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In environments with scarce resources, adopting the right search strategy can make the difference between succeeding and failing, even between life and death. At different scales, this applies to molecular encounters in the cell cytoplasm, to animals looking for food or mates in natural landscapes, to rescuers during search and rescue operations in disaster zones, and to genetic computer algorithms exploring parameter spaces. When looking for sparse targets in a homogeneous environment, a combination of ballistic and diffusive steps is considered optimal; in particular, more ballistic Lévy flights with exponent [Formula: see text] are generally believed to optimize the search process. However, most search spaces present complex topographies. What is the best search strategy in these more realistic scenarios? Here, we show that the topography of the environment significantly alters the optimal search strategy toward less ballistic and more Brownian strategies. We consider an active particle performing a blind cruise search for nonregenerating sparse targets in a 2D space with steps drawn from a Lévy distribution with the exponent varying from [Formula: see text] to [Formula: see text] (Brownian). We show that, when boundaries, barriers, and obstacles are present, the optimal search strategy depends on the topography of the environment, with [Formula: see text] assuming intermediate values in the whole range under consideration. We interpret these findings using simple scaling arguments and discuss their robustness to varying searcher's size. Our results are relevant for search problems at different length scales from animal and human foraging to microswimmers' taxis to biochemical rates of reaction.
This article was published in the following journal.
Name: Proceedings of the National Academy of Sciences of the United States of America
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Dressings comprised of a self-adhesive matrix to which hydrophilic absorbent particles are embedded. The particles consist of CELLULOSE derivatives; calcium ALGINATES; PECTINS; or GELS. The utility is based on providing a moist environment for WOUND HEALING.
The illumination of an environment and the arrangement of lights to achieve an effect or optimal visibility. Its application is in domestic or in public settings and in medical and non-medical environments.
The systematic surveying, mapping, charting, and description of specific geographical sites, with reference to the physical features that were presumed to influence health and disease. Often associated with Hippocrates, the process became a significant part of public health investigation and epidemiological methodology, particularly between the 17th and 19th centuries. Medical topography should be differentiated from EPIDEMIOLOGY in that the former emphasizes geography whereas the latter emphasizes disease outbreaks. (Dr. James H. Cassedy, NLM History of Medicine Division)
The interactions of particles responsible for their scattering and transformations (decays and reactions). Because of interactions, an isolated particle may decay into other particles. Two particles passing near each other may transform, perhaps into the same particles but with changed momenta (elastic scattering) or into other particles (inelastic scattering). Interactions fall into three groups: strong, electromagnetic, and weak. (From McGraw-Hill Encyclopedia of Science & Technology, 7th ed)
A strategy for purchasing health care in a manner which will obtain maximum value for the price for the purchasers of the health care and the recipients. The concept was developed primarily by Alain Enthoven of Stanford University and promulgated by the Jackson Hole Group. The strategy depends on sponsors for groups of the population to be insured. The sponsor, in some cases a health alliance, acts as an intermediary between the group and competing provider groups (accountable health plans). The competition is price-based among annual premiums for a defined, standardized benefit package. (From Slee and Slee, Health Care Reform Terms, 1993)
Food is any substance consumed to provide nutritional support for the body. It is usually of plant or animal origin, and contains essential nutrients, such as carbohydrates, fats, proteins, vitamins, or minerals. The substance is ingested by an organism ...