scholarly journals Managing uncertainty: information and insurance under the risk of starvation

2002 ◽  
Vol 357 (1427) ◽  
pp. 1519-1526 ◽  
Author(s):  
Sasha R. X. Dall ◽  
Rufus A. Johnstone
Keyword(s):  
Value Of Information ◽  
Food Sources ◽  
Initial Increase ◽  
Energy Reserves ◽  
Relative Value ◽  
Uncertainty Information ◽  
Starvation Risk ◽  
Overall Risk

In an uncertain world, animals face both unexpected opportunities and danger. Such outcomes can select for two potential strategies: collecting information to reduce uncertainty, or insuring against it. We investigate the relative value of information and insurance (energy reserves) under starvation risk by offering model foragers a choice between constant and varying food sources over finite foraging bouts. We show that sampling the variable option (choosing it when it is not expected to be good) should decline both with lower reserves and late in foraging bouts; in order to be able to reap the reduction in uncertainty associated with exploiting a variable resource effectively, foragers must be able to afford and compensate for an initial increase in the risk of an energetic shortfall associated with choosing the option when it is bad. Consequently, expected exploitation of the varying option increases as it becomes less variable, and when the overall risk of energetic shortfall is reduced. In addition, little activity on the variable alternative is expected until reserves are built up early in a foraging bout. This indicates that gathering information is a luxury while insurance is a necessity, at least when foraging on stochastic and variable food under the risk of starvation.

scholarly journals Mass-dependent predation risk and lethal dolphin–porpoise interactions

2007 ◽  
Vol 274 (1625) ◽  
pp. 2587-2593 ◽  
Author(s):  
R MacLeod ◽  
C.D MacLeod ◽  
J.A Learmonth ◽  
P.D Jepson ◽  
R.J Reid ◽  
...  
Keyword(s):  
Predation Risk ◽  
Bottlenose Dolphins ◽  
Flight Performance ◽  
Energy Reserves ◽  
Trade Off ◽  
Fat Reserves ◽  
Ecological Principle ◽  
Mass Dependent ◽  
Starvation Risk ◽  
Individual Mass

In small birds, mass-dependent predation risk (MDPR) is known to make the trade-off between avoiding starvation and avoiding predation dependent on individual mass. This occurs because carrying increased fat reserves not only reduces starvation risk but also results in a higher predation risk due to reduced escape flight performance and/or the increased foraging exposure needed to maintain a higher body mass. In principle, the theory of MDPR could also apply to any animal capable of storing energy reserves to reduce starvation and whose escape performance decreases with increasing mass. We used a unique situation along certain parts of coastal Britain, where harbour porpoises ( Phocoena phocoena ) are pursued and killed but crucially not eaten by bottlenose dolphins ( Tursiops truncatus ), to investigate whether a MDPR effect can occur in non-avian species. We show that where high levels of dolphin ‘predation’ occur, porpoises carry significantly less energy reserves than would otherwise be expected and this equates to reducing by approximately 37% the length of time that a porpoise could survive without feeding. These results provide the first evidence that a mass-dependent starvation–predation risk trade-off may be a general ecological principle that can apply to widely different animal types rather than, as is currently thought, only to birds.

scholarly journals Determination of structural and damage detection system influencing parameters on the value of information

2020 ◽  
pp. 147592171990091 ◽  
Author(s):  
Lijia Long ◽  
Michael Döhler ◽  
Sebastian Thöns
Keyword(s):  
Service Life ◽  
Damage Detection ◽  
Value Of Information ◽  
Type I Error ◽  
Detection System ◽  
System Model ◽  
Type I ◽  
Information Analysis ◽  
Relative Value ◽  
Influencing Parameters

A method to determine the influencing parameters of a structural and damage detection system is proposed based on the value of information analysis. The value of information analysis utilizes the Bayesian pre-posterior decision theory to quantify the value of damage detection system for the structural integrity management during service life. First, the influencing parameters of the structural system, such as deterioration type and rate are introduced for the performance of the prior probabilistic system model. Then the influencing parameters on the damage detection system performance, including number of sensors, sensor locations, measurement noise, and the Type-I error are investigated. The pre-posterior probabilistic model is computed utilizing the Bayes’ theorem to update the prior system model with the damage indication information. Finally, the value of damage detection system is quantified as the difference between the maximum utility obtained in pre-posterior and prior analysis based on the decision tree analysis, comprising structural probabilistic models, consequences, as well as benefit and costs analysis associated with and without monitoring. With the developed approach, a case study on a statically determinate Pratt truss bridge girder is carried out to validate the method. The analysis shows that the deterioration rate is the most sensitive parameter on the effect of relative value of information over the whole service life. Furthermore, it shows that more sensors do not necessarily lead to a higher relative value of information; only specific sensor locations near the highest utilized components lead to a high relative value of information; measurement noise and the Type-I error should be controlled and be as small as possible. An optimal sensor employment with highest relative value of information is found. Moreover, it is found that the proposed method can be a powerful tool to develop optimal service life maintenance strategies—before implementation—for similar bridges and to optimize the damage detection system settings and sensor configuration for minimum expected costs and risks.

scholarly journals Which species discovers novel food sources first? A camera trap study in a natural environment

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Christoph Randler
Keyword(s):  
Food Source ◽  
Parus Major ◽  
Camera Trap ◽  
Camera Traps ◽  
Food Sources ◽  
Source Population ◽  
Circadian Pattern ◽  
Woodland Birds ◽  
Novel Food ◽  
Starvation Risk

AbstractBirds underlie a predation-starvation risk, and foraging should show a diurnal/circadian pattern. Camera traps were used to study visitation patterns and discovery of a novel food source in woodland birds in SW Germany. A total of 18 species occurred at feeders with nine of them being exploratory species. Great Tits (Parus major) discovered novel food sources first in most instances, and first discoveries occurred on average at 10:38, while it took 97 h for the first detection of the food source. Population size was correlated with discovery. The study supports the predation-starvation risk hypothesis with discovery of food sources in the morning.

scholarly journals Familial genetic risks: how can we better navigate patient confidentiality and appropriate risk disclosure to relatives?

2019 ◽  
Vol 45 (8) ◽  
pp. 504-507 ◽  
Author(s):  
Edward S Dove ◽  
Vicky Chico ◽  
Michael Fay ◽  
Graeme Laurie ◽  
Anneke M Lucassen ◽  
...  
Keyword(s):  
Value Of Information ◽  
Healthcare Professionals ◽  
Family Members ◽  
Duty Of Care ◽  
Risk Disclosure ◽  
High Profile ◽  
Relative Value ◽  
Genetic Risks ◽  
Legal Duty ◽  
Close Relatives

This article investigates a high-profile and ongoing dilemma for healthcare professionals (HCPs), namely whether the existence of a (legal) duty of care to genetic relatives of a patient is a help or a hindrance in deciding what to do in cases where a patient’s genetic information may have relevance to the health of the patient’s family members. The English case ABC v St George’s Healthcare NHS Trust and others considered if a duty of confidentiality owed to the patient and a putative duty of care to the patient’s close relatives could coexist in this context. This article examines whether embracing the concept of coexisting duties could enable HCPs to respect duties in line with their clinical judgement, thereby providing legal support and clarity to professionals to allow them to provide the best possible genetics service to both the patient and their family. We argue that these dual duties, framed as a novel, composite duty to consider the interests of genetic relatives, could allow HCPs to exercise and act on their professional judgements about the relative value of information to family members, without fears of liability for negligence or breach of confidence.

scholarly journals Value of Information in Bayesian Routing Games

2020 ◽  
Author(s):  
Manxi Wu ◽  
Saurabh Amin ◽  
Asuman E. Ozdaglar
Keyword(s):  
Market Share ◽  
Value Of Information ◽  
Traffic Information ◽  
Theoretic Approach ◽  
Relative Value ◽  
Game Theoretic ◽  
Route Choices ◽  
Routing Games ◽  
Game Theoretic Approach

Over the years, travelers are increasingly relying on navigation services to inform their route choices and save time. How much value—in terms of saved time—can these services indeed provide to their users? The answer is not as simple as one may think because the value of traffic information not only depends on its accuracy, but also on how widely it is shared among travelers. For instance, information on an incident has the highest value for a traveler when the traveler is the only person who knows about it and takes a detour. However, this information becomes less valuable when it is shared with more travelers, who may take the same detour and cause congestion. Our work uses a game-theoretic approach to analyze how the relative value of information provided by different navigation services changes with their market share and how travelers may choose from different available services.

EELS white line intensities calculated for the 3d and 4d metals

1989 ◽  
Vol 47 ◽  
pp. 388-389
Author(s):  
C. C. Ahn ◽  
D. H. Pearson ◽  
P. Rez ◽  
B. Fultz
Keyword(s):  
Experimental Data ◽  
Line Intensity ◽  
Transition Probabilities ◽  
Initial Increase ◽  
White Line ◽  
Hartree Fock ◽  
Line Intensities ◽  
Integrated Intensity ◽  
X Ray Absorption ◽  
The Continuum

Previous experimental measurements of the total white line intensities from L2,3 energy loss spectra of 3d transition metals reported a linear dependence of the white line intensity on 3d occupancy. These results are inconsistent, however, with behavior inferred from relativistic one electron Dirac-Fock calculations, which show an initial increase followed by a decrease of total white line intensity across the 3d series. This inconsistency with experimental data is especially puzzling in light of work by Thole, et al., which successfully calculates x-ray absorption spectra of the lanthanide M4,5 white lines by employing a less rigorous Hartree-Fock calculation with relativistic corrections based on the work of Cowan. When restricted to transitions allowed by dipole selection rules, the calculated spectra of the lanthanide M4,5 white lines show a decreasing intensity as a function of Z that was consistent with the available experimental data.Here we report the results of Dirac-Fock calculations of the L2,3 white lines of the 3d and 4d elements, and compare the results to the experimental work of Pearson et al. In a previous study, similar calculations helped to account for the non-statistical behavior of L3/L2 ratios of the 3d metals. We assumed that all metals had a single 4s electron. Because these calculations provide absolute transition probabilities, to compare the calculated white line intensities to the experimental data, we normalized the calculated intensities to the intensity of the continuum above the L3 edges. The continuum intensity was obtained by Hartree-Slater calculations, and the normalization factor for the white line intensities was the integrated intensity in an energy window of fixed width and position above the L3 edge of each element.

Talk or Walk? Gait Speed over Self-Report in Association with Cognitive Speed in Healthy Older Adults

GeroPsych ◽  
2019 ◽  
Vol 32 (1) ◽  
pp. 41-52
Author(s):  
Matthew C. Costello ◽  
Shane J. Sizemore ◽  
Kimberly E. O’Brien ◽  
Lydia K. Manning
Keyword(s):  
Older Adults ◽  
Older Adult ◽  
Gait Speed ◽  
Well Being ◽  
Self Report ◽  
Subjective Report ◽  
Healthy Older Adults ◽  
Relative Value ◽  
Cognitive Speed ◽  
Age Range

Abstract. This study explores the relative value of both subjectively reported cognitive speed and gait speed in association with objectively derived cognitive speed. It also explores how these factors are affected by psychological and physical well-being. A group of 90 cognitively healthy older adults ( M = 73.38, SD = 8.06 years, range = 60–89 years) were tested in a three-task cognitive battery to determine objective cognitive speed as well as measures of gait speed, well-being, and subjective cognitive speed. Analyses indicated that gait speed was associated with objective cognitive speed to a greater degree than was subjective report, the latter being more closely related to well-being than to objective cognitive speed. These results were largely invariant across the 30-year age range of our older adult sample.

Guilty Pleasure No More

2017 ◽  
Vol 29 (3) ◽  
pp. 126-136 ◽  
Author(s):  
Robin L. Nabi ◽  
Debora Pérez Torres ◽  
Abby Prestin
Keyword(s):  
Stress Management ◽  
Perceived Stress ◽  
Media Use ◽  
Well Being ◽  
Breast Cancer Patients ◽  
Positive Role ◽  
Individual Difference Variables ◽  
Relative Value ◽  
Management Techniques ◽  
Managing Stress

Abstract. Despite the substantial attention paid to stress management in the extant coping literature, media use has been surprisingly overlooked as a strategy worthy of close examination. Although media scholars have suggested media use may be driven by a need to relax, related research has been sporadic and, until recently, disconnected from the larger conversation about stress management. The present research aimed to determine the relative value of media use within the broader range of coping strategies. Based on surveys of both students and breast cancer patients, media use emerged as one of the most frequently selected strategies for managing stress across a range of personality and individual difference variables. Further, heavier television consumers and those with higher perceived stress were also more likely to use media for coping purposes. Finally, those who choose media for stress management reported it to be an effective tool, although perhaps not as effective as other popular strategies. This research not only documents the centrality of media use in the corpus of stress management techniques, thus highlighting the value of academic inquiry into media-based coping, but it also offers evidence supporting the positive role media use can play in promoting psychological well-being.

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