One of the more prominent early childhood interventions focused on the development of executive function skills is Tools of the Mind. Intervention studies comparing Tools classrooms with control classrooms, however, reveal inconsistent findings for children’s EF outcomes. The current study utilizes Head Start CARES teachers assigned to the Tools of the Mind enhancement intervention and the children in their classrooms. Relations between teachers’ characteristics, training attendance and implementation, and the interaction among these factors were examined as predictors of classroom-level gains (...) in EF. Results revealed several significant moderation effects indicating that Tools implementation is related to classroom EF gains for some but not all teachers. (shrink)

The use of slang, abusive, and offensive language has become common practice on social media. Even though social media companies have censorship polices for slang, abusive, vulgar, and offensive language, due to limited resources and research in the automatic detection of abusive language mechanisms other than English, this condemnable act is still practiced. This study proposes USAD, a lexicon-based intelligent framework to detect abusive and slang words in Perso-Arabic-scripted Urdu Tweets. Furthermore, due to the nonavailability of the standard dataset, we (...) also design and annotate a dataset of abusive, offensive, and slang word Perso-Arabic-scripted Urdu as our second significant contribution for future research. The results show that our proposed USAD model can identify 72.6% correctly as abusive or nonabusive Tweet. Additionally, we have also identified some key factors that can help the researchers improve their abusive language detection models. (shrink)

Muhammad Iqbal (d. 1938) was one of the most influential modernist Islamic thinkers of the early twentieth century. His work as a poet, politician, philosopher, and public intellectual was widely recognized in his lifetime and plays a major role in contemporary conversations about Islam, modernity, and tradition. The Ambiguities of Modern Islamic Thought examines the patterns of reasoning at work in Iqbal's philosophic magnum opus, arguably the most significant text of modernist Islamic philosophy, The Reconstruction of Religious Thought in Islam. (...) Since its initial publication in 1934, The Reconstruction has left scholars in a quandary: its themes appear eclectic, and its arguments contradictory and philosophically perplexing. In this groundbreaking study, Nauman Faizi argues that the keys to demystifying the contradictions of The Reconstruction are two competing epistemologies at play within the work. Iqbal takes knowledge to be descriptive, essential, foundational, and binary, but he also takes knowledge to be performative, contextual, probabilistic, and vague. Faizi demonstrates how these approaches to knowledge shape Iqbal's claims about personhood, God, scripture, philosophy, and science. The Ambiguities of Modern Islamic Thought offers an original approach to interpreting Islamic thought as it crafts relationships between scriptural texts, philosophic thought, and scientific claims for modern Muslim subjects. (shrink)

Lives and works of great thinkers from Jonathan Edwards to Albert Einstein, from Wiliam Penn, escaping English tyranny, to Paul tillich, fleeing German despotism.

Drawing on Conservation of resources (COR) theory, this study examined the underlying mechanism through which workplace bullying (WB) affects employees’ life satisfaction via job- related anxiety and insomnia. Time-lagged data were collected at two points in time from 211 doctor interns working in various hospitals in Pakistan. Results fully support a proposed serial multiple-mediator model. Workplace bullying is indirectly related to life satisfaction via job-related anxiety and insomnia. This study provides evidence of a spillover effect as to how workplace bullying (...) increases employees’ job-related anxiety which in turn leads to insomnia resulting in reduced employees’ life satisfaction. The present study extends research on workplace bullying to display its theoretical as well as empirical effects on life satisfaction. It demonstrates that workplace bullying as an occupational and psychological stressor has multiple effects on employees’ life satisfaction through a serial mediation model in the context of a developing country. It further explains that workplace bullying not only affects an employee’s workplace behaviors but also extends to the employee’s over-all life satisfaction. Keywords: Workplace bullying, job-related anxiety, insomnia, life satisfaction. (shrink)

