Ultimate Cause Research Articles

Developmental feedbacks and the emergence of individuality.

Behavioural individuality is a hallmark of animal life, with major consequences for fitness, ecology, and evolution. One of the most widely invoked explanations for this variation is that feedback loops between an animal's behaviour and its state (e.g. physiology, informational state, social rank, etc.) trigger and shape the development of individuality. Despite their often-cited importance, however, little is known about the ultimate causes of such feedbacks. Expanding on a previously employed model of adaptive behavioural development under uncertainty, we find that (i) behaviour-state feedbacks emerge as a direct consequence of adaptive behavioural development in particular selective environments and (ii) that the sign of these feedbacks, and thus the consequences for the development of behavioural individuality, can be directly predicted by the shape of the fitness function, with increasing fitness benefits giving rise to positive feedbacks and trait divergence and decreasing fitness benefits leading to negative feedbacks and trait convergence. Our findings provide a testable explanatory framework for the emergence of developmental feedbacks driving individuality and suggest that such feedbacks and their associated patterns of behavioural diversity are a direct consequence of adaptive behavioural development in particular selective environments.

Temporal and spatial variations of high-resolution strontium, carbon, and oxygen isotopic chemostratigraphy at the end-Permian crisis boundary in South China

Variable degrees of strontium, carbon, and oxygen isotopic perturbations related to the end-Permian mass extinction (EPME) were recorded from the Latest Permian (i.e., the Lopingian stage prior to the extinction event) to the Earliest Triassic recovery (i.e., the Induan stage), while the underlying causes for their temporal and spatial variations and marine paleoenvironmental indications were poorly understood. In this study, integrated high-resolution 87Sr/86Sr, δ13C, and δ18O proxies are presented across the Wuchiapingian/Changhsingian and Permian/Triassic boundaries within the stratigraphic framework calibrated with high-resolution conodont biostratigraphy and high-precision geochronology in three South China sections, i.e., the Liangfengya, the Meishan, and the Shangsi sections. High-resolution strontium isotopes revealed that the water-mass segregation and accelerated precipitation rate of strontium probably resulted in local heterogeneity and provincial features of 87Sr/86Sr values at short-time interval less than 1 Myr. This provincialism of 87Sr/86Sr values can serve high-resolution chemostratigraphy. Integrated δ13C and 87Sr/86Sr isotopes from the studied sections at the Wuchiapingian/Changhsingian boundary (WCB) revealed that spatial heterogeneity with respect to drift magnitudes and peak values of δ13C negative excursion was not associated with oceanic stratification or high terrestrial input, while the releasing of 13C-depleted CO2 by deep-marine volcanism could be a plausible cause. Moreover, integrated δ18O and 87Sr/86Sr isotopes indicated that the “cooling event” occurring at the WCB was a provincial event, which was influenced by water depth and marine volcanism. The integrated high-resolution 87Sr/86Sr, δ13C, and δ18O proxies confirmed that the oceanic stratification was an ultimate cause for shallow-to-deep-water δ13C gradient at the Permian/Triassic boundary (PTB), but having no link to paleoproductivity increase. The positive excursion of 87Sr/86Sr postdated negative shift of δ13C by ∼ 40 Kyr across the PTB from the studied intervals. This temporal chemostratigraphic variation revealed that terrestrial influx was not a major cause for negative excursion of δ13C. The shallow-to-deep-water 87Sr/86Sr gradient was observed across the PTB in the studied sections, which was probably caused by water segregation resulting from oceanic stratification and distances from high- or low-radiogenic strontium sources supplied by terrestrial input or marine volcanism.

