953,948 research outputs found
Leptinotarsa decemlineata (Coleoptera: Chrysomelidae) Observed Feeding on Chamaesaracha sp. in Eastern Colorado.
Egg, larval, and adult life stages of Colorado potato beetle, Leptinotarsa decemlineata (Say), were observed feeding on or attached to a previously undocumented host plant belonging to the genus Chamaesaracha in eastern Colorado on July 2017. At one site, L. decemlineata were more abundant on Chamaesaracha sp. than the accepted ancestral host plant, Solanum rostratum (Dunal). While future studies should confirm the ancestral status of the observed L. decemlineata and suitability of Chamaesaracha sp. for completion of development, our observations suggest a need for further characterization of the ancestral host range of L. decemlineata
Cooking shapes the structure and function of the gut microbiome
Diet is a critical determinant of variation in gut microbial structure and function, outweighing even host genetics1-3. Numerous microbiome studies have compared diets with divergent ingredients1-5, but the everyday practice of cooking remains understudied. Here, we show that a plant diet served raw versus cooked reshapes the murine gut microbiome, with effects attributable to improvements in starch digestibility and degradation of plant-derived compounds. Shifts in the gut microbiota modulated host energy status, applied across multiple starch-rich plants, and were detectable in humans. Thus, diet-driven host-microbial interactions depend on the food as well as its form. Because cooking is human-specific, ubiquitous and ancient6,7, our results prompt the hypothesis that humans and our microbiomes co-evolved under unique cooking-related pressures
Long Gamma-Ray Burst Host Galaxies and their Environments
In this book-chapter we first briefly discuss some basic observational issues
related to what a GRB host galaxy is (whether they are operationally well
defined as a class) and sample completeness. We then describe some of the early
studies of GRB hosts starting with statistical studies of upper limits done
prior to the first detections, the first host detection after the BeppoSAX
breakthrough and leading up to the current Swift era. Finally, we discuss the
status of efforts to construct a more complete sample of GRBs based on Swift
and end with an outlook. We only consider the host galaxies of long-duration
GRBs.Comment: 31 pages, 14 figures; Chapter 13 in "Gamma-Ray Bursts", eds. C.
Kouveliotou, R. A. M. J. Wijers, S. E. Woosley, Cambridge University Press,
201
Does the anaesthetic influence behavioural transmission of the monogenean Gyrodactylus gasterostei Glaser, 1974 off the host?
The aim of this study was to investigate the use of the anaesthetic 2-phenoxyethanol on the transmission factors of gyrodactylid and to ascertain how this may affect in the colonisation of new hosts using the Gyrodactylus gasterostei Glaser, 1974 - Gasterosteus aculeatus L. model which is a simple and successful system to examine aspects of transmission of parasites from live and dead fish. Laboratory experiments include determining the maturity (presence of male copulate organ) and reproductive (presence of daughter) status of transmitting worms, in order to consider the factors that influence parasite option to migrate to a new individual of the same host species. This study demonstrates that parasites with a Male Copulate Organ (MCO) present are more likely to abandon the host and attempt a host transfer. The use of the anaesthetic 2-phenoxyethanol does not affect transmission of gyrodactylids which leave the host to colonise a new host. Finally, the use of other anaesthetic although its relative importance with respect to transmission remains uncertain.Department of the Environment, Food and Rural Affairs (Defra); Overseas Research Students Awards Scheme (ORSAS) UK; Consejo Nacional Ciencia y Tecnologia, Mexico CONACyT [171032]info:eu-repo/semantics/publishedVersio
Extrasolar Planets and Their Host Stars
In order to understand the exoplanet, you need to understand its parent star.
Astrophysical parameters of extrasolar planets are directly and indirectly
dependent on the properties of their respective host stars. These host stars
are very frequently the only visible component in the systems. This book
describes our work in the field of characterization of exoplanet host stars
using interferometry to determine angular diameters, trigonometric parallax to
determine physical radii, and SED fitting to determine effective temperatures
and luminosities. The interferometry data are based on our decade-long survey
using the CHARA Array. We describe our methods and give an update on the status
of the field, including a table with the astrophysical properties of all stars
with high-precision interferometric diameters out to 150 pc (status Nov 2016).
