scholarly journals Evolution of social learning when high expected payoffs are associated with high risk of failure

2011 ◽  
Vol 8 (64) ◽  
pp. 1604-1615 ◽  
Author(s):  
Michal Arbilly ◽  
Uzi Motro ◽  
Marcus W. Feldman ◽  
Arnon Lotem

In an environment where the availability of resources sought by a forager varies greatly, individual foraging is likely to be associated with a high risk of failure. Foragers that learn where the best sources of food are located are likely to develop risk aversion, causing them to avoid the patches that are in fact the best; the result is sub-optimal behaviour. Yet, foragers living in a group may not only learn by themselves, but also by observing others. Using evolutionary agent-based computer simulations of a social foraging game, we show that in an environment where the most productive resources occur with the lowest probability, socially acquired information is strongly favoured over individual experience. While social learning is usually regarded as beneficial because it filters out maladaptive behaviours, the advantage of social learning in a risky environment stems from the fact that it allows risk aversion to be circumvented and the best food source to be revisited despite repeated failures. Our results demonstrate that the consequences of individual risk aversion may be better understood within a social context and suggest one possible explanation for the strong preference for social information over individual experience often observed in both humans and animals.

Author(s):  
N.V. Rudakov ◽  
N.A. Penyevskaya ◽  
D.A. Saveliev ◽  
S.A. Rudakova ◽  
C.V. Shtrek ◽  
...  

Research objective. Differentiation of natural focal areas of Western Siberia by integral incidence rates of tick-borne infectious diseases for determination of the strategy and tactics of their comprehensive prevention. Materials and methods. A retrospective analysis of official statistics for the period 2002-2018 for eight sub-federal units in the context of administrative territories was carried out. The criteria of differentiation were determined by means of three evaluation scales, including long-term mean rates of tick-borne encephalitis, tick-borne borreliosis, and Siberian tick-borne typhus. As a scale gradation tool, we used the number of sample elements between the confidence boundaries of the median. The integral assessment was carried out by the sum of points corresponding to the incidence rates for each of the analyzed infections. Results. The areas of low, medium, above average, high and very high risk of tick-borne infectious diseases were determined. Recommendations on the choice of prevention strategy and tactics were given. In areas of very high and high incidence rates, a combination of population-based and individual prevention strategies is preferable while in other areas a combination of high-risk and individual strategies is recommended. Discussion. Epidemiologic zoning should be the basis of a risk-based approach to determining optimal volumes and directions of preventive measures against natural focal infections. It is necessary to improve the means and methods of determining the individual risk of getting infected and developing tick-borne infectious diseases in case of bites, in view of mixed infection of vectors, as well as methods of post-exposure disease prevention (preventive therapy).


Cancers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 2808
Author(s):  
Tzong-Yun Tsai ◽  
Jeng-Fu You ◽  
Yu-Jen Hsu ◽  
Jing-Rong Jhuang ◽  
Yih-Jong Chern ◽  
...  

(1) Background: The aim of this study was to develop a prediction model for assessing individual mPC risk in patients with pT4 colon cancer. Methods: A total of 2003 patients with pT4 colon cancer undergoing R0 resection were categorized into the training or testing set. Based on the training set, 2044 Cox prediction models were developed. Next, models with the maximal C-index and minimal prediction error were selected. The final model was then validated based on the testing set using a time-dependent area under the curve and Brier score, and a scoring system was developed. Patients were stratified into the high- or low-risk group by their risk score, with the cut-off points determined by a classification and regression tree (CART). (2) Results: The five candidate predictors were tumor location, preoperative carcinoembryonic antigen value, histologic type, T stage and nodal stage. Based on the CART, patients were categorized into the low-risk or high-risk groups. The model has high predictive accuracy (prediction error ≤5%) and good discrimination ability (area under the curve >0.7). (3) Conclusions: The prediction model quantifies individual risk and is feasible for selecting patients with pT4 colon cancer who are at high risk of developing mPC.