Radiolarian size and silicification across the Paleocene-Eocene boundary and into the early Eocene

The Paleocene-Eocene Thermal Maximum (PETM) was a major environmental perturbation that drove range shifts, adaptation, and faunal turnover in marine and terrestrial clades. Open ocean planktonic responses—including body size trends—have been characterized for calcareous nannoplankton, dinocysts, and planktonic foraminifera. Relatively little, however, is known about the response of radiolarians, which share life modes and phylogenetic history with planktonic foraminifera but make their tests (i.e., ‘shells’) out of silica rather than calcium carbonate. Here, we compare radiolarian assemblage changes in the Southwest Pacific with assemblages from Atlantic and Indian Ocean sites. We also measured radiolarian test size before, during, and after the PETM in a pelagic sedimentary succession at Mead Stream, South Island, New Zealand. Our results show a substantial positive shift in mean radiolarian test size at Mead Stream at the assemblage level concurrent with the onset of the PETM, primarily due to an increase in the size and relative abundance of spumellarian radiolarians. We investigate oligotrophy, elevated seawater silica concentration, and redeposition as potential drivers for this size shift. Mead Stream radiolarians remain large for 1.3 Myr, long past the recovery of the carbon isotope excursion and a return to baseline in terrigenous sedimentation, bioturbation, and benthic foraminifera diversity, leaving the ultimate cause of the observed changes in test size uncertain. We find little evidence for a uniform morphological response to the event or its aftermath across sites, particularly as relates to the relative extent of silicification of different groups of radiolarians.

Pain in the world of the Old Testament : Linguistic images, cultural concepts, literary conceptions

For along time, biblical views of pain were used to relieve and legitimize suffering. Nowadays, however, pain is seen as an evil to be fought. Despite this difference, it is worth researching the variety of images of pain in the Old Testament in order to include them in current debates. 1)To reveal pain as acomplex experience of physical, spiritual and social aspects in the Old Testament texts and 2)to search for correspondences and differences between biblical and contemporary approaches to pain. Aphenomenology of pain in the times of ancient Israel is based on analysis of the Old Testament texts in the original Hebrew language. Even if native speakers are no longer available for comparison, the written language expresses an authentic attitude towards pain. In the Bible there are neither clear terms nor theoretical treatises on pain but linguistically coded patterns of processing complex painful experiences. Because, according to the biblical body image, feelings do not exist in human beings, pain is often experienced as an alien destructive force. Images of pain developed with aview to the individual are used as metaphors for collective situations of suffering that last over along period of time. Social and political upheavals played acrucial role in the development of Old Testament images of pain. That is why the ultimate cause of pain is only partially attributed to the divine, but more to human violence structures. The texts focus their hope on God as adeliverer from distress because he allows himself to be affected by pain.

Paleozoic Extinctions in Cosmoclimatological Context: ‘Non-Bolide’ Extraterrestrial Causes for Global Chilling

The Paleozoic Era experienced 4 major mass extinctions; i.e., end-Ordovician, Late Devonian, end-Guadalupian, and end-Permian episodes. As a cause of significant biodiversity decline, non-biological environmental change on global scale was inevitable; nonetheless, popular claims of bolide impact and/or large igneous province (LIP) with too many ad-hoc assumptions have not yet been accepted as common/universal explanations for the Paleozoic extinctions. Recent research on extinction causes evolved through two stages; i.e., the heyday of the bolide impact scenario in the 1980s, and the overtaking by a LIP-mantle plume scenario in the 1990–2000s. Lately, we may sense a return trend to extraterrestrial causes since the late 2000s, which is not a simple revival of the old bolide-impact model but a new proposal for a cosmoclimatological scenario relevant to extra-solar processes; i.e., supernovae explosions and relevant migration of dark clouds over the Solar System. This short article reviews the current status of extinction-related research, which emphasizes two key issues; i.e., the categorization of extinction causes and new perspectives on non-bolide extraterrestrial causes. The categorizing of extinction causes at four distinct levels is effective in separating “global triggers” on the Earth's surface from more essential “ultimate cases” within the Earth and/or on outside of the planet. Causes of extinction can be grouped into four distinct categories in a hierarchy, from small to large scale: i.e., Category 1 – direct kill mechanism for each local biota, Category 2 – background change in global environment, Category 3 – major geological phenomenon on the planet's surface, and Category 4 – ultimate cause from the interior and exterior of the planet. Recent advances in He isotope analysis for extinction-related sedimentary records suggest extraterrestrial causes, not of bolide impact but of the encounter with a dark cloud (nebula). Emerging new perspectives of cosmoclimatology leads to an alternative extinction scenario; e.g. 1) increased flux of galactic cosmic radiation (GCR) with extensive cloud cover and 2) passage of a dark cloud (nebula) enriched with micro-dusts (IDPs) enveloping the Solar System. Both meteoric cloud coverage and IDP-screen can induce lowering/shutdown of solar irradiance, which may drive global cooling and sea-level drop associated with biodiversity decline. The past star-burst events detected in the Milky Way Galaxy apparently coincide in timing with the cooling episodes associated with major extinctions of the Paleozoic, i.e., at the end-Ordovician, Late Devonian, and Late Permian. Given such astronomical processes associated with global cooling in the past, much older global freezing episodes, i.e., Proterozoic snowball Earth events developed under high atmospheric CO2 levels, can be likewise explained. The study of mass extinctions on the Earth is entering a new stage under new astrobiological perspectives.

