Why Do Hills Look So Steep?

2017 ◽  
Author(s):  
Frank H. Durgin ◽  
Zhi Li
Keyword(s):  
Current Knowledge ◽  
Perceptual Bias ◽  
Biological Information ◽  
Information Coding ◽  
Slant Perception ◽  
Perceived Environment ◽  
Surface Layout ◽  
Angular Declination ◽  
Coding Strategies ◽  
Biological Measurement

This chapter discusses the visual perception of hills. Hills look much steeper than they are. This chapter reviews current knowledge of the phenomenology of slant perception in relation to both functionalist and mechanistic accounts of this perceptual bias. Recent discoveries suggest that this misperception of the geometry of our environment may be related to useful biological information coding strategies with respect to not only slant but also other angular variables relevant to the biological measurement of surface layout. Even in the absence of hills, people misperceive the angular declination of their gaze systematically in ways that seem to contribute to the vertical expansion of the perceived environment.

scholarly journals The Ecology and Phylogeny of Hosts Drive the Enzootic Infection Cycles of Hantaviruses

Viruses ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 671
Author(s):  
Matthew T. Milholland ◽  
Iván Castro-Arellano ◽  
Gabriel E. Garcia-Peña ◽  
James N. Mills
Keyword(s):  
Small Mammal ◽  
Predictive Models ◽  
Current Knowledge ◽  
Disease Outbreaks ◽  
Biological Information ◽  
Hantavirus Infection ◽  
Infection Prevalence ◽  
Continental Scale ◽  
Mammal Assemblages ◽  
Published Research

Hantaviruses (Family: Hantaviridae; genus: Orthohantavirus) and their associated human diseases occur globally and differ according to their geographic distribution. The structure of small mammal assemblages and phylogenetic relatedness among host species are suggested as strong drivers for the maintenance and spread of hantavirus infections in small mammals. We developed predictive models for hantavirus infection prevalence in rodent assemblages using defined ecological correlates from our current knowledge of hantavirus-host distributions to provide predictive models at the global and continental scale. We utilized data from published research between 1971–2014 and determined the biological and ecological characteristics of small mammal assemblages to predict the prevalence of hantavirus infections. These models are useful in predicting hantavirus disease outbreaks based on environmental and biological information obtained through the surveillance of rodents.

The biology and palaeontology of the Peramelemorphia: a review of current knowledge and future research directions

2016 ◽  
Vol 64 (3) ◽  
pp. 151 ◽  
Author(s):  
N. M. Warburton ◽  
K. J. Travouillon
Keyword(s):  
Human Impacts ◽  
Current Knowledge ◽  
Urban Environments ◽  
Biological Information ◽  
Future Research ◽  
Biological Traits ◽  
European Settlement ◽  
Introduced Predators ◽  
History Of ◽  
Fossil Records

Bandicoots and bilbies (Marsupialia : Peramelemorphia) represent the dominant omnivorous clade of Australasian marsupials and, as ground-dwelling, small- to medium-sized mammals, have not fared well in the 200 years since European settlement. Unlike large or charismatic marsupial species, the cryptic nature of bandicoots and bilbies tends to keep them out of the public eye, at a time when public interest plays a significant role in conservation efforts. The inconspicuous ‘rat-like’ appearance of many bandicoots and a generalist ecological strategy belie a complex biology of adaptive traits and evolutionary diversity. For a few species these biological traits have enabled them to make use of urban environments. In the main, however, peramelemorphians are facing ongoing pressure from introduced predators and human impacts. Basic biological information for many species, particularly those from New Guinea, is still lacking. In this review, we examine advances in the knowledge of the biology of this group over the past 25 years including anatomical, physiological and ecological studies. We also provide a comprehensive review of the fossil records of bandicoots in order to provide an up-to-date platform for future studies. From this work, it is clear that there is still much to be done regarding the taxonomy and biology of these animals before a more detailed understanding of the evolutionary history of this group can be elucidated.

