Ultimate Cause Research Articles

A novel role of sphingolipids and mitochondria in glutamate‐induced programmed necrosis in oligodendrocytes

Oligodendrocytes play a prominent role in axon myelination and provide trophic factors and substrates for neurons. Under pathological conditions (e.g., ischemia/reperfusion, traumatic brain injury and stroke), the increase in extracellular glutamate levels evokes oligodendrocyte cell death, thus contributing to neuronal dysfunction. In contrast to the activation of ionotropic glutamate receptors in neurons, glutamate induces cell death in oligodendrocytes by depleting cells of cystine through the reversal of glutamate/cystine antiport mediated by system xc−. Our experiment revealed ferroptosis as a major contributing factor to glutamate‐initiated primary oligodendrocytes (OLs) death, while the contribution of necroptosis and apoptosis was excluded both on biochemical and pharmacological ground. However, in contrast to general view that disintegration of plasma membrane as a result of uncontrolled lipid peroxidation is the final step in execution of ferroptotic program, we demonstrate that inhibitors of the mitochondrial permeability transition pore, (MPTP) cyclosporine A and NIM811, attenuate glutamate‐induced cell death without affecting lipid peroxidation. This suggests bioenergetic failure as the ultimate cause of cell demise. We also identified a novel controlling factor of ferroptosis‐like cell death in OLs, sphingosine, a sphingolipid whose level in the mitochondrial compartment is increased in response to glutamate. This leads to suppression of the respiratory chain and enhanced production of reactive oxygen species, which contributes to MPTP opening. Experiments indicate that the enhanced sphingosine level originates from activation of acid sphingomyelinase (ASM) in the lysosomal compartment, which produces ceramide with its subsequent hydrolysis to sphingosine by acid ceramidase. The results of these studies highlight a novel mechanism of ASM involvement in governing mitochondrial ROS production and integrity, and suggest an important role of ASM in system xc−‐ dependent ferroptosis in the brain.Support or Funding InformationSupported by NIH grants NS083544 (TIG) and RO1 DK073336 (JJL).This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

The Course of History: Substantive Philosophy of History and the Scientific Study of History Explained

The ultimate cause of much historical, social and cultural change is the gradual accumulation of human knowledge of the environment. Human beings use the materials in their environment to meet their needs and increased human knowledge of the environment enables human needs to be met in a more efficient manner. The human environment has a particular structure so that human knowledge of the environment is acquired in a particular order. The simplest knowledge is acquired first and more complex knowledge is acquired later. The order of discovery determines the course of human social and cultural history as knowledge of new and more efficient means of meeting human needs, results in new technology, which results in the development of new social and ideological systems. This means human social and cultural history, has to follow a particular course, a course that is determined by the structure of the human environment. Given that a certain level of knowledge will result in a particular type of society, it is possible to ascertain the types of societies that were inevitable in human history. The course of history is not random and can be rationally and scientifically understood.

Acoustic interactions between plants and animals

Acoustic communication and reactions to acoustic cues are widespread and intensively studied in animals but have largely been neglected in other organisms such as plants. However, there is growing evidence for acoustic communication in plant-animal interactions. While knowledge about active acoustic signaling in plants (i.e. active sound production) is still in its infancy, research on passive acoustic signaling (i.e. reflection of animal sounds) revealed that bat-dependent plants have adapted to the bats’ echolocation systems by providing acoustic reflectors, which attract mutualistic animal partners. Studies also show that plants are able to perceive sound and thus, potentially can react to animals (e.g., physiologically). Moreover, in the course of evolution plants should become acoustically more attractive to mutualistic animals that find their plant partners based on sound and less conspicuous to parasites. The current challenge is to discover further examples of plants and animals that acoustically interact with each other. Understanding the underlying proximate mechanisms and ultimate causes of acoustic communication will shed light on an underestimated dimension of information transfer between plants and animals.Acoustic communication and reactions to acoustic cues are widespread and intensively studied in animals but have largely been neglected in other organisms such as plants. However, there is growing evidence for acoustic communication in plant-animal interactions. While knowledge about active acoustic signaling in plants (i.e. active sound production) is still in its infancy, research on passive acoustic signaling (i.e. reflection of animal sounds) revealed that bat-dependent plants have adapted to the bats’ echolocation systems by providing acoustic reflectors, which attract mutualistic animal partners. Studies also show that plants are able to perceive sound and thus, potentially can react to animals (e.g., physiologically). Moreover, in the course of evolution plants should become acoustically more attractive to mutualistic animals that find their plant partners based on sound and less conspicuous to parasites. The current challenge is to discover further examples of plants and animals that acoustically ...

