It is optimal to be optimistic about survival

We investigate the optimal behaviour of an organism that is unable to obtain a reliable estimate of its mortality risk. In this case, natural selection will shape behaviour to be approximately optimal given the probability distribution of mortality risks in possible environments that the organism and its ancestors encountered. The mean of this distribution is the average mortality risk experienced by a randomly selected member of the species. We show that if an organism does not know the exact mortality risk, it should act as if the risk is less than the mean risk. This can be viewed as being optimistic. We argue that this effect is likely to be general.     

It is better to be ignorant of our moral enhancement: A reply to Zambrano

In a recent issue of Bioethics, I argued that compulsory moral bioenhancement should be administered covertly. Alexander Zambrano has criticized this argument on two fronts. First, contrary to my claim, Zambrano claims that the prevention of ultimate harm by covert moral bioenhancement fails to meet conditions for permissible liberty-restricting public health interventions. Second, contrary to my claim, Zambrano claims that covert moral bioenhancement undermines autonomy to a greater degree than does overt moral bioenhancement. In this paper, I rebut both of these arguments, then finish by noting important avenues of research that Zambrano’s arguments motivate.     

Contemporary approaches to protein structure classification

In a similar manner to sequence database searching, it is also possible to compare three-dimensional protein structures. Such methods can be extremely useful because a structural similarity may represent a distant evolutionary relationship that is undetectable by sequence analysis. In this review, we summarise the most popular structure comparison methods, show how they can be used for database searching, and then describe some of the most advanced attempts to develop comprehensive protein structure classifications. With such data, it is possible to identify distant evolutionary relationships, provide libraries of unique folds for structure prediction, estimate the total number of folds that exist, and investigate the preference for certain types of structures over others. BioEssays 20:884–891, 1998. © 1998 John Wiley & Sons, Inc.     

On What It is to Fly Can Tell Us Something About What It is to Live

The plurality of definitions of life is often perceived as an unsatisfying situation stemming from still incomplete knowledge about ‘what it is to live’ as well as from the existence of a variety of methods for reaching a definition. For many, such plurality is to be remedied and the search for a unique and fully satisfactory definition of life pursued. In this contribution on the contrary, it is argued that the existence of such a variety of definitions of life undermines the very feasibility of ever reaching a unique unambiguous definition. It is argued that focusing on the definitions of specific types of ‘living systems’—somehow in the same way that one can define specific types of ‘flying systems’—could be more fruitful from a heuristic point of view than looking for ‘the’ right definition of life, and probably more accurate in terms of carving Nature at its joints.     

Metabolomic approaches to the normal aging process

Aging is a multifaceted process involving the accumulation of diverse deleterious changes in biological systems over time, so significant alterations in cellular metabolism are detected throughout aging. In the present study, the metabolic processes relevant to the normal aging process were investigated via non-targeted metabolomics using liquid chromatography–mass spectrometry. To exclude physiological and environmental differences, the metabolic profiles and the relevant metabolic pathways were analyzed in plasma from two separate study groups comprising two distinctly aged cohorts of healthy individuals, the elderly and the younger. The first group was recruited from an urban hospital, and the second group was recruited from a rural community. Alterations in fatty acid beta-oxidation, glycerophospholipid metabolism, and sphingolipid metabolism were identified as significant metabolic pathways relevant to normal aging. It was also found that sphingosine in sphingolipid metabolism, long-chain acylcarnitines in beta-oxidation, and lysophosphatidylcholines (LysoPCs) in glycerophospholipid metabolism could be critical candidate metabolites in the aging process. These results suggest that the metabolic profile of the healthiest individuals could be associated with the normal function of mitochondria, the primary organelle of redox homeostasis, as indicated by their low acylcarnitine to l-carnitine ratio and low levels of LysoPCs and sphingosine in plasma. The present study provides a critical contribution to the entire picture of the aging process.     