2021 ◽  
pp. 019459982110231
Author(s):  
Ying Kou ◽  
Guohua Shen ◽  
Zhuzhong Cheng ◽  
Anren Kuang

Objective We systematically investigated the predictive value of gross extranodal extension (gENE) for differentiated thyroid carcinoma persistence/recurrence. Study Design Retrospective study. Setting A tertiary care hospital. Methods This study was divided into 2 groups according to gENE status: the gENE group and non-gENE group. We compared the disease persistence/recurrence rates of these 2 groups in the entire cohort and by individual risk group (intermediate/high risk), analyzed whether gENE was an independent risk factor for disease persistence/recurrence, and explored the impact of gENE-specific features on disease persistence/recurrence. Results There were 989 patients who satisfied the inclusion criteria: 57 patients in the gENE group and 932 in the non-gENE group. The disease persistence/recurrence rate of the gENE group was higher than that of the non-gENE group in the entire cohort and by individual risk group ( P < .05 for each). Unexpectedly, the outcomes of the gENE group with intermediate risk were similar to those of the non-gENE group with high risk ( P = .72). For the entire cohort, gENE was an independent predictor for disease persistence/recurrence (odds ratio, 2.89; 95% CI, 1.39-6.00; P = .005). Specific features of gENE ( P > .05 for each) were not related to disease persistence/recurrence. Conclusion Patients with gENE and intermediate risk might be regraded as high risk. Specific features of gENE have no impact on disease persistence/recurrence.


2021 ◽  
Vol 13 (10) ◽  
pp. 5411
Author(s):  
Elisabeth Bloder ◽  
Georg Jäger

Traffic and transportation are main contributors to the global CO2 emissions and resulting climate change. Especially in urban areas, traffic flow is not optimal and thus offers possibilities to reduce emissions. The concept of a Green Wave, i.e., the coordinated switching of traffic lights in order to favor a single direction and reduce congestion, is often discussed as a simple mechanism to avoid breaking and accelerating, thereby reducing fuel consumption. On the other hand, making car use more attractive might also increase emissions. In this study, we use an agent-based model to investigate the benefit of a Green Wave in order to find out whether it can outweigh the effects of increased car use. We find that although the Green Wave has the potential to reduce emissions, there is also a high risk of heaving a net increase in emissions, depending on the specifics of the traffic system.


2017 ◽  
Vol 20 (1) ◽  
pp. 21930 ◽  
Author(s):  
Ragna S. Boerma ◽  
Torsak Bunupuradah ◽  
Dorothy Dow ◽  
Joseph Fokam ◽  
Azar Kariminia ◽  
...  

2017 ◽  
Vol 18 (6) ◽  
pp. 296-300 ◽  
Author(s):  
Lasantha Ratnayake ◽  
Amy Harris ◽  
Doreen Ko ◽  
Linda Hawtin

Background: Incidence of carbapenemase-producing enterobacteriaceae (CPE) in the UK is increasing. In 2013, Public Health England (PHE) published a toolkit to control spread of CPE within healthcare settings. Aim: To assess compliance to hospital CPE policy (adapted from PHE) in the identification, isolation and screening of suspected CPE patients. Methods: Admission booklets of 150 patients were evaluated to see whether the relevant section had been completed to identify high-risk CPE patients. Where necessary, patients were interviewed or their GPs were contacted to assess their CPE risk. Additionally, 28 patients screened for CPE were audited to assess compliance to screening and isolation. Findings: Only 23 patients out of 147 (15.6%) were risk assessed on admission. Risk status of 27 (18.4%) patients could not be assessed due to lack of data. Fifteen patients out of 28 (54%) screened for CPE were identified and isolated on admission. Ten out of 19 patients (53%) had three screens 48 h apart. Discussion: This audit highlights difficulties in screening based on individual risk factors as the majority of patients were not screened on admission and documentation on isolation and screening was poor. More needs to be done to raise awareness of the requirements for routine assessment, isolation and screening.


2021 ◽  
Vol 2021 ◽  
pp. 1-32
Author(s):  
Yue Wu ◽  
Xi Zhang ◽  
Xian Wei ◽  
Huan Feng ◽  
Bintao Hu ◽  
...  

