Birds: blowin’ by the wind?

Migration is a task that implies a route, a goal and a period of time. To achieve this task, it requires orientation abilities to find the goal and energy to cover the distance. Completing such a journey by flying through a moving airspace makes this relatively simple task rather complex. On the one hand birds have to avoid wind drift or have to compensate for displacements to reach the expected goal. On the other hand flight costs make up a large proportion of energy expenditure during migration and, consequently, have a decisive impact on the refuelling requirements and the time needed for migration. As wind speeds are of the same order of magnitude as birds’ air speeds, flight costs can easily be doubled or, conversely, halved by wind effects. Many studies have investigated how birds should or actually do react to winds aloft, how they avoid additional costs or how they profit from the winds for their journeys. This review brings together numerous theoretical and empirical studies investigating the flight behaviour of migratory birds in relation to the wind. The results of these studies corroborate that birds select for favourable wind conditions both at departure and aloft to save energy and that for some long-distance migrants a tail-wind is an indispensable support to cover large barriers. Compensation of lateral wind drift seems to vary between age classes, depending on their orientation capacities, and probably between species or populations, due to the variety of winds they face en route. In addition, it is discussed how birds might measure winds aloft, and how flight behaviour with respect to wind shall be tested with field data.     

Russia’s Annexation of Crimea and the Passage of Ships Through Kerch Strait: A Law of the Sea Perspective

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This article discusses potential Ukrainian rights of passage through Kerch Strait against the background of restrictions on passage imposed by Russia since the annexation of Crimea, taking into account the ongoing arbitral proceedings under Annex VII of the UN Convention on the Law of the Sea. The article addresses first the question of the status of Kerch Strait and the Sea of Azov under the international law of the sea. In a second step, the article deals with the issue of potential Ukrainian passage rights through Kerch Strait based on the legal status discussed in the first section as well as relevant bilateral treaties between Ukraine and Russia.     

Response by H. H. Pattee to Jon Umerez’s Paper: “Where Does Pattee’s “How Does a Molecule Become a Message?” Belong in the History of Biosemiotics?”

Umerez’s analysis made me aware of the fundamental differences in the culture of physics and molecular biology and the culture of semiotics from which the new field of biosemiotics arose. These cultures also view histories differently. Considering the evolutionary span and the many hierarchical levels of organization that their models must cover, models at different levels will require different observables and different meanings for common words, like symbol, interpretation, and language. These models as well as their histories should be viewed as complementary rather than competitive. The relation of genetic language and human language is the central issue. They are separated by 4 billion years and require entirely different models. Nevertheless, these languages have in common a unique unlimited expressive power that allows open-ended evolution and creative thought. Understanding the nature of this expressive power and how it arises remains a basic unsolved problem of biosemiotics.     

Pigeon homing: Does initial orientation include a ‘preferred compass direction’?

Summary To find out whether the initial orientation of pigeons is affected by a spontaneous directional tendency, as postulated by Wallraff's (1974, 1978, 1982) hypothesis, experienced birds were released at test sites distributed symmetrically around their loft. — The length of the mean vectors of the single releases, the deviations from the home direction, the homeward components as well as the homing speed did not show a correlation with the geographic position of the home direction. Summarizing four sites each on 21 experimental circles, we frequently obtained significant compass vectors, but they varied in direction between 115° ESE and 351° N, depending on what sites had been used, and did not indicate a uniform trend.A preferred compass direction as an integrated part of pigeon navigation, being the reason for the frequently observed deviations from the home direction, could not be confirmed. — The problematic nature of simply pooling the data of several symmetrically distributed test sites and calling any resulting significant vector a preferred compass direction is discussed, together with other possible reasons for asymmetrical distributions of release site biases.Abbreviation PCD preferred compass direction     

‘It’s Always About the Eating Disorder’: Finding the Person Through Recovery-Oriented Practice for Bulimia

Culture, Medicine, and Psychiatry - Bulimia is an eating disorder characterised primarily by binging and ‘inappropriate’ compensatory behaviours, such as purging or excessive exercise....     