This study investigates the connection between following Islamic work ethics (IWE) and workplace deviance, and explores the role of perceived organizational politics as a mediator and the impact of incivility initiated by supervisors as a second-stage moderator. Data were collected via a two-wave survey of 205 professionals in various industries. Results show that those who adhere to IWE exhibit a negative link to workplace deviance, as they have less involvement in organizational politics. The study also finds that incivility initiated by (...) supervisors intensifies the positive relationship between perceived organizational politics and workplace deviance. Interestingly, the study shows that the effect of IWE in reducing workplace deviance through organizational politics is stronger when incivility is high. The findings offer valuable insights for organizations on the positive impact of adhering to IWE on reducing perceived organizational politics and workplace deviance. (shrink)

This article investigates the nexus between bank-specific risks and the financial stability of the banks for a panel data set of 15 scheduled banks in Pakistan over a 12-year period from 2009 to 2020. Using the fixed-effect model, the study result shows that bank-specific risks, i.e., credit risk and liquidity risk are detrimental to bank stability, whereas funding risk has no significant impact on bank stability. Besides these, bank size has also a negative impact on bank stability, whereas the return (...) on assets revealed a positive influence. To ensure stability, bank management should establish policies that confirm secure loan granting and timely reimbursement from customers to minimize the credit risk. Besides this, management should keenly observe the liquidity position and should also effectively mobilize the customer deposits to attain financial stability. (shrink)

In lieu of an abstract, here is a brief excerpt of the content:Acts of Askēsis, Scenes of PoiēsisThe Dramatic Phenomenology of Another Violence in a Muslim Painter-PoetNauman Naqvi (bio)[End Page 50]The Divinity is beautiful and loves beauty. Cultivate the ethos of the Divinity. Askēsis is my glory, and all askēsis is from me.— Hadith of the Prophet Muhammad, Sahih al-Bukhari>> Introduction: Presenting the Drama of the Gnostic Ontology of Violence in IslamIn current discourse on violence in Islam, the fundamental importance (...) of the Prophetic distinction—a distinction iterated in a number of hadith, or speech-events of the Prophet Muhammad—between the greater, inner jihad, against the ego (al-jihad al-akbar), and the lesser, outward jihad, against oppression and animosity (al-jihad al-asghar), has often been cited. Even so, an originary measure of the significance of this exemplary distinction—abyssal in its simplicity, disclosing as it does the divinity proper to the divinely ordained imperative of jihad (such disclosure of divinity being the very task and telos of the Prophetic speech-event, its very eventfulness (hadatha)—has hardly been taken or heeded.It has not, to begin with, been explored that both forms strikingly share the violent word, jihad: in Arabic, forceful effort or struggle. It is as if the reality and intensity of these two radically different forms of force are adequated a priori in the Prophetic speech-event—if anything, it is the former, the inner jihad, that has the greater reality, the more violent, imperative intensity. With their difference a matter of degree and quality, the two are at once intimately related and violently real, linguistically leaving us little space for the distinction between the metaphoric and the literal in this demanding economy, language, and ontology of violence.1The line that has been drawn between the two forms of violence in the Prophetic speech-event is not ontological per se—it is the axis of the stage of their dramatic encounter, the battle line of their distinction. This axis, this vertical battle line of distinction, is the strait, but upwardly infinite, dramaturgical space wherein is enacted the gnostic ontology of violence in Islam. It is the axial line of force emanating from Islam’s extraordinary emphasis on the radical purification of one’s intention, one’s very intentionality (i.e., the purification not just of the springing ground of one’s comportment, but of the anterior ground where one receives and apprehends the real as such), in a quest for the demanding Divinity that would hurl the Islamic subject both inside and outside itself in its own endless search and infinite encounter. It is the battle line of distinction that races through the world stage of Islam’s arts, knowledges, and practices—the auratic line of force pulsating through the fields of its charismatic inheritance of generous visions, discourses, and gestures. Indeed, it is the piercing erotic arrow of divine love and mercy that is the subtle motus animi continuus of Islam’s graceful works of poiēsis.For the violent task of askēsis assigned by the great imperative of inner jihad is closely related both to the imperative of beauty in Islam—where the effects of askēsis: virtue and virtuosity, are densely, passionately cathected and imbricated with the beautiful2 by [End Page 51] virtue of the latter’s manifestation of divinity—as well as to the imperative of knowledge, wherein theory and praxis are united in askēsis.3Beauty and its creation—the act of poiēsis —are also, then, violently real, as are knowledge and its effects, since together they all have a kenotically violent askēsis as the condition and telos of their possibility, as the very ground(s) of their emergence and potentiality. Thus, the significance of the greater jihad is (again) to be read potentially, in the entire range of the arts, gestures, habits, and letters of Islam, its artifacts and bodies, where generous, kenotic, sacrificial logics are on display, not just in the lesser archive of jihad (in acts of greater jihad on far bygone battlefields), but in the epic world-panorama of the acts and scenes of askēsis and poiēsis that are... (shrink)

