scholarly journals Joint assessment of density correlations and fluctuations for analysing spatial tree patterns

2021 ◽  
Vol 8 (1) ◽  
pp. 202200
Author(s):  
P. Villegas ◽  
A. Cavagna ◽  
M. Cencini ◽  
H. Fort ◽  
T. S. Grigera
Keyword(s):  
Single Species ◽  
Barro Colorado Island ◽  
Tropical Rainforests ◽  
Forest Plot ◽  
Density Correlation ◽  
Tree Patterns ◽  
Joint Assessment ◽  
Shed Light ◽  
Density Correlations ◽  
Made In

Inferring the processes underlying the emergence of observed patterns is a key challenge in theoretical ecology. Much effort has been made in the past decades to collect extensive and detailed information about the spatial distribution of tropical rainforests, as demonstrated, e.g. in the 50 ha tropical forest plot on Barro Colorado Island, Panama. These kinds of plots have been crucial to shed light on diverse qualitative features, emerging both at the single-species or the community level, like the spatial aggregation or clustering at short scales. Here, we build on the progress made in the study of the density correlation functions applied to biological systems, focusing on the importance of accurately defining the borders of the set of trees, and removing the induced biases. We also pinpoint the importance of combining the study of correlations with the scale dependence of fluctuations in density, which are linked to the well-known empirical Taylor’s power law. Density correlations and fluctuations, in conjunction, provide a unique opportunity to interpret the behaviours and, possibly, to allow comparisons between data and models. We also study such quantities in models of spatial patterns and, in particular, we find that a spatially explicit neutral model generates patterns with many qualitative features in common with the empirical ones.

scholarly journals Whole-Body Regeneration in Sponges: Diversity, Fine Mechanisms, and Future Prospects

Genes ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 506
Author(s):  
Alexander Ereskovsky ◽  
Ilya E. Borisenko ◽  
Fyodor V. Bolshakov ◽  
Andrey I. Lavrov
Keyword(s):  
Single Species ◽  
Whole Body ◽  
Phylogenetic Position ◽  
Main Body ◽  
Regenerative Processes ◽  
Cellular Mechanisms ◽  
Different Types ◽  
Dissociated Cells ◽  
Shed Light ◽  
Regeneration Processes

While virtually all animals show certain abilities for regeneration after an injury, these abilities vary greatly among metazoans. Porifera (Sponges) is basal metazoans characterized by a wide variety of different regenerative processes, including whole-body regeneration (WBR). Considering phylogenetic position and unique body organization, sponges are highly promising models, as they can shed light on the origin and early evolution of regeneration in general and WBR in particular. The present review summarizes available data on the morphogenetic and cellular mechanisms accompanying different types of WBR in sponges. Sponges show a high diversity of WBR, which principally could be divided into (1) WBR from a body fragment and (2) WBR by aggregation of dissociated cells. Sponges belonging to different phylogenetic clades and even to different species and/or differing in the anatomical structure undergo different morphogeneses after similar operations. A common characteristic feature of WBR in sponges is the instability of the main body axis: a change of the organism polarity is described during all types of WBR. The cellular mechanisms of WBR are different across sponge classes, while cell dedifferentiations and transdifferentiations are involved in regeneration processes in all sponges. Data considering molecular regulation of WBR in sponges are extremely scarce. However, the possibility to achieve various types of WBR ensured by common morphogenetic and cellular basis in a single species makes sponges highly accessible for future comprehensive physiological, biochemical, and molecular studies of regeneration processes.

scholarly journals Coronavirus and Soft Law in Germany: Business as Usual?

2021 ◽  
pp. 1-17
Author(s):  
Matthias Knauff
Keyword(s):  
Legal Order ◽  
Soft Law ◽  
Constitutional Order ◽  
Binding Forms ◽  
Almost All ◽  
Business As Usual ◽  
Shed Light ◽  
Made In

In combating the coronavirus pandemic in Germany, soft law has played an important, albeit not a central, role. Its use basically corresponds to that of under “normal circumstances”. In accordance with the German constitutional order, almost all substantial decisions are made in a legally binding form. However, these are often prepared through or supplemented by soft law. This article shows that soft law has played an important role in fighting the pandemic and its effects in Germany, although there cannot be any doubt that legally binding forms of regulation have prevailed. At the same time, the current pandemic has shed light on the advantages and effects of soft law in the context of the German legal order.

scholarly journals The graffiti art and the discover of the Keith Haring’s mural in Amsterdam

