The Better Assessment of Illness Study for Delirium Severity: Study Design, Procedures, and Cohort Description
Conclusion: The BASIL study presents an innovative effort to advance the conceptualization and measurement of delirium severity. Unique strengths include the diverse cohort with complete high quality data and longitudinal follow-up, along with detailed collection of multiple delirium measures daily during hospitalization.Gerontology (Source: Gerontology)
Source: Gerontology - July 20, 2018 Category: Geriatrics Source Type: research

Thyroid Function Changes in the Elderly and Their Relationship to Cardiovascular Health: A Mini-Review
Conclusions: The absence of large prospective interventional data does not allow the formulation of strict clinical recommendations, but a higher TSH threshold for treating both subclinical hypothyroidism and subclinical hyperthyroidism in the elderly seems reasonable.Gerontology (Source: Gerontology)
Source: Gerontology - July 20, 2018 Category: Geriatrics Source Type: research

Frailty and Associated Factors among Centenarians in the 5-COOP Countries
Conclusions: This study shows that reaching 100 years of age rarely goes without frailty and sheds light on factors associated with frailty at a very old age.Gerontology (Source: Gerontology)
Source: Gerontology - July 20, 2018 Category: Geriatrics Source Type: research

The Gut Microbiota and Healthy Aging: A Mini-Review
The gut microbiota shows a wide inter-individual variation, but its within-individual variation is relatively stable over time. A functional core microbiome, provided by abundant bacterial taxa, seems to be common to various human hosts regardless of their gender, geographic location, and age. With advancing chronological age, the gut microbiota becomes more diverse and variable. However, when measures of biological age are used with adjustment for chronological age, overall richness decreases, while a certain group of bacteria associated with frailty increases. This highlights the importance of considering biological or f...
Source: Gerontology - July 19, 2018 Category: Geriatrics Source Type: research

The Glymphatic System and Waste Clearance with Brain Aging: A Review
The glymphatic system is a glial-dependent waste clearance pathway in the brain, in place of lymphatic vessels, dedicated to drain away soluble waste proteins and metabolic products. Specifically, the glymphatic network serves as a “front end” for waste clearance, and is connected downstream to an authentic lymphatic network, associated with dura covering the brain as well as cranial nerves and large vessels at the skull exits. The anatomical and functional interconnections between these two networks are not completely und erstood. Several key physiological processes have been identified that control glymphatic...
Source: Gerontology - July 11, 2018 Category: Geriatrics Source Type: research

Concern about Falling and Complexity of Free-Living Physical Activity Patterns in Well-Functioning Older Adults
Conclusions: These results extend our understanding of the interplay between low concern about falling and physical activity behavior of community-dwelling older persons in their everyday life context. This information could serve to better design and evaluate personalized intervention programs in future prospective studies.Gerontology (Source: Gerontology)
Source: Gerontology - July 4, 2018 Category: Geriatrics Source Type: research

The Trajectories of the Number of Pain Sites and Their Associated Factors in Older Adults: Results from the Korean Longitudinal Study of Ageing
Conclusions: The pain status at the early stage is predictive of future pain. In this study, we identified gender differences in the trends of the number of pain sites and associated factors. Further comprehensive studies on pain intensity and duration are required.Gerontology (Source: Gerontology)
Source: Gerontology - July 3, 2018 Category: Geriatrics Source Type: research

Prognostic Models Associated with 6-Month Survival of Patients Admitted to Nursing Homes
Conclusions: Prognostic models such as ours that include variables commonly included in clinical assessments can help nursing home professionals prioritize and ensure adequate mobilization of palliative care resources, which are very limited in these institutions.Gerontology (Source: Gerontology)
Source: Gerontology - June 29, 2018 Category: Geriatrics Source Type: research

Cost-Effectiveness of a Multifaceted Podiatry Intervention for the Prevention of Falls in Older People: The REducing Falls with Orthoses and a Multifaceted Podiatry Intervention Trial Findings
Conclusion: The benefits of the intervention justified the moderate cost. The intervention could be a cost-effective option for falls prevention when compared with usual care in the UK.Gerontology (Source: Gerontology)
Source: Gerontology - June 26, 2018 Category: Geriatrics Source Type: research

Editor ’s Note
Gerontology (Source: Gerontology)
Source: Gerontology - June 22, 2018 Category: Geriatrics Source Type: research