Comparative evaluation of patient response and appearance after being treated for gingival hyperpigmentation with various surgical techniques involving the use of diamond bur, scalpel, laser and, electrocautery technique: A case series

The gingival colour is important in facial beauty of individual. Excessive melanin deposition is ultimate cause of ginigival hyperpigmentation. The degree of pigmentation varies from person to person and is determined by variety of factors, particularly melanoblastic activity. Gingival depigmentation is an periodontal plastic procedure in which hyperpigmented gingiva can be removed by various techniques. The technique selection should primarily be based on clinical experience and individual preferences, with primary indication of demand for improved esthetics. Each technique has its own advantages and disadvantages. Re-pigmentation after gingival depigmentation is important point of which clinicians should be aware. The present case series describes four treatment modalities and their outcomes in patients.

Revisiting the case for ‘feral’ humans under the light of the human self-domestication hypothesis: Focusing on language

Contemporary descriptions of ‘feral’ children generally preclude any insightful inference about the language deficits exhibited by these children, as well as the ultimate causes of their problems with language. However, they have been regularly used to support the view that language acquisition requires a proper social environment in order to occur. In this paper, we revisit the case for ‘feral’ children with the viewpoint that human evolution entailed a process of self-domestication that parallels what we find in domesticated animals. Because feralization commonly occurs in nature and because it entails a partial reversion of features of domestication, this self-domestication approach to the evolution of language reassesses the case for ‘feral’ children, particularly when compared with present-day conditions involving abnormal patterns of socialization, whether they are genetically-triggered as in autism spectrum disorder, or environmentally-triggered, as in reactive attachment disorder.

Toolkit article: Approaches to measuring social inequities in health in human biology research.

Across populations, human morbidity and mortality risks generally follow clear gradients, with socially-disadvantaged individuals and groups tending to have higher morbidity and mortality at all life stages relative to those more socially advantaged. Anthropologists specialize in understanding the proximate and ultimate factors that shape variation in human biological functioning and health and are therefore well-situated to explore the relationships between social position and health in diverse ecological and cultural contexts. While human biologists have developed sophisticated methods for assessing health using minimally-invasive methods, at a disciplinary level, we have room for conceptual and methodological improvement in how we frame, measure, and analyze the social inequities that might shape health inequities. This toolkit paper elaborates on some steps human biologists should take to enhance the quality of our research on health inequities. Specifically, we address: (1) how to frame unequal health outcomes (i.e., inequalities vs. disparities vs. inequities) and the importance of identifying our conceptual models of how these inequities emerge; (2) how to measure various axes of social inequities across diverse cultural contexts, and (3) approaches to community collaboration and dissemination. We end by discussing (4) future directions in human biology research of health inequities, including understanding the ultimate causes of sensitivity to social inequities and transitioning from research to action.

Adaptation of the yeast gene knockout collection is near-perfectly predicted by fitness and diminishing return epistasis.

Adaptive evolution of clonally dividing cells and microbes is the ultimate cause of cancer and infectious diseases. The possibility of constraining the adaptation of cell populations, by inhibiting proteins enhancing the evolvability, has therefore attracted interest. However, our current understanding of how genes influence adaptation kinetics is limited, partly because accurately measuring adaptation for many cell populations is challenging. We used a high-throughput adaptive laboratory evolution platform to track the adaptation of >18,000 cell populations corresponding to single-gene deletion strains in the haploid yeast deletion collection. We report that the preadaptation fitness of gene knockouts near-perfectly (R2= 0.91) predicts their adaptation to arsenic, leaving at the most a marginal role for dedicated evolvability gene functions. We tracked the adaptation of another >23,000 gene knockout populations to a diverse range of selection pressures and generalized the almost perfect (R2=0.72-0.98) capacity of preadaptation fitness to predict adaptation. We also reconstructed mutations in FPS1, ASK10, and ARR3, which together account for almost all arsenic adaptation in wild-type cells, in gene deletions covering a broad fitness range and show that the predictability of arsenic adaptation can be understood as a by global epistasis, where excluding arsenic is more beneficial to arsenic unfit cells. The paucity of genes with a meaningful evolvability effect on adaptation diminishes the prospects of developing adjuvant drugs aiming to slow antimicrobial and chemotherapy resistance.

CircEXOC5 facilitates cell pyroptosis via epigenetic suppression of Nrf2 in septic acute lung injury.

Acute lung injury (ALI) caused by sepsis is characterized by a destructive high inflammatory response in lungs, which is the ultimate cause of high mortality to patients diagnosed with sepsis. The objective of the present study is to explore the effect and related mechanisms of circEXOC5 on pyroptosis in septic ALI. Sepsis ALI mouse model was induced and established by CLP induction and sepsis MPVEC cell model by LPS. HE staining was used to detect lung tissue pathological changes. ELISA, flow cytometry, and Western blot were utilized to evaluate the release of inflammatory cytokines and cell pyroptosis, and RIP was applied to verify the binding relationship between EZH2 and circEXOC5 or Nrf2. Finally, the interaction between CircEXOC5 and EZH2, H3k27me3, and Nrf2 promoter regions was clarified using ChIP. CircEXOC5 levels were notably ascended in the lung tissues of septic ALI mice. And silencing circEXOC5 inhibited cell pyroptosis and the release of inflammatory cytokines in MPVEC stimulated by LPS. In addition, RIP and ChIP indicated that Nrf2 expression in MPVECs cells could be inhibited by circEXOC5 via recruiting EZH2. In addition, ML385 (a specific inhibitor of Nrf2) reversed the efficacy of Knockdown of circEXOC5 on the Inhibition of pyroptosis and inflammation of MPVEC cells stimulated by LPS. These results indicated that CircEXOC5 could promote cell pyroptosis through epigenetic inhibition of Nrf2 in septic ALI.

Possible impact of winter conditions and summer temperature on bank vole (Myodes glareolus) population fluctuations in Central Norway

In recent decades, population fluctuations of microtine rodents have frequently faded out in parts of northern Europe, possibly because of climate change. Weather events may affect the rodents directly, but also indirectly, by acting on factors that generate population fluctuations. However, few studies have addressed the latter aspect. A species well suited for such a study is the bank vole (Myodes glareolus), which usually increases in number after a year with high seed production of bilberry (Vaccinium myrtillus). We analysed two snap-trapping time series of bank vole from Central Norway. When controlling for the impact of seed production of bilberry and Norway spruce (Picea abies), the number of bank voles trapped in the low-altitude area was negatively related to a summer temperature index of the two previous years, possibly because of the impact of temperature on the nutritional status of food plants. In the area situated at the highest altitude, there was a negative relationship with the winter NAO-index and a positive relationship with a snow depth index. Wet and mild winters are assumed to give unfavourable snow conditions, with alternating thawing and freezing, sometimes also creating an ice-layer at ground level, whereas a sufficient thick snow cover protects the rodents in periods with critical low temperatures. We conclude that an understanding of the ultimate cause of population fluctuations is needed to reveal the disturbing effects of weather events or other factors.

The Self-Constrained Hand-to-Mouth

Abstract Many studies have shown that consumption responds to the arrival of predictable income (excess sensitivity). This paper uses a buffer stock model of consumption to understand what causes excess sensitivity and to test which parameterization is consistent with empirical excess sensitivity estimates. Using high-frequency granular data from a personal finance app, I find that while liquidity constraints are a proximate cause, preferences are the ultimate cause of excess sensitivity. Furthermore, it finds that for feasible parameters, a quasi-hyperbolic version of the model is more consistent with the level of excess sensitivity relative to a standard exponential model.

Evaluation of fitness capacities of children and young adults with Marfan and related conditions

Early diagnosis of Marfan syndrome (MFS) leads us to a comprehensive approach to the multisystem damage related to connective tissue fragility. Impairment in exercise capacity has a great impact on quality of life (QoL) and rehabilitation programs need to address his ultimate causes. We have analysed fitness capacities of patients from a young age until early adulthood, and analysed the causes of limitation. This study included 28 Marfan or associated syndrome patients between 7 and 20 years (average 12.6 years), with mild aortic dilatation for 50% (mean z -score +2,4), no major valvulopathy, no cardiac impairment and history of pneumothorax for 3 of them; most where under preventive betablocker treatment (93%). All of them performed a cardiopulmonary exercise test (CPET) on step incremental cycloergometer. All but one patient reached maximum effort. Results confirm the disease's significant impact on the exercise capacity from a young age. The VO2max values were severely impaired in this population, on average reaching 63.4% of the expected values (mean peak of 104 Watts, 72% of expected work), with a limitation occurring in 71% and resulting from peripheral muscle deconditioning beside chronotropic limitation from betablockers (mean heart rate at peak of 163 bpm, 80.7% of the theoretical maximum). No intrinsic cardiac or pulmonary limitation was observed whereas dyspnoea was a major limiting factor in our patients, over muscular fatigue (dotted 6.5/10 vs. 5.8/10, respectively). These results were correlated to QoL when compared to a control population. The impact of the Marfan syndrome's multisystemic damage and physical impairment through muscular deconditioning is evident from a young age and should not be neglected. Namely, the care provided to patients should include adapted physical activity programs from a young age.

Learning from Experience? COVID-19 Conspiracy Theories and Their Implications for Democratic Discourse

Learning from Experience?COVID-19 Conspiracy Theories and Their Implications for Democratic Discourse Jennifer Hochschild (bio) and David Beavers (bio) in a survey fielded on march 7, 2020, more than three times as many Democrats as Republicans (61 percent and 20 percent, respectively) agreed that the United States was concealing the true scale of SARS-CoV-2 deaths. Republicans were nearly 20 percentage points more likely than Democrats (57 percent and 38 percent, respectively) to agree that the coronavirus is a man-made epidemic. With fewer than 300 confirmed COVID-19 cases in the United States (CDC 2020), pandemic beliefs with no clear basis in fact were already flourishing and were already colored by Americans' partisan lenses. This case points to large questions. Although research shows that "basically all Americans hold conspiracy beliefs" (Smallpage et al. 2020, 264), we do not know enough about adherence to these beliefs and consequences for American politics. The very concept is contested—one person's plausible hypothesis or praise for imaginative thinking is another's conspiracy theory. But at least for those who see conspiracy theories as a threat to democratic governance, definitions share a few features. Karen Douglas and coauthors define [End Page 859] them as "attempts to explain the ultimate causes of significant social and political events and circumstances with claims of secret plots by two or more powerful actors" (Douglas et al. 2019, 4). Joseph Uscinski and his colleagues, who are among the most influential political scientists writing on this topic, similarly define a conspiracy theory as "a proposed explanation of events that cites as a main causal factor a small group of persons (the conspirators) acting in secret for their own benefit, against the common good" (Uscinski, Klofstad, and Atkinson 2016, 58). Such theories are not new to American politics. Richard Hofstadter set their pejorative framework by "borrowing a clinical term for other purposes" in describing conspiracism as a mental illness ([1964] 2008, 3). Although some argue that conspiracy theories should be analyzed neutrally or even favorably in some circumstances (Butter and Knight 2020a), most analysts of democracy agree with Hofstadter in fearing and condemning them. They worry that conspiracy theories are gaining importance in our era of partisan polarization, hyperpartisan media, disdain for norms of civility and facticity among some political elites, and digital networks' capacity to create "a global network of village idiots" (Lenny Pozner, in Kolbert 2019). Adherence to conspiracy theories might even be deadly. Early in the COVID-19 pandemic, exposure to misinformation was associated with increased cases and deaths, most likely by discouraging individuals from wearing masks, socially distancing, and minimizing travel (Ash et al. 2020; Bursztyn et al. 2020). By March 2022, Americans over age 12 who were not vaccinated, sometimes due to acceptance of theories about vaccines' harms to one's body, were 17 times more likely to die from COVID-19 than were those who had received primary vaccines and a booster dose (CDC 2022). Coronavirus-related conspiracy narratives may also undermine democratic discourse and practice. Furious encounters between people with opposing views on COVID-19 are commonplace on- and offline. Patients and their families who deny the disease's existence have spit on and threatened medical staff, and some public health [End Page 860] experts feel under threat (McKay et al. 2020). Belief in a connection between COVID-19 and 5G telecommunications technology was positively associated with state anger and greater justification for violence now or perhaps in the future (Jolley and Paterson 2020). More generally, as one scholar summarizes, "conspiracy theories … have been linked to climate denial, vaccine refusal, political apathy, apathy in the workplace, prejudice, crime, and violence. … Conspiracy theories about COVID-19 are no exception" (Douglas 2021, 271). Despite the fact that some beliefs arguably endanger public health, democratic polities must be cautious about restraining conspiracy narratives. Commitments to freedom of speech and assembly, along with protections for privacy, civil liberty, and freedom from surveillance, make it difficult to balance the need for effective governance and public safety against the imperative of individual freedom. And disagreement about how to attempt the balance itself adds another layer of challenge to democracy. In the survey that we describe and analyze...

Michael L. Raposa Plays with Peirce, Love, and Signs: Review Essay on Theosemiotic: Religion, Reading, and the Gift of Meaning

Michael L. Raposa Plays with Peirce, Love, and Signs: Review Essay on <i>Theosemiotic: Religion, Reading, and the Gift of Meaning</i>

Russia-Ukraine Crisis And Economic Sanction: Power Politics Through Geoeconomic Means

The nature of international politics has always been volatile, chaotic and anarchic. The state’s national interest remains permanent when dealing with others. Although the current Russian invasion of Ukraine has been driven by the national interests objective and forthcoming security threat from North Atlantic Treaty Organisation (NATO). Ukraine’s wish to join NATO is the ultimate cause of War. Now, military escalation has taken place and this war has created the largest humanitarian crisis Europe has seen in decades. The war also leads to the global crisis in rising oil and gas prices, and food stuff shortages. Now, the Eurasian region has become a hotbed of power struggles between the Western bloc and Russia. However, Western countries placed a series of sanctions on Russia in response to the invasion, aimed at weakening its economy. Despite this, most European countries still purchase Russian oil and gas. As a result, it has become ambiguous due to geopolitical and geoeconomic interplay in the ongoing war. On the other hand, Ukraine is also receiving military aid from western countries to fight Russia. So, this paper will discuss the current crisis via a geoeconomic lens, as well as how power politics is played through geoeconomic methods.

Model-based orbital-scale precipitation δ18O variations and distinct mechanisms in Asian monsoon and arid regions

The past Asian precipitation δ18O (δ18Op) records from stalagmites and other deposits have shown significant orbital-scale variations, but their climatic implications and regional differences are still not fully understood. This study, as the first attempt of a 300-kyr transient stable isotope-enabled simulation, investigated the characteristics and mechanisms of the orbital-scale δ18Op variations in three representative regions of Asia: arid Central Asia (CA), monsoonal South Asia (SA) and monsoonal East Asia (EA). The modelling results showed that the variations in the CA, SA and EA annual δ18Op exhibited significant but asynchronous 23-kyr precession cycles. Further analyses revealed that although the precession-induced insolation variation was the ultimate cause of the δ18Op variation in all three regions, the dominant mechanisms and the involved physical processes were distinct among them. For the CA region, the rainy-season (November-March) temperature effect and water vapour transport by the westerly circulation were identified as the key precession-scale processes linking the October-February boreal mid-latitude insolation to the rainy-season or annual δ18Op. In the SA region, the rainy-season (June-September) precipitation amount effect and upstream depletion of the monsoonal water vapour δ18O served as the main mechanisms linking the rainy-season or annual δ18Op to the April-July insolation variation at the precession scale. For the EA region, however, the precession-scale annual δ18Op was mainly controlled by the late-monsoon (August-September) and pre-monsoon (April-May) water vapour transport patterns, which were driven by the July-August insolation and the global ice volume, respectively. These results suggest that the climatic implications of the orbital-scale Asia δ18Op variations are sensitive to their geographic locations as determined by the combined effects of insolation and regional circulation patterns associated with the respective rainy seasons. This study provides new insights into understanding the regional differences and formation mechanisms of the Asian orbital-scale δ18Op variations.