In addition, we elaborate in more detail on a number of particularly
significant or important exoplanet systems, particularly with respect to (1)
insights gained from transiting exoplanets, (2) the determination of system
habitable zones, and (3) the discrepancy between directly determined and
model-based stellar radii. Finally, we discuss current and future work
including the calibration of semi-empirical methods based on interferometric
data.Comment: 80 pages in SpringerBrief format containing a few blank pages, 16
figures, 1 table of all stars with high-precision interferometric diameters,
glossary of commonly encountered terms, SpringerBrief 2017, ISBN
978-3-319-61198-
Mathematical models for vaccination, waning immunity and immune system boosting: a general framework
When the body gets infected by a pathogen or receives a vaccine dose, the
immune system develops pathogen-specific immunity. Induced immunity decays in
time and years after recovery/vaccination the host might become susceptible
again. Exposure to the pathogen in the environment boosts the immune system
thus prolonging the duration of the protection. Such an interplay of within
host and population level dynamics poses significant challenges in rigorous
mathematical modeling of immuno-epidemiology. The aim of this paper is twofold.
First, we provide an overview of existing models for waning of
disease/vaccine-induced immunity and immune system boosting. Then a new
modeling approach is proposed for SIRVS dynamics, monitoring the immune status
of individuals and including both waning immunity and immune system boosting.
We show that some previous models can be considered as special cases or
approximations of our framework.Comment: 18 pages, 1 figure keywords: Immuno-epidemiology, Waning immunity,
Immune status, Boosting, Physiological structure, Reinfection, Delay
equations, Vaccination. arXiv admin note: substantial text overlap with
arXiv:1411.319
Tax sensitivity of foreign direct investment : an empirical assessment
Tax sensitivity of foreign direct investment (FDI) has important policy implications. If FDI is not responsive to taxation, then it may be an appropriate target for taxation by the host country, which can raise revenue without sacrificing any economic benefits FDI produces. This paper examines the effects of taxation on FDI in Mexico. The empirical model used for this purpose distinguishes FDI finance by transfers and retained earnings and incorporates host and home country tax and non-tax factors including host country risk factors and credit status of multinationals. The paper concludes that empirical evidence on tax sensitivity of FDI in Mexico is quite strong. It suggests that FDI transfers and reinvested earnings respond negatively to the Mexican effective tax rate and to regulations. It is further dampened by the excess credit status of multinationals. It is encouraged by a favorable economic and political climate in Mexico, as indicated by the country credit rating of The Institutional Investor and by tariffs.International Terrorism&Counterterrorism,Banks&Banking Reform,Environmental Economics&Policies,Public Sector Economics&Finance,Economic Theory&Research
Gamma-ray burst host galaxies and the link to star-formation
We briefly review the current status of the study of long-duration gamma-ray
burst (GRB) host galaxies. GRB host galaxies are mainly interesting to study
for two reasons: 1) they may help us understand where and when massive stars
were formed throughout cosmic history, and 2) the properties of host galaxies
and the localisation within the hosts where GRBs are formed may give essential
clues to the precise nature of the progenitors. The main current problem is to
understand to what degree GRBs are biased tracers of star formation. If GRBs
are only formed by low-metallicity stars, then their host galaxies will not
give a representative view of where stars are formed in the Universe (at least
not a low redshifts). On the other hand, if there is no dependency on
metallicity then the nature of the host galaxies leads to the perhaps
surprising conclusion that most stars are formed in dwarf galaxies. In order to
resolve this issue and to fully exploit the potential of GRBs as probes of
star-forming galaxies throughout the observable universe it is mandatory that a
complete sample of bursts with redshifts and host galaxy detections is built.Comment: 9 pages, 3 figures. To appear in the proceedings of the Eleventh
Marcel Grossmann Meeting on General Relativity, eds. H. Kleinert, R. T.
Jantzen & R. Ruffini, World Scientific, Singapore, 200
Caenorhabditis elegans and probiotics interactions from a prolongevity perspective
Probiotics exert beneficial effects on host health through different mechanisms of action, such as production of antimicrobial substances, competition with pathogens, enhancement of host mucosal barrier integrity and immunomodulation. In the context of ageing, which is characterized by several physiological alterations leading to a low grade inflammatory status called inflammageing, evidences suggest a potential prolongevity role of probiotics. Unraveling the mechanisms underlying anti-ageing effects requires the use of simple model systems. To this respect, the nematode Caenorhabditis elegans represents a suitable model organism for the study of both host-microbe interactions and for ageing studies, because of conserved signaling pathways and host defense mechanisms involved in the regulation of its lifespan. Therefore, this review analyses the impact of probiotics on C. elegans age-related parameters, with particular emphasis on oxidative stress, immunity, inflammation and protection from pathogen infections. The picture emerging from our analysis highlights that several probiotic strains are able to exert anti-ageing effects in nematodes by acting on common molecular pathways, such as insulin/insulin-like growth factor-1 (IIS) and p38 mitogen-activated protein kinase (p38 MAPK). In this perspective, C. elegans appears to be advantageous for shedding light on key mechanisms involved in host prolongevity in response to probiotics supplementation
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