Does the mitochondrial genome play a role in the etiology of Alzheimer’s disease?

We report here the analyses of complete mtDNA coding region sequences from more than 270 Alzheimer’s disease (AD) patients and normal controls to determine if inherited mtDNA mutations contribute to the etiology of AD. The AD patients and normal individuals were carefully screened and drawn from two populations of European descent in an effort to avoid spurious effects due to local population anomalies. Overall, there were no significant haplogroup associations in the combined AD and normal control sequence sets. Reduced median network analysis revealed that the AD mtDNA sequences contained a higher number of substitutions in tRNA genes, and that there was an elevated frequency of replacement substitutions in the complex I genes of the control sequences. Analysis of the replacement substitutions indicated that those arising in the AD mtDNAs were no more deleterious, on average, than those in the control mtDNAs. The only evidence for the synergistic action of mutations was the presence of both a rare non-conservative replacement substitution and a tRNA mutation in 2 AD mtDNAs, from a total of 145, whereas such a combination of mutations was not observed in the control sequences. Overall, the results reported here indicate that pathogenic inherited mtDNA mutations do not constitute a major etiological factor in sporadic AD. At most, a small proportion of AD patients carry a pathogenic mtDNA mutation and a small proportion of cognitively normal aged individuals carry a mtDNA mutation that reduces the risk of AD.Electronic Supplementary Material Supplementary material is available for this article at and is accessible for authorized users.     

More Productive Than Maize in the Midwest: How Does Miscanthus Do It?

In the first side-by-side large-scale trials of these two C₄ crops in the U.S. Corn Belt, Miscanthus (Miscanthus × giganteus) was 59% more productive than grain maize (Zea mays). Total productivity is the product of the total solar radiation incident per unit land area and the efficiencies of light interception (ε_i) and its conversion into aboveground biomass (ε_ca). Averaged over two growing seasons, ε_ca did not differ, but ε_i was 61% higher for Miscanthus, which developed a leaf canopy earlier and maintained it later. The diurnal course of photosynthesis was measured on sunlit and shaded leaves of each species on 26 dates. The daily integral of leaf-level photosynthetic CO₂ uptake differed slightly when integrated across two growing seasons but was up to 60% higher in maize in mid-summer. The average leaf area of Miscanthus was double that of maize, with the result that calculated canopy photosynthesis was 44% higher in Miscanthus, corresponding closely to the biomass differences. To determine the basis of differences in mid-season leaf photosynthesis, light and CO₂ responses were analyzed to determine in vivo biochemical limitations. Maize had a higher maximum velocity of phosphoenolpyruvate carboxylation, velocity of phosphoenolpyruvate regeneration, light saturated rate of photosynthesis, and higher maximum quantum efficiency of CO₂ assimilation. These biochemical differences, however, were more than offset by the larger leaf area and its longer duration in Miscanthus. The results indicate that the full potential of C₄ photosynthetic productivity is not achieved by modern temperate maize cultivars.     