2020 ◽  
pp. 236-249
Author(s):  
Caterina Soliani
Keyword(s):  
New York ◽  
Collective Memory ◽  
Street Art ◽  
Art World ◽  
Continuous Growth ◽  
The World ◽  
To Come ◽  
The Many ◽  
Shed Light ◽  
Made In

The purpose of this work is to contribute to the continuous growth of the art world (Street Art in particular) and to discuss how it is essential for the discovery of artists. These artists have been pioneers and forerunners of new pictorial techniques, freeing creative and psychological flair, and combining the latter with the artistic technology that promises great things despite limited materials.  The intention of this article is to consider the elements of artistic expression that are less commonly subject to discussion, such as the world of Street Art. This form of artwork has not always been understood or accepted, with street artists waiting for the opportune moment to express the narrative, experiences, and emotions of society through their artwork, a power that unites sentiment and encourages change.  It is art which affects the community, the population and society. It is designed above all others to become part of the collective memory through violence of image and colour.  This project led me to come into contact with one of the many artistic artefacts of the Street Art movement, the Keith Haring’s mural in Amsterdam, a piece that makes me. understand and appreciate the problems inherent to these type of works, simple, synthetic, but never simplistic.  Therefore, a project, a study and a restoration hypothesis were conducted on one of the many works by Haring. The purpose of this was to shed light once again on the mural made in 1986 by the artist, situated in the Groothandeles Market of Amsterdam. No longer visible for thirty years, the mural was covered by insulation panels placed two years after its creation. With professors Antonio Rava and William Shank, the association Keith Haring Foundation of New York, the Stedelijk Museum of Amsterdam, in collaboration with the gallery Vroom & Varossieau, specialised in road art, on 8 June, the large metal sheet panels were removed and one of the greatest murals by Haring could once again be admired.

scholarly journals Two new frog species (Microhylidae: Cophixalus) from the Australian Wet Tropics region, and redescription of Cophixalus ornatus

Zootaxa ◽  
2012 ◽  
Vol 3271 (1) ◽  
pp. 1 ◽  
Author(s):  
CONRAD J. HOSKIN
Keyword(s):  
Single Species ◽  
Biological Species ◽  
Tropical Rainforests ◽  
Genetic Lineages ◽  
North East ◽  
The North ◽  
Mating Call ◽  
The Family ◽  
Wet Tropics ◽  
Multiple Species

In Australia the frog family Microhylidae is largely restricted to tropical rainforests of the Wet Tropics region in the north-east of the country, but in that region the family is diverse. Only one species, Cophixalus ornatus, is widespread in the WetTropics but there has been suspicion that it may comprise multiple species. A recent study (Hoskin et al. 2011) assessedgenetic and phenotypic variation across the range of C. ornatus, finding three deeply divergent genetic lineages that differin mating call and some aspects of morphology. Two of these lineages abutt in the central Wet Tropics and in that areahybridization was found to be very limited despite sympatry at high densities. Based on multiple lines of data, Hoskin etal. (2011) concluded that the three genetic lineages represent biological species. The taxonomy of these three lineages isresolved here. I describe two new species, Cophixalus australis sp. nov. and Cophixalus hinchinbrookensis sp. nov., andredescribe C. ornatus. The three species are not distinguishable based on any single morphological or call trait and arebest identified by genetics or locality. The distributions of the three species are largely allopatric. Cophixalus ornatus isfound in rainforest in the northern Wet Tropics, C. australis sp. nov. occurs in rainforest and adjacent wet sclerophyllforests in the central and southern Wet Tropics, and C. hinchinbrookensis sp. nov. inhabits rainforest and montane heathon Hinchinbrook Island. All three species are common. Cophixalus australis sp. nov. contains three genetic subgroupsthat are considered a single species based on phenotypic similarity and high levels of hybridization at contact zones. Thedescription of Cophixalus australis sp. nov. and Cophixalus hinchinbrookensis sp. nov. brings the number of Australian Cophixalus species to 18, 15 of which are restricted to the Wet Tropics region.

scholarly journals TRPV1: Structure, Endogenous Agonists, and Mechanisms

2020 ◽  
Vol 21 (10) ◽  
pp. 3421 ◽  
Author(s):  
Miguel Benítez-Angeles ◽  
Sara Luz Morales-Lázaro ◽  
Emmanuel Juárez-González ◽  
Tamara Rosenbaum
Keyword(s):  
Ion Channel ◽  
Binding Sites ◽  
Transient Receptor Potential ◽  
Receptor Potential ◽  
Transient Receptor Potential Vanilloid ◽  
Trpv1 Channel ◽  
Field Of Study ◽  
Transient Receptor ◽  
Shed Light ◽  
Made In

