Biodegradability of polymers in the environment: complexities and significance of definitions and measurements

Abstract There is a world-wide research effort to develop biodegradable polymers as a waste-management option for polymers in the environment. This effort may prove to be fruitless unless we can agree on a definition and test protocols—what do we expect biodegradable polymers to do in the environment and how do we demonstrate that they do what we expect? Establishing a definition and test protocols is not trivial; the task is made complex by the wide range of disciplines involved directly in or interested in the subject, including polymer scientist, biochemists, environmentalists, legislators, and laypeople, all with their own perspectives and expectations. In this paper, I present arguments in favor of biodegradable polymers and indicate what remains to be done to satisfy detractors that they represent a viable option for polymer waste-management.     

Mucosal delivery of therapeutic and prophylactic molecules using lactic acid bacteria

Studies of lactic acid bacteria (LAB) as delivery vehicles have focused mainly on the development of mucosal vaccines, with much effort being devoted to the generation of genetic tools for antigen expression in different bacterial locations. Subsequently, interleukins have been co-expressed with antigens in LAB to enhance the immune response that is raised against the antigen. LAB have also been used as a delivery system for a range of molecules that have different applications, including anti-infectives, therapies for allergic diseases and therapies for gastrointestinal diseases. Now that the first human trial with a Lactococcus strain that expresses recombinant interleukin-10 has been completed, we discuss what we have learnt, what we do not yet understand and what the future holds for therapy and prophylaxis with LAB.     

Rational desires and the limitation of life-sustaining treatment

It is accepted that treatment of previously competent, now incompetent patients can be limited if that is what the patient would desire, if she were now competent. Expressed past preferences or an advance directive are often taken to constitute sufficient evidence of what a patient would now desire. I distinguish between desires and rational desires. I argue that for a desire to be an expression of a person's autonomy, it must be or satisfy that person's rational desires. A person rationally desires a course of action if that person desires it while being in possession of all available relevant facts, without committing relevant error of logic, and "vividly imagining" what its consequences would be like for her. I argue that some competent, expressed desires obstruct autonomy. I show that several psychological mechanisms operate to prevent a person rationally evaluating what future life in a disabled state would be like. Rational evaluation is difficult. However, treatment limitation, if it is to respect autonomy, must be in accord with a patient's rational desires, and not merely her expressed desires. I illustrate the implications of these arguments for the use of advance directives and for the treatment of competent patients.     

Spencerism and the Causal Theory of Reference

Spencer’s heritage, while almost a forgotten chapter in the history of biology, lives on in psychology and the philosophy of mind. I particularly discuss externalist views of meaning, on which meaning crucially depends on a notion of reference, and ask whether reference should be thought of as cause or effect. Is the meaning of a word explained by what it refers to, or should we say that what we use a word to refer to is explained by what concept it expresses? I argue for the latter view, which I call ‘Darwinian’, and against the former, ‘Spencerian’ one, assuming conceptual structures in humans to be an instance of adaptive structures, and adaptive relations to an environment to be the effect rather than the cause of evolutionary novelties. I conclude with the deficiency – both empirically and methodologically – of a functionalist study of human concepts and the languages they are embedded in, as it would be undertaken in a paradigm that identifies meaning with reference or that gives reference an explanatory role to play for what concepts we have.     

Presumed Behavior: Modification of the Ideal-Real Dichotomy

Anthropologists have long been aware of the difference between the ideal pattern in society (what people think should or should not be done) and real behavior (what actually is done). This article calls attention to the importance of a third element, presumed behavior, or what people think is being done in the society. Since people tend to act on the basis of what they think others are doing (which may not coincide at all with what people are actually doing, or with the ideal pattern) knowledge of the presumed behavior is highly significant in understanding and predicting social behavior.     

Source monitoring and memory distortion.

Memory distortion reflects failures to identify the sources of mental experience (reality monitoring failures or source misattributions). For example, people sometimes confuse what they inferred or imagined and what actually happened, what they saw and what was suggested to them, one person''s actions and another''s what they heard and what they previously knew, and fiction and fact. Source confusions arise because activated information is incomplete or ambiguous and the evaluative processes responsible for attributing information to sources are imperfect. Both accurate and inaccurate source attributions result from heuristic processes and more reflectively complex processes that evaluate a mental experience for various qualities such as amount and type of perceptual, contextual, affective, semantic and cognitive detail, that retrieve additional supporting or disconfirming evidence, and that evaluate plausibility and consistency given general knowledge, schemes, biases and goals. Experimental and clinical evidence regarding cognitive mechanisms and underlying brain structures of source monitoring are discussed.     