Whether all educationists were philosophers or not, one thing is clear – that all philosophers were educationists – directly or indirectly. May it be Plato, Aristotle, Rousseau or Dewey, they all came up with the notion that to bring about any change at a greater level in a society, change in its educational system is fundamental. Dr. Mohammad Allama Iqbal, though was a philosopher and a poet, also touched the very core of the problems existing in the Muslim societies of (...) his time, through his reflection and recommendation upon the changes required in the educational system. Iqbal’s educational philosophy is not only the solution to the problems that existed in his time, but also holds solutions to the prevalent problems of the Muslim societies. This essay seeks to explain the education policy that stems out of Iqbal’s education philosophy. For the same purpose, a three-pillar visual diagram has been introduced that will help the readers grasp the importance given by Iqbal to the cultivation of ego in his education philosophy. (shrink)

The number of technical terms employed by existentialist philosophy must be precisely defined in order that the intended thought may be properly understood. This book is designed to present such definitions based on documentary source materials by the major existentialists, such as Kierkegaard, Nietzsche, Sartre, Jaspers, Marcel, Heidegger, Camus and Berdysev.

Background and ObjectivesThe purpose of this study was to draw the attention toward the implications of COVID-19 and the related restrictions imposed worldwide especially in Pakistan. The primary objective was to highlight the levels of psychological distress, anxiety, family violence, suicidality, and well-being due to COVID-19 and the secondary objective was to associate it to social demographic factors.Materials and MethodsIt is designed as a cross-sectional study by employing an online questionnaire in the English language and obtaining responses using a snowball (...) sampling technique. We used three validated measures including Kessler Psychological Distress Scale, Generalized Anxiety Disorder index and World Health Organization Well-Being Index.ResultsA sample of 420 participants was recruited from across Pakistan, with most participants were females, students and belonging to Punjab. Nearly one-fourth of the participants scored above the minimum value set for moderate or high psychological distress. There was a higher prevalence of distress among females and resident of province Punjab. The majority of individuals reported that they were living with their family and more than half were neutral regarding their satisfaction with their living conditions. 40.5% believed that the lockdown has had a negative impact on their mental health. 31.4% have reported that they themselves have experienced abuse from a family member. 48.6% scored high on the GAD-7 scale and low wellbeing score was found among 80.2%. Students were found to be more vulnerable to mental illness and anxiety.ConclusionWith the lockdown restrictions, psychosocial distress has become prevalent in Pakistan. (shrink)

The role of digitization and globalization have changed consumers’ online buying behaviors, specifically in the times of the COVID-19 pandemic crisis. This seriously influences the online retail industry in developing countries that are already struggling to move toward digital trading through e-business. Pakistan being a developing country is no exception, and it is, therefore, pertinent to examine factors that contribute to digital trading. Employing theories of reasoned action and the technology acceptance model, this study aims to investigate how personal innovativeness (...) and perceived usefulness impact consumers’ online purchase intentions through a serial mediational model. The data were collected through an online survey from 410 respondents. Structural Equation Modeling was used to test the proposed model. This study showed significant results for the direct effect of personal innovativeness and perceived usefulness on online purchase intentions as well as the indirect serial effect via internet browsing and attitude toward online purchasing. The study results have some important practical implications for selling firms, especially in the times of COVID-19. The study suggests that online retailers should be more responsive to the aforementioned factors to facilitate consumers to spend more time browsing, which influences consumers’ interest and intention to make online purchases. As the social distancing and lockdown approaches were implemented in Pakistan and other parts of the world, the trend toward online purchases has increased. Due to this shift in the overall purchasing behavior of consumers and the potential for strong growth in e-commerce, organizations need to consider the post-COVID situation to expand their business in an online platform for addressing the future pandemic crisis. (shrink)

