Evolution by Sexual Selection

Charles Darwin published his second book “Sexual selection and the descent of man” in 1871 150 years ago, to try to explain, amongst other things, the evolution of the peacock’s train, something that he famously thought was problematic for his theory of evolution by natural selection. He proposed that the peacock’s train had evolved because females preferred to mate with males with more elaborate trains. This idea was very controversial at the time and it wasn’t until 1991 that a manuscript testing Darwin’s hypothesis was published. The idea that a character could arise as a result of a female preference is still controversial. Some argue that there is no need to distinguish sexual from natural selection and that natural selection can adequately explain the evolution of extravagant characteristics that are characteristic of sexually selected species. Here, I outline the reasons why I think that this is not the case and that Darwin was right to distinguish sexual selection as a distinct process. I present a simple verbal and mathematical model to expound the view that sexual selection is profoundly different from natural selection because, uniquely, it can simultaneously promote and maintain the genetic variation which fuels evolutionary change. Viewed in this way, sexual selection can help resolve other evolutionary conundrums, such as the evolution of sexual reproduction, that are characterised by having impossibly large costs and no obvious immediate benefits and which have baffled evolutionary biologists for a very long time. If sexual selection does indeed facilitate rapid adaptation to a changing environment as I have outlined, then it is very important that we understand the fundamentals of adaptive mate choice and guard against any disruption to this natural process.

Is COVID-19 a turning point in stopping global sourcing? Differentiating between declining continental and increasing transcontinental sourcing

Purpose This research aims to investigate the impact of the current COVID-19 pandemic (C19, Corona) on trends of transcontinental sourcing as an extreme form of global sourcing. This study starts by observing that the sideward movement of international trade in the past decade can be differentiated into an increase in transcontinental sourcing and a relative decline of intra-EU sourcing. By differentiating between continental and transcontinental sourcing, this study gains insights into global sourcing trends and conducts a fine-grained analysis of the impact of COVID-19. Design/methodology/approach After analysing Eurostat statistics, the authors conducted 21 semi-structured interviews with companies from multiple industry sectors affected by a high share of transcontinental suppliers. Using the Gioia method, data from the interviews were structured. By examining the identified motives, challenges and solutions, the authors analyse the impact of COVID-19 on transcontinental sourcing. Findings The COVID-19 pandemic seems not to represent a turning point stopping global sourcing. The authors did not find evidence for a trend reversal. Most of the interviewed companies share the opinion that transcontinental sourcing will remain important or slightly increase in the future. Based on the analysis of their specific motives for transcontinental sourcing, it became clear that factors supportive as well as detrimental to transcontinental sourcing are levelling each other out. Originality/value To the best of the authors’ knowledge, this is the first study explicitly differentiating between continental and transcontinental sourcing as different types of global sourcing. While in European sourcing, a decreasing trend is already evident, as shown by our data analysis, there is a lack of investigations addressing transcontinental sourcing. In this study, the authors concentrated on motives, challenges and solutions of transcontinental sourcing. Extending beyond the immediate COVID-19 impact assessment, findings suggest that purchasing would benefit from treating transcontinental, remote sourcing as a distinct process from continental sourcing, particularly intra-EU-sourcing.

The Birth of a Business Icon through Cultural Branding: Ferrari and the Prancing Horse, 1923–1947

This article examines the origin of the “Prancing Horse” symbol and its role in helping the racing team Ferrari survive under the fascist regime in Italy. Enzo Ferrari, the company’s founder, adopted the coat of arms of Francesco Baracca, the most renowned Italian military aviator during World War I, as the logo of his new racing team. By repurposing it from military aviation to motorsport, he benefitted from powerful cultural associations and strong political and cultural endorsement of Baracca’s persona. Drawing from scholarship on cultural branding and consumer culture, this study shows how new companies can establish powerful business icons by borrowing symbols connected to populist worlds and national ideologies, and transferring them to various industries. Strategic repurposing thus emerges as a distinct process within cultural branding to obtain institutional support and establish powerful brand identities in challenging contexts.

Enhancing Cyberweapon Effectiveness Methodology With SE Modeling Techniques

A recent cyberweapons effectiveness methodology clearly provides a parallel but distinct process from that of kinetic weapons – both for defense and offense purposes. This methodology promotes consistency and improves cyberweapon system evaluation accuracy – for both offensive and defensive postures. However, integrating this cyberweapons effectiveness methodology into the design phase and operations phase of weapons systems development is still a challenge. The paper explores several systems engineering modeling techniques (e.g., SysML) and how they can be leveraged towards an enhanced effectiveness methodology. It highlights how failure mode analyses (e.g., FMEA) can facilitate cyber damage determination and target assessment, how block and parametric diagraming techniques can facilitate characterizing cyberweapons and eventually assess the effectiveness of such weapons and conversely assess vulnerabilities of systems to certain types of cyberweapons.