Building Bridges between Gerontology and Elder Law
Conclusions: The authors identify ways gerontologists can be encouraged to integrate elder law into their teaching and research, and suggest how this integration could enhance understanding of the aging experience.Gerontology (Source: Gerontology)
Source: Gerontology - June 20, 2018 Category: Geriatrics Source Type: research

Does Sample Attrition Affect the Assessment of Frailty Trajectories Among Older Adults? A Joint Model Approach
Conclusion: Linear mixed models assuming MAR sample attrition provided good estimates of frailty trajectories up until high age. Thus, the validity of existing studies estimating frailty trajectories based on standard linear mixed models seems not threatened by substantial sample attrition.Gerontology (Source: Gerontology)
Source: Gerontology - June 20, 2018 Category: Geriatrics Source Type: research

HIV and Aging – Perhaps Not as Dramatic as We Feared?
Ever since the introduction of highly active antiretroviral therapy (ART) in 1995, HIV infection has been linked to “metabolic” complications (insulin resistance, dyslipidemia, osteoporosis, and others). Studies suggested increased rates of myocardial infarction, renal insufficiency, neurocognitive dysfunction, and fractures in HIV-postitive patients. Even long-term suppression of HIV seemed to be accompanied by an excess of deleterious inflammation that could promote these complications. The aims of this viewpoint paper are to summarize recent data and to examine the possibility that the problem of aging-relat...
Source: Gerontology - June 15, 2018 Category: Geriatrics Source Type: research

The Role of Frailty in Acute Coronary Syndromes in the Elderly
Conclusion: Frailty is an independent prognostic marker of the composite of mortality and reinfarction and of overall mortality in patients aged ≥75 years admitted due to MI.Gerontology (Source: Gerontology)
Source: Gerontology - June 1, 2018 Category: Geriatrics Source Type: research

Cytoplasmic RNA Granules in Somatic Maintenance
Cytoplasmic RNA granules represent subcellular compartments that are enriched in protein-bound RNA species. RNA granules are produced by evolutionary divergent eukaryotes, including yeast, mammals, and plants. The functions of cytoplasmic RNA granules differ widely. They are dictated by the cell type and physiological state, which in turn is determined by intrinsic cell properties and environmental factors. RNA granules provide diverse cellular functions. However, all of the granules contribute to aspects of RNA metabolism. This is exemplified by transcription, RNA storage, silencing, and degradation, as well as mRNP remod...
Source: Gerontology - May 30, 2018 Category: Geriatrics Source Type: research

Tetrahydroxystilbene Glucoside Delayed Senile Symptoms in Old Mice via Regulation of the AMPK/SIRT1/PGC-1 α Signaling Cascade
Conclusion: Our findings show that TSG could be a potential drug candidate for the treatment of aging- and high-calorie intake-associated disorders.Gerontology (Source: Gerontology)
Source: Gerontology - May 29, 2018 Category: Geriatrics Source Type: research

The Relationship between Cardiorespiratory Fitness and Montreal Cognitive Assessment Scores in Older Adults
Conclusion: The association between CRF and MoCA score in older adults suggests that meeting or exceeding public health guidelines for physical activity is likely to increase CRF in low fit individuals, maintain CRF in those with a moderate to high level of CRF, and thereby help to maintain cognitive function in healthy older adults.Gerontology (Source: Gerontology)
Source: Gerontology - May 29, 2018 Category: Geriatrics Source Type: research

Lower Plasma Klotho Concentrations Are Associated with Vascular Dementia but Not Late-Onset Alzheimer ’s Disease
Conclusion: In a sample of elderly individuals, we found a significant association between low plasma Klotho levels and VD, but not LOAD. This finding suggests that, although these 2 forms of dementia might overlap, some physiopathological mechanisms related to VD and LOAD remain distinct.Gerontology (Source: Gerontology)
Source: Gerontology - May 16, 2018 Category: Geriatrics Source Type: research

Rising above It: Status Ambivalence in Older Adults
Conclusion: We discussstatus ambivalence as a potential protective mechanism in the context of negative societal perceptions of age-related social status that may be important for well-being in later life.Gerontology (Source: Gerontology)
Source: Gerontology - May 9, 2018 Category: Geriatrics Source Type: research