Using Shahzad Bashir’s open-access publication A New Vision for Islamic Pasts and Futures as a baseline, this symposium debates whether and how intellectual history can be done otherwise. Mohamed ‘Arafa follows Bashir’s invitation to explore the potential of open-ended historiographies when he thinks about the viability of a flexible method to interpret Sharī ʿ a. Nader El-Bizri interrogates whether the assemblage of personal experiential accounts offered by Bashir can be framed within the discourse of intellectual history at all. Nauman (...) Faizi reads Bashir’s approach as a radical attempt to open up hermeneutical possibilities. Lena Salaymeh suggests that modern aesthetics can contribute to neo-colonial distortions of the Islamic tradition, rather than offering alternatives to positivist historiography. Bashir proposes in his response that academics adopt generosity as an analytical gesture in their academic writing, a generosity that would enable different ways of being human in the world. (shrink)

Whooping cough is a highly transmitted disease around the world. According to the World Health Organization, 0.15 million cases had reported globally in 2018. Most of the Asian and African states are infected regions. Through the study, we investigated the whole population into the four classes susceptible, exposed, infected, and vaccinated or recovered. The transmission dynamics of whooping cough disease are studied analytically and numerically. Analytical analyses are positivity, boundedness, reproduction number, equilibria, and local and global stabilities. In numerical analysis, (...) we developed an implicit numerical integration scheme consistent with the biological problem’s properties. The analysis of the implicit method for the said model is dynamically consistent, positive, and bounded. Furthermore, an implicit numerical integration scheme is suitable for studying a particular epidemic model such as the whooping cough disease. (shrink)

Around 540 million years ago there was a sudden, dramatic adaptive radiation known as the Cambrian Explosion. This event marked the origin of almost all of the phyla (major lineages characterized by fundamental body plans) of animals that would ever live on earth, as well the appearance of many notable features such as rigid skeletons and other hard parts, complex jointed appendages, eyes, and brains. This radical evolutionary event has been a major puzzle for evolutionary biologists since Darwin, and (...) while our understanding of it has recently improved with new fossil finds, richer molecular phylogenies, and better grasp of ecological, evolutionary, and developmental processes generally, unanswered questions remain. In this paper I argue that a basic cognitive toolkit for embodied, object-oriented, spatial cognition (what I call Basic Cognitive Embodiment) is a practical necessity for control of a large, mobile, complexly articulated body in space. This hypothesis allows us to relate the complexification of animal bodies to the complexification of perception, cognition and behavior in a way that can help to fill in gaps in our emerging picture of the Cambrian Explosion, as well as shed light on the deep evolutionary origins of the mind. (shrink)

The sudden appearance in the fossil record of the major animal phyla apparently records a phase of unparalleled, rapid evolution at the base of the Cambrian period, 545 Myr ago. This has become known as the Cambrian evolutionary ‘explosion’, and has fuelled speculation about unique evolutionary processes operating at that time. The acceptance of the palaeontological evidence as a true reflection of the evolutionary narrative has been criticised in two ways: from a reappraisal of the phylogenetic relationships of (...) the early fossils, and from predicitions of molecular divergence times, based on six appropriate metazoan genes. Phylogenetic analysis of the arthropods implies an earlier, Precambrian history for most clades, and hence an extensive period of cladogenesis unrecorded by fossils. A similar argument can be applied to molluscs, lophophorates and deuterostomes. Molecular evidence implies divergence between clades to at least 1000 Myr ago. The apparent paradox between the sudden appearance of recognisable metazoans and their extended evolutionary history might be explained by a sudden Cambrian increase in body size, which was accompanied by skeletisation. A new paradigm suggests that the ‘explosion’ in the record may have been decoupled from the evolutionary innovation. (shrink)

