonstrated significant changes in social contacts during the first-wave coronavirus disease 2019 (COVID-19) in Chinese mainland. The purpose of this study was to quantify the time-varying contact patterns by age in Chinese mainland in 2020 and evaluate their impact on the transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Diary-based contact surveys were performed for four periods: baseline (prior to 2020), outbreak (February 2020), post-lockdown (March-May 2020), and post-epidemic (September-November 2020). We built a Susceptible-Infected-Recovered (SIR) model to evaluate the effect of reducing contacts on transmission. During the post-epidemic period, daily contacts resumed to 26.7%, 14.8%, 46.8%, and 44.2% of the pre-COVID levels in Wuhan, Shanghai, Shenzhen, and Changsha, respectively. This suggests a moderate risk of resurgence in Changsha, Shenzhen, and Wuhan, and a low risk in Shanghai. School closure alone was not enough to interrupt transmission of SARS-CoV-2 Omicron BA.5, but with the addition of a 75% reduction of contacts at the workplace, it could lead to a 16.8% reduction of the attack rate. To control an outbreak, concerted strategies that target schools, workplaces, and community contacts are needed. Monitoring contact patterns by age is key to quantifying the risk of COVID-19 outbreaks and evaluating the impact of intervention strategies.

Shame in the Clash of Two “Normals”: The Case of Covid-19 in Tasmania

This paper deals with the general question of what a segment of sociocultural reality in the capital of Tasmania looked like over the time span from the emergence of the SARS-CoV-2 virus in China up to Australia's lockdown in mid-March 2020, or more specifically, what took place in direct, daily contacts between people, in the meeting or clash of coexisting incongruous behavioral norms – the “old” (habitual up until then) and the “new” (modified due to the crisis) patterns of interpersonal behavior. In this period of health and social crises, which is here termed liminal, shame was generated. It arose as an emotional reaction to the discrepancy between the thinking, feeling and behavior of interviewees and the thinking, feeling and behavior of members of their social environment, a discrepancy that became apparent in the course of their mutual interactions and whose object was a different emotion – fear. The fieldwork was conducted in mid-2020 in Hobart, in the form of semi-structured interviews with several immigrants from the states of the former Yugoslavia. As it was aimed at studying their fear, and only in second place their feeling of shame, in this paper I have limited myself to a narrative interpretation of the origins and object of shame, with the intention of, on the one hand, highlighting the principal factors in the construction of shame and, on the other, examining what it was in connection with fear that aroused shame in the given context. It was noted that, among other things, shame was culturally generated in the given interactions which occurred within secondary relationships and specific environmental contexts and, still more broadly, as part of the crisis caused by the general spread of the virus, and that, as the object of shame, fear emerged as an inappropriate emotion, initially in the sense of the disproportion between the intensity of fear and its object (i.e. the threat posed by the virus).

Modeling the impact of surveillance activities combined with physical distancing interventions on COVID-19 epidemics at a local level.

Physical distancing and contact tracing are two key components in controlling the COVID-19 epidemics. Understanding their interaction at local level is important for policymakers. We propose a flexible modeling framework to assess the effect of combining contact tracing with different physical distancing strategies. Using scenario tree analyses, we compute the probability of COVID-19 detection using passive surveillance, with and without contact tracing, in metropolitan Barcelona. The estimates of detection probability and the frequency of daily social contacts are fitted into an age-structured susceptible-exposed-infectious-recovered compartmental model to simulate the epidemics considering different physical distancing scenarios over a period of 26 weeks. With the original Wuhan strain, the probability of detecting an infected individual without implementing physical distancing would have been 0.465, 0.515, 0.617, and 0.665 in designated age groups (0-14, 15-49, 50-64, and >65), respectively. As the physical distancing measures were reinforced and the disease circulation decreased, the interaction between the two interventions resulted in a reduction of the detection probabilities; however, despite this reduction, active contact tracing and isolation remained an effective supplement to physical distancing. If we relied solely on passive surveillance for diagnosing COVID-19, the model required a minimal 50% (95% credible interval, 39-69%) reduction of daily social contacts to keep the infected population under 5%, as compared to the 36% (95% credible interval, 22-56%) reduction with contact tracing systems. The simulation with the B.1.1.7 and B.1.167.2 strains shows similar results. Our simulations showed that a functioning contact tracing program would reduce the need for physical distancing and mitigate the COVID-19 epidemics.