Reactions to Media Violence: It’s in the Brain of the Beholder

Media portraying violence is part of daily exposures. The extent to which violent media exposure impacts brain and behavior has been debated. Yet there is not enough experimental data to inform this debate. We hypothesize that reaction to violent media is critically dependent on personality/trait differences between viewers, where those with the propensity for physical assault will respond to the media differently than controls. The source of the variability, we further hypothesize, is reflected in autonomic response and brain functioning that differentiate those with aggression tendencies from others. To test this hypothesis we pre-selected a group of aggressive individuals and non-aggressive controls from the normal healthy population; we documented brain, blood-pressure, and behavioral responses during resting baseline and while the groups were watching media violence and emotional media that did not portray violence. Positron Emission Tomography was used with [¹⁸F]fluoro-deoxyglucose (FDG) to image brain metabolic activity, a marker of brain function, during rest and during film viewing while blood-pressure and mood ratings were intermittently collected. Results pointed to robust resting baseline differences between groups. Aggressive individuals had lower relative glucose metabolism in the medial orbitofrontal cortex correlating with poor self-control and greater glucose metabolism in other regions of the default-mode network (DMN) where precuneus correlated with negative emotionality. These brain results were similar while watching the violent media, during which aggressive viewers reported being more Inspired and Determined and less Upset and Nervous, and also showed a progressive decline in systolic blood-pressure compared to controls. Furthermore, the blood-pressure and brain activation in orbitofrontal cortex and precuneus were differentially coupled between the groups. These results demonstrate that individual differences in trait aggression strongly couple with brain, behavioral, and autonomic reactivity to media violence which should factor into debates about the impact of media violence on the public.     

Finding autophagy: It’s a question of how you look at it

To tell the truth, I find it difficult to work when flying, or even when sitting in an airport for an extended period of time. So, typically I take along a book to read. And when I truly cannot concentrate, for example when a flight is considerably delayed, I have even been known to resort to word puzzles. Depending on the type, they do not require much attention (that is, you can pick up right where you left off after you glance at the flight status screen for the twentieth or so time, even though you know nothing has changed), or effort (although you need to use a pen or pencil, not a keyboard), but nonetheless they can keep your mind somewhat occupied. I even rationalize doing them based on the assumption that they are sharpening my observational/pattern-finding skills. One type of word puzzle that is particularly mindless, but for that very reason I still enjoy in the above circumstances, is a word search; you are given a grid with letters and/or numbers, and a list of “hidden” terms, and you circle them within the grid, crossing them off the list as you go along. I do admit that the categories of terms used in the typical word searches can become rather mundane (breeds of dog, types of food, words that are followed by “stone,” words associated with a famous movie star, words from a particular television show, etc.). Therefore, on one of my last seminar trips I decided to generate my own word search, using the category of autophagy.     

Assessment of the Bioaccessibility of Trace Elements in Cat’s Claw Teas by In Vitro Simulated Gastrointestinal Digestion Using FAAS

Beer is a widely consumed drink throughout the world, and because its manufacture involves the use of water, beer can be, in some cases, a source of fluorides. For this reason, the objective of this study was to determine the concentration of fluorides in 50 samples of beers from different sources sold in two different types of container (aluminum can and glass bottle). The possible significant differences between the different types of packaging and the intake of fluoride from the consumption of these beers were evaluated. The concentration of fluoride in beers has been determined using the potentiometric method of fluoride determination by standard addition. The concentration of fluoride ranged between 0.06 and 1.77 mg/L. In general, the concentration was below 1 mg/L, except for three beer samples from Ireland and the USA, whose concentration was over 1.5 mg/L. No significant differences were found between the types of packaging. The contribution of fluoride to the diet from beer consumption is not high (<27%); however, it is necessary to warn consumers whenever they are in areas of high concentrations of fluoride in the water supply.     

It’s a dog-eat-croc world: dingo predation on the nests of freshwater crocodiles in tropical Australia

Predation on eggs is an important source of mortality for many long-lived organisms, but causes of egg mortality from specific predators remain poorly known in most cases. Understanding the identity of predators, and the rates and determinants of their effects on a cohort of recruits, can provide a valuable background for attempts to exploit, control or conserve populations. We used remotely triggered cameras to study predation on the nests of freshwater crocodiles (Crocodylus johnstoni) inhabiting Lake Argyle, in tropical Australia. We also supplemented our work on natural crocodile nests with artificial nests. Overall, 80 of 111 natural nests were opened by predators, and predation occurred throughout the study period (7 weeks). Unlike in other parts of the species’ range, most nest-robbers were dingoes (Canis lupus dingo, responsible for 98% of all predator visits in the northern sites, and 54% in the Ord River site), with minimal additional predation by reptiles and birds. Contrary to expectation, rates of nest predation were not influenced by spatial clumping of nests: the probability of predation per nest did not change with total numbers of nests laid in an area, and artificially aggregated versus dispersed nests experienced similar levels of predation. Nest vulnerability was linked to abiotic features including slope of surrounding banks, compactness of nesting substrate, and distance from the nearest forest. Abundant aquatic food resources support a large crocodile population, but a lack of suitable nest-sites forces the crocodiles to concentrate nesting in small areas readily accessible to wide-ranging nest predators. Collectively, our results suggest that distinctive attributes of the lakeside landscape alter predator guilds and fashion unique predator–prey interactions.     