LAPAROSCOPY FOR THE RECOVERY OF REPRODUCTIVE HEALTH IN WOMEN WITH POLYCYSTIC OVARY SYNDROME

Aim: to analyze the usefulness of laparoscopic methods for the recovery of reproductive health in women with polycystic ovary syndrome (PCOS). Materials and methods. A continuous retrospective analysis of 56 outpatient cards and case histories of women with PCOS and concomitant infertility for the period from 2013 to 2015 was conducted using the documentation from the Kursk Regional Perinatal Center. The average age of the patients was 28.29 ± 4.43 years, the duration of infertility – from 1 to 15 years. Anamnestic and clinical data, concomitant pathology and long-term results of laparoscopic treatment and diagnostic procedures were studied. Results. The patients underwent surgical treatment after conservative therapy failed to restore their fertility. As a result, 49 women (87.5%) were able to restore the regular menstrual cycle and 35 women (62.5%) got pregnant. Conclusion. The use of laparoscopy revealed the ultimate cause of infertility and allowed for surgical treatment able to restore the reproductive women’s health.

The causes and evolutionary consequences of variation in female mate choice in insects: the effects of individual state, genotypes and environments.

Sexual selection generally involves males evolving secondary sexual characters that satisfy the mating preferences of females. Behavioral ecologists have spent considerable research effort on identifying how variation in sexually-selected traits in insects is maintained among males at the expense of investigating the proximate and ultimate causes of variation in female mating preferences for those male traits. The past decade has witnessed improved effort in redressing this bias in insects with researchers identifying a host of factors intrinsic and extrinsic to the female as mediating flexibility in female mating behavior. Evidence is mounting that a female's social environment, whether experienced during development or as an adult, is key to shaping her mating preferences. Others have extended these observations to show that the genetic identity of the conspecific individuals comprising the social environment can have profound effects on female mating preferences via indirect genetic effects (IGEs), or through interspecific indirect genetic effects (IIGEs) if the genotype of heterospecifics influences plasticity in mating preferences. Considerably more work is needed to not only expand our list of mediating intrinsic and extrinsic factors but also to identify how their interaction influences individual variation in male and female mating preferences.

Æternus Est: Divinity as a Conceptual Necessity in the Principle of Causation

The modern belief that mindless forces can be ultimate efficient causes of natural events is a conceptual impossibility. The logically ultimate cause of any change, the something that is ultimately making it occur in the present moment, is either a mind or not. More specifically, the cause either chooses to act or it does not. By choice here, I mean an act of free will in the libertarian sense. Where there is choosing in this sense there must be a mind. And when we say that an agent acts thus freely, we mean that it acts without being causally determined to act by anything beyond itself. However, this is conceptually indistinguishable from the idea of an ultimate efficient cause. To say that an agent is the ultimate cause in a causal chain is, by definition, to say that it acts without being caused to act by anything beyond itself. It is the head of the causal chain. It is, therefore, a matter of conceptual necessity that ultimate causes be minds, a fact that we have been blind to since the Scientific Revolution on the bad analogy of machines. Thus, every force ultimately governing the universe must be a mind corresponding either to the polytheist’s or the monotheist’s generic definition of divinity, and monotheism’s eternal mind will always be the most complete and justifiable explanation for the existence of the universe as a whole, even for the existence of the gods themselves.

Can Ebola virus evolve to be less virulent in humans?

Understanding Ebola virus (EBOV) virulence evolution not only is timely but also raises specific questions because it causes one of the most virulent human infections and it is capable of transmission after the death of its host. Using a compartmental epidemiological model that captures three transmission routes (by regular contact, via dead bodies and by sexual contact), we infer the evolutionary dynamics of case fatality ratio on the scale of an outbreak and in the long term. Our major finding is that the virus's specific life cycle imposes selection for high levels of virulence and that this pattern is robust to parameter variations in biological ranges. In addition to shedding a new light on the ultimate causes of EBOV's high virulence, these results generate testable predictions and contribute to informing public health policies. In particular, burial management stands out as the most appropriate intervention since it decreases the R0 of the epidemics, while imposing selection for less virulent strains.