The Transient Receptor Potential Vanilloid 1 (TRPV1) channel is a polymodal protein with functions widely linked to the generation of pain. Several agonists of exogenous and endogenous nature have been described for this ion channel. Nonetheless, detailed mechanisms and description of binding sites have been resolved only for a few endogenous agonists. This review focuses on summarizing discoveries made in this particular field of study and highlighting the fact that studying the molecular details of activation of the channel by different agonists can shed light on biophysical traits that had not been previously demonstrated.

scholarly journals Host-Microbiome Synergistic Control on Sphingolipid Metabolism by Mechanotransduction in Model Arthritis

Biomolecules ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 144 ◽  
Author(s):  
Zhou ◽  
Devescovi ◽  
Liu ◽  
Dent ◽  
Nardini
Keyword(s):  
Autoimmune Disorders ◽  
Host Immunity ◽  
Sphingolipid Metabolism ◽  
Systemic Diseases ◽  
Collagen Induced Arthritis ◽  
Invariant Natural Killer ◽  
Shed Light ◽  
Therapy Methotrexate ◽  
Important Progress ◽  
Made In

Chronic inflammatory autoimmune disorders are systemic diseases with increasing incidence and still lack a cure. More recently, attention has been placed in understanding gastrointestinal (GI) dysbiosis and, although important progress has been made in this area, it is currently unclear to what extent microbiome manipulation can be used in the treatment of autoimmune disorders. Via the use of appropriate models, rheumatoid arthritis (RA), a well-known exemplar of such pathologies, can be exploited to shed light on the currently overlooked effects of existing therapies on the GI microbiome. In this direction, we here explore the crosstalk between the GI microbiome and the host immunity in model arthritis (collagen induced arthritis, CIA). By exploiting omics from samples of limited invasiveness (blood and stools), we assess the host-microbiome responses to standard therapy (methotrexate, MTX) combined with mechanical subcutaneous stimulation (MS) and to mechanical stimulation alone. When MS is involved, results reveal the sphingolipid metabolism as the trait d’union among known hallmarks of (model) RA, namely: Imbalance in the S1P-S1PR1 axis, expansion of Prevotella sp., and invariant Natural Killer T (iNKT)-penia, thus offering the base of a rationale to mechanically modulate this pathway as a therapeutic target in RA.

Lifting the veil: the circumstances that caused Alfred Wegener's death on the Greenland icecap, 1930

Polar Record ◽  
2000 ◽  
Vol 36 (197) ◽  
pp. 139-154 ◽  
Author(s):  
Cornelia Lüdecke
Keyword(s):  
Weather Conditions ◽  
Single Individual ◽  
Geographical Society ◽  
Memorial Address ◽  
German Science ◽  
The Veil ◽  
A Chain ◽  
Bad Weather ◽  
Shed Light ◽  
Made In

AbstractWhen the Geographical Society of Berlin officially welcomed Alfred Wegener's expedition back from Greenland in 1931, a memorial address was made in honour of the expedition leader who died on the Greenland icecap in 1930. This address included a report that shed light on the difficulties that had confronted the expediton. Wegener was remembered as a researcher who provided an example of ‘a magnificent conception of his duty as leader’ and who risked his life to rescue his comrades. Wegener's death was blamed on a chain of unfortunate accidents, especially bad weather conditions. Using material that was hidden in the archives, this paper examines several additional aspects of the story, such as the influence of the Notgemeinschaft der Deutschen Wissenschaft (Emergency Society for German Science), which financed the expedition; the erroneous judgements of the expedition leader as well as some expedition members; and the lack of radio transmission. The conclusion is that no single individual can be blamed for Wegener's death, despite the fact that one expedition member, Johannes Georgi, was made the scapegoat.

scholarly journals Density-density correlations in a Luttinger liquid: Lattice approximation in the Calogero-Sutherland model

1999 ◽  
Vol 77 (5) ◽  
pp. 327-341 ◽  
Author(s):  
D Sen ◽  
R K Bhaduri
Keyword(s):  
Luttinger Liquid ◽  
Exact Results ◽  
Dimensional Model ◽  
Lattice Method ◽  
One Dimensional ◽  
Density Correlation ◽  
Time Correlations ◽  
Sutherland Model ◽  
Lattice Approximation ◽  
Density Correlations