Long-Term Moderate Exercise Rescues Age-Related Decline in Hippocampal Neuronal Complexity and Memory
Conclusion: The hippocampus-related memory function declines from middle age, but long-term moderate-intensity running effectively increased hippocampal neuroplasticity and memory in mice of different ages, even when the memory impairment had progressed to an advanced stage. Thus, long-term, moderate intensity exercise training might be a way of delaying and treating aging-related memory decline.Gerontology (Source: Gerontology)
Source: Gerontology - May 7, 2018 Category: Geriatrics Source Type: research

Automatic Change Detection in Older and Younger Women: A Visual Mismatch Negativity Study
Conclusion: Automatic detection of violated sequential regularities, reflected by the vMMN, emerged in the two age groups (earlier vMMN). However, detection of stimulus change, a preattentive visual process delayed in the elderly, and identification of the specific change was compromised in the older participants.Gerontology (Source: Gerontology)
Source: Gerontology - April 26, 2018 Category: Geriatrics Source Type: research

Effects of Driving Skill Training on Safe Driving in Older Adults with Mild Cognitive Impairment
Conclusion: The driving skill program significantly improved safe driving performance in older adults with cognitive impairment who were at a potentially high risk of a car accident.Gerontology (Source: Gerontology)
Source: Gerontology - April 12, 2018 Category: Geriatrics Source Type: research

Age, Loss Minimization, and the Role of Probability for Decision-Making
Conclusion: Results suggest that older adults are more willing to select a risky option when it increases the likelihood that larger losses be avoided, whereas younger adults are more willing to select a risky option when it allows for slightly larger gains. This finding supports expectations based on theoretical accounts of goal orientation shifting away from securing gains in younger adulthood towards maintenance and avoiding losses in older adulthood. Findings are also discussed in respect to the affective enhancement perspective and socioemotional selectivity theory.Gerontology (Source: Gerontology)
Source: Gerontology - April 5, 2018 Category: Geriatrics Source Type: research

Subjective Social Status Predicts Late-Life Memory Trajectories through Both Mental and Physical Health Pathways
Conclusion: Results provide preliminary behavioral evidence for the deleterious effects of social stress on cognitive aging. These results may help inform the development of policies and interventions to reduce cognitive morbidity among older adults who perceive a low position on the social hierarchy.Gerontology (Source: Gerontology)
Source: Gerontology - March 29, 2018 Category: Geriatrics Source Type: research

Testosterone Deprivation Aggravates Left-Ventricular Dysfunction in Male Obese Insulin-Resistant Rats via Impairing Cardiac Mitochondrial Function and Dynamics Proteins
Conclusion: We concluded that testosterone deprivation during adulthood aggravated the impairment of mitochondrial function, mitochondrial respiratory complex, mitochondrial dynamics proteins, and apoptosis, leading to LV dysfunction in obese insulin-resistant rats.Gerontology (Source: Gerontology)
Source: Gerontology - March 23, 2018 Category: Geriatrics Source Type: research

Biology Explaining Tooth Repair and Regeneration: A Mini-Review
The tooth is an intricate composition of precisely patterned, mineralized matrices and soft tissues. Mineralized tissues include enamel (produced by the epithelial cells called ameloblasts), dentin and cementum (produced by mesenchymal cells called odontoblasts and cementoblasts, respectively), and soft tissues, which include the dental pulp and the periodontal ligament along with the invading nerves and blood vessels. It was perceived for a very long time that teeth primarily serve an esthetical function. In recent years, however, the role of healthy teeth, as well as the impact of oral health on general well-being, becam...
Source: Gerontology - March 13, 2018 Category: Geriatrics Source Type: research

Negative Aging Stereotypes Disrupt both the Selection and Execution of Strategies in Older Adults
Conclusion: Our findings have important implications to further understand age-based (and other) stereotype threat effects, and how noncognitive factors modulate age-related changes in human cognition.Gerontology (Source: Gerontology)
Source: Gerontology - February 15, 2018 Category: Geriatrics Source Type: research

The Impact of Advanced Age on Driving Safety in Adults with Medical Conditions
Conclusion: Advanced age adversely affected driving safety outcomes. The oldest-old are a unique age group with medical conditions known to interfere with safe driving. Driving safety strategies should particularly target the oldest-old since they are the fastest-growing group and their increased frailty is associated with severe or fatal injuries due to MVCs.Gerontology (Source: Gerontology)
Source: Gerontology - February 14, 2018 Category: Geriatrics Source Type: research