Atlantic Multidecadal Variability and the U.K. ACSIS Program

Abstract Atlantic multidecadal variability (AMV) is the term used to describe the pattern of variability in North Atlantic sea surface temperatures (SSTs) that is characterized by decades of basinwide warm or cool anomalies, relative to the global mean. AMV has been associated with numerous climate impacts in many regions of the world including decadal variations in temperature and rainfall patterns, hurricane activity, and sea level changes. Given its importance, understanding the physical processes that drive AMV and the extent to which its evolution is predictable is a key challenge in climate science. A leading hypothesis is that natural variations in ocean circulation control changes in ocean heat content and consequently AMV phases. However, this view has been challenged recently by claims that changing natural and anthropogenic radiative forcings are critical drivers of AMV. Others have argued that changes in ocean circulation are not required. Here, we review the leading hypotheses and mechanisms for AMV and discuss the key debates. In particular, we highlight the need for a holistic understanding of AMV. This perspective is a key motivation for a major new U.K. research program: the North Atlantic Climate System Integrated Study (ACSIS), which brings together seven of the United Kingdom’s leading environmental research institutes to enable a broad spectrum approach to the challenges of AMV. ACSIS will deliver the first fully integrated assessment of recent decadal changes in the North Atlantic, will investigate the attribution of these changes to their proximal and ultimate causes, and will assess the potential to predict future changes.

The missing link between philosophy and psychopathology.

The uncertainty regarding the scientific status of psychiatry arises from psychiatry's involvement with some unsolved problems, or put in another way, from its enmeshment in certain points of transition of contemporary science. There is, in primis, the unsolved problem of the relationship between the mind and the body and, moreo- ver, the intricate relationship of connection/disjunction among biology, social science, anthropology, philosophy, etc. To speak about what psychopathology can expect from philosophy is, above all, to immerse oneself in a debate about the conditions of possibility of psychiatry as a science. This debate is especially concerned with the models of knowledge that have, until now, been proposed to psychiatry. Those models oscillate between the Dilthey's paradigms of the "Science of Nature" and the "Science of Spirit". It is certain that psychopathology, as already indicated by Jaspers, is a discipline which is among the most involved regard- ing the use of the two different cognitive strategies. The first strategy concerns the concept of "explanation" and its rigid approach to the objective and ultimate cause of the phenomenon. The second strategy is the "comprehensive" approach. This model, which the hermeneutic thought defines "interpretative", theorizes the provisional character, the subjectiveness and the finiteness of every cognitive project. The interest of the authors is orientated towards the hermeneutic side (comprehensive-interpretative) of psychiatry, that which deals with the specificity of every clinical history, with the continuity of sense, and with intrinsic narrative intelligibility of every human event, psychopathological or not. This approach to psychopathology is based on the statement: "a clinical history is a text which must be interpreted". From this perspective, every clinical history should be perceived as a text to decipher but, above all, as a "text" to listen to, in the persevering expectation that it could disclose its particular "project of world". When speaking about psychiatry, we always face a problem which dominates all the others: the unsolved problem of the relation- ship between typicalness and singularity of subjective events. B.B. Mandelbrot, theorist of "fractals", sums this dilemma up clearly. He suggests that the innumerable variety of the configurations of Nature is a challenge to investigate the morphology of that which is "irregu- lar" in order to discover in it, as far as possible, a rule.

Function, Dysfunction, and Normality in Biological Sciences

A biological function is supposed to be performed adequately, and hence may fail to do so: this is dysfunction. This raises two questions. One is how to make explicit the way in which function can be discriminated from dysfunction without confusing dysfunction with non-function. The second question is how what is “right” and “wrong” can be legitimated by natural regulatory norms. A function can be viewed as a quality to which at least one variable with a definite set of values is associated. Accordingly, function and dysfunction are the same quality of the same trait, but differ in the values associated to this variable. Dysfunction occurs when the associated set of values does not match this normal state. Biological systems have the epistemic singularity that their existence is the consequence of two distinct causal regimes, the so-called “proximate” and “ultimate” causes, whose convergence defines a system’s prescriptive normality. Each cause imposes restrictive rules that limit the possible ways these systems can putatively exist. When a system is insensitive to ultimate cause, it is determined by proximate causation alone, and hence escapes its own prescriptive norms. In conclusion: (1) The normality of a biological system is defined by the convergence of proximate and ultimate causes. (2) A function is a variable-associated quality whose values are defined relative to the norms of the system. (3) Dysfunction occurs when the set of values of the same variable does not match the normality of the system, which can occur when the system is insensitive to ultimate causation.

Economic complexities and cognitive hurdles: Accounting for specific economic misconceptions without an ultimate cause.

Do folk-economic beliefs have an ultimate cause? We argue that, in many cases, the answer is negative. Cognition is constrained in both scope (via long-term memory [LTM]) and depth (via working memory [WM]). Consequently, laypeople are challenged by concepts essential for understanding complex systems, economics included: aggregation, indirect causation, and equilibrium. We discuss several economic misconceptions arising from this acute mismatch.

Aristotle’s consideration of Anaximander’s concept of [τὸ] ἄπειρον

In this paper we try to show that, according to Aristotle, Anaximandar, like Thales, Anaximenes and Heraclitus, is a monist in respect of the type of ultimate cause of composition and change in the phenomenal world, since he is a materialist, but not a material monist. According to Aristotle?s understanding, his ultimate material cause, which he, according to some testimonies, called [??] ???????, is a ?mixture? and not a homogeneous fundamental substance. The paper will also try to show that, according to Aristotle, the theory of the ultimate material cause is strictly related to the theory of change. Thales, Anaximens and Heraclitus explain cosmogony and changes in the phenomenal world by condensation and rarefaction of the ultimate homogeneous material cause, while Anaksimandar explains them by separating (and by merging) the heterogeneous parts of that cause.

D.H. Robertsonʼs ʻRealʼ Theory of Economic Fluctuation:

Abstract: This paper aims to explore the two essential factors of Dennis Holme Robertsonʼs theory of economic fluctuation. Of the two, his ʻeffortʼ concept is important as the core of his real theo-ry, and his ʻindustryʼ concept is methodologically significant. These concepts in his first book, A Study of Industrial Fluctuation, offer clarity regarding his economic view and a method of macroeconomic analysis. The ʻeffortʼ concept implicates the behavioural decision of individuals （micro-analysis）. All humans exert ʻeffortʼ for getting ʻsatisfactionʼ to maximise their ʻnet satisfaction,ʼ that is, the difference between utility and disutility. In other words, any behavioural decisions are based upon the ʻeffortʼ of individuals. The ʻindustryʼ concept is provisionally considered as a coordinated group of individuals. Therefore, the behavioural decision of ʻindustryʼ is assumed to be the same as that of individuals, which is based on an individualʼs ʻeffort.ʼ With these two concepts, Robertson gradually extended his analysis from an individual （micro-analysis） to industries and industry in general （macro-analysis）. This is the very macro analytical method of Robertsonian economics. The ʻeffortʼ concept is also the core of overall Robertsonian economics; for his subse-quent major theories, ʻcapitalismʼs golden ruleʼ and ʻlacking,ʼ also are grounded in his ʻeffortʼ concept. Any factors, such as the labour-capital conflict or monetary disturbance, can cause fluctuations. For Robertson, however, ʻeffortʼ is the only ʻrealʼ measure and should be assigned the highest weight as the essential factor. Such a re-evaluation of Robertsonʼs ʻrealʼ theory is expected to furnish some hints with regards to certain outstanding issues of Robertsonian economics: （1） the ultimate cause of discord with Keynes, （2） inheritances from Marshall, and （3） the unified understanding of the ʻrealʼ and ʻmonetaryʼ theories in Robertsonʼs works. JEL classification numbers: B 13, E 32.

Responding to multiple climate-linked stressors in a remote island context: The example of Yadua Island, Fiji

