Long-term Studies Research Articles

Removal of intrahepatic bile duct stone could reduce the risk of cholangiocarcinoma

Hepatolithiasis (HL) poses a significant risk for cholangiocarcinoma (CCA) development, with reported incidences ranging from 5%-13%. Risk factors include older age, smoking, hepatitis B infection, and prolonged HL duration. Chronic inflammation and mechanical stress on the biliary epithelium contribute to CCA pathogenesis. Hepatectomy reduces CCA risk by removing stones and atrophic liver segments. However, residual stones and incomplete removal increase CCA risk. Kim et al identified carbohydrate antigen 19-9, carcinoembryonic antigen, and stone laterality as CCA risk factors, reaffirming the importance of complete stone removal. Nonetheless, challenges remain in preventing CCA recurrence post-surgery. Longer-term studies are needed to elucidate CCA risk factors further.

It's About Timing: Contrasting the Metabolic Effects of Early vs. Late Time-Restricted Eating in Humans.

Time-restricted eating (TRE), a form of intermittent fasting, restricts feeding time across the day, imposing a daily 'eating window'. The time of day when the eating window occurs could result in differential metabolic effects. Here, we describe recent intervention studies in humans assessing the metabolic consequences of an early- (i.e., eating window starting in the early morning) vs. late (i.e., eating window starting after midday)-TRE protocol. Well-controlled studies indicate that both TRE protocols effectively reduce body weight and improve altered glucose metabolism, lipid profile, inflammation, or blood pressure levels. An early-TRE (e-TRE) might have a further positive impact on improving blood glucose, insulin levels, and insulin resistance. However, the studies directly assessing the metabolic consequences of an early- vs. late-TRE have shown dissimilar findings, and more well-controlled clinical trials are needed on the metabolic benefits of these two types of TRE. Evidence suggests that an e-TRE might have enhanced metabolic results, particularly regarding glucose homeostasis. More long-term studies, including larger sample sizes, are needed to assess the metabolic, circadian, and adherence benefits, together with socio-cultural acceptance of both TRE approaches.

Presence of the crab-eating fox Cerdocyon thous in La Rioja, Argentina, and implications for its geographic and environmental niche modeling

Abstract The crab-eating fox Cerdocyon thous is one of South America’s most common species of canids; its generalist habits and plasticity allowed the species to adapt to numerous habitats and human presence. In 2020, we registered a specimen of C. thous on a trap camera placed in the vicinity of the Huaco River in La Rioja Province, Argentina. This record was the starting point for evaluating past and present environmental niche models (ENMs) of the species throughout their entire distribution in South America. ENMs models suggest that the presence of C. thous in La Rioja has low suitability values and suggest that we may be facing a sink population scenario due to the low frequency of records in the province. Also, the model indicated that the parameters delimiting the areas with the highest suitability values are related to temperature, isothermality, and precipitation. Long-term studies in the region are needed to determine the population dynamics of C. thous in La Rioja.

A meta-analysis comparing treatment of benign prostatic hyperplasia with holmium laser enucleation and photoselective greenlight vaporization

Abstract Background We compared the safety and efficacy of treating benign prostatic hyperplasia with photoselective greenlight vaporization (PVP) versus holmium laser enucleation of the prostate (HoLEP). Methods Databases (PubMed, Embase, Cochrane Library, Chinese CBM, and CNKI) were searched for eligible studies evaluating HoLEP or PVP outcomes, published until May 2022. We analyzed the incidence of relative complications and postoperative outcomes, including the international prostate symptom score, maximum flow rate (Qmax), postvoid residual urine volume, quality of life index, and prostate-specific antigen levels. Results Eleven studies involving 4763 patients were included in this meta-analysis. The significant differences in postoperative Qmax at 1 month (mean difference [MD], 3.31, 95% confidence interval [CI], 0.45–6.16, p = 0.02, I 2 = 92%), 3 months (MD, 2.78, 95% CI, 0.53 to 5.02, p = 0.02, I 2 = 89%), 6 months (MD, 2.13, 95% CI, 1.11 to 3.15, p < 0.0001, I 2 = 87%), and 12 months (MD, 3.98, 95% CI, 2.06 to 5.89, p < 0.0001, I 2 = 58%) further confirmed unique advantage of HoLEP over PVP. We used forest plots to determine significant differences in the severe complication rates among patients in the PVP and HoLEP groups (odds ratio, 0.05, 95% CI, 0.01 to 0.28, p = 0.0005). Conclusions Holmium laser enucleation of the prostate and PVP showed comparable international prostate symptom scores, quality of life index, postvoid residual urine volumes, prostate-specific antigen levels, perioperative factors, and total complication rates. Compared with PVP, HoLEP had a greater Qmax 1 year postoperatively, decreased energy expenditure, and fewer high-grade complications. These results need to be verified in long-term follow-up studies with well-structured randomized controlled trials.

