This article discusses the diffusion process in an online social network given the individual connections between members. The authors model the adoption decision of individuals as a binary choice ...affected by three factors: (1) the local network structure formed by already adopted neighbors, (2) the average characteristics of adopted neighbors (influencers), and (3) the characteristics of the potential adopters. Focusing on the first factor, the authors find two marked effects. First, an individual who is connected to many adopters has a greater adoption probability (degree effect). Second, the density of connections in a group of already adopted consumers has a strong positive effect on the adoption of individuals connected to this group (clustering effect). The article also records significant effects for influencer and adopter characteristics. For adopters, specifically, the authors find that position in the entire network and some demographic variables are good predictors of adoption. Similarly, in the case of already adopted individuals, average demographics and global network position can predict their influential power on their neighbors. An interesting counterintuitive finding is that the average influential power of individuals decreases with the total number of their contacts. These results have practical implications for viral marketing, a context in which a variety of technology platforms are increasingly considering leveraging their consumers' revealed connection patterns. The model performs particularly well in predicting the next set of adopters.
Full text
Available for:
IZUM, KILJ, NUK, OILJ, PILJ, SAZU, UKNU, UL, UM, UPUK
Digital advertising markets are growing and attracting increased scrutiny. This article explores four market inefficiencies that remain poorly understood: ad effect measurement, frictions between and ...within advertising channel members, ad blocking, and ad fraud. Although these topics are not unique to digital advertising, each manifests in unique ways in markets for digital ads. The authors identify relevant findings in the academic literature, recent developments in practice, and promising topics for future research.
Full text
Available for:
IZUM, KILJ, NUK, OILJ, PILJ, SAZU, UKNU, UL, UM, UPUK
The COVID-19 pandemic has posed unprecedented challenges for societies. Emerging data have indicated that the younger population are the most vulnerable group to the development of mental health ...problems during this pandemic. The present study aimed to examine the effects of the changes in health behaviors on mental health problems to identify an at-risk group among adolescents and young adults.
In the present cross-sectional study, secondary school students (N = 2556) ages 15–21 years participated in Hungary. A self-report questionnaire was developed to measure the changes in health behaviors. Mental health problems were measured by the Beck Hopelessness Scale and the 20-item UCLA Loneliness Scale.
A significant proportion of the students showed moderate/severe hopelessness or high loneliness which were more pronounced among adolescent females. An at-risk group was identified among adolescents and young adults. Students who have a lower number of friends, spend less time in front of a screen, and feel lonely often/very often are more likely to have moderate/severe hopelessness with high loneliness.
All data were collected online, and students completed the questionnaires voluntarily. Cross-sectional, non-preregistered study.
Loneliness and hopelessness were prevalent in the young population during the COVID-19 pandemic. The at-risk group of adolescents characterized by moderate/severe hopelessness with high loneliness highlights the need for follow-up mental health to avoid future poor mental and physical health. It is also recommended to develop effective interventions targeted to gender and age, with the promotion of resiliencies and buffers against vulnerabilities of negative life events.
•More than half of the students reported mild hopelessness and moderate loneliness.•Moderate/severe hopelessness or loneliness were more frequent in younger females.•An at-risk group can be identified in adolescents during distance learning education.•The at-risk group was described by moderate/severe hopelessness with high loneliness.•It is an urge to develop effective interventions targeted to gender and age.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
A defining property of the World Wide Web is a content site's ability to place virtually costless hyperlinks to third-party content as a substitute or complement to its own content. Costless ...hyperlinking has enabled new types of players, usually referred to as content aggregators, to successfully enter content ecosystems, attracting traffic and revenue by hosting links to the content of others. This, in turn, has sparked a heated controversy between content creators and aggregators regarding the legitimacy and costs/benefits of uninhibited free linking. To our knowledge, this work is the first to model the complex interplay between content and links in settings where a set of sites compete for traffic. We develop a series of analytical models that distill how hyperlinking affects the (a) incentives of content nodes to produce quality content versus link to third-party content, (b) profits of the various stakeholders, (c) average quality of content that becomes available to consumers, and (d) impact of content aggregators. Our results provide a nuanced view of the so-called link economy, highlighting both the beneficial consequences and the drawbacks of free hyperlinks for content creators and consumers.
This paper was accepted by Lorin Hitt, information systems.
Full text
Available for:
BFBNIB, CEKLJ, IZUM, KILJ, NMLJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
A prominent hallmark of competitive interaction is the desire to differentiate from rivals. In this article, the authors examine under what conditions firms will differentiate through product quality ...versus advertising intensity. Firms select quality in a first stage, advertising in a second stage, and price in the last stage. The probability that a consumer is informed of a firm’s offering depends on its advertising expenditure. The authors find that when advertising is not cost effective, both firms choose a light ad spending. This allows them to minimally differentiate in quality without concern of intense price competition, as each firm has a segment of “captive” consumers. When advertising is moderately cost effective, one firm spends heavily on advertising. The rival advertises lightly, while choosing the same maximal quality level. This strategy softens price competition by inducing the heavy advertiser to price high more often to capitalize on its large captive segment. When advertising is very cost effective, both firms advertise heavily and differentiate in quality. Three extensions are examined: upfront fixed quality costs, continuous advertising levels, and simultaneous advertising and pricing decisions. This research reveals that letting market awareness be determined endogenously suggests less product differentiation than previously suspected and regions of advertising differentiation.
Full text
Available for:
IZUM, KILJ, NUK, OILJ, PILJ, SAZU, UKNU, UL, UM, UPUK
The aim of this study was to determine sexual differentiation in the anthropometric and physiological characteristics of Hungarian rowers in different age categories. These characteristics were ...measured for 15–16-year-old juniors (55 men and 36 women), 17–18-year-old older juniors (52 men and 26 women), and 19–22-year-old seniors (23 men and 8 women). The degree of sexual dimorphism was expressed in units of measurement as percentages and the dimorphism index. In all age categories, females had significantly higher body fat indices. Body fat percentage was determined by electrical impedance and by the Pařízková formula, BMI, and skinfold thicknesses. Males had significantly higher body mass, body height, skeletal muscle mass, sitting height, arm span, lower limb length, and body surface area. Males also scored significantly higher values for the following physiological characteristics: peak power, relative peak power, ErVO2max, jump height, speed max, force max, and relative maximal power. Analysis of anthropometric and physiological characteristics in Hungarian rowers revealed that sexual dimorphism tended to increase with age, regardless of whether it was expressed in units of measurement, percentages, or dimorphism index values. The age-related increase in the sexual dimorphism of Hungarian rowers suggests that training methods should be carefully selected to accommodate the needs of various age and gender groups.
High school education took place in the form of distance learning during SARS-CoV-2 pandemic worldwide, including Hungary. Decreased physical activity and an increase in inactive behaviours may lead ...to an increased risk of obesity, diabetes, and cardiovascular disease.
Our study targeted changes in physical activity (aerobic exercise, muscle strengthening) and screen time in adolescents and young adults during the pandemic.
High school students were interviewed in 66 public schools in 37 Hungarian cities (N = 2508). Survey items on physical activity and screen time were derived from the WHO Health Behaviour of School-aged Children Survey and the Centers for Disease Control Youth Risk Behavior Survey. A 2 × 2 factorial ANCOVA was used to test the effects of gender (male vs. female) and/or age (adolescents vs. young adults) on the reported changes in physical activity and screen time before and during lockdown (covariate: BMI Z-score).
The majority of the cohort indicated less physical activity. Aerobic and muscle-strengthening type of exercises significantly decreased, and screen time increased during distance education. Male individuals showed a higher decrease in the level of aerobic exercise, and young adults reported a higher increase in the time spent in front of the screen.
Background: Motocross riders’ performance is highly dependent on the characteristics of the motorcycles and the skills of the riders, and the actual environmental conditions. This study aims to ...describe the differences in anthropometric and physiological characteristics between internationally ranked adolescent males and nationally ranked motorcross (MX) peer competitors; Methods: Data obtained from young riders (n=14) were divided into internationally ranked G1 (n=5) and - nationally ranked G2 (n=9) young MX riders. We determined body composition and cardiorespiratory variables, and measured heart rate and movement-related data with Polar Team Pro system during the race; (3) Results: Blood lactate concentrations were evaluated before and after the race session. MX riders with an international ranking performed significantly better during both races (R1 and R2), which manifested itself in significantly shorter times per lap on average (difference for R1=14.8 s and for R2=16.7 s, respectively, p=0.017), more laps completed (G1 vs G2 approx.: 11.2 : 9.9 laps for R1 and R2, p=0.019) and points scored (difference: R1=9.3 pts and R2=9.0 pts, p=0.014). There were no statistically significant differences in age between the two compared groups (p=0.559) and other anthropometric and physiological characteristics tested, with an exception of muscle mass percent (p<0.001); Conclusions: Current results showed that motocross probably places a heavy burden on riders, who need to be fit enough to maintain their position in the field.
The goal of this study was to explore the factor structure of the First Aid Willingness Questionnaire and determine its correlations and associations between sociodemographic and sport-related ...variables. A total of 413 adolescents participated in this study (mean age = 14.2 years). They consisted of 221 boys and 193 girls. Besides sociodemographic and sport-related questions, the First Aid Willingness Questionnaire was used to understand the student’s first aid attitudes. The exploratory factor analysis revealed a four-factor model. The first factor was named first aid willingness for peers, which includes willingness to help friends and family members. The second factor contained factors to help strangers; thus, it was named first aid willingness for strangers. The analysis revealed a third factor that assessed the students’ knowledge of first aid. The last factor contained the students’ negative emotions. The correlation between the factors showed that knowledge had a positive association with all the other factors. Adolescents’ willingness to help their peers was highly associated with helping strangers, but negative emotions had a negative correlation with helping unknown people. Sport-related variables were investigated to determine the effects on first aid attitudes. Even though sport seemed to increase first aid willingness, future studies need to explore its associations. We believe that a deeper understanding of this topic could help prevent serious injuries or death in emergencies.
We model the commercial World Wide Web as a directed graph that emerges as the equilibrium of a game in which utility maximizing websites purchase (advertising) in-links from each other while also ...setting the price of these links. In equilibrium, higher content sites tend to purchase more advertising links (mirroring the Dorfman-Steiner rule) while selling less advertising links themselves. As such, there seems to be specialization across sites in revenue models: high content sites tend to earn revenue from the sales of content, whereas low content ones earn revenue from the sales of traffic (advertising). In an extension, we also allow sites to establish (reference) out-links to each other and find that there is a general tendency to establish reference links to sites with higher content. Finally, we explore network formation in the presence of search engines and find that the higher the proportion of people using them, the more sites have an incentive to specialize in certain content areas. Our results have interesting practical implications for search-engine optimization, the pricing of online advertising, and the choice of Internet business models. They also shed light on why Google can use the web's link structure to rank sites by content.
Full text
Available for:
BFBNIB, CEKLJ, IZUM, KILJ, NMLJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
PDF