Cerebral blood flow is associated with markers of neurodegeneration in Huntington’s disease

IntroductionThe ultimate cause of neuronal death in Huntington's disease (HD) is still uncertain. Apart from impairment in systems handling abnormal proteins, other mechanisms might contribute to neurodegeneration and progression of HD. Decreased cerebral blood flow (CBF) has been described in other neurodegenerative disorders and may play a role in HD. ObjectivesTo investigate CBF changes in HD gene carriers. MethodsA group of 39 HD gene carriers (18 premanifest and 21 manifest HD) and 16 controls underwent a comprehensive clinical evaluation and a brain magnetic resonance imaging protocol that included pseudo-continuous arterial spin labeling to quantify CBF. Regions of interest (ROI) analyses were performed to compare CBF in controls vs premanifest HD vs manifest HD. Correlation analyses were performed to ascertain the relationship between CBF and clinical and biomarkers data. ResultsWe found a decrease in CBF in bilateral caudate and putamen of patients with manifest HD in comparison with controls. CBF of premanifest HD carriers in the same ROIs was midway between controls and the HD patients, with differences not reaching statistical significance. Lower CBF in caudate and putamen was associated with worse motor symptoms, functionality, and cognitive performance. CBF was also associated with markers of neurodegeneration: higher CBF in caudate and putamen significantly correlated to higher volumes in the same ROI and to lower levels of neurofilament light chain. ConclusionAs CBF changes in caudate and putamen nuclei were associated with markers of neurodegeneration and with clinical outcomes, decreased CBF and oxygen supply could emerge as a relevant mechanism contributing to degeneration in HD.

Linking personality traits and reproductive success in common marmoset (Callithrix jacchus)

Animal personality can affect individual fitness and population growth. Personality traits of either parent or parents’ combination may facilitate reproduction and offspring survival across species. However, previous studies focused mainly on the role of only one sex, and the link between personality and fitness has not been confirmed in primates. We examined this link in both sexes of captive common marmosets (Callithrix jacchus), a cooperatively breeding primate with extensive paternal care. We studied the effects of five personality traits of the parents (Agreeableness, Assertiveness, Conscientiousness, Inquisitiveness, and Patience), including their absolute and directional differences within pairs, on key components of reproductive performance. We expected pairs with more similar personality scores to have higher reproductive success as found in other species with long-term pairs and biparental care, but found no evidence for this hypothesis. Instead, we detected strong effects of female traits on inter-birth intervals, which were shorter in more agreeable females, and fecundity rates, which were higher in more inquisitive females. Male traits appeared to have only a limited effect on reproductive success of the pair. Our study demonstrates that various aspects of animal personality underpin reproductive performance in captive common marmosets and provides novel insights into the possible ultimate causes of personality in cooperatively breeding species.

Juvenile-to-adult transition invariances in fishes: Perspectives on proximate and ultimate causation.

To bridge physiological and evolutionary perspectives on size at maturity in fishes, the authors focus on the approximately invariant ratio between the estimated oxygen supply at size at maturity (Qm ) relative to that at asymptotic size (Q∞ ) among species within a taxonomic group, and show how two important theories related to this phenomenon complement each other. Gill-oxygen limitation theory proposes a mechanistic basis for a universal oxygen supply-based threshold for maturation, which applies among and within species. On the contrary, the authors show that a generalisation of life-history theory for the invariance of size at maturity (Lm ) relative to asymptotic size (L∞ ) can provide an evolutionary rationale for an oxygen-limited maturation threshold (Qm /Q∞ ). Extending previous inter- and intraspecific analyses, the authors show that maturation invariances also occur in lake whitefish Coregonus clupeaformis (Mitchill 1818), but at both scales, theory seems to underestimate the value of the maturation threshold. They highlight some key uncertainties in the model that should be addressed to help resolve the mismatch.