A perspective: Photosynthetic production of fatty acid-based biofuels in genetically engineered cyanobacteria

Biofuels are expected to play a key role in the development of a sustainable, economical and environmentally safe source of energy. Microbes offer great potential for applications in technology based biofuel production. Three fundamental questions need to be addressed in order for the development of microbial synthesis of biofuels to be successful. Firstly, what energy resource platform could be used to make biofuels. Secondly, what type of biofuel is the ideal fuel molecule that should be targeted. Finally, what microbial system could be used to transform energy resources into the targeted biofuel molecules. In this perspective, the potential of using photosynthetic microbes (cyanobacteria in particular) in the solar energy driven conversion of carbon dioxide to fatty acid-based biofuels is explored.     

Conservation breeding programmes: an important ingredient for species survival

Captive populations for the primary purpose of securing the survival of species through stable self-sustaining populations need to be founded and managed according to sound scientific principles. Given the current rate of habitat fragmentation and its effect on animal populations, species conservation over the long term increasingly will require management to reduce risk of extinction. This may include ex situ populations which can support and interact demographically and genetically with wild populations. This paper presents a review of what can be achieved through a multidisciplinary approach, involving science, interactive management, politics, environmental education, habitat preservation and habitat restoration. Examples of what conservation-oriented breeding programmes have contributed to date, what represents a viable population and what is meant by effective conservation are provided, and various scenarios for the future are discussed.     

What scatter-hoarding animals have taught us about small-scale navigation

Many animals use cues for small-scale navigation, including beacons, landmarks, compasses and geometric properties. Scatter-hoarding animals are a unique system to study small-scale navigation. They have to remember and relocate many individual spatial locations, be fairly accurate in their searching and have to remember these locations for long stretches of time. In this article, we review what is known about cue use in both scatter-hoarding birds and rodents. We discuss the importance of local versus global cues, the encoding of bearings and geometric rules, the use of external compasses such as the Sun and the influence of the shape of experimental enclosures in relocating caches or hidden food. Scatter-hoarding animals are highly flexible in how and what they encode. There also appear to be differences in what scatter-hoarding birds and rodents encode, as well as what scatter-hoarding animals in general encode compared with other animals. Areas for future research with scatter-hoarding animals are discussed in light of what is currently known.     

Thinking and Ways of Investigating It

The thought process, of course, breaks down into different elements. Thus, in problem solving, analysis articulates what is given (known) and what unknown; and analysis of information in accordance with the requirements of the particular problem leads to identification of the conditions constituting what is known and what is unknown. Each element of the thought process, viewed from the perspective of the result achieved, is a unitary act (a mental action, an operation). However, in studying thought we must not forget that what makes each element a unitary act is the objectively determined and explicit end result of the thought process. What is initial and primary are not these operations, but the integral thought process of which they are discrete constituents.     

Focus: Zoonotic Disease: The Practice of Science as the Pursuit of Knowledge

Choosing what scientific project to pursue is the most important decision that scientists at all levels continually face. Time devoted to a project can further desirable knowledge and advance a career or cost years in lost opportunity. Knowing what to consider before embarking on a specific scientific journey, as well as when to drop a project and change course, offers a way of practicing science that keeps us mindful of what is relevant at a given time and place while preserving our freedom to explore the most exciting findings. This article explores both the pressures that restrict this delicate decision-making process and the processes that scientists can apply to overcome those pressures. Above all else, as it turns out, we must still love the pursuit of knowledge for its own sake – and this love directly impacts our results.     

The North American Waterfowl Management Plan and Wetlands for the Americas programmes: a summary

Bird conservation is a global environmental issue which requires innovative approaches to species and habitat protection and management and the promotion of sustainable development practices. This paper presents some of the highlights in the evolution of two programmes, what may or may not have made them succeed, what lessons were learned and what recommendations can be made for the future of bird conservation. The evolution of the North American Waterfowl Management Plan (NAWMP) and Wetlands for the Americas (WA) bears a lot of similarity to the evolution of International Waterfowl and Wetlands Research Bureau and Ramsar.     

