Exaptation and emergence as mechanisms to cross fitness valleys during evolution: an example using simulated homing behaviour

Evolution is often considered a gradual hill climbing process, slowly increasing the fitness of organisms. I investigate the evolution of homing behaviour in simulated intertidal limpets. In order to evolve path integration as a homing mechanism, a temporary reduction in an organism’s fitness is required – since high developmental costs occur before a successful homing strategy evolves. Simple hill-climbing algorithms, therefore, only rarely result in the evolution of a functional homing behaviour. The inclusion of a second behaviour (trail-following) greatly increases the frequency of success of evolution of a path integration strategy. Initially an emergent homing behaviour is formed combining path integration with trail following. This also demonstrates evolution through exaptation, since the original role of trail following is likely to be unrelated to homing. Analysis of the fitness landscapes of homing in the presence of trail-following behaviour shows a high variability of fitness, which results in the formation of ‘stepping-stones’ of high fitness across fitness valleys. By using these stepping-stones, simple hill-climbing algorithms can reach the global maximum fitness value

Evaluating a Bayesian approach to improve accuracy of individual photographic identification methods using ecological distribution data

Photographic identification of individual organisms can be possible from natural body markings. Data from photo-ID can be used to estimate important ecological and conservation metrics such as population sizes, home ranges or territories. However, poor quality photographs or less well-studied individuals can result in a non-unique ID, potentially confounding several similar looking individuals. Here we present a Bayesian approach that uses known data about previous sightings of individuals at specific sites as priors to help assess the problems of obtaining a non-unique ID. Using a simulation of individuals with different confidence of correct ID we evaluate the accuracy of Bayesian modified (posterior) probabilities. However, in most cases, the accuracy of identification decreases. Although this technique is unsuccessful, it does demonstrate the importance of computer simulations in testing such hypotheses in ecology

Hairy Leukoplakia

Oral hairy leukoplakia (OHL) is a disease of the mucosa first described in 1984. This pathology is associated with Epstein-Barr virus (EBV) and occurs mostly in people with HIV infection, both immunocompromised and immunocompetent, and can affect patients who are HIV negative. [1, 2] The first case in an HIV-negative patient was reported in 1999 in a 56-year-old patient with acute lymphocytic leukemia. Later, many cases were reported in heart, kidney, and bone marrow transplant recipients and patients with hematological malignancies. [3, 4

Variations in Cholesterol Management Practices of U.S. Physicians

AbstractObjectives. This study sought to evaluate national cholesterol management practices of U.S. physicians.Background. Past studies show that nonclinical factors affect physician practices. We tested the hypothesis that physician and patient characteristics influence cholesterol management.Methods. We used a stratified, random sample of 2,332 office-based physicians providing 56,215 visits to adults in the 1991–1992 National Ambulatory Medical Care Surveys. We investigated physicians’ reporting of cholesterol-related screening, counseling or medications during office visits and used multiple logistic regression to assess independent predictors.Results. An estimated 1.12 billion adult office visits occurred in 1991 and 1992 (95% confidence interval 1.06 to 1.18 billion). For the 1.03 billion visits by patients without reported hyperlipidemia, cholesterol screening (2.8% of visits) and counseling (1.2%) were not frequent. The likelihood of screening increased with older age, cardiovascular disease risk factors, white race and private insurance. We estimate that only 1 in 12 adults received cholesterol screening annually. In the 85 million visits by patients with hyperlipidemia, cholesterol testing was reported in 22.9%, cholesterol counseling in 34.4% and lipid-lowering medications in 23.1%. Testing was more likely in diabetic and nonobese patients. Counseling was more likely with younger age, cardiovascular disease and private insurance. Medications use was associated with cardiovascular disease, Northeast region of the United States, nonobese patients and visits to internists. Physician practices did not differ by patient gender.Conclusions. Although clinical conditions strongly influence cholesterol management, the appropriateness of variations noted by payment source, geographic region and physician specialty deserve further evaluation. These variations and the low estimated volume of services suggest that physicians have not fully adopted recommended cholesterol management practices.(J Am Coll Cardiol 1997;29:139–46)

Foreign Currency Options: Ex Post and Ex Ante Market Efficiency Tests

R. Stafford Johnson is Professor and Chair of the Department of Finance at Xavier University. Richard Zuber is Professor of Economics in the Department of Economics at the University of North Carolina at Charlotte. Lyle Fiore is Trust Fund Manager in the Trust Department of the First Third Bank in Cincinnati, Ohio. John Gandar is an Associate Professor of Economics in the Department of Economics at the University of North Carolina at Charloue

Avian Foods, Foraging and Habitat Conservation in World Rice Fields

Worldwide, rice (Oryza sativa) agriculture typically involves seasonal flooding and soil tillage, which provides a variety of microhabitats and potential food for birds. Water management in rice fields creates conditions ranging from saturated mud flats to shallow (\u3c30 cm) water, thereby attracting different guilds of birds. Grain not collected during harvest (i.e. waste rice) is typically the most abundant potential food of birds in rice fields, with estimates of seed mass from North America ranging from 66-672 kg/ha. Although initially abundant after harvest, waste rice availability can be temporally limited. Few abundance estimates for other foods, such as vertebrate prey or forage vegetation, exist for rice fields. Outside North America, Europe and Japan, little is known about abundance and importance of any avian food in rice fields. Currently, flooding rice fields after harvest is the best known management practice to attract and benefit birds. Studies from North America indicate specific agricultural practices (e.g. burning stubble) may increase use and improve access to food resources. Evaluating and implementing management practices that are ecologically sustainable, increase food for birds and are agronomically beneficial should be global priorities to integrate rice production and avian conservation. Finally, land area devoted to rice agriculture appears to be stable in the USA, declining in China, and largely unquantified in many regions. Monitoring trends in riceland area may provide information to guide avian conservation planning in rice-agriculture ecosystems

The Jacobian algebras

A new class of algebras (the Jacobian algebras) is introduced and studied in detail. The Jacobian algebras are obtained from the Weyl algebras by inverting (not in the sense of Ore) certain elements. Surprisingly, the Jacobian algebras and the Weyl algebras have little in common. Moreover, they have almost opposite properties

The Role of Citizen Science and Volunteer Data Collection in Zoological Research

In many ways, science has never been as popular as it is now. With an ever-increasing number of popular science books on everything from astronomy to climate change and evolution and entire TV channels devoted to science output, the public seems spoilt for choice. However, paradoxically, there is also an increasing disconnect between science—and scientists—and society, and this is certainly evident in the life sciences. This disconnect comes in two forms: interest and level of knowledge. Indeed, one has only to look at the 2012 US presidential election campaign to see the lack of scientific knowledge possessed by many of the political elite about topics such as climate change. If high profile scientific topics are still so widely misunderstood by those in the public eye, it is unsurprising that there is such a lack of understanding of, and interest in, scientific topics in the general public. It should, in theory, be the easiest to address this discontent in subjects like zoology, where the evidence is all around us and can be easily seen, appreciated, and studied by the world’s citizens