scholarly journals Are global hotspots of endemic richness shaped by plate tectonics?

2017 ◽  
Author(s):  
Pellissier Loïc ◽  
Christian Heine ◽  
Camille Albouy
Keyword(s):  
Plate Tectonics ◽  
Large Fraction ◽  
Spatial Models ◽  
Future Research ◽  
Deep Time ◽  
Current Location ◽  
Lithospheric Plates ◽  
Taxonomic Groups

AbstractSingular regions of the globe harbour a disproportionally large fraction of extant biodiversity. Spatial biodiversity gradients are frequently associated to extant ecological conditions using statistical models, but more rarely to paleo-environmental conditions, especially beyond the Quaternary. On one hand the role of plate tectonics in shaping the extant diversity of lineages is supported by numerous phylogenetic and fossil evidences, and on the other hand the spatial variation of biodiversity across the globe is rarely associated to geodynamic variables. In this study, we propose that plate tectonics explain the current location of hotspots of endemic richness across the globe. As an illustration, we used paleogeographies in a model, which quantifies through time and for each cell the potential dispersal across disconnected habitat patches. Rare events of dispersal across dynamic straits of unsuitable habitats allows species colonisation and that a subsequent absence of gene flow could lead to in-situ speciation. We evaluated whether this process could pinpoint the locations of hotspots of endemic richness computed from the ranges of 181,603 species across 14 taxonomic groups. The significant congruence between the regions highlighted by the model and the endemic richness provides evidences of the contribution of plate tectonics in shaping global biodiversity gradients. Places with high tectonic complexity, predominantly located at the confluence of major lithospheric plates such as the Mediterranean basin, Central America, Madagascar and South East Asia likely provided favourable circumstances for allopatric speciation and the emergence of new species across straits. While our illustration supports the role of plate tectonics, accounting for deep time geological events in spatial models of extant biodiversity is not straightforward. Future research should develop quantitative spatial models of biodiversity including the dynamic of ancient habitats.

scholarly journals Fundamental Role Of The H2A.Z C-Terminal Tail In The Formation Of Constitutive Heterochromatin

2021 ◽  
Author(s):  
László Imre ◽  
Péter Nánási ◽  
Rosevalentine Bosire ◽  
Ágota Csóti ◽  
Kata Nóra Enyedi ◽  
...  
Keyword(s):  
Posttranslational Modifications ◽  
Constitutive Heterochromatin ◽  
Large Fraction ◽  
Gene Expression Pattern ◽  
Histone Variant ◽  
Unusual Behavior ◽  
Isoform Specificity ◽  
The Stability

ABSTRACTNucleosome stability, a crucial determinant of gene regulation, was measured in a robust in situ assay to assess the molecular determinants of the stability of H2A.Z-containig nucleosomes. Surprisingly, a large fraction of H2A.Z detected by three different antibodies was released from the nucleosomes by salt together with H3, and was associated with H3K9me3 but not with H3K27me3 marked nucleosomes. This unusual behavior relied on the presence of the unstructured C-terminal chain of the histone variant, rather than on isoform specificity, posttranslational modifications or binding of the reader protein PWWPA2, as determined using cell lines expressing only particular forms of the variant. In the absence of this tail, or upon addition of an excess of the tail peptide to the nuclei of control cells, the canonical H2A-like stability features were readily restored and most of the H2A.Z-containing nucleosomes left the periphery and ended up in scattered foci in the nuclei. Concomitantly, the H3K9me3-marked constitutive heterochromatin was also dispersed, what was accompanied by increased overall nuclease sensitivity and significantly enhanced binding of intercalating dyes to the DNA. The DT40 cells expressing the tailless H2A.Z showed marked differences in their gene expression pattern and were distinguished by compromised DNA damage response. Thus, interactions involving a short H2A.Z peptide chain simultaneously determine the stability and accessibility features of chromatin involving the nucleosomes containing this histone variant and the localization of these large chromatin regions in the nucleus. Our data suggest that H2A.Z can function in both heterochromatic and in euchromatic scenarios depending on the molecular interactions involving its C-terminal unstructured tail, shedding light on the enigmatic double-faced character of this histone variant.

scholarly journals EXPRESS: Platelets, extracellular vesicles & coagulation in pulmonary arterial hypertension

2021 ◽  
pp. 204589402110210
Author(s):  
Sarah Cullivan ◽  
Claire A Murphy ◽  
Luisa Weiss ◽  
Shane P Comer ◽  
Barry Kevane ◽  
...  
Keyword(s):  
Pulmonary Arterial Hypertension ◽  
Arterial Hypertension ◽  
Therapeutic Interventions ◽  
Pulmonary Vasculature ◽  
Future Research ◽  
Regulatory Pathways ◽  
Paracrine Signalling ◽  
Pulmonary Arterial

Pulmonary arterial hypertension (PAH) is a rare disease of the pulmonary vasculature, characterised pathologically by proliferation, remodelling and thrombosis in situ. Unfortunately, existing therapeutic interventions do not reverse these findings and the disease continues to result in significant morbidity and premature mortality. A number of haematological derangements have been described in PAH which may provide insights into the pathobiology of the disease and also provide opportunities to target new therapeutic pathways. These include quantitative and qualitative platelet abnormalities, such as thrombocytopaenia, increased mean platelet volume (MPV) and altered platelet bioenergetics. Furthermore, a hypercoagulable state and aberrant negative regulatory pathways can be observed, which could contribute to thrombosis in situ in distal pulmonary arteries and arterioles. Finally, there is increasing interest in the role of extracellular vesicle (EV) autocrine and paracrine signalling in PAH, and their potential utility as biomarkers and novel therapeutic targets. This review focuses on the potential role of platelets, EVs and coagulation pathways in the pathobiology of PAH. We highlight important unanswered clinical questions and the implications of these observations for future research and PAH directed therapies.

scholarly journals Lithospheric mantle buoyancy: the role of tectonic convergence and mantle composition

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
K. Boonma ◽  
A. Kumar ◽  
D. Garcia-Castellanos ◽  
I. Jiménez-Munt ◽  
M. Fernández
Keyword(s):  
Lithospheric Mantle ◽  
Plate Tectonics ◽  
Convergence Rates ◽  
Chemical Compositions ◽  
Mineral Physics ◽  
Plate Convergence ◽  
Lithospheric Plates ◽  
Negative Buoyancy ◽  
Plate Subduction

AbstractPlate subduction and delamination, two key processes driving plate tectonics, are thought to be controlled by the buoyancy of the lithospheric mantle relative to the underlying asthenosphere. Most mantle delamination models consider a lithospheric density higher than the asthenosphere to ensure negative buoyancy (slab pull). However, mineral physics show that the continental lithospheric mantle density is lighter than the asthenosphere, and that only its pressure-temperature-composition dependence makes it become denser and unstable when sinking adiabatically. Here, we explore the controls on buoyancy using a 2D thermal-diffusive model of plate convergence, considering five chemical compositions and tectonothermal ages, namely Archon (>2.5 Ga), Proton (2.5–1.0 Ga), Tecton (<1.0 Ga), and two oceanic lithospheric plates of 30 Ma and 120 Ma. While the advection of colder rock in oceanic-like plates always results in negative buoyancy, Protons and Tectons exhibit an ability to slowly flip from negative to positive buoyancy at low convergence rates: they first favour the sinking due to advection and then become more buoyant because they are thinner and heat up faster during subduction. In contrast, the lighter density of cratons overprints this effect and hinders delamination or subduction, regardless of the convergence rate. This may explain why Archons are more stable during the Wilson cycle.

scholarly journals Reconstructing the ecology of a Jurassic pseudoplanktonic megaraft colony

2019 ◽  
Author(s):  
Aaron W. Hunter ◽  
David Casenove ◽  
Emily G. Mitchell ◽  
Celia Mayers
Keyword(s):  
Moisture Diffusion ◽  
Oceanic Islands ◽  
Diffusion Models ◽  
Deep Time ◽  
Cast Doubt ◽  
Commercial Logging ◽  
Mode Of Life ◽  
First Time

AbstractPseudoplanktonic crinoid megaraft colonies are an enigma of the Jurassic. They are among the largest in-situ invertebrate accumulations ever to exist in the Phanerozoic fossil record. These megaraft colonies and are thought to have developed as floating filter-feeding communities due to an exceptionally rich relatively predator free oceanic niche, high in the water column enabling them to reach high densities on these log rafts. However, this pseudoplanktonic hypothesis has never actually been quantitatively tested and some researchers have cast doubt that this mode of life was even possible. The ecological structure of the crinoid colony is resolved using spatial point process techniques and its longevity using moisture diffusion models. Using spatial analysis we found that the crinoids would have trailed preferentially positioned at the back of migrating structures in the regions of least resistance, consistent with a floating, not benthic ecology. Additionally, we found using a series of moisture diffusion models at different log densities and sizes that ecosystem collapse did not take place solely due to colonies becoming overladen as previously assumed. We have found that these crinoid colonies studied could have existed for greater than 10 years, even up to 20 years exceeding the life expectancy of modern documented megaraft systems with implications for the role of modern raft communities in the biotic colonisation of oceanic islands and intercontinental dispersal of marine and terrestrial species.Significance statementTransoceanic rafting is the principle mechanism for the biotic colonisation of oceanic island ecosystems. However, no historic records exist of how long such biotic systems lasted. Here, we use a deep-time example from the Early Jurassic to test the viability of these pseudoplanktonic systems, resolving for the first time whether these systems were truly free floating planktonic and viable for long enough to allow its inhabitants to grow to maturity. Using spatial methods we show that these colonies have a comparable structure to modern marine pesudoplankton on maritime structures, whilst the application of methods normally used in commercial logging is used to demonstrate the viability of the system which was capable of lasting up to 20 years.

Coping Humor as a Mediator Between Emotional Intelligence and Job Satisfaction

2017 ◽  
Vol 16 (3) ◽  
pp. 155-159 ◽  
Author(s):  
Peizhen Sun ◽  
Jennifer J. Chen ◽  
Hongyan Jiang
Keyword(s):  
Job Satisfaction ◽  
Emotional Intelligence ◽  
Future Research ◽  
Satisfaction Scale ◽  
Primary School Teachers ◽  
Mediating Role ◽  
Regulation Of Emotion ◽  
The Relationship ◽  
Overall Job Satisfaction

Abstract. This study investigated the mediating role of coping humor in the relationship between emotional intelligence (EI) and job satisfaction. Participants were 398 primary school teachers in China, who completed the Wong Law Emotional Intelligence Scale, Coping Humor Scale, and Overall Job Satisfaction Scale. Results showed that coping humor was a significant mediator between EI and job satisfaction. A further examination revealed, however, that coping humor only mediated two sub-dimensions of EI (use of emotion and regulation of emotion) and job satisfaction. Implications for future research and limitations of the study are discussed.

Public Administration in the Islamic World: Considering the Importance of Religion, its Values and Culture

2019 ◽  
Vol 19 (2) ◽  
pp. 23-38
Author(s):  
Daniel Hummel
Keyword(s):  
Public Administration ◽  
Core Values ◽  
Comparative Perspective ◽  
Religious Values ◽  
Future Research ◽  
Islamic World ◽  
Salient Region ◽  
The People ◽  
Comparative Public Administration

A small but growing area of public administration scholarship appreciates the influence of religious values on various aspects of government. This appreciation parallels a growing interest in comparative public administration and indigenized forms of government which recognizes the role of culture in different approaches to government. This article is at the crossroads of these two trends while also considering a very salient region, the Islamic world. The Islamic world is uniquely religious, which makes this discussion even more relevant, as the nations that represent them strive towards legitimacy and stability. The history and core values of Islam need to be considered as they pertain to systems of government that are widely accepted by the people. In essence, this is being done in many countries across the Islamic world, providing fertile grounds for public administration research from a comparative perspective. This paper explores these possibilities for future research on this topic.

Moderating Role of Gender in the Relationship between Cognitive Errors and Anxiety among Adolescents

2020 ◽  
Vol 4 (1) ◽  
pp. 86-102
Author(s):  
Tasnim Rehna ◽  
Rubina Hanif ◽  
Muhammad Aqeel
Keyword(s):  
Mental Health Problems ◽  
Adolescent Psychopathology ◽  
Future Research ◽  
Cognitive Errors ◽  
Adolescent Anxiety ◽  
Study Results ◽  
The Status ◽  
Manifest Anxiety ◽  
The Relationship

Background: Widespread social paradigms on which the status variances are grounded in any society, gender plays pivotal role in manifestation of mental health problems (Rutter, 2007). A hefty volume of research has addressed the issue in adults nonetheless, little is vividly known about the role of gender in adolescent psychopathology. Sample: A sample of 240 adolescents (125 boys, 115 girls) aging 12-18 years was amassed from various secondary schools of Islamabad with the approval of the Federal Directorate of Education (FDE), relevant authorities of the schools and the adolescents themselves. Instruments: Taylor Manifest Anxiety Scale (Taylor & Spence, 1953) and Children’s Negative Cognitive Errors Questionnaire (CNCEQ) by Leitenberg et al., (1986) were applied in present study. Results: Multiple regression analysis revealed that cognitive errors jointly accounted for 78% of variance in predicting anxiety among adolescents. Findings also exhibited that gender significantly moderated the relationship between cognitive errors and adolescent anxiety. Implications of the findings are discoursed for future research and clinical practice.

IN SITU AND PILOT ORGAN PERFUSION TECHNIQUES FOR THE STUDY OF METABOLIC DYNAMICS

1972 ◽  
Vol 68 (2_Supplb) ◽  
pp. S9-S25 ◽  
Author(s):  
John Urquhart ◽  
Nancy Keller
Keyword(s):  
Cardiac Output ◽  
Large Fraction ◽  
Experimental Studies ◽  
Test Substance ◽  
Organ Perfusion ◽  
Systemic Blood ◽  
Experimental Control ◽  
Arterial Blood ◽  
Vascular Connections

ABSTRACT Two techniques for organ perfusion with blood are described which provide a basis for exploring metabolic or endocrine dynamics. The technique of in situ perfusion with autogenous arterial blood is suitable for glands or small organs which receive a small fraction of the animal's cardiac output; thus, test stimulatory or inhibitory substances can be added to the perfusing blood and undergo sufficient dilution in systemic blood after passage through the perfused organ so that recirculation does not compromise experimental control over test substance concentration in the perfusate. Experimental studies with the in situ perfused adrenal are described. The second technique, termed the pilot organ method, is suitable for organs which receive a large fraction of the cardiac output, such as the liver. Vascular connections are made between the circulation of an intact, anaesthetized large (> 30 kg) dog and the liver of a small (< 3 kg) dog. The small dog's liver (pilot liver) is excised and floated in a bath of canine ascites, and its venous effluent is continuously returned to the large dog. Test substances are infused into either the hepatic artery or portal vein of the pilot liver, but the small size of the pilot liver and its blood flow in relation to the large dog minimize recirculation effects. A number of functional parameters of the pilot liver are described.

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