Associations of Near-Miss Traffic Incidents with Attention and Executive Function among Older Japanese Drivers
Conclusion: Male sex, high driving frequency, and poor performance in attention (in young-old drivers) were associated with near-miss traffic incidents. Improvement in attention may play a role in decreasing the risk of traffic accidents among older drivers.Gerontology (Source: Gerontology)
Source: Gerontology - February 9, 2018 Category: Geriatrics Source Type: research

Medical Overtreatment: Friend or Foe?
“Overtreatment” is a neologism coined some 15 years ago to denote medical and surgical interventions that are unnecessary. It is a topical term for an old concept. However, it has rapidly become a shibboleth for those inclined toward finger-pointing and blaming in matters of health policy. As su ch, it is a “foe” that heats up rather than modulates debate. But if one examines the notion in the context of the contemporary patient-physician dialogue, it is anything but a foe. Overtreatment and its fellow travelers, overutilization and overprescription, face off with contrary notions when a patient con...
Source: Gerontology - February 9, 2018 Category: Geriatrics Source Type: research

Sex Differences in the Impact of < b > < i > BDNF < /i > < /b > Genotype on the Longitudinal Relationship between Physical Activity and Cognitive Performance
Conclusion: We observed longitudinal, but not cross-sectional, effects of physical activity on cognitive performance. Our study highlights the importance of longitudinal follow-up and consideration of sex differences in the relationships between physical activity,BDNF genotype, and cognitive decline. The findings contribute to understanding gene-lifestyle interactions in promoting cognitive health.Gerontology (Source: Gerontology)
Source: Gerontology - February 2, 2018 Category: Geriatrics Source Type: research

Age Estimation with DNA: From Forensic DNA Fingerprinting to Forensic (Epi)Genomics: A Mini-Review
Forensic genetics developed from protein-based techniques a quarter of a century ago and became famous as “DNA fingerprinting,” this being based on restriction fragment length polymorphisms (RFLPs) of high-molecular-weight DNA. The amplification of much smaller short tandem repeat (STR) sequences using the polymerase chain reaction soon replaced RFLP analysis and advanced to become the gold standard in genetic identification. Meanwhile, STR multiplexes have been developed and made commercially available which simultaneously amplify up to 30 STR loci from as little as 15 cells or fewer. The enormous information ...
Source: Gerontology - January 23, 2018 Category: Geriatrics Source Type: research

Four-Week Strategy-Based Training to Enhance Prospective Memory in Older Adults: Targeting Intention Retention Is More Beneficial than Targeting Intention Formation
Conclusion: Strategy-based PM training in older adults targeting the maintenance of the PM intention in the intention-retention phase may be more effective in enhancing PM accuracy in terms of PM cue detection than the strategy targeting the encoding of the PM intention in the intention-formation phase. This suggests that for successful prospective remembering, older adults may need more support to keep the PM cues active in memory while working on the ongoing task than to initially encode the PM intention.Gerontology (Source: Gerontology)
Source: Gerontology - January 19, 2018 Category: Geriatrics Source Type: research

Social and Behavioural Determinants of the Difference in Survival among Older Adults in Japan and England
Conclusion: Compared to participants in England, Japanese older people lived longer mainly because of non-smoking for women and family-based social relationships for men. In contrast, a lower rate of underweight, men ’s better friendship-based social relationships, and a lower smoking rate contributed to survival among participants in England.Gerontology (Source: Gerontology)
Source: Gerontology - January 19, 2018 Category: Geriatrics Source Type: research

Recent Advances and Future Opportunities to Address Challenges in Offloading Diabetic Feet: A Mini-Review
Diabetic foot ulcers (DFU) are a substantial dilemma for geriatric individuals with diabetes. The breakdown in tissue associated with DFU is typically a result of repetitive cycles of physical stress placed on the feet during weight-bearing activity. Accordingly, a key tenet in healing as well as preventing DFU is the use of offloading footwear to redistribute physical stress away from high stress locations such as bony prominences. Over the last several years there has been a substantial amount of effort directed at better understanding and implementing the practice of offloading. A review of this work as well as relevant...
Source: Gerontology - January 16, 2018 Category: Geriatrics Source Type: research