For a one-dimensional model in which the two-body interactions are long-range and strong, the system almost crystallizes. The harmonic modes of such a lattice were used by Krivnov and Ovchinnikov to compute the ground-state wave function and the dynamical density-density correlations. We review this method, and apply it to the Calogero-Sutherland model, whose density-density correlation functions are exactly known for certain values of the coupling constant. We show numerically that the correlations obtained are quite accurate even if the coupling is not very large. Such comparisons have been made earlier by Forrester. The lattice method is considerably simpler than the ones used to derive the exact results, and yields expressions for the correlations- which are easily plotted. The equal-time correlations can be expanded in inverse powers of coupling; we show that the two leading order terms agree with the exact results which are known for integer values of the coupling. The strength-dependent power law fall-off is typical of a Luttinger liquid.In a general one-dimensional model where the two-body interaction decreases as a power of the relative distance, we argue, following Schulz, that at zero temperature the system behaves as a Luttinger liquid if the power exceeds 1, and as a Wigner crystal if it is less than 1.PACS Nos.: 63.20-e, 71.10Pm

Why so many mammalian spermatozoa - a clue from marsupials?

1984 ◽  
Vol 221 (1223) ◽  
pp. 221-233 ◽  
Keyword(s):  
Didelphis Virginiana ◽  
High Survival ◽  
High Survival Rate ◽  
Sperm Production ◽  
Australian Family ◽  
Cauda Epididymidis ◽  
Virginia Opossum ◽  
Shed Light ◽  
Mammalian Spermatozoa ◽  
Made In

Mammals generally ejaculate many more spermatozoa than seem to be needed for fertilization. This apparent profligacy has not been explained, but observations made in marsupials may shed light on it. The Virginia opossum, Didelphis virginiana , inseminates only about three million spermatozoa, a very low number. As a corollary, relatively few ( ca . 13 x 10 6 ) are stored in each cauda epididymidis. However, some 5% of the spermatozoa that the opossum ejaculates populate the oviduct about 12 h later when ovulation can be anticipated - a success rate in the female orders of magnitude greater than in eutherian mammals. I t is not certain what determines the unusually efficient transport to and the high survival rate of spermatozoa in the oviduct of Didelphis , but two unusual features suggest themselves as possible contributors. Didelphis (and all other American marsupial) spermatozoa undergo a head-to-head pairing in the epididymis by the acrosomal face; this serves to isolate the acrosome of ejaculated spermatozoa from the female milieu until the pairs separate in the oviduct. Secondly, spermatozoa are housed in special crypts in the isthmus of the oviduct. Australian marsupials, which usually lack such features, store spermatozoa in the epididymis in numbers more close to those in comparably sized eutheriam mammals. Exceptions which store very low sperm numbers there can be seen in one Australian Family, the Dasyuridae. The spermatozoa of dasyurids are not paired, but the species examined possess distinctive sperm storage crypts in the oviducal isthmus similar to those in the opossum. The present findings suggest that where mechanisms exist that could protect the acrosome and, or, the whole spermatozoon in the female tract, a much lower level of sperm production can be maintained without compromising fertility. While the number ejaculated typically by any one species is probably determined ultimately by several interacting factors, it therefore seems likely that a most important one in this respect relates to conditions spermatozoa face in the female tract.

Genetic basis of Parkinson disease

2010 ◽  
Vol 28 (1) ◽  
pp. E7 ◽  
Author(s):  
Georgia Xiromerisiou ◽  
Efthimios Dardiotis ◽  
Vaïa Tsimourtou ◽  
Persa Maria Kountra ◽  
Konstantinos N. Paterakis ◽  
...  
Keyword(s):  
Parkinson Disease ◽  
Molecular Mechanisms ◽  
Autosomal Recessive Inheritance ◽  
Alpha Synuclein ◽  
Collaborative Studies ◽  
Common Genetic Variants ◽  
Cellular Pathways ◽  
Meta Analyses ◽  
Shed Light ◽  
Made In

Over the past few years, considerable progress has been made in understanding the molecular mechanisms of Parkinson disease (PD). Mutations in certain genes are found to cause monogenic forms of the disorder, with autosomal dominant or autosomal recessive inheritance. These genes include alpha-synuclein, parkin, PINK1, DJ-1, LRRK2, and ATP13A2. The monogenic variants are important tools in identifying cellular pathways that shed light on the pathogenesis of this disease. Certain common genetic variants are also likely to modulate the risk of PD. International collaborative studies and meta-analyses have identified common variants as genetic susceptibility risk/protective factors for sporadic PD.

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