Conserving the Birds of Uganda’s Banana-Coffee Arc: Land Sparing and Land Sharing Compared

Reconciling the aims of feeding an ever more demanding human population and conserving biodiversity is a difficult challenge. Here, we explore potential solutions by assessing whether land sparing (farming for high yield, potentially enabling the protection of non-farmland habitat), land sharing (lower yielding farming with more biodiversity within farmland) or a mixed strategy would result in better bird conservation outcomes for a specified level of agricultural production. We surveyed forest and farmland study areas in southern Uganda, measuring the population density of 256 bird species and agricultural yield: food energy and gross income. Parametric non-linear functions relating density to yield were fitted. Species were identified as “winners” (total population size always at least as great with agriculture present as without it) or “losers” (total population sometimes or always reduced with agriculture present) for a range of targets for total agricultural production. For each target we determined whether each species would be predicted to have a higher total population with land sparing, land sharing or with any intermediate level of sparing at an intermediate yield. We found that most species were expected to have their highest total populations with land sparing, particularly loser species and species with small global range sizes. Hence, more species would benefit from high-yield farming if used as part of a strategy to reduce forest loss than from low-yield farming and land sharing, as has been found in Ghana and India in a previous study. We caution against advocacy for high-yield farming alone as a means to deliver land sparing if it is done without strong protection for natural habitats, other ecosystem services and social welfare. Instead, we suggest that conservationists explore how conservation and agricultural policies can be better integrated to deliver land sparing by, for example, combining land-use planning and agronomic support for small farmers.     

Does the tail wag the dog? How the structure of a glycosylphosphatidylinositol anchor affects prion formation

There is increasing interest in the role of the glycosylphosphatidylinositol (GPI) anchor attached to the cellular prion protein (PrP^C). Since GPI anchors can alter protein targeting, trafficking and cell signaling, our recent study examined how the structure of the GPI anchor affected prion formation. PrP^C containing a GPI anchor from which the sialic acid had been removed (desialylated PrP^C) was not converted to PrP^Sc in prion-infected neuronal cell lines and in scrapie-infected primary cortical neurons. In uninfected neurons desialylated PrP^C was associated with greater concentrations of gangliosides and cholesterol than PrP^C. In addition, the targeting of desialylated PrP^C to lipid rafts showed greater resistance to cholesterol depletion than PrP^C. The presence of desialylated PrP^C caused the dissociation of cytoplasmic phospholipase A₂ (cPLA₂) from PrP-containing lipid rafts, reduced the activation of cPLA₂ and inhibited PrP^Sc production. We conclude that the sialic acid moiety of the GPI attached to PrP^C modifies local membrane microenvironments that are important in PrP-mediated cell signaling and PrP^Sc formation.     

The Efficiency of the Human CD8+ T Cell Response: How Should We Quantify It,What Determines It,and Does It Matter?

Multidisciplinary techniques, in particular the combination of theoretical and experimental immunology, can address questions about human immunity that cannot be answered by other means. From the turnover of virus-infected cells in vivo, to rates of thymic production and HLA class I epitope prediction, theoretical techniques provide a unique insight to supplement experimental approaches. Here we present our opinion, with examples, of some of the ways in which mathematics has contributed in our field of interest: the efficiency of the human CD8+ T cell response to persistent viruses.