Autophagic Cell Death During Development – Ancient and Mysterious

While cell death is a normal and essential component of development and homeostasis, dysregulation of this process underlies most human diseases, including cancer, autoimmunity and neurodegeneration. The best characterized mechanism for cell death is apoptosis, although some cells die by a distinct process known as autophagy-dependent cell death (ADCD). Autophagy is mediated by the formation of double membrane vesicles that contain protein aggregates, damaged organelles like mitochondria, and bulk cytoplasm, which then fuse with lysosomes to degrade and recycle their contents. Autophagy is typically viewed as an adaptive process that allows cells to survive stresses like nutrient deprivation, although increasing evidence suggests that it may also mediate cell death during development and pathogenesis. An aggressive form of autophagy termed autosis has been described in cells following either ischemia/reperfusion injury or in response to autophagy-inducing proteins like Tat-Beclin 1. Despite an extensive literature on autophagic cell death in a variety of contexts, there are still fundamental gaps in our understanding of this process. As examples: Does autophagy directly kill cells and if so how? Is ADCD activated concurrently when cells are triggered to die via apoptosis? And is ADCD essentially a more protracted version of autosis or a distinct pathway? The goal of this mini-review is to summarize the field and to identify some of the major gaps in our knowledge. Understanding the molecular mechanisms that mediate ADCD will not only provide new insights into development, they may facilitate the creation of better tools for both the diagnostics and treatment of disease.

Savings in human force field learning supported by feedback adaptation

Savings have been described as the ability of healthy humans to relearn a previously acquired motor skill faster than the first time, which in the context of motor adaptation suggests that the learning rate in the brain could be adjusted when a perturbation is recognized. Alternatively, it has been argued that apparent savings were the consequence of a distinct process that instead of reflecting a change in the learning rate, revealed an explicit re-aiming strategy. Based on recent evidence that feedback adaptation may be central to both planning and control, we hypothesized that this component could genuinely accelerate relearning in human adaptation to force fields during reaching. Consistent with our hypothesis, we observed that upon re-exposure to a previously learned force field, the very first movement performed by healthy volunteers in the relearning context was better adapted to the external disturbance, and this occurred without any anticipation or cognitive strategy because the relearning session was started unexpectedly. We conclude that feedback adaptation is a medium by which the nervous system can genuinely accelerate learning across movements.

Source of circular polarization in radio pulsars

ABSTRACT It is known that the concept of limiting polarization introduced 70 yr ago by K. G. Budden has the capacity to explain the magnitude of circular polarization seen in normal pulsars with light-cylinder radii of the order of 109–10 cm under the assumption of a high-multiplicity electron–positron plasma. However, a review of limiting polarization under the same assumption in millisecond pulsars indicates that it is inapplicable there because the region of limiting polarization lies far outside the light cylinder. This paper, using the ion–proton model, evaluates circular polarization both generally and specifically for J2144−3933, and gives a fairly detailed understanding of the observations in normal pulsars including the change of sign as a function of frequency seen in J0908−4913. But it also fails to explain circular polarization in millisecond pulsars owing to the smaller particle number densities and birefringence of the magnetosphere in these objects. However, the review of limiting polarization finds that, within the ion–proton model, this distinct process can describe their circular polarization. It is argued that certain features of millisecond pulsar Stokes profiles are clearly consistent with limiting polarization.

Somite surface tension buffers imprecise segment lengths to ensure left-right symmetry

The body axis of vertebrate embryos is periodically segmented into bilaterally symmetric pairs of somites. The anteroposterior (AP) length of somites, their position and left-right symmetry are thought to be molecularly determined prior to somite morphogenesis. Here we discover that in zebrafish embryos, initial somite AP lengths and positions are imprecise and consequently many somite pairs form left-right asymmetrically. Strikingly, these imprecisions are not left unchecked and we find that AP lengths adjust within an hour after somite formation, thereby increasing morphological symmetry. We find that AP length adjustments result entirely from changes in somite shape without change in somite volume, with changes in AP length being compensated by corresponding changes in mediolateral length. The AP adjustment mechanism is facilitated by somite surface tension, which we show by comparing in vivo experiments and in vitro single-somite explant cultures with a mechanical model. Length adjustment is inhibited by perturbation of Integrin and Fibronectin, consistent with their involvement in surface tension. In contrast, the adjustment mechanism is unaffected by perturbations to the segmentation clock, thus revealing a distinct process that determines morphological segment lengths. We propose that tissue surface tension provides a general mechanism to adjust shapes and ensure precision and symmetry of tissues in developing embryos.

Islam and the Discursive Landscape of Globalisation

Globalisation is a multidimensional process, involving both intrinsic and extrinsic factors, playing out simultaneously within the domains of economy, politics, technology—particularly media and information communication technology (ICT)—culture and environmental change. By contrast, the spread of knowledge that transforms global Islamic authority in heterogeneous forms, challenging conventional understandings, location and mode of articulation of authority, is considered to be a distinct process. This paper attempts to investigate the role of knowledge in the construction of globalised Islamic authority in Islam. It explores the evolution of Islamic authority vis-à-vis the rapidly developing network of interconnections and interdependencies. Focusing on identifying the element of consensus (ijmā) in sustaining and upholding religious authority in Islam, the paper examines how modernist critiques of consensus take various forms in light of what modernists consider to be “true” and how they see the challenges and opportunities of global transformations. While shedding light on a growing fragmentation and decentralisation of religious authority in the Muslim world, this paper argues that the authoritative religious knowledge was established and sustained down to 18th century when new methods of interpretation emerged challenging the authoritative corpus of religious structures. Consideration is also given to the causes, spectrum, and effects of increasingly diverse, and disjointed transformations of religious authority in Muslim societies, the outcome of which is a spectacularly wild growth of interpretation.