scholarly journals Intrinsic and environmental factors modulating autonomous robotic search under high uncertainty

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Carlos Garcia-Saura ◽  
Eduardo Serrano ◽  
Francisco B. Rodriguez ◽  
Pablo Varona
Keyword(s):  
Environmental Factors ◽  
Deep Ocean ◽  
Reference Points ◽  
Extrinsic Factors ◽  
Knowledge Based ◽  
Uncertainty Sources ◽  
Lévy Walks ◽  
Temporal Aspects ◽  
Autonomous Search ◽  
High Uncertainty

AbstractAutonomous robotic search problems deal with different levels of uncertainty. When uncertainty is low, deterministic strategies employing available knowledge result in most effective searches. However, there are domains where uncertainty is always high since information about robot location, environment boundaries or precise reference points is unattainable, e.g., in cave, deep ocean, planetary exploration, or upon sensor or communications impairment. Furthermore, latency regarding when search targets move, appear or disappear add to uncertainty sources. Here we study intrinsic and environmental factors that affect low-informed robotic search based on diffusive Brownian, naive ballistic, and superdiffusive strategies (Lévy walks), and in particular, the effectiveness of their random exploration. Representative strategies were evaluated considering both intrinsic (motion drift, energy or memory limitations) and extrinsic factors (obstacles and search boundaries). Our results point towards minimum-knowledge based modulation approaches that can adjust distinct spatial and temporal aspects of random exploration to lead to effective autonomous search under uncertainty.

Environmental Factors Determining the Growth and Development of Whole Bone Transplants

Development ◽  
1963 ◽  
Vol 11 (3) ◽  
pp. 537-547
Author(s):  
R. Mawdsley ◽  
G. Ainsworth Harrison
Keyword(s):  
Environmental Factors ◽  
Growth And Development ◽  
Environmental Temperature ◽  
Skeletal Growth ◽  
Extrinsic Factors ◽  
Intrinsic Factors ◽  
Functional Sites ◽  
Bone Transplants

Intrinsic factors are known to play an integral part in skeletal morphogenesis (Willis, 1936; Fell, 1956). In particular, it has recently been demonstrated that the humerus (Felts, 1959) and femur (Chalmers & Ray, 1962) of the mouse develop, grow, and in many ways preserve their distinctive form when transplanted to non-functional sites. However, it is also widely recognized that internal and external environmental factors are important in determining skeletal growth and form (Sissons, 1956). The aim of this paper is to examine some of these extrinsic factors in terms of the effects of various types of host on the growth of subcutaneous transplants of the mouse humerus. The factors studied were environmental temperature, age and genotype including sex. It has been shown that the growth of the tail and foot of the mouse is influenced by environmental temperature, with higher temperatures producing longer extremities (Sumner, 1909; Harrison, Morton & Weiner, 1959).

scholarly journals Defining Post-COVID Symptoms (Post-Acute COVID, Long COVID, Persistent Post-COVID): An Integrative Classification

2021 ◽  
Vol 18 (5) ◽  
pp. 2621
Author(s):  
César Fernández-de-las-Peñas ◽  
Domingo Palacios-Ceña ◽  
Víctor Gómez-Mayordomo ◽  
María L. Cuadrado ◽  
Lidiane L. Florencio
Keyword(s):  
Reference Points ◽  
Extrinsic Factors ◽  
Multiple Systems ◽  
Relapsing Remitting ◽  
Underlying Mechanisms ◽  
Intrinsic And Extrinsic Factors

The pandemic of the coronavirus disease 2019 (COVID-19) has provoked a second pandemic, the “long-haulers”, i.e., individuals presenting with post-COVID symptoms. We propose that to determine the presence of post-COVID symptoms, symptoms should appear after the diagnosis of SARS-CoV-2 infection; however, this situation has some problems due to the fact that not all people infected by SARS-CoV-2 receive such diagnosis. Based on relapsing/remitting nature of post-COVID symptoms, the following integrative classification is proposed: potentially infection related-symptoms (up to 4–5 weeks), acute post-COVID symptoms (from week 5 to week 12), long post-COVID symptoms (from week 12 to week 24), and persistent post-COVID symptoms (lasting more than 24 weeks). The most important topic is to establish the time reference points. The classification also integrates predisposing intrinsic and extrinsic factors and hospitalization data which could promote post-COVID symptoms. The plethora of symptoms affecting multiple systems exhibited by “long-haulers” suggests the presence of different underlying mechanisms.

Incentive-based and knowledge-based theories of the firm: some recent developments

2010 ◽  
pp. 69-91
Author(s):  
Nicola Meccheri ◽  
Mario Morroni
Keyword(s):  
Critical Review ◽  
Dynamic Capabilities ◽  
Reference Points ◽  
Relational Contracts ◽  
Main Research ◽  
Knowledge Based ◽  
Recent Developments ◽  
Made In

The article presents a critical review of the advances made in incentive-based and knowledge-based theories of the firm. In particular, the authors explore some developments in the incentive-based approach regarding relational contracts and contracts as "reference points", while the evolution of knowledge-based theories has led us to focus on the interesting implications of the concept of dynamic capabilities. Finally, we investigate some recent attempts to bridge these two main research streams, which have long been considered to clash with rather than complement each other.

A- AND V-UNCERTAINTY: AN EXPLORATION ABOUT UNCERTAINTY MODELING FROM A KNOWLEDGE ENGINEERING PERSPECTIVE

2007 ◽  
Vol 16 (02) ◽  
pp. 161-194 ◽  
Author(s):  
PIETRO BARONI ◽  
GIOVANNI GUIDA ◽  
MASSIMILIANO GIACOMIN
Keyword(s):  
Domain Knowledge ◽  
Knowledge Engineering ◽  
Uncertainty Modeling ◽  
Uncertain Reasoning ◽  
Correct Treatment ◽  
Knowledge Based ◽  
Uncertainty Sources ◽  
Concrete Experience ◽  
The One ◽  
Uncertainty Models

This paper presents a concrete experience of Knowledge Engineering, which, starting from a specific problem which occurred during the development of ASTRA, a knowledge-based system for preventive diagnosis of power transformers, turned out to provide significant insights concerning modeling of uncertain knowledge. In particular, it was observed that there are (at least) two conceptually distinct types of uncertainty affecting knowledge, namely uncertainty about applicability (A-uncertainty, for short) and uncertainty about validity (V-uncertainty, for short), which are different in nature and play different roles in uncertain reasoning. The concepts of A- and V-uncertainty are applicable in any context where uncertainty affecting domain knowledge can be ascribed to two kinds of sources: on the one hand, the existence of exceptions, on the other hand, deep-rooted doubts about the foundations themselves of the relevant domain knowledge. The introduction of these concepts allows one to define articulated uncertainty models, supporting the representation of the reasoning mechanisms used by experts in domains where both such uncertainty sources are present. This general claim was confirmed by the experience developed with ASTRA, where the explicit representation and management of A- and V-uncertainty enabled the correct treatment of some critical diagnostic cases.

scholarly journals Perinatal and Early-Life Nutrition, Epigenetics, and Allergy

Nutrients ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 724
Author(s):  
Nathalie Acevedo ◽  
Bilal Alashkar Alhamwe ◽  
Luis Caraballo ◽  
Mei Ding ◽  
Antonio Ferrante ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Allergic Disease ◽  
Current Knowledge ◽  
Time Frame ◽  
Metabolic Reprogramming ◽  
Optimal Time ◽  
Epigenetic Mechanisms ◽  
Extrinsic Factors ◽  
The Impact ◽  
Insight Into

Epidemiological studies have shown a dramatic increase in the incidence and the prevalence of allergic diseases over the last several decades. Environmental triggers including risk factors (e.g., pollution), the loss of rural living conditions (e.g., farming conditions), and nutritional status (e.g., maternal, breastfeeding) are considered major contributors to this increase. The influences of these environmental factors are thought to be mediated by epigenetic mechanisms which are heritable, reversible, and biologically relevant biochemical modifications of the chromatin carrying the genetic information without changing the nucleotide sequence of the genome. An important feature characterizing epigenetically-mediated processes is the existence of a time frame where the induced effects are the strongest and therefore most crucial. This period between conception, pregnancy, and the first years of life (e.g., first 1000 days) is considered the optimal time for environmental factors, such as nutrition, to exert their beneficial epigenetic effects. In the current review, we discussed the impact of the exposure to bacteria, viruses, parasites, fungal components, microbiome metabolites, and specific nutritional components (e.g., polyunsaturated fatty acids (PUFA), vitamins, plant- and animal-derived microRNAs, breast milk) on the epigenetic patterns related to allergic manifestations. We gave insight into the epigenetic signature of bioactive milk components and the effects of specific nutrition on neonatal T cell development. Several lines of evidence suggest that atypical metabolic reprogramming induced by extrinsic factors such as allergens, viruses, pollutants, diet, or microbiome might drive cellular metabolic dysfunctions and defective immune responses in allergic disease. Therefore, we described the current knowledge on the relationship between immunometabolism and allergy mediated by epigenetic mechanisms. The knowledge as presented will give insight into epigenetic changes and the potential of maternal and post-natal nutrition on the development of allergic disease.

scholarly journals Environmental factors dominate over host genetics in shaping human gut microbiota composition

2017 ◽  
Author(s):  
Daphna Rothschild ◽  
Omer Weissbrod ◽  
Elad Barkan ◽  
Tal Korem ◽  
David Zeevi ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Human Genetics ◽  
Human Microbiome ◽  
Density Lipoprotein ◽  
Hdl Cholesterol ◽  
Nucleotide Polymorphisms ◽  
Human Gut ◽  
Extrinsic Factors ◽  
Host Genetics ◽  
Microbiome Composition

AbstractHuman gut microbiome composition is shaped by multiple host intrinsic and extrinsic factors, but the relative contribution of host genetic compared to environmental factors remains elusive. Here, we genotyped a cohort of 696 healthy individuals from several distinct ancestral origins and a relatively common environment, and demonstrate that there is no statistically significant association between microbiome composition and ethnicity, single nucleotide polymorphisms (SNPs), or overall genetic similarity, and that only 5 of 211 (2.4%) previously reported microbiome-SNP associations replicate in our cohort. In contrast, we find similarities in the microbiome composition of genetically unrelated individuals who share a household. We define the termbiome-explainabilityas the variance of a host phenotype explained by the microbiome after accounting for the contribution of human genetics. Consistent with our finding that microbiome and host genetics are largely independent, we find significant biome-explainability levels of 16-33% for body mass index (BMI), fasting glucose, high-density lipoprotein (HDL) cholesterol, waist circumference, waist-hip ratio (WHR), and lactose consumption. We further show that several human phenotypes can be predicted substantially more accurately when adding microbiome data to host genetics data, and that the contribution of both data sources to prediction accuracy is largely additive. Overall, our results suggest that human microbiome composition is dominated by environmental factors rather than by host genetics.

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