Island societies are being disproportionately affected by climate change, a situation likely to continue for some decades. Using an example of an island affected by multiple climate-linked stressors, a situation likely to become more common in the future, this paper examines the nature of these, the ways they are perceived and responded to by local residents, and how these people believe environmental changes might unfold in the future. Yadua Island has one settlement (Denimanu), where most of the 170 residents sustain themselves largely by fishing and farming. Like most Pacific Island settlements, Denimanu is coastal and has experienced progressive shoreline erosion that, a decade ago, washed away a row of houses. In 2012, a storm surge (during Tropical Cyclone Evan) demolished most of the remaining bure (traditional dwellings) in the village. The Fiji Government relocated the affected families to a new upslope location (Korovou), 80–230 m from the beach, and up to 20 m above mean sea level. In March 2017, heavy rain caused a landslide at the back of Denimanu that endangered the primary school, forcing its abandonment. Some questionnaires were given to representative members of the community in an attempt to understand and quantify the pressures that Yadua Island people are subject to, and how they plan to manage them. All respondents believed that climate change has affected their livelihoods and will continue to do so in the future. Clear majorities stated that climate change – especially higher temperatures and increased frequency/magnitudes of heavy-rain events – had negatively affected the supply of marine and terrestrial foods. Most respondents noted increased temperature and decreased precipitation. Clear majorities stated they would eventually relocate their homes further inland, and would consider planting mangroves. Most participants were contemplating the effects of climate change (especially sea-level rise) on food supply, prompting them to consider relocating lowland crop production further inland and planting crops that are more tolerant of saline groundwater and/or periodic wave over-wash. The people of Denimanu recognise how the environment has been changing but debate the ultimate cause of this and therefore how best to respond. It is likely that Yadua will become impacted more by tropical cyclones and sea-level rise (in particular) in the future. To be effective and sustainable, adaptation strategies should acknowledge residents’ worldviews and beliefs rather than try to uncritically substitute them.

REASSESSING “TOWARD A THEORY OF RACE, CRIME, AND URBAN INEQUALITY”

AbstractIn “Toward a Theory of Race, Crime, and Urban Inequality,” Sampson and Wilson (1995) argued that racial disparities in violent crime are attributable in large part to the persistent structural disadvantages that are disproportionately concentrated in African American communities. They also argued that the ultimate causes of crime were similar for both Whites and Blacks, leading to what has been labeled the thesis of “racial invariance.” In light of the large scale social changes of the past two decades and the renewed political salience of race and crime in the United States, this paper reassesses and updates evidence evaluating the theory. In so doing, we clarify key concepts from the original thesis, delineate the proper context of validation, and address new challenges. Overall, we find that the accumulated empirical evidence provides broad but qualified support for the theoretical claims. We conclude by charting a dual path forward: an agenda for future research on the linkages between race and crime, and policy recommendations that align with the theory’s emphasis on neighborhood level structural forces but with causal space for cultural factors.

A Question of Faith?: Stengers and Whitehead on Causation and Conformation

A Question of Faith? Stengers and Whitehead on Causation and Conformation Michael Halewood (bio) Introduction Generalized solutions with apparently limitless applications are anathema to Isabelle Stengers, who demands that we recognize the specificity of the remit of the abstractions that we are constructing. One hallmark of her work is the distrust of any response that appears to be able to mollify a wide range of positions, problems or questions. Stengers is also wary of denouncing the positions held by opponents by claiming to trap them in a logical vice or pinning them in an absurdity. This is why, in this article, I do not set out to solve either the problem of cause or the problem of faith. Instead, I want to eavesdrop on the ongoing conversation between Stengers and Whitehead and to provide some comments on how their remarks could help us reorient how we approach some of the unexpected interrelations between faith and cause in science, philosophy, and social science. Stengers’s stance does not imply that we should not be ambitious in the questions or problems that we address; though there is a need to pay attention to that which has been isolated as being of concern. In the discussions that follow, I will ask some apparently general questions, but these are motivated by a central problem, namely, the very status of cause and causation. When we take a strict theoretical approach to science, or adopt a purely philosophical position, we might find it easy to say that there is no such thing as cause in the abstract. There is no hidden ultimate cause that sits behind the world, governing, regulating and explaining every single moment, item and process of existence. Yet, we also believe that smoking causes cancer; we tell children that matches can cause fires; we inform our insurance company that it was the other car that caused the accident. However, such mentions of causation lack the strength of a full concept of cause. It is not that smoking inevitably and always leads to cancer; or that all matches are determined to produce fires; or that the other driver was compelled to crash into us. The effect is not present in the cause: the same cause does not always produce the same effect. This leaves us in the tricky position where we may dismiss cause on theoretical [End Page 80] grounds, but we find it harder to do without some notion of causation in our everyday lives. It is this problematic status of causation, as something that we may deny in some aspects of our lives and yet require in others, that I want to address in this article. For reasons which I hope will become clear, I will also link this to the notion of faith in science and in social science. I will use Stengers’s ideas to argue that we need some clarity with regard to the distinctions between cause as an abstract concept, individual causes, and the very notion of causation. Too often these are mixed, the boundaries blurred, and this can lead to unnecessary confusion and a premature rejection of “cause” as a genuine factor in the world and our experience of it. This lack of clarity certainly constitutes a problem for many a sociologist who have all been carefully schooled to talk only of correlations and to avoid, like the plague, any mention of direct causes; so that they unthinkingly cite the modern sociologist’s mantra –“Correlation is not causation”– a mantra which only makes sense if the very concept of cause is seen as problematic, as something to be shunned. In the analyses which follow, there are three elements that I want to draw out, in place of a solution. These are, first, the particular, and slightly peculiar, stance of modern science with regard to cause. Second, the idea that the problem of the problem of cause is one that we have inherited in a very specific way. A recognition of this legacy could allow for us to rethink the scope of this problem. Third, a reconsideration of the role of faith in both science and social science. Perhaps social science has lost faith in cause, when there...