When and where did consciousness emerge in the course of evolution? Did it happen as recently as the past million years, for example concomitant with language or tool making in humans or primates? Or did consciousness arrive somewhat earlier, with the advent of mammalian neocortex 200 million years ago (Eccles, 1992)? At the other extreme, is primitive consciousness a property of even simple unicellular organisms of several billion years ago (e.g. as suggested by Margulis and Sagan, 1995)? Or did consciousness (...) appear at some intermediate point, and if so, where and why? Whenever it first occurred, did consciousness alter the course of evolution? (shrink)

In recent years, two schools of thought have emerged with regard to the Cambrian “explosion”. One argues that it was very quick, with phyla tumbling into existence in a virtual geological instant. The other view has a more relaxed temporal perspective. It looks to slow aeons of cryptic metazoan history, which led to a final breakthrough in the Cambrian, not in evolution but of fossilization potential. Yet both views have serious difficulties. Now, in a recent issue of Biological (...) Reviews, Graham Budd and Sören Jensen(1) argue for a third way. In an intriguing blend of functional morphology, the fossil record and cladistic thinking, they suggest that the assembly of metazoan bodyplans took place in a surprisingly straightforward manner. BioEssays 22:1053–1056, 2000. © 2000 John Wiley & Sons, Inc. (shrink)

Phillips et al. make a compelling case for a reversal in the current paradigm in “other minds” research by considering the representation of other people's knowledge more basic than the attribution of belief. Unfortunately, they only discuss primates. In this commentary, I argue that the representation of others' knowledge is an evolutionary ancient trait, first appearing during the Cambrian explosion.

This article examines the ways in which Bruce Nauman’s art installations provoke audience experiences analogous to those felt during traumatic events. A central assertion of the present study is that the looping mechanisms of Nauman’s video artworks produce a theoretical stilling of the moving image that is reflective of the fight-flight-or-freeze response to a highly charged incident, which often entails a temporal shift as time appears to slow to a halt. Whereas in the past, the human response to (...) acute stress was typically prompted by a physical threat in the natural environment, today an evolutionary misfire occurs when this survival mechanism becomes prompted instead during everyday situations. Throughout human history, the experience of viewing an artwork has developed into an act of aesthetic appreciation involving a search for meaning. However, in this case, the sensory overload triggered by Nauman’s artwork purposefully impedes neuroprocessing, highlighting the adverse effects of mediation saturation in contemporary society; therefore, a stilling of the moving image in essence functions as a biological adaptation strategy in an attempt to come to terms with the puzzling nature of these artworks. By applying French philosopher Roland Barthes’s theories of the image, this article expands Barthes’s thought from the image to the performative as a reflection of human adaptation to technological advancement. (shrink)

During the early Cambrian period metazoan life forms diverged at an accelerated rate to occupy multiple ecological niches on earth. A variety of explanations have been proposed to address this major evolutionary phenomenon termed the “Cambrian explosion.” While most hypotheses address environmental, developmental, and ecological factors that facilitated evolutionary innovations, the biological basis for accelerated emergence of species diversity in the Cambrian period remains largely conjectural. Herein, we posit that morphogenesis by self‐organization enables the uncoupling of genomic (...) mutational landscape from phenotypic diversification. Evidence is provided for a two‐tiered interpretation of genomic changes in metazoan animals wherein mutations not only impact upon function of individual cells, but also alter the self‐organization outcome during developmental morphogenesis. We provide evidence that the morphological impacts of mutations on self‐organization could remain repressed if associated with an unmet negative energetic cost. We posit that accelerated morphological diversification in transition to the Cambrian period has occurred by emergence of dormant (i.e., reserved) morphological novelties whose molecular underpinnings were seeded in the Precambrian period. (shrink)

About 540 million years ago, a rapid radiation of animal phyla radically changed the Earth’s biota in a geological eye-blink. What caused this “Cambrian explosion”? Over the years, paleontologists have pointed to a wide array of different physical mechanisms as the causal “trigger” for the explosion. More recently, some paleontologists have proposed complex causal pathways to which multiple physical mechanisms are said to have contributed. Despite their variety, these answers share an assumption that a single explanation can in principle (...) be constructed that identifies some factor or confluence of factors as the cause of the Cambrian explosion. That assumption is unjustifiable. The Cambrian explosion had multiple causes, and different aspects of the event are best explained by different causes. These different causes cannot, even in principle, be integrated into a single causal explanation. We can learn much about the causes of the Cambrian explosiondor for that matter about any historical eventdbut only by attending more carefully to how we frame our causal questions about the past. (shrink)

This paper is about rewilding and the tensions it involves. Rewilding is a relatively novel approach to nature conservation, which seeks to be proactive and ambitious in the face of continuing environmental decline. Whilst definitions of rewilding place a strong emphasis on non-human agency, it is an inescapably human aspiration resulting in a range of social conflicts. The paper focuses on the case study of the Cambrian Wildwood project in Mid Wales (UK), evaluating the ways in which debate and (...) strategic action to advance rewilding is proceeding, assessing the extent to which compromise and learning has occurred amongst advocates. As such, we provide an important addition to the field, by detailing how conflicts play out over time and how actors' positioning and approach shifts, and why. In this case, tempers have flared around the threat that rewilding is seen to pose to resident farming communities. Tensions discussed include the differing social constructions of landscape and nature involved; the distribution of impacts on different stakeholders; and the relative power of different actors to make decisions and gain representation. Responding to these, the paper outlines how rewilding advocates have sought to advance a more peopled and culturally responsive vision, which seeks to champion sustainable livelihood strategies. The changes in approach detailed demonstrate a reflexive stance from rewilders, which suggests that learning and adaptation can occur. Nonetheless, caution is expressed regarding the extent to which rewilding can truly advance inclusive opportunities for rural change, given a continued return amongst stakeholders to exclusionary narratives of belonging and authenticity, suggesting substantive difficulty in moving beyond longstanding concerns over identity and the re-imagination of place. Rewilding, it would seem, is about who we think we are and how we co-constitute our sense of self. We, therefore, close by arguing that tactics and politicking can only have so much bearing, tensions over rewilding are unavoidably emotional. (shrink)

This book is unique in both its subject matter and its approach. It focuses on the collaboration of J. Derrida, J.-F. Lyotard, J. Hillis Miller, D. Carroll, F. Jameson and others at the Critical Theory Institute at the University of California, Irvine and on the application of critical theory for the analysis of contemporary American visual art. The critical and philosophical analysis concerns the art of Bruce Nauman, Kosuth, Burden, Christo, Wodiczko, Johns, Rauschenberg, and others. The focus of the (...) book is on irony and the sublime. The book also includes the original Prologue by G. van Den Abbeele (Dean of the School of Humanities at UC Irvine 2013-2018) on the history of Critical Theory in the United States, and at UCI, in particular. The CTI's uniqueness consisted in it being one of the best centers of the Critical Theory studies in the United States. (shrink)

One of the most interesting challenges facing paleobiologists is explaining the Cambrian explosion, the dramatic appearance of most metazoan animal phyla in the Early Cambrian, and the subsequent stability of these body plans over the ensuing 530 million years. We propose that because phenotypic variation decreases through geologic time, because microRNAs (miRNAs) increase genic precision, by turning an imprecise number of mRNA transcripts into a more precise number of protein molecules, and because miRNAs are continuously being added to (...) metazoan genomes through geologic time, miRNAs might be instrumental in the canalization of development. Further, miRNAs ultimately allow for natural selection to elaborate morphological complexity, because by reducing gene expression variability, miRNAs increase heritability, allowing selection to change characters more effectively. Hence, miRNAs might play an important role in shaping metazoan macroevolution, and might be part of the solution to the Cambrian conundrum. (shrink)

The early evolution of metazoans is a major focus of biological attention, but is the historical record revealed in the Cambrian “explosion” an accurate reflection of original events? The key questions concern the nature of the earliest animals and when they originated. One widely-mooted suggestion is that planktotrophic larvae, typified by the annelidan trochophore and echinoid pluteus, existed long before the metazoan radiations evident in the Cambrian fossil record. This idea could be consistent for recent evidence of divergence (...) times, based on molecular “clocks,” of phyla appearing well before the Cambrian. Now a surprising new discovery of eggs with blastomeres and embryos with well-defined anatomy from the Cambrian (c.530 Myr ago) of China and Siberia promises to extend the arena of debate. In one case a convincing ontogeny can be traced from eggs to adult tube-dwelling cnidarians. In the other example a possible protostome, unhatched and wrapped around the egg, shows segmentation and possibly nascent sclerites. In both, these cases development is direct, i.e., there is no evidence for any planktotrophic larval stage. The implications for our perceptions of both the Cambrian ‘explosion’ and metazoan phylogeny could be considerable. BioEssays 20:676–682, 1998.© 1998 John Wiley & Sons Inc. (shrink)

The Cambrian explosion is characterized by the sudden outburst of organized animal plans, which occurred circa 530 M years ago. Around that time, many forms of animal life appeared, including several which have since disappeared. There is no general consensus about “why” this happened, and why it had any form of suddenness. However, all organized animal plans share a common feature: they are triploblastic, i.e., composed of 3 layers of tissue, endoderm, ectoderm and mesoderm. I show here that, within (...) simple hypotheses, the formation of the mesoderm has intrinsically a physical exponential dynamics, leading rapidly to triploblastism, and eventually, to animal formation. A novel physico-mathematical framework including epithelium-mesenchyme transition, visco-elastic constitutive equations, and conservation laws, is presented which allows one to describe gastrulation as a self-wetting phenomenon of a soft solid onto itself. This phenomenon couples differentiation and migration during gastrulation, and leads in a closed form to an exponential scaling law for the formation of the mesoderm. Therefore, the Cambrian explosion might have started, actually, by a true visco-elastic “explosion”: the exponential run-away of mesenchymal cells. (shrink)

There are many gene families that are specific to multicellular animals. These have either diverged from ancestral genes that are shared with fungi and/or plants or evolved from an ancestral gene unique to animals. The evolution of gene families involved in cell–cell communication and developmental control has been studied to establish whether the number of member genes increased dramatically immediately prior to or in concert with the Cambrian explosion. A molecular phylogeny‐based analysis of several animal‐specific gene families has revealed (...) that gene diversification by duplication occurred during two active periods interrupted by a long intervening quiescent period. Intriguingly, the Cambrian explosion is situated in the silent period, indicating that there is no direct link between the first burst of gene diversification and the Cambrian explosion itself. The importance of gene recruitment as a possible molecular mechanism for morphological diversity, and its possible role for the Cambrian explosion, are discussed. BioEssays 23:1018–1027, 2001. © 2001 John Wiley & Sons, Inc. (shrink)

Analysis of the degree of intraspecific morphological polymorphism during the evolutionary history of trilobites using an informatic approach1 provides striking evidence of a long‐suspected but previously unsubstantiated pattern: degrees of polymorphism are markedly higher in phylogenetically basal, stratigraphically early species. This unequivocal pattern prompts further exploration of the relationship between microevolutionary variance and macroevolutionary history. It demonstrates that the ‘traditional’ fossil record of skeletonized organisms can provide unique insight into questions of major evolutionary interest. BioEssays 29:1081–1084, 2007. © 2007 Wiley (...) Periodicals, Inc. (shrink)