Developmental Origins of Health Span and Life Span: A Mini-Review
Background: A vast body of research has demonstrated that disease susceptibility and offspring health can be influenced by perinatal factors, which include both paternal and maternal behavior and environment. Offspring disease risk has the potential to affect the health span and life span of offspring.Key Findings: Various maternal factors, such as environmental toxicant exposure, diet, stress, exercise, age at conception, and longevity have the potential to influence age-associated diseases such as cardiovascular disease, obesity, diabetes, and cancer risk in offspring. Paternal factors such as diet, age at conception, an...
Source: Gerontology - January 12, 2018 Category: Geriatrics Source Type: research

A Perfect sTORm: The Role of the Mammalian Target of Rapamycin (mTOR) in Cerebrovascular Dysfunction of Alzheimer's Disease: A Mini-Review
This article examines the available evidence for a role of mTOR-driven cerebrovascular dysfunction in the pathogenesis of AD and of vascular cognitive impairment and dementia (VCID) and highlights the therapeutic potential of targeting mTOR and/or specific downstream effectors for vasculoprotection in AD, VCID, and other age-associated neurological diseases with cerebrovascular etiology.Gerontology (Source: Gerontology)
Source: Gerontology - January 10, 2018 Category: Geriatrics Source Type: research

The Impact of Aging on Mechanisms of Mammalian Epimorphic Regeneration
Aging is associated with a significant decline of tissue repair and regeneration, ultimately resulting in tissue dysfunction, multimorbidity, and death. Salamanders possess remarkable regenerative abilities and have been studied with the prospect of inducing regeneration in humans and counteracting regenerative decline with aging. However, epimorphic regeneration, the full replacement of amputated structures, also occurs in mammals. One of the best studied models is digit tip regeneration, which is described for mice, and occurs in humans in a comparable manner. To accomplish regeneration, the amputated digit tip has to un...
Source: Gerontology - January 9, 2018 Category: Geriatrics Source Type: research

Psychometric Properties of the MyotonPRO in Dementia Patients with Paratonia
Conclusion: The MyotonPRO is potentially applicable for cross-sectional studies between groups of paratonia patients and appears less suitable to measure intraindividual changes in paratonia. Because of the inherent variability in movement resistance in paratonia, the outcomes from the MyotonPRO should be interpreted with care; therefore, future research should focus on additional guidelines to increase the clinical interpretation and improving reproducibility.Gerontology (Source: Gerontology)
Source: Gerontology - December 21, 2017 Category: Geriatrics Source Type: research

Is Social Network a Protective Factor for Cognitive Impairment in US Chinese Older Adults? Findings from the PINE Study
This study aims to provide an analytic framework to examine quantity, composition, and quality of social network and investigate the association between social network, global cognition, and cognitive domains among US Chinese older adults.Methods: Data were derived from the Population Study of Chinese Elderly (PINE), a community-engaged, population-based epidemiological study of US Chinese older adults aged 60 and above in the greater Chicago area, with a sample size of 3,157. Social network was assessed by network size, volume of contact, proportion kin, proportion female, proportion co-resident, and emotional closeness. ...
Source: Gerontology - December 21, 2017 Category: Geriatrics Source Type: research

Social Dimensions of Personal Growth following Widowhood: A Three-Wave Study
Conclusion: Findings underline the importance of a longitudinal and linked-lives perspective on personal growth and point to different pathways regarding its various subdimensions. Future research should further examine the validity of personal growth scales for other populations and consider the possibility to experience personal growth already during the anticipation of a traumatic event (e.g., in the case of long-term caretaking).Gerontology (Source: Gerontology)
Source: Gerontology - December 19, 2017 Category: Geriatrics Source Type: research

Predicting Trajectories of Functional Decline in 60- to 70-Year-Old People
Conclusion: Already in people aged 60-70 years, 3 distinct trajectories of functional decline were identified in these cohorts over a 9-year follow-up. Predictors of trajectories differed between males and females, except for gait speed. Identification of people at risk is the basis for targeting interventions.Gerontology (Source: Gerontology)
Source: Gerontology - December 12, 2017 Category: Geriatrics Source Type: research