Lead Gunshot Ingestion By A Peregrine Falcon

Summary. Lead ammunition represents a source of poisoning for raptors eating game. Although the Peregrine Falcon Falco peregrinus commonly preys on gamebirds, only a few cases of lead poisoning have been recorded, probably owing to the lack of specific investigations. We document an adult female found dead with many lead shot in the digestive tract, mixed with the remains of a feral Pigeon Columba livia domestica and a European Starling Sturnus vulgaris. Concentrations in heart blood clot, liver, kidney and bone suggest that lead poisoning was not the ultimate cause of death. However, lead levels in the blood clot suggest that a small amount of lead may have been absorbed from the shot. The two prey species involved cannot be hunted in Italy but they are intensively shot all year round to prevent damage to crops. —Andreotti, A., Fabbri, I., Menotta, S. & Borghesi, F. (2018). Lead gunshot ingestion by a Peregrine Falcon. Ardeola, 65: 53–58.

Motor asymmetries in fishes, amphibians, and reptiles.

The study of brain and behavioral lateralization in so-called "lower vertebrates" (fish, amphibians, and reptiles) has received increasing attention in the last years, in an attempt to understand its phylogenetic origins and evolutionary significance. Observations on the earliest tetrapods, the amphibians, have helped us to understand the evolution of limb preference and suggest that laterality could have appeared even prior to the evolution of tetrapods. Insights into lateralized behaviors in fish-such as the turning behavior-have had an important role in uncovering proximate and ultimate causes of motor lateralization in the vertebrate subphylum. Additionally, investigations on the alignment of behavioral preferences in fish populations have helped do develop formal models to explain the unequal distribution of left- and right-lateralized individuals as the result of evolutionarily stable strategies among lateralized asymmetric individuals that interact cooperatively or competitively.

The Decline in the U.S. Labor Force Participation Rate

After peaking around the year 2000, the Labor Force Participation Rate (LFPR) of Americans declined substantially, falling faster after the financial crisis of 2007. Since 2015, the LFPR has remained at its lowest in four decades. In this paper, we produce a comprehensive review of the literature investigating the causes of the recent decline in LFPR. We include works from the academic literature as well as the gray literature from research institutes and labor market experts, and published and unpublished studies. The literature reviewed signals multiple causes behind this decline. The research on the extent to which the Great Recession had caused the decline establishes that most of it cannot be attributed to cyclical factors. Additionally, the literature examines the relative importance of trend factors, such as long-running demographic patterns, which explain at least part of the decline. The review includes articles that aim to quantify the impact of one or more factors through statistical or econometric analysis or economic modeling. Demographic trends, like the aging of the Baby Boom Generation, explain a large portion of the decline. The rest of the decline can be attributed to factors that affect the participation rates of specific subpopulations, such as technological innovations and trade, as well as to changes in social programs, such as Social Security Disability Insurance. Some subpopulation trends are clear, but their ultimate causes are not fully understood, as is the case for female and youth LFPRs. We list these factors and point to important areas for future research.

The Roots of Global Inequality: The Role of Biogeography and Genetic Diversity

This paper adds further evidence supporting Jared Diamond’s hypothesis that global technological differences in the pre-modern era were fundamentally due to bio-geographic factors: the time elapsed since the onset of agriculture and husbandry, the size of the population relative to the territories, the shape of continents. An alternative hypothesis, that genetic diversity within populations is the ultimate cause of global inequalities, is also examined. Results show how there is no robust evidence supporting a possible effect of genetic diversity on international differences in population density and technology in the pre-modern era.