It pays to be sweet: sugars in mutualistic interactions

It is common knowledge that many flowering plants produce nectar to reward pollinators. Not so well known is the fact that plants, fungi and insects also employ sugar-rich solutions to obtain transport or defensive services. However, not all of these interactions are honest. In many cases, cheaters use tricks instead of treats.     

It is alive

We need to familiarize ourselves with the facts of evolution, so that we can mount a spirited defense against creationism and the forces of ignorance.     

Numerical approaches to lake classification with special reference to macrophyte communities

Summary Various approaches to the classification of S. Swedish lakes on the basis of their macrophyte composition are discussed. A main division is made between species or life-form, and synusia or community approaches. Three steps in the classification are discussed: primary clustering of sites to arrive at a local classification, secondary classification of clusters of sites to arrive at general community types and classification of lakes according to their community composition.The estimation of species performance is discussed and a logarithmic transformation advocated. The analysis of belt transects is suggested as a satisfactory general approach.Some problems regarding synusial independence and possible synusial interactions are mentioned. A survey of boundary types in lakes is given.Examples are given of classifications based on single life-forms and life-form combinations. Helophyte community composition of lakes is effectively shown by a combination of classification and ordination. The idea of aquatic community complexes is discussed with reference to the recent sigma-syntaxon approach in phytosociology.Nomenclature follows Lid (1974).     

Synthetic approaches towards structurally diverse gamma-butyrolactone natural-product-like compounds

Natural products containing a gamma-butyrolactone ring are abundant in nature; however, few general synthetic approaches to their stereoselective synthesis with broad structural variety are known. In this article, recent developments towards mono- and polycyclic gamma-butyrolactone natural products and analogs are discussed. A special focus is given to asymmetric methods applying transition metal or organocatalysts that allow not only the efficient introduction of a broad variety of functional groups but ideally also the flexible construction of various natural-product-like, polycyclic scaffolds from common precursors.     

Assigning fossil specimens to a given recent classification when the distribution of character variation is not normal

To help assign fossil material to Recent taxa we present a methodology that offers systematic quantitative tools to explore several continuous characters. It also enables the quantitative determination of which characters amongst several alternatives give results more consistent with a given classification.

The Gini Mean Difference ('Gini') is the expected absolute difference between two randomly drawn observations. In a fossil assemblage comprising several taxa, the Gini of the overall assemblage may be decomposed into three components: the weighted sum of intra‐taxon Gini, the index of overlap, and the inter‐taxon Gini. The parameter that is additional to alternative methods is the overlap index, which serves as a quantitative measure for evaluating the quality of identification. The Gini is advantageous in that it does not require the assumption of a normal distribution in character variation.

The Gini methodology is described in both mathematical and non‐mathematical terms. We demonstrate it by application to a hypothetical gastropod genus consisting of five species, in which we show in orderly, quantitative terms that one character is better for identification of the various species than another character.     

Strategic testing approaches for targeted disease monitoring can be used to inform pandemic decision-making

More than 1.6 million Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) tests were administered daily in the United States at the peak of the epidemic, with a significant focus on individual treatment. Here, we show that objective-driven, strategic sampling designs and analyses can maximize information gain at the population level, which is necessary to increase situational awareness and predict, prepare for, and respond to a pandemic, while also continuing to inform individual treatment. By focusing on specific objectives such as individual treatment or disease prediction and control (e.g., via the collection of population-level statistics to inform lockdown measures or vaccine rollout) and drawing from the literature on capture–recapture methods to deal with nonrandom sampling and testing errors, we illustrate how public health objectives can be achieved even with limited test availability when testing programs are designed a priori to meet those objectives.

COVID-19 testing programs are very important to help control the pandemic. In this Essay, the authors show that objective-driven, strategic sampling designs and analytics can be used to maximize the information gained by COVID-19 testing programs and improve population-level decisions, while maintaining the value of these programs for patient-level management.