Scheduled, Simultaneous Dosing of Pregabalin, Celecoxib, and Acetaminophen Markedly Reduces or Eliminates Opioid Use After ACL Reconstruction Using Allograft or Hamstring Tendon Autograft: A Randomized Clinical Trial

Opioid analgesics continue to be prescribed after ambulatory surgery despite untoward adverse effects, risk of overdose, and association with substance use disorder. The purpose was to investigate the use of a novel system to provide scheduled and simultaneous dosing of acetaminophen, celecoxib, and pregabalin after anterior cruciate ligament reconstruction (ACLR). It was hypothesized that this system would markedly reduce pain and opioid use compared with existing best practice. Randomized controlled trial; Level of evidence, 1. Included were 100 patients scheduled for elective, primary ACLR using allograft or hamstring tendon autograft. Selection criteria included age between 18 and 65 years and weight between 65 and 120 kg. Exclusion criteria were a known allergy to any drug used in the study or the use of opioid analgesics before surgery. Patients in the intervention group received a blister pack with scheduled, simultaneous doses of acetaminophen, celecoxib, and pregabalin; patients were also given oxycodone 5 mg as needed for breakthrough pain. Patients in the control group were prescribed ibuprofen and oxycodone 5 mg/acetaminophen 325 mg as needed for pain. The primary outcome measure was pain. Secondary outcomes were nausea, itching, and daily oxycodone use. Patients were asked to quantify their average pain at rest, nausea, and itching on an 11-point verbal scale (from 0 to 10). These data were recorded for 6 days during daily telephone contacts with patients after hospital discharge. Cumulative results for 6 days showed significantly lower values in the intervention group compared with the control group for pain (median [interquartile range], 28 [14-35] vs 35 [28-41], respectively; P = .009) and oxycodone use (median [interquartile range] number of tablets, 0 [0-2] vs 8 [1.25-16], respectively; P < .001). Based on these data, the upper tolerance limits for the number of oxycodone tablets required by 90% of patients in the intervention and control groups were 8 tablets and 30 tablets, respectively. Cumulative results for nausea and itching were also significantly lower for the intervention group. Most patients in the intervention group used no opioids during recovery. Simultaneous dosing of 3 nonopioid analgesics resulted in reduced postoperative pain and markedly lower opioid use. NCT04015908 (ClinicalTrials.gov identifier).

Use of temporal contact graphs to understand the evolution of COVID-19 through contact tracing data

Digital contact tracing has been recently advocated by China and many countries as part of digital prevention measures on COVID-19. Controversies have been raised about their effectiveness in practice as it remains open how they can be fully utilized to control COVID-19. In this article, we show that an abundance of information can be extracted from digital contact tracing for COVID-19 prevention and control. Specifically, we construct a temporal contact graph that quantifies the daily contacts between infectious and susceptible individuals by exploiting a large volume of location-related data contributed by 10,527,737 smartphone users in Wuhan, China. The temporal contact graph reveals five time-varying indicators can accurately capture actual contact trends at population level, demonstrating that travel restrictions (e.g., city lockdown) in Wuhan played an important role in containing COVID-19. We reveal a strong correlation between the contacts level and the epidemic size, and estimate several significant epidemiological parameters (e.g., serial interval). We also show that user participation rate exerts higher influence on situation evaluation than user upload rate does, indicating a sub-sampled dataset would be as good at prediction. At individual level, however, the temporal contact graph plays a limited role, since the behavior distinction between the infected and uninfected individuals are not substantial. The revealed results can tell the effectiveness of digital contact tracing against COVID-19, providing guidelines for governments to implement interventions using information technology.