1,261 research outputs found
GLADE: A galaxy catalogue for multimessenger searches in the advanced gravitational-wave detector era
We introduce a value-added full-sky catalogue of galaxies, named as Galaxy List for the Advanced Detector Era, or GLADE. The purpose of this catalogue is to (i) help identifications of host candidates for gravitational-wave events, (ii) support target selections for electromagnetic follow-up observations of gravitational-wave candidates, (iii) provide input data on the matter distribution of the local Universe for astrophysical or cosmological simulations, and (iv) help identifications of host candidates for poorly localized electromagnetic transients, such as gamma-ray bursts observed with the InterPlanetary Network. Both being potential hosts of astrophysical sources of gravitational waves, GLADE includes inactive and active galaxies as well. GLADE was constructed by cross-matching and combining data from five separate (but not independent) astronomical catalogues: GWGC, 2MPZ, 2MASS XSC, HyperLEDA, