scholarly journals Opportunistic Behavior Governance in PPP Projects: An Analysis Based on Trust Networks

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Xiang Wang ◽  
Yilin Yin ◽  
Jiaojiao Deng ◽  
Zhichao Xu

Stakeholders of PPP projects may induce opportunistic behaviors in long-term cooperation. Existing studies emphasized the inhibitory effect of trust on opportunistic behaviors, but most of them simplified the trust relationship into a two-subject perspective. From the perspective of social network analysis, this research constructs a network-level trust relationship between the stakeholders of PPP projects. The index analysis of the trust network shows that the PPP project stakeholders have obvious centrality and there are structural holes in the networks. From the perspective of the stakeholder alliance, different forms of alliances differ in the degree, betweenness, and closeness centrality of the trust network. On this basis, the analysis results of different trust network indicators match the corresponding preventive measures of opportunistic behavior, and this research provides comprehensive suggestions for project management.

2019 ◽  
Vol 8 (4) ◽  
pp. 4324-4328

The modern technology has great interring on building relationships between users on social networking. Therefore, it is possible to promote goods, advertisements and rumors among people easily. A trust network is created for each member. With this model, Members are represented as nodes in the graph, and trust relationships are represented between members according to the directed edges.This approach is based on the premise the neighbors with higher trust ratings are likely to agree with each other about the trustworthiness.The question here is: how can trust networks be built between users? This work proposed to build a social network based on the Mole algorithm. The user’s behavior is extracted to be use instead of user's rates in the original mole algorithm. The outcomes of this method were of a higher satisfactory level and a remarkably increased accuracy value by 15% over traditional Mole algorithm.


2000 ◽  
Vol 22 (1) ◽  
Author(s):  
Vincent Buskens ◽  
Jeroen Weesie

AbstractSufficiently frequent interaction between partners has been identified by, a.o., Axelrod as a more-or-less sufficient condition for stable cooperation. The underlying argument is that rational cooperation is ensured if short-term benefits from opportunistic behavior are offset by the long-term costs of sanctions imposed on the culprit. In this paper, we develop a model for ‘embedded trust’ in which a trustee interacts with a number of trustors who may communicate via a social network with each other about the behavior of the trustor. The analysis reconfirms the standard predictions about how the level of trust depends on the payoffs and shadow of the future. We provide new predictions both on between-network effects (“which network is more favorable for cooperation?”) and on within-network effects (“in what network position can you trust more?”).


Author(s):  
Юлия Владимировна Татаркова ◽  
Татьяна Николаевна Петрова ◽  
Олег Валериевич Судаков ◽  
Александр Юрьевич Гончаров ◽  
Ольга Николаевна Крюкова

В настоящей статье представлен обзор основных решений, доступных сегодня для формирования как краткосрочных, так и долгосрочных проекций заболеваемости болезней глаза и его придаточного аппарата в студенческой среде. С другой стороны, существует ряд проблем, связанных с многообразием факторов, влияющих на заболеваемость, статистической необоснованностью и противоречивостью имеющихся результатов анализа данных. Представлены результаты математического моделирования зависимости показателя заболеваемости от наиболее влиятельных факторов образовательной и социальной среды. Перечислены важнейшие направления разработки математических моделей распространения заболеваемости. С помощью разработанного программного комплекса проведена серия вычислительных экспериментов по оценке и прогнозированию заболеваемости обучающихся в вузах разного профиля. Показана эффективность применения методики многовариантного моделирования и прогнозирования, указаны их ограничения и возможности практического применения. По расположению обобщенной области благоприятного прогноза в факторном пространстве можно определить время воздействия неблагоприятных для зрения факторов, которое должно составлять не более 10 ... 11 часов в сутки, количество профилактических мероприятий должно составлять не менее 3 ... 4. При этом риск развития миопии составит не более 0,4, вероятность усталости глаз за компьютером составит не более 0,4, вероятность дискомфорта глаз на занятиях составит не более 0,15. Исходя из характера прогноза, определяется длительность диспансерного наблюдения, а также потребность профилактических мероприятий по устранению или ослаблению действия неблагоприятно влияющих социально-гигиенических и медико-биологических факторов конкретного больного. Использование прогностической матрицы в практическом здравоохранении позволяет существенно улучшить работу по профилактике офтальмологической заболеваемости и является одним из эффективных мероприятий диспансеризации студенческой молодежи, так как дает возможность выделить из числа обучающихся группу с высоким риском неблагоприятного исхода заболевания This article provides an overview of the main solutions available today for the formation of both short-term and long-term projections of the incidence of eye diseases and its adnexa in the student environment. On the other hand, there are a number of problems associated with a variety of factors affecting the incidence, statistical unreasonability and inconsistency of the available data analysis results. The results of mathematical modeling of the dependence of the incidence rate on the most influential factors of the educational and social environment are presented. The most important areas of developing mathematical models for the spread of morbidity are listed. With the help of the developed software package, a series of computational experiments was carried out to assess and predict the incidence of students in universities of various profiles. The effectiveness of the application of multivariate modeling and forecasting methods is shown, their limitations and practical application possibilities are indicated. By the location of the generalized region of favorable prognosis in the factor space, it is possible to determine the exposure time of factors unfavorable for vision, which should be no more than 10 ... 11 hours a day, the number of preventive measures should be at least 3 ... 4. At the same time, the risk of development myopia will be no more than 0.4, the probability of eye fatigue at the computer will be no more than 0.4, the likelihood of eye discomfort in the classroom will be no more than 0.15. Based on the nature of the forecast, the duration of the follow-up observation is determined, as well as the need for preventive measures to eliminate or weaken the action of adverse social, hygienic and biomedical factors of a particular patient. The use of the prognostic matrix in practical health care can significantly improve the work on the prevention of ophthalmic morbidity and is one of the effective medical examinations for students, since it makes it possible to distinguish among the students a group with a high risk of an unfavorable outcome of the disease


Author(s):  
Joseph Nelson Siewe Fodjo ◽  
Leonard Ngarka ◽  
Wepnyu Y. Njamnshi ◽  
Leonard N. Nfor ◽  
Michel K. Mengnjo ◽  
...  

Since March 2020, the Cameroonian government implemented nationwide measures to stall COVID-19 transmission. However, little is known about how well these unprecedented measures are being observed as the pandemic evolves. We conducted a six-month online survey to assess the preventive behaviour of Cameroonian adults during the COVID-19 outbreak. A five-point adherence score was constructed based on self-reported observance of the following preventive measures: physical distancing, face mask use, hand hygiene, not touching one’s face, and covering the mouth when coughing or sneezing. Predictors of adherence were investigated using ordinal logistic regression models. Of the 7381 responses received from all ten regions, 73.3% were from male respondents and overall mean age was 32.8 ± 10.8 years. Overall mean adherence score was 3.96 ± 1.11 on a scale of 0–5. Mean weekly adherence scores were initially high, but gradually decreased over time accompanied by increasing incidence of COVID-19 during the last study weeks. Predictors for higher adherence included higher age, receiving COVID-19 information from health personnel, and agreeing with the necessity of lockdown measures. Meanwhile, experiencing flu-like symptoms was associated with poor adherence. Continuous observance of preventive measures should be encouraged among Cameroonians in the medium- to long-term to avoid a resurgence in COVID-19 infections.


Viruses ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 248
Author(s):  
Noemi Messmer ◽  
Patricia Bohnert ◽  
Stefan Schumacher ◽  
René Fuchs

Viral diseases in viticulture lead to annual losses in the quantity and quality of grape production. Since no direct control measures are available in practice, preventive measures are taken to keep the vines healthy. These include, for example, the testing of propagation material for viruses such as Arabis mosaic virus (ArMV), Grapevine fanleaf virus (GFLV) or Grapevine leafroll-associated virus 1 (GLRaV-1) and 3 (GLRaV-3). As long-term investigations have shown, GLRaV-1 (2.1%) occurs most frequently in southwestern German wine-growing regions, whereas GLRaV-3 (<0.1%) is almost never found. However, tests conducted over 12 years indicate that there is no general decline in virus-infected planting material. Thus, it can be assumed that a spread of the viruses via corresponding vectors still takes place unhindered. Beyond the examinations regulated within the German Wine Growing Ordinance, one-time tests were carried out on Grapevine Pinot gris virus (GPGV). This analysis showed that GPGV was found in 17.2% of the samples.


2021 ◽  
pp. 002076402110175
Author(s):  
Roberto Rusca ◽  
Ike-Foster Onwuchekwa ◽  
Catherine Kinane ◽  
Douglas MacInnes

Background: Relationships are vital to recovery however, there is uncertainty whether users have different types of social networks in different mental health settings and how these networks may impact on users’ wellbeing. Aims: To compare the social networks of people with long-term mental illness in the community with those of people in a general adult in-patient unit. Method: A sample of general adult in-patients with enduring mental health problems, aged between 18 and 65, was compared with a similar sample attending a general adult psychiatric clinic. A cross-sectional survey collected demographic data and information about participants’ social networks. Participants also completed the Short Warwick Edinburgh Mental Well-Being Scale to examine well-being and the Significant Others Scale to explore their social network support. Results: The study recruited 53 participants (25 living in the community and 28 current in-patients) with 339 named as important members of their social networks. Both groups recorded low numbers in their social networks though the community sample had a significantly greater number of social contacts (7.4 vs. 5.4), more monthly contacts with members of their network and significantly higher levels of social media use. The in-patient group reported greater levels of emotional and practical support from their network. Conclusions: People with serious and enduring mental health problems living in the community had a significantly greater number of people in their social network than those who were in-patients while the in-patient group reported greater levels of emotional and practical support from their network. Recommendations for future work have been made.


2021 ◽  
Vol 50 (Supplement_1) ◽  
pp. i7-i11
Author(s):  
S Rafnsson ◽  
A Maharani ◽  
G Tampubolon

Abstract Introduction Frequent social contact benefits cognition in later life although evidence is lacking on the potential importance of the modes chosen by older adults for interacting with others in their social network. Method 11,513 participants in the English Longitudinal Study of Ageing (ELSA) provided baseline information on hearing status and social contact mode and frequency of use. Multilevel growth curve models compared episodic memory (immediate and delayed recall) at baseline and long-term in participants who interacted frequently (offline only or offline and online combined), compared to infrequently, with others in their social network. Results Frequent offline (β = 0.29; p &lt; 0.05) and combined offline and online (β = 0.76; p &lt; 0.001) social interactions predicted better episodic memory after adjustment for multiple confounding factors. We observed positive long-term influences of combined offline and online interactions on memory in participants without hearing loss (β = 0.48, p = 0.001) but not of strictly offline interactions (β = 0.00, p = 0.970). In those with impaired hearing, long-term memory was positively influenced by both modes of engagement (offline only: β = 0.93, p &lt; 0.001; combined online and offline: β = 1.47, p &lt; 0.001). Sensitivity analyses confirmed the robustness of these findings. Conclusion Supplementing conventional social interactions with online communication modes may help older adults, especially those living with hearing loss, sustain, and benefit cognitively from, personal relationships.


1977 ◽  
Vol 53 (1) ◽  
pp. 75-80
Author(s):  
H. Taguchi ◽  
Z. Abdul-Cader ◽  
J. Perry ◽  
E. H. Reynolds ◽  
I. Chanarin

1. The isolated choroid plexus of the rabbit takes up 5-methyltetrahydrofolate from the incubation medium. 2. Other folate analogues (pteroylglutamic acid, methotrexate, 5-formyltetrahydrofolate = folinic acid) inhibited the uptake of 5-methyltetrahydrofolate. 3. The uptake of 5-methyltetrahydrofolate was inhibited by low temperature, anaerobic conditions and dinitrophenol. 4. The anticonvulsant drugs, diphenylhydantoin and phenobarbital, had no effect on 5-methyltetrahydrofolate uptake. 5. The inhibitory effect of pteroylglutamic acid on the uptake of 5-methyltetrahydrofolate by the choroid plexus may explain the effect of long-term folic acid therapy in aggravating vitamin B12 neuropathy in pernicious anaemia.


1993 ◽  
Vol 137 (2) ◽  
pp. 247-NP ◽  
Author(s):  
H. F. Urbanski ◽  
M. M. Fahy ◽  
P. M. Collins

ABSTRACT The influence of excitatory amino acids (EAAs) on reproductive neuroendocrine function was investigated in adult male Syrian hamsters of the LSH/Ss Lak strain. Before the study, the animals were maintained in a sexually regressed condition, under short days (SD) and subsequently were either transferred to long days (LD) or kept under SD, for a further 4 weeks. In the former group, photostimulation produced a predictable elevation in the hypophysial contents and serum concentrations of FSH and LH. This was accompanied by an increase in testicular size, an elevation in serum testosterone levels and an increase in spermatogenic activity; the SD hamsters remained sexually quiescent throughout the study. In contrast, SD hamsters that were given daily injections of the EAA agonist, N-methyl-d,l-aspartate (NMA: 50 mg/kg body weight, s.c.), showed stimulatory responses that were generally even more pronounced than those shown by the LD group. Surprisingly, an identical NMA treatment paradigm failed to cause a similar activation of the reproductive axis in LD hamsters that were given daily afternoon injections of melatonin (25 μg, s.c), even though the inhibitory effect of this melatonin treatment is generally regarded as being comparable with that produced by exposure to SD. Although EAAs can acutely stimulate the neurocircuitry that controls LH-releasing hormone secretion, the present findings suggest that EAAs might also exert a long-term stimulatory action by acting further upstream in the photoneuroendocrine pathway. Journal of Endocrinology (1993) 137, 247–252


1993 ◽  
Vol 53 (3) ◽  
pp. 206-209 ◽  
Author(s):  
Kohei Notoya ◽  
Keiji Yoshida ◽  
Shigehisa Taketomi ◽  
Iwao Yamazaki ◽  
Masayoshi Kumegawa

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