A primer of community ecology using the R language

Community ecology beginners often struggle to understand theories expressed in complex mathematical formulas and to master computer programming. To remedy this situation, this article provides a practical, R-based introduction to community ecology by illustrating core concepts (vital rates, carrying capacity, and density dependence) and models that can be used to explore the patterns of species abundance and diversity. The structure of this article consists of three modeling exercises, each asking a general question that can be answered by a combination of theory and R programming: (1) what determines the abundance of species, and what makes a population persist and go extinct?; (2) what determines the distribution of species and species diversity?; (3) what determines the relative abundance of species and what allows species to coexist? Through the exercises, I discuss the following five concepts and ideas that provide valuable insights into the questions: (i) the tragedy of the commons, (ii) the theory of island biogeography, (iii) competitive exclusion, (iv) the neutral theory of biodiversity, and (v) frequency dependence. These materials are thus designed to guide the reader in developing an intuition for ecological thinking that will help capture the essence of the global environmental and biodiversity crisis. Although this article does not delineate the scope and depth of the vast field of community ecology, I hope that it will motivate the reader to step up to a more formal introduction to community ecology.     

The macroecology of infectious diseases: a new perspective on global‐scale drivers of pathogen distributions and impacts

Identifying drivers of infectious disease patterns and impacts at the broadest scales of organisation is one of the most crucial challenges for modern science, yet answers to many fundamental questions remain elusive. These include what factors commonly facilitate transmission of pathogens to novel host species, what drives variation in immune investment among host species, and more generally what drives global patterns of parasite diversity and distribution? Here we consider how the perspectives and tools of macroecology, a field that investigates patterns and processes at broad spatial, temporal and taxonomic scales, are expanding scientific understanding of global infectious disease ecology. In particular, emerging approaches are providing new insights about scaling properties across all living taxa, and new strategies for mapping pathogen biodiversity and infection risk. Ultimately, macroecology is establishing a framework to more accurately predict global patterns of infectious disease distribution and emergence.     

The journey of tandem running: the twists, turns and what we have learned

Tandem running, whereby one worker recruits another is utilised by many ant species. Since first being recorded, it has provided a valuable experimental tool for testing hypotheses about collective decision making, communication and even teaching. In this review I explore the journey tandem running has taken, the twists and turns in the theories surrounding it and what tandem running has taught us. This review examines the empirical research conducted on tandem running, from when it was first described, considers the theories that have arisen from that research and ultimately what has been learnt and what is still yet to be explored.     

Coronaviruses: Important Emerging Human Pathogens

The identification of Middle East respiratory syndrome coronavirus (MERS-CoV) in 2012 reaffirmed the importance of understanding how coronaviruses emerge, infect, and cause disease. By comparing what is known about severe acute respiratory syndrome coronavirus (SARS-CoV) to what has recently been found for MERS-CoV, researchers are discovering similarities and differences that may be important for pathogenesis. Here we discuss what is known about each virus and what gaps remain in our understanding, especially concerning MERS-CoV.     

A Measure of Biochemical Individual Variability

Once a questionable substance is found in a polluted area, we determine its MLD, LD₅₀ etc. by animal experiments and then taking the species difference into consideration, we provide its MTD, LD₅₀ etc. for the man. However, there exists clearly a wide difference in its tolerance among persona even with the same sex and age belonging to the same race. Our main themes are (i) what is a rational measure of the biochemical individual variability, (ii) what kind of empirical law holds with respect to this measure, and (iii) what is the reason why it holds. This is a summary of my research sponsored by our Agency of Science and Technology [1979a] with some additional results.     

Bioethicists to the Barricades!

In this article I begin with an anecdote as a way of exploring just exactly what activism entails. Are we talking about the kind of activism every citizen ought to engage in? Should we confine our topic to activism in health care settings? Just what is activism anyway, and how much and what kind ought bioethicists to engage in? Finally, I consider the possibility that it’s perfectly permissible for bioethicists not to be activists of any kind.