Aging and Decision-Making: A Conceptual Framework for Future Research - A Mini-Review
Age differences in decision-making are of theoretical interest and have important practical implications, but relevant lines of work are distributed across multiple disciplines and often lack integration. The present review proposes an overarching conceptual framework with the aim of connecting disjointed aspects of this field of research. The framework builds on process models of decision-making and specifies potential mechanisms behind age effects as well as relevant moderators including task characteristics and contextual factors. After summarizing the extant literature for each aspect of the framework, compensatory mec...
Source: Gerontology - December 6, 2017 Category: Geriatrics Source Type: research

Age-Induced Changes in White, Brite, and Brown Adipose Depots: A Mini-Review
In conclusion, the aging process is a lifelong, creeping process with gradual decline in (pre-)adipocyte function over time. Thus, slowing down the accumulation of (pre-)adipocyte damage and dysfunction, removal of senescent preadipocytes as well as blocking deleterious compounds of the senescent secretome are protective measures to maintain a lasting state of health at old age.Gerontology (Source: Gerontology)
Source: Gerontology - December 6, 2017 Category: Geriatrics Source Type: research

How Virtue Was Born
This paper summarizes the Opening Lecture of the European Forum Alpbach 2017 in Tyrol/Austria (https://www.alpbach.org/de/). It deals with the evolution of cooperation throughout the history of life on Earth, and in particular human cooperation based on partnership. It emphasizes the role of institutions providing incentives for cooperation, and the role of praise and blame in guiding our actions. This helps for a better understanding of the social contract, based on evolutionary biology and psychology.Gerontology (Source: Gerontology)
Source: Gerontology - December 5, 2017 Category: Geriatrics Source Type: research

mTOR as Regulator of Lifespan, Aging, and Cellular Senescence: A Mini-Review
The mechanistic target of rapamycin (mTOR) network is an evolutionary conserved signaling hub that senses and integrates environmental and intracellular nutrient and growth factor signals to coordinate basic cellular and organismal responses such as cell growth, proliferation, apoptosis, and inflammation depending on the individual cell and tissue. A growing list of evidence suggests that mTOR signaling influences longevity and aging. Inhibition of the mTOR complex 1 (mTORC1) with rapamycin is currently the only known pharmacological treatment that increases lifespan in all model organisms studied. This review discusses th...
Source: Gerontology - November 30, 2017 Category: Geriatrics Source Type: research

User-Oriented Evaluation of a Robotic Rollator That Provides Navigation Assistance in Frail Older Adults with and without Cognitive Impairment
Conclusion: The RR-integrated navigation system was effective for improving navigation within a real-life environment in potential end-users, especially in those with cognitive impairment. This is the first study to provide statistical evidence on the effectiveness of an RR-integrated navigation system in the intended user group.Gerontology (Source: Gerontology)
Source: Gerontology - November 28, 2017 Category: Geriatrics Source Type: research

Mild-to-Moderate Chronic Kidney Disease and Geriatric Outcomes: Analysis of Cross-Sectional Data from the Berlin Aging Study II
Conclusion: GA identified impairments in 21 versus 15.9% of older adults with and without mild-to-moderate CKD, respectively. However, except for an increased likelihood of impaired gait performance (TUG) with mild-to-moderate CKD, we did not find independent associations between mild-to-moderate CKD and geriatric conditions.Gerontology (Source: Gerontology)
Source: Gerontology - November 28, 2017 Category: Geriatrics Source Type: research

Toward Using a Smartwatch to Monitor Frailty in a Hospital Setting: Using a Single Wrist-Wearable Sensor to Assess Frailty in Bedbound Inpatients
In this study, we proposed an enhanced automated algorithm to identify frailty using a single wrist-worn sensor.Methods: The data collected from 100 geriatric inpatients (age: 78.9 ± 9.1 years, 49% frail) were reanalyzed to validate the new algorithm. The frailty status of the participants was determined using a validated modified frailty index. Different FM phenotypes (31 features) including velocity of elbow rotation, decline in velocity of elbow rotation over 20 s, range o f motion, etc. were extracted. A regression model, bootstrap with 2,000 iterations, and recursive feature elimination technique were used for ...
Source: Gerontology - November 24, 2017 Category: Geriatrics Source Type: research

How Old Are You It's on Your Face!
Gerontology (Source: Gerontology)
Source: Gerontology - November 23, 2017 Category: Geriatrics Source Type: research