Crohn's disease after surgery: Changes in post-operative management strategies over time and their impact on long-term re-operation rate-A retrospective multicentre real-world study.

Few data are available addressing the impact of post-operative management of Crohn's disease (CD) on long-term clinical course. To assess the evolution of post-operative management strategies over the last 40 years and their impact on the re-operation rate of CD. We included 657 patients with CD who had undergone their first radical ileo-caecal resection between 1980 and 2020. Three cohorts were defined according to year of surgery: cohort 1 (1980-1998; n = 198), cohort 2 (1999-2009; n = 218) and cohort 3 (2010-2020; n = 241). We estimated exposure to immunomodulators and anti-TNFα agents after surgery and rates of re-operation using Kaplan-Meier survival analyses. We used Cox proportional hazards regression to assess the association of clinical variables with time to re-operation. Immunosuppressants, (IMMs) and anti-TNFα exposure within 5 years after surgery increased significantly from cohort 1 to cohort 2 and cohort 3 (IMMs: 1.6%, 38.2% and 28.0%, respectively, p < 0.001; anti-TNFα: 0.0%, 20.7% and 52.0%, respectively, p < 0.001). There was no significant difference across cohorts regarding the cumulative probability of re-operation within 5 and 10 years. Multivariate analysis identified IMMs/anti-TNFα exposure before the first surgery (HR 9.15; 95% CI 2.77-30.21) and post-operatively (HR: 0.24; 95% CI 0.07-0.74) as variables associated with the risk of re-operation. However, these associations had a time-varying effect and become non-significant after 5 and 2 years after surgery, respectively. Despite increased post-operative use of IMMs and anti-TNFα agents in the last two decades, the impact of these strategies on the risk of long-term re-operation rate has been modest.

Ejaculation sparing of classic and minimally invasive surgical treatments of LUTS/BPH.

The surgical landscape for Lower Urinary Tract Symptoms (LUTS) and Benign Prostatic Hyperplasia (BPH) has evolved with the introduction of Minimally Invasive Surgical Therapies (MISTs), recognizing the impact of sexual function on patients' well-being, and prioritizing ejaculation-sparing approaches. This systematic review explored ejaculation sparing after classic endoscopic procedures and MISTs (iTind, Rezūm, Urolift, Aquablation, and TPLA) and a literature search yielded 41 studies. While all procedures demonstrated efficacy in improving LUTS/BPH symptoms (IPSS, QoL, Qmax), a subset of studies evaluated ejaculatory function. Positive outcomes were noted, challenging the historical association of BPH surgeries with ejaculatory dysfunction. Variations in study design, patient cohorts, and limited long-term data present challenges. Notably, the lack of baseline specificity, use of alpha-blockers, and non-specific sexual function assessments underscore potential biases. Despite limitations, the review tentatively concluded that MISTs, including iTind, Rezūm, Urolift, Aquablation, and TPLA, appear comparable in sparing ejaculation. Long-term studies are essential to validate sustainability, and comparative research should assess trade-offs between MISTs and traditional surgeries. Incorporating patient-reported outcomes and quality of life assessments will enhance future investigations, refining MISTs as standard therapeutic options for LUTS/BPH.

Association between Homocysteine and Vitamin D Levels in Asymptomatic Korean Adults

An increased homocysteine level is a risk factor for cardiovascular disease, venous thromboembolism, cerebrovascular disease, and chronic kidney disease. In addition, vitamin D deficiency is associated with coronary artery disease and metabolic disorders. The present study included data from 1375 adults (895 men and 480 women) with a mean age of 52.62 ± 9.94 years who visited the Health Promotion Center of the University Hospital in Gyeonggi-do, Republic of Korea from January 2018 to December 2022 for routine checkups that included assessments of their homocysteine and vitamin D levels. Homocysteine levels were positively associated with age, a history of hypertension, a history of diabetes, current smoking habits, and levels of low-density lipoprotein cholesterol, creatinine, uric acid, and high-sensitivity C-reactive protein. By contrast, vitamin D levels were negatively associated with serum levels of homocysteine after adjusting for covariates (β = −0.033, p &lt; 0.001). Additional long-term prospective studies are needed to elucidate the presence of a causal relationship between vitamin D status and serum levels of homocysteine in asymptomatic Korean adults. An intervention trial is warranted to determine whether the administration of vitamin D is helpful for the primary prevention of cardiovascular disease by lowering the homocysteine level in this population.

The role of debt maturity in stock price crash risk: a comparison of developing and developed Asian economies

PurposeThis study examines the impact of debt maturity structure on stock price crash risk (SPCR) in Asian economies and the moderating effect of firm age on this relationship.Design/methodology/approachThe study utilized annual data from 432 nonfinancial firms publicly listed in six Asian countries: China, Hong Kong, Japan, Singapore, Pakistan and India. The observation period covers 14 years, from 2007 to 2020. The sample was categorized into three groups: the entire sample and one group each for developing and developed Asian economies. A generalized least squares panel regression method was employed to test the research hypotheses.FindingsThe results suggest that long-term debt has a significant negative influence on SPCR in Asian economies, indicating that firms with high long-term debt experience lower future SPCR. Moreover, firm age negatively moderates this relationship, implying that older firms may experience a more pronounced reduction in SPCR due to high long-term debt. Finally, firms in developed Asian economies with high long-term debt are more effective in mitigating the risk of a significant drop in their stock prices than firms in developing Asian economies.Originality/valueThis study contributes to the literature in several ways. To the best of the researcher’s knowledge, this is the first of such efforts to investigate the relationship between debt maturity structure and crash risk in Asia. Additionally, it reveals that long-term debt influences SPCR directly and indirectly in Asia through the moderating role of firm age. Lastly, it is likely one of the first studies by a research team in Asia to compare the nonfinancial markets of developed and developing Asian countries.

Comprehensive Assessment of NDVI Products Derived from Fengyun Satellites across China

NDVI data are crucial for agricultural and environmental research. The Fengyun-3 (FY-3) series satellites are recognized as primary sources for retrieving NDVI products on a global scale. To apply FY-3 NDVI data for long-term studies, such as climate change, this study conducted a thorough evaluation to detect the potentials of the FY-3B and FY-3D satellites for generating a long time series NDVI dataset. For this purpose, the spatiotemporal consistency between the FY-3B and FY-3D satellites was evaluated, and their performances were compared. Then, a grey relational analysis (GRA) method was applied to detect the factors influencing the consistency among the different satellites, and a gradient boosting regression (GBR) model was constructed to create a long-term FY-3 NDVI product. The results indicate an overall high consistency between the FY-3B and FY-3D NDVIs, suggesting that they could be used as complementary datasets for generating a long-term NDVI dataset. The correlations between the FY-3D NDVI and the MODIS NDVI, as well as the leaf area index (LAI) measurements, were both higher than those of FY-3B, which indicates a better performance of FY-3D in retrieving NDVI data. The grey correlation degrees between the NDVI differences and four parameters, which were land cover (LC), DEM, latitude (LAT) and longitude (LON), were calculated, revealing that the LC was the most related to the NDVI differences. Finally, a GBR model with FY-3B NDVI, LC, DEM, LAT and LON as the input variables and FY-3D NDVI as the target variable was established and achieved a robust performance. The R values between the GBR-estimated NDVI and FY-3D NDVI reached 0.947, 0.867 and 0.829 in the training, testing and validation datasets, respectively, indicating the feasibility of the established model for generating long time series NDVI data by combining data from the FY-3B and FY-3D satellites.

Inhibition of Metalloproteinases Extends Longevity and Function of In Vitro Human iPSC-Derived Skeletal Muscle

In vitro culture longevity has long been a concern for disease modeling and drug testing when using contractable cells. The dynamic nature of certain cells, such as skeletal muscle, contributes to cell surface release, which limits the system’s ability to conduct long-term studies. This study hypothesized that regulating the extracellular matrix (ECM) dynamics should be able to prolong cell attachment on a culture surface. Human induced pluripotent stem cell (iPSC)-derived skeletal muscle (SKM) culture was utilized to test this hypothesis due to its forceful contractions in mature muscle culture, which can cause cell detachment. By specifically inhibiting matrix metalloproteinases (MMPs) that work to digest components of the ECM, it was shown that the SKM culture remained adhered for longer periods of time, up to 80 days. Functional testing of myofibers indicated that cells treated with the MMP inhibitors, tempol, and doxycycline, displayed a significantly reduced fatigue index, although the fidelity was not affected, while those treated with the MMP inducer, PMA, indicated a premature detachment and increased fatigue index. The MMP-modulating activity by the inhibitors and inducer was further validated by gel zymography analysis, where the MMP inhibitor showed minimally active MMPs, while the inducer-treated cells indicated high MMP activity. These data support the hypotheses that regulating the ECM dynamics can help maximize in vitro myotube longevity. This proof-of-principle strategy would benefit the modeling of diseases that require a long time to develop and the evaluation of chronic effects of potential therapeutics.

Methane sink of subterranean space in an integrated atmosphere-soil-cave system

CH4 serves as an important greenhouse gas, yet limited knowledge is available in global and regional CH4 cycling, particularly in widely distributed karst terrain. In this study, we investigated an upland in Puding Karst Ecosystem Research Station, and explored CH4 concentration and/or flux in atmosphere, soil and cave using a closed static chamber method and an eddy covariance system. Meanwhile, we monitored atmospheric temperature, precipitation, temperature and wind velocity in the cave entrance. The results demonstrated that atmospheric CH4 and actual soil CH4 fluxes in the source area of eddy covariance system were -0.19±8.64 nmols-1m-2 and -0.16 nmols-1m-2 respectively. The CH4 concentrations in Shawan Cave exhibited 10∼100-fold lower than that of the external atmosphere. CH4 oxidation rate dominated by methane-oxidizing bacteria was 1.98 nmols-1m-2 in Shawan Cave when it combined with temperature difference between cave and external atmosphere. Therefore, CH4 sink in global karst subterranean spaces was estimated at 106.2 Tg CH4 yr-1. We supplemented an understanding of CH4 cycling paths and fluxes in karst terrain, as well as CH4 sinks in karst subterranean space. Further works require to establish a karst ecosystem observation network to conduct long-term integrated studies on CH4 fluxes regarding atmosphere, soils, plants and caves.

Применение корреляционного анализа для определения рассогласования показателей для двух разных выборок: сопоставление интеллектуального и личностного развития детей младшего школьного возраста, исследуемых с интервалом в 10 лет

&lt;p&gt;Correlation analysis, which is actively used in psychological research to identify the relationship between psychological parameters, loses its meaning when the samples being compared are different. At the same time, studying possible connections of psychological indicators between samples may have some meaning in special cases. Purpose of the work: to show the possibilities and propose a technology for using correlation analysis to determine the agreement of indicators for two different samples using the example of a long-term (retrospective and modern) study of the intellectual and personal characteristics of the development of schoolchildren in the 2nd grade of a general school with an age difference of 10 years. For correlation analysis, we used assessments of intellectual development according to the level of work in the &amp;ldquo;Beasts in the Circus&amp;rdquo; method of the &amp;ldquo;Creative Field&amp;rdquo; method (Bogoyavlenskaya, 1971) and intelligence according to the &amp;ldquo;Standard Progressive Matrices&amp;rdquo; test by J. Raven. To implement the possibility of a full correlation analysis of general indicators of different samples, the work proposed a technique for preliminary linking two different samples of the same size to each other by matching them on one of the common sample variables.&lt;/p&gt;

ICH S1 prospective evaluation study: weight of evidence approach to predict outcome and value of 2-year rat carcinogenicity studies. A report from the regulatory authorities subgroup

Introduction: The International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH) initiated a process in 2012 to revise the S1B Guideline “Testing for Carcinogenicity of Pharmaceuticals”. Previous retrospective analysis indicated the importance of histopathological risk factors in chronic toxicity studies, evidence of endocrine perturbation, and positive genetic toxicology results as potentially predictive indicators of carcinogenic risk. In addition, a relationship between pharmacodynamic activity and carcinogenicity outcome in long-term rodent studies has been reported. It was postulated that these factors could be evaluated in a Weight-of-Evidence (WoE) approach to predict the outcome of a 2-year rat study.Methods: The ICH S1B(R1) Expert Working Group (EWG) conducted a Prospective Evaluation Study (PES) to determine the regulatory feasibility of this WoE approach. Drug Regulatory Authorities (DRAs) evaluated 49 Carcinogenicity Assessment Documents (CADs), which describe the WoE for submitted pharmaceutical compounds. Each compound was categorized into a carcinogenic risk category including a statement of the value of the 2-year rat study. The outcome of the completed 2-year rat studies was evaluated in relation to the prospective CAD to determine the accuracy of predictions.Results: Based on the results of the PES, the EWG concluded that the evaluation process for assessing human carcinogenic risk of pharmaceuticals described in ICH S1B could be expanded to include a WoE approach. Approximately 27% of 2-year rat studies could be avoided in cases where DRAs and sponsors unanimously agreed that such a study would not add value.Discussion: Key factors supporting a WoE assessment were identified: data that inform carcinogenic potential based on drug target biology and the primary pharmacologic mechanism of the parent compound and major human metabolites; results from secondary pharmacology screens for this compound and major human metabolites that inform carcinogenic risk; histopathology data from repeated-dose toxicity studies; evidence for hormonal perturbation; genotoxicity data; and evidence of immune modulation. The outcome of the PES indicates that a WoE approach can be used in place of conducting a 2-year rat study for some pharmaceuticals. These data were used by the ICH S1B(R1) EWG to write the R1 Addendum to the S1B Guideline published in August 2022.

The BALA project: A pioneering monitoring of Azorean forest invertebrates over two decades (1999–2022)

Globally, there is a concerning decline in many insect populations, and this trend likely extends to all arthropods, potentially impacting unique island biota. Native non-endemic and endemic species on islands are under threat due to habitat destruction, with the introduction of exotic, and potentially invasive, species, further contributing to this decline. While long-term studies of plants and vertebrate fauna are available, long-term arthropod datasets are limited, hindering comparisons with better-studied taxa. The Biodiversity of Arthropods of the Laurisilva of the Azores (BALA) project has allowed gathering comprehensive data since 1997 in the Azorean Islands (Portugal), using standardised sampling methods across islands. The dataset includes arthropod counts from epigean (pitfall traps) and canopy-dwelling (beating samples) communities, enriched with species information, biogeographic origins, and IUCN categories. Metadata associated with the sample protocol and events, like sample identifier, archive number, sampled tree species, and trap type are also recorded. The database is available in multiple formats, including Darwin Core, which facilitates the ecological analysis of pressing environmental concerns, such as arthropod population declines and biological invasions.