Mitochondria not only are the main source of ATP synthesis but also regulate cellular redox balance and calcium homeostasis. Its dysfunction can lead to a variety of diseases and promote cancer and metastasis. In this study, we aimed to explore the molecular characteristics and prognostic significance of mitochondrial genes (MTGs) related to oxidative stress in clear cell renal cell carcinoma (ccRCC). A total of 75 differentially expressed MTGs were analyzed from The Cancer Genome Atlas (TCGA) database, including 46 upregulated and 29 downregulated MTGs. Further analysis screened 6 prognostic-related MTGs (ACAD11, ACADSB, BID, PYCR1, SLC25A27, and STAR) and was used to develop a signature. Kaplan-Meier survival and receiver operating characteristic (ROC) curve analyses showed that the signature could accurately distinguish patients with poor prognosis and had good individual risk stratification and prognostic potential. Stratified analysis based on different clinical variables indicated that the signature could be used to evaluate tumor progression in ccRCC. Moreover, we found that there were significant differences in immune cell infiltration between the low- and high-risk groups based on the signature and that ccRCC patients in the low-risk group responded better to immunotherapy than those in the high-risk group (46.59% vs 35.34%, P = 0.008 ). We also found that the expression levels of these prognostic MTGs were significantly associated with drug sensitivity in multiple ccRCC cell lines. Our study for the first time elucidates the biological function and prognostic significance of mitochondrial molecules associated with oxidative stress and provides a new protocol for evaluating treatment strategies targeting mitochondria in ccRCC patients.


Fire Safety ◽  
2021 ◽  
Vol 38 ◽  
pp. 24-31
Author(s):  
Yu. Rudyk ◽  
O. Nazarovets ◽  
I. Golovatchuk ◽  
N. Beznos

Introduction. Today requires the introduction and arrangement of modern enterprises automation of the technological process using various electronic and electrical equipment. The breakdown of one sensor leads to a stoppage of the technical process and thousands of losses. This equipment is sensitive to impulse overvoltages that occur for various reasons, as well as when hit by lightning. There is a misconception that the danger of lightning arises only when struck directly, forgetting about the socalled secondary phenomena, namely electromagnetic and electrostatic pulses. Pulse overvoltage is a short-term increase in voltage above the allowable value. Lightning protection systems are designed and designed to protect objects from dangerous lightning.Purpose. Given the automation of the process and the saturation of boilers with electronic and electrical equipment, there is a high risk of lightning and high potentials, which can lead to large-scale accidents. The purpose of this article is to validate the risk indicators for the boiler environment that occur during a thunderstorm.Methods. The use of various methods of calculation, assessment and ordering of risks during the design and layout of the system allows to implementation system lightning protection of buildings, equipment and people. General principles of risk assessment for the boiler environment must take into account: risk and determine the need for protection; the contribution of various risk components to the overall risk; the effect of various protection measures to reduce risk; selection of protection measures taking into account their economic efficiency.Results. Neglecting the high risk of a dangerous event leads to excessive damage and m irreparable losses, with which a person or community will not be able to achieve sustainable development. Therefore, it is a comprehensive, systematic approach to achieving safety, starting from the assessment stage, should take into account both the characteristics of the hazard, including a fire in the relevant facilities, and personal, the individual risk of death or injury. Lightning is an unpredictable natural event, no one in the world fully understands the mechanism of lightning and it is impossible to provide 100% protection under any circumstances under any standardization. For this purpose, the following calculations are given: loss of human life, including injuries; loss of the ability to provide public services; losses of cultural heritage and economic value of the building (structure) and economic losses required for the installation and operation of the system. Based on the obtained data, it is seen how the reduction of each risk is achieved depending on the proposed solution and the economic effect in general.Conclusion. Statistics on deaths and injuries from lightning hazards, losses from damage to property, buildings and struc-tures confirm that in risk assessment, which is standardized in DSTU EN 62305-2, it is necessary to introduce a methodology that would meet the conditions of Ukraine. The arrangement of the lightning protection system depends on the risk assessment, the reaction of the owner, the influence of control bodies. Therefore, it is important to decide on fire protection measures in lightning risk assessment procedures, but it can also be taken regardless of the results of the risk assessment where there is a desire to avoid unacceptable risk. Equipment that is often associated with two different services, e.g. power lines and data lines suffer a lot of surge damage. This case is not covered by the RX risk component. However, appropriate protection measures can be selected and established (see IEC 62305-4).


1983 ◽  
Vol 15 (11) ◽  
pp. 1489-1500
Author(s):  
J R Bohland ◽  
J Gist

The research tests the proposition that risk aversion is a basic goal of bureaucratic decisionmaking within the Urban Development Action Grant Program (UDAGP) and that this type of behavior influences the spatial distribution of UDAGP grants. The results demonstrate that risk aversion is evident and that it tends to divert funds away from those cities with high distress. Political accommodation is shown to be evident in cases where bureaucrats are faced with high-risk projects. This accommodation influences the spatial distribution of UDAGP funds.


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