Holopothrips diversity—a Neotropical genus of gall-inducing insects (Thysanoptera, Phlaeothripidae)

Zootaxa ◽  
2018 ◽  
Vol 4494 (1) ◽  
pp. 1 ◽  
Author(s):  
MARIANA F. LINDNER ◽  
AUGUSTO FERRARI ◽  
LAURENCE A. MOUND ◽  
ADRIANO CAVALLERI
Keyword(s):  
New Species ◽  
Phylogenetic Relationships ◽  
Host Plants ◽  
Current Knowledge ◽  
Morphological Diversity ◽  
Biological Information ◽  
Key To Species ◽  
Future Studies ◽  
Plant Galls

The genus Holopothrips represents the main Neotropical group of thrips associated with plant galls, and several of the 36 currently described species are known to induce or invade galls of other organisms. The existence of several Holopothrips specimens in collections that do not belong to any of the already described species, allied to the absence of basic biological information for several species, such as host plants and habit, shows that the current knowledge on the genus is severely lacking. Here we start addressing these problems, by describing 24 new species: H. acrioris, H. atlanticus, H. bicolor, H. brevicapitatum, H. cardosoi, H. curiosus, H. flavisetis, H. graziae, H. inconspicuus, H. infestans, H. irregularis, H. johanseni, H. kaminskii, H. longihamus, H. longisetus, H. magnus, H. maiae, H. nigrisetis, H. nigrum, H. punctatus, H. reticulatus, H. singularis, H. spermathecus, H. varicolor. This study also includes information on galls for several species; an updated and illustrated key to species; and comments on the morphological diversity of the group. With that, we hope to lay the taxonomic and morphological bases for future studies in this group, focusing on its diversity, ecology and phylogenetic relationships. 

Systematics of Simothraulopsis Demoulin, 1966 (Ephemeroptera: Leptophlebiidae)

Zootaxa ◽  
2017 ◽  
Vol 4285 (1) ◽  
pp. 1 ◽  
Author(s):  
JEANE M. C. DO NASCIMENTO ◽  
FREDERICO F. SALLES ◽  
NEUSA HAMADA
Keyword(s):  
Phylogenetic Analysis ◽  
New Species ◽  
Current Knowledge ◽  
External Morphology ◽  
Biological Information ◽  
Phylogenetic Study ◽  
First Time

In the present paper, based on specimens from different regions of Brazil, we review the current knowledge of the Neotropical genus Simothraulopsis. A phylogenetic study was performed in order to address the relationships between all species and to test the monophyly of Simothraulopsis. For this purpose, 48 characters related to the external morphology of adults and nymphs were investigated. As a result, four new species are described; S. caliginosus sp.nov., S. dominguezi sp. nov., S. eurybasis sp. nov., S. inaequalis sp. nov. New taxonomic and biological information are added to this genus. Nymphs of S. diamantinensis Mariano, 2010 and S. janae Mariano, 2010 are described for the first time and several new distributional records for Brazil are provided. Additionally, keys for male imagos and nymphs of the genus are proposed. The phylogenetic analysis corroborated the monophyly of Simothraulopsis, however, the division in two subgenera as previously proposed was not recovered in our reconstruction. 

scholarly journals Extracellular Vesicles: Overview and Clinical Implications

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. SCI-25-SCI-25
Author(s):  
Francoise Dignat-George
Keyword(s):  
Extracellular Vesicles ◽  
Conflicts Of Interest ◽  
Current Knowledge ◽  
Body Fluids ◽  
Biological Information ◽  
Current Debate ◽  
Target Cells ◽  
Biological Functions ◽  
Disease Evolution ◽  
Methodological Guidelines

Abstract The release of extracellular vesicles (EVs) is a phenomenon shared by all cell types as a means of communication. Characterization and classification of EVs is challenging and still a matter of debate. However, a general consensus on EVs nomenclatura has been made, on the basis of their size, formation and release mechanisms. EVs has been classified into exosomes, secreted via exocytosis from the late endosome multivesicular bodies, whereas microvesicles (MVs) bud from the plasma membrane and apoptotic bodies are released by cells undergoing apoptosis. Initially regarded as cellular debris, EVs have gained considerable interest in basic sciences and medical research, both as biomarkers and mediators of biological functions. Indeed, EVs carry regulatory molecules including lipid, proteins and different RNA species through the extracellular spaces and deliver these cargos to target cells to modify cellular activity, thereby contributing to both physiological and pathological responses. Because EVs bear markers derived from their parent cells and can be detected in most body fluids, characterization of EVs of different cellular origin is an underestimated source of biological information on cellular activation during disease evolution, and will probably serve as valuable diagnostic and prognostic biomarker in the future. However, the current methods used for the EVs isolation and analysis have several limitations and lack standardization, leading to uncertainties regarding the subtypes of EVs studied and how to interpret the data. After a rapid overview of the current knowledge on the mechanisms of formation, subcellular origin and composition of the different types of EVs, this presentation will focus on microvesicles (MVs). We will first address how their structure/function diversity determines their multifaceted biological functions in coagulation, inflammation, angiogenesis and endothelial dysfunction (ref 1, 2, 3). Secondly, we will summarize the current debate on the different methodologies available for their analysis and quantification in body fluids. A specific attention will be devoted to standardization of sample processing and MVs analysis, and also to recommendations from scientific societies for EVs translational applications as emerging biomarkers measurable in liquid biopsies (ref 4, 5, 6). Finally, focusing on cardiovascular diseases and cancer as emerging field where MVs detection have promising impact to improve patient management, we will illustrate how combination of increasing fundamental knowledge, technological progress and standardization will push MVs towards reliable biomarkers ready for the clinics. 1- Ridger VC, Boulanger CM, Angelillo-Scherrer A, Badimon L, Blanc-Brude O, Bochaton-Piallat ML, Boilard E, Buzas EI, Caporali A, Dignat-George F, Evans PC, Lacroix R, Lutgens E, Ketelhuth DFJ, Nieuwland R, Toti F, Tunon J, Weber C, Hoefer IE. Microvesicles in vascular homeostasis and diseases. Position Paper of the European Society of Cardiology (ESC) Working Group on Atherosclerosis and Vascular Biology. Thromb Haemost. 2017;28;117(7):1296-1316. 2- Todorova D, Simoncini S, Lacroix R, Sabatier F, Dignat-George F. Extracellular Vesicles in Angiogenesis. Circ Res. 2017;12;120(10):1658-1673. 3- Lacroix R, Dubois C, Leroyer AS, Sabatier F, Dignat-George F. Revisited role of microparticles in arterial and venous thrombosis. J Thromb Haemost. 2013;11 Suppl 1:24-35. 4- Coumans FAW, Brisson AR, Buzas EI, Dignat-George F, Drees EEE, El-Andaloussi S, Emanueli C, Gasecka A, Hendrix A, Hill AF, Lacroix R, Lee Y, van Leeuwen TG, Mackman N, Mäger I, Nolan JP, van der Pol E, Pegtel DM, Sahoo S, Siljander PRM, Sturk G, de Wever O, Nieuwland R. Methodological Guidelines to Study Extracellular Vesicles. Circ Res. 2017;12;120(10):1632-1648. 5-Lacroix R, Judicone C, Mooberry M, Boucekine M, Key NS, Dignat-George F; The ISTH SSC Workshop. Standardization of pre-analytical variables in plasma microparticle determination: results of the International Society on Thrombosis and Haemostasis SSC Collaborative workshop. J Thromb Haemost. 2013 Apr 2. 6- Cointe S, Judicone C, Robert S, Mooberry MJ, Poncelet P, Wauben M, Nieuwland R, Key NS, Dignat-George F, Lacroix R. Standardization of microparticle enumeration across different flow cytometry platforms: results of a multicenter collaborative workshop. J Thromb Haemost. 2017;15(1):187-193. Disclosures No relevant conflicts of interest to declare.

Macroorganisation and flexibility of thylakoid membranes

2019 ◽  
Vol 476 (20) ◽  
pp. 2981-3018 ◽  
Author(s):  
Petar H. Lambrev ◽  
Parveen Akhtar
Keyword(s):  
Light Harvesting ◽  
Current Knowledge ◽  
Three Dimensional ◽  
Photosynthetic Apparatus ◽  
Dynamic Responses ◽  
State Transitions ◽  
Photochemical Quenching ◽  
Light Harvesting Complex ◽  
Complex Ii ◽  
Light Harvesting Complex Ii

Abstract The light reactions of photosynthesis are hosted and regulated by the chloroplast thylakoid membrane (TM) — the central structural component of the photosynthetic apparatus of plants and algae. The two-dimensional and three-dimensional arrangement of the lipid–protein assemblies, aka macroorganisation, and its dynamic responses to the fluctuating physiological environment, aka flexibility, are the subject of this review. An emphasis is given on the information obtainable by spectroscopic approaches, especially circular dichroism (CD). We briefly summarise the current knowledge of the composition and three-dimensional architecture of the granal TMs in plants and the supramolecular organisation of Photosystem II and light-harvesting complex II therein. We next acquaint the non-specialist reader with the fundamentals of CD spectroscopy, recent advances such as anisotropic CD, and applications for studying the structure and macroorganisation of photosynthetic complexes and membranes. Special attention is given to the structural and functional flexibility of light-harvesting complex II in vitro as revealed by CD and fluorescence spectroscopy. We give an account of the dynamic changes in membrane macroorganisation associated with the light-adaptation of the photosynthetic apparatus and the regulation of the excitation energy flow by state transitions and non-photochemical quenching.

The glycomes of Caenorhabditis elegans and other model organisms

2002 ◽  
Vol 69 ◽  
pp. 117-134 ◽  
Author(s):  
Stuart M. Haslam ◽  
David Gems ◽  
Howard R. Morris ◽  
Anne Dell
Keyword(s):  
Caenorhabditis Elegans ◽  
Current Knowledge ◽  
Structural Data ◽  
Model Organisms ◽  
Entire Genome ◽  
C Elegans ◽  
The Face ◽  
Area Of Concern ◽  
Nematode Worm

There is no doubt that the immense amount of information that is being generated by the initial sequencing and secondary interrogation of various genomes will change the face of glycobiological research. However, a major area of concern is that detailed structural knowledge of the ultimate products of genes that are identified as being involved in glycoconjugate biosynthesis is still limited. This is illustrated clearly by the nematode worm Caenorhabditis elegans, which was the first multicellular organism to have its entire genome sequenced. To date, only limited structural data on the glycosylated molecules of this organism have been reported. Our laboratory is addressing this problem by performing detailed MS structural characterization of the N-linked glycans of C. elegans; high-mannose structures dominate, with only minor amounts of complex-type structures. Novel, highly fucosylated truncated structures are also present which are difucosylated on the proximal N-acetylglucosamine of the chitobiose core as well as containing unusual Fucα1–2Gal1–2Man as peripheral structures. The implications of these results in terms of the identification of ligands for genomically predicted lectins and potential glycosyltransferases are discussed in this chapter. Current knowledge on the glycomes of other model organisms such as Dictyostelium discoideum, Saccharomyces cerevisiae and Drosophila melanogaster is also discussed briefly.

Nucleosome dynamics

2006 ◽  
Vol 73 ◽  
pp. 109-119 ◽  
Author(s):  
Chris Stockdale ◽  
Michael Bruno ◽  
Helder Ferreira ◽  
Elisa Garcia-Wilson ◽  
Nicola Wiechens ◽  
...  
Keyword(s):  
High Resolution ◽  
Chromatin Structure ◽  
Current Knowledge ◽  
Dynamic Properties ◽  
Structure And Dynamics ◽  
Nucleosome Dynamics ◽  
Sharp Focus ◽  
Recent Advances ◽  
Insight Into ◽  
Chromatin Structure And Dynamics

In the 30 years since the discovery of the nucleosome, our picture of it has come into sharp focus. The recent high-resolution structures have provided a wealth of insight into the function of the nucleosome, but they are inherently static. Our current knowledge of how nucleosomes can be reconfigured dynamically is at a much earlier stage. Here, recent advances in the understanding of chromatin structure and dynamics are highlighted. The ways in which different modes of nucleosome reconfiguration are likely to influence each other are discussed, and some of the factors likely to regulate the dynamic properties of nucleosomes are considered.

Mesophyll conductance: the leaf corridors for photosynthesis

2020 ◽  
Vol 48 (2) ◽  
pp. 429-439 ◽  
Author(s):  
Jorge Gago ◽  
Danilo M. Daloso ◽  
Marc Carriquí ◽  
Miquel Nadal ◽  
Melanie Morales ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Current Knowledge ◽  
Main Role ◽  
Mesophyll Conductance ◽  
Future Studies ◽  
Cell Structures ◽  
Leaf Tissues ◽  
Change Framework ◽  
Chloroplast Stroma

Besides stomata, the photosynthetic CO2 pathway also involves the transport of CO2 from the sub-stomatal air spaces inside to the carboxylation sites in the chloroplast stroma, where Rubisco is located. This pathway is far to be a simple and direct way, formed by series of consecutive barriers that the CO2 should cross to be finally assimilated in photosynthesis, known as the mesophyll conductance (gm). Therefore, the gm reflects the pathway through different air, water and biophysical barriers within the leaf tissues and cell structures. Currently, it is known that gm can impose the same level of limitation (or even higher depending of the conditions) to photosynthesis than the wider known stomata or biochemistry. In this mini-review, we are focused on each of the gm determinants to summarize the current knowledge on the mechanisms driving gm from anatomical to metabolic and biochemical perspectives. Special attention deserve the latest studies demonstrating the importance of the molecular mechanisms driving anatomical traits as cell wall and the chloroplast surface exposed to the mesophyll airspaces (Sc/S) that significantly constrain gm. However, even considering these recent discoveries, still is poorly understood the mechanisms about signaling pathways linking the environment a/biotic stressors with gm responses. Thus, considering the main role of gm as a major driver of the CO2 availability at the carboxylation sites, future studies into these aspects will help us to understand photosynthesis responses in a global change framework.

Assessment of Tongue Position and Laryngeal Height in Two Professional Voice Populations

2020 ◽  
Vol 63 (1) ◽  
pp. 109-124
Author(s):  
Carly Jo Hosbach-Cannon ◽  
Soren Y. Lowell ◽  
Raymond H. Colton ◽  
Richard T. Kelley ◽  
Xue Bao
Keyword(s):  
Vocal Fold ◽  
Vocal Tract ◽  
Current Knowledge ◽  
Acoustic Resonance ◽  
Contact Dynamics ◽  
Voice Disorder ◽  
Music Program ◽  
Tongue Position ◽  
Singer Groups ◽  
Professional Voice

Purpose To advance our current knowledge of singer physiology by using ultrasonography in combination with acoustic measures to compare physiological differences between musical theater (MT) and opera (OP) singers under controlled phonation conditions. Primary objectives addressed in this study were (a) to determine if differences in hyolaryngeal and vocal fold contact dynamics occur between two professional voice populations (MT and OP) during singing tasks and (b) to determine if differences occur between MT and OP singers in oral configuration and associated acoustic resonance during singing tasks. Method Twenty-one singers (10 MT and 11 OP) were included. All participants were currently enrolled in a music program. Experimental procedures consisted of sustained phonation on the vowels /i/ and /ɑ/ during both a low-pitch task and a high-pitch task. Measures of hyolaryngeal elevation, tongue height, and tongue advancement were assessed using ultrasonography. Vocal fold contact dynamics were measured using electroglottography. Simultaneous acoustic recordings were obtained during all ultrasonography procedures for analysis of the first two formant frequencies. Results Significant oral configuration differences, reflected by measures of tongue height and tongue advancement, were seen between groups. Measures of acoustic resonance also showed significant differences between groups during specific tasks. Both singer groups significantly raised their hyoid position when singing high-pitched vowels, but hyoid elevation was not statistically different between groups. Likewise, vocal fold contact dynamics did not significantly differentiate the two singer groups. Conclusions These findings suggest that, under controlled phonation conditions, MT singers alter their oral configuration and achieve differing resultant formants as compared with OP singers. Because singers are at a high risk of developing a voice disorder, understanding how these two groups of singers adjust their vocal tract configuration during their specific singing genre may help to identify risky vocal behavior and provide a basis for prevention of voice disorders.

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