Relevance of the Get Active Questionnaire for Pre-Participation Exercise Screening in the General Population in a Tropical Environment

The Get Active Questionnaire (GAQ), developed by the Canadian Society for Exercise Professionals (CSEP), was recently recommended for pre-participation screening of the general population in Singapore before increasing their exercise levels. This literature review examines the evidence behind the GAQ and its relevance to our tropical environment. Searches were carried out via Pubmed, MEDLINE and the Cochrane Central Register of Controlled Trials. Resources referenced by the CSEPs were hand searched. The CSEP was also contacted for further information. The evidence behind each GAQ question was compared to international literature and guidelines, where applicable. Out of 273 studies, 49 were suitable for analysis. Two GAQ studies commissioned by the CSEP showed a high negative predictive value but high false negative rate. Of the nine GAQ questions, those on dizziness, joint pains and chronic diseases appear to be justified. Those on heart disease/stroke, hypertension, breathlessness and concussion require modification. The one on syncope can be amalgamated into the dizziness question. The remaining question may be deleted. No long-term studies were available to validate the use of the GAQ. Heat disorders were not considered in the GAQ. Modification of the GAQ, including the inclusion of environmental factors, may make it more suitable for the general population and should be considered.

Booster visits in the management of the acute musculoskeletal injuries: Transforming care to improve outcomes-A perspective review.

The current healthcare delivery system for patients with acute musculoskeletal injury is failing. Current rehabilitation management of acute musculoskeletal injury typically includes physical therapy, focused on management of impairments, with an eventual transition to functional activities and release to prior level of function. At that point, formal physical therapy is often discontinued, despite the knowledge that a high percentage of patients fail to maintain preinjury level of activity and often reduce participation in regular physical activity. Further, for those who attempt to return to prior levels of pivoting and cutting activities, there is a high second injury rate. The long-term human experience is compromised by the current model of care which terminates at the point of transition to activity. This model of care fails to meet the continued needs of these patients and may result in long term deficits and potential disability. Extended care models include intermittent follow up visits after discharge from an acute episode of care and have been efficacious and cost effective in some patient populations with musculoskeletal conditions. Specifically, a type of extended care model, labeled "booster sessions," represents an opportunity to provide structured, intermittent care to assist in a smooth transition back to function, following an acute episode of care and promote a healthier life outcome. This perspective review will discuss the opportunity to transform acute musculoskeletal care to booster visit care model in an attempt to develop a more efficacious and cost-effective system of care which could be generalizable to all musculoskeletal conditions.

Occupational stress among Norwegian physicians: A literature review of long-term prospective studies 2007-2019.

There are signs of increased stress at work among Norwegian physicians over the last decades, not least among general practitioners (GPs). In this review, we identify trends in both occupational stress and adverse work-related predictors of such stress and burnout in Norwegian physicians. We performed an extensive literature search using MEDLINE, Embase and PsycINFO. We included prospective and repeated cross-sectional studies of work stress among Norwegian physicians published in 2007-2019. Nine studies with observation periods of 1-20 years were included. Occupational stress (global measure) among all doctors decreased gradually from medical school to 20 years later. The prevalence of an effort-reward imbalance increased fourfold among GPs during the period 2010-2019. Five studies reported higher levels of occupational stress among female physicians than among their male colleagues. Work-home conflict levels increased after graduation until 10 years after leaving medical school and plateaued thereafter. Physicians who graduated in a later cohort reported lower levels of work-home conflict and less workplace violence. Work-home conflict, low colleague support, number of work hours and workload/low autonomy were all independent predictors of occupational stress. The reduction in occupational stress during the years after leaving medical school may result from increased competency in clinical work and decreased on-call work. The Co-ordination Act implemented in 2012 may explain the increase in occupational stress among GPs. These findings suggest that both reducing work-home conflict and increasing colleague support are important for doctors' well-being.

Cross-angled versus flat-trim bristle tuft configurations in manual toothbrushes: A systematic review.

This systematic review synthesizes and evaluates the literature regarding the effect of manual toothbrushes (MTBs) with cross-angled bristle tufts (CA-TB) compared to flat-trim (FT-TB) configurations on plaque scores and parameters of gingival health in adult patients. PubMed-MEDLINE and Cochrane-CENTRAL databases were searched, from their insertion up to August 1st, 2023, to detect appropriate papers. Clinical trials involving adult patients without periodontitis who performed self-brushing were eligible for inclusion. Primary outcome parameters included plaque, bleeding, and gingival scores. Secondary outcomes encompassed signs of soft and hard tissue abnormalities. A descriptive analysis was conducted. When feasible, a meta-analysis was performed using either the 'fixed' or 'random effects' model, as appropriate. Nine eligible papers were retrieved, presenting 20 comparisons. There was considerable heterogeneity in the clinical and methodological design aspects of the included studies. In the descriptive analysis, eight out of 12 comparisons demonstrated a difference in plaque removal performance in favour of the CA-TB. However, data regarding bleeding and gingival index scores were inconclusive. A meta-analysis was performed on plaque, bleeding, and gingival index scores, including different indices used for scoring. The meta-analysis of short-term studies showed a medium effect statistically significant difference in the reduction of plaque scores in favour of the CA-TB (SMD = 0.75; 95% CI (0.51; 0.99)), but this was not substantiated in longer-term studies (SMD = -0.06; 95% CI(-0.44; 0.31)). No adverse events were described in any group. Within the limitations of the present study design, short-term evaluations, as assessed with various plaque indices, show a weak certainty in favour of the cross-angled toothbrush over the flat-trim toothbrush. However, based on longer-term evaluations, there is insufficient support due to the inconsistent outcomes of the analysis.

Personalizing Activity Selection in Assistive Social Robots from Explicit and Implicit User Feedback

AbstractRobots in multi-user environments require adaptation to produce personalized interactions. In these scenarios, the user’s feedback leads the robots to learn from experiences and use this knowledge to generate adapted activities to the user’s preferences. However, preferences are user-specific and may suffer variations, so learning is required to personalize the robot’s actions to each user. Robots can obtain feedback in Human–Robot Interaction by asking users their opinion about the activity (explicit feedback) or estimating it from the interaction (implicit feedback). This paper presents a Reinforcement Learning framework for social robots to personalize activity selection using the preferences and feedback obtained from the users. This paper also studies the role of user feedback in learning, and it asks whether combining explicit and implicit user feedback produces better robot adaptive behavior than considering them separately. We evaluated the system with 24 participants in a long-term experiment where they were divided into three conditions: (i) adapting the activity selection using the explicit feedback that was obtained from asking the user how much they liked the activities; (ii) using the implicit feedback obtained from interaction metrics of each activity generated from the user’s actions; and (iii) combining explicit and implicit feedback. As we hypothesized, the results show that combining both feedback produces better adaptive values when correlating initial and final activity scores, overcoming the use of individual explicit and implicit feedback. We also found that the kind of user feedback does not affect the user’s engagement or the number of activities carried out during the experiment.

Intraspecific chemical variation of Tanacetum vulgare affects plant growth and reproductive traits in field plant communities.

The study investigated the impact of intraspecific plant chemodiversity on plant growth and reproductive traits at both the plant and plot levels. It also aimed to understand how chemodiversity at stand level affects ecosystem functioning and plant-plant interactions. We describe a biodiversity experiment in which we manipulated intraspecific plant chemodiversity at the plot level using six different chemotypes of common tansy (Tanacetum vulgare L., Asteraceae). We tested the effects of chemotype identity and plot-level chemotype richness on plant growth and reproductive traits and plot-level headspace emissions. The study found that plant chemotypes differed in growth and reproductive traits and that traits were affected by the chemotype richness of the plots. Although morphological differences among chemotypes became less pronounced over time, reproductive phenology patterns persisted. Plot-level trait means were also affected by the presence or absence of certain chemotypes in a plot, and the direction of the effect depended on the specific chemotype. However, chemotype richness did not lead to overyielding effects. Lastly, chemotype blends released from plant communities were neither richer nor more diverse with increasing plot-level chemotype richness, but became more dissimilar as they became more dissimilar in their leaf terpenoid profiles. We found that intraspecific plant chemodiversity is crucial in plant-plant interactions. We also found that the effects of chemodiversity on plant growth and reproductive traits were complex and varied depending on the chemotype richness of the plots. This long-term field experiment will allow further investigation into plant-insect interactions and insect community assembly in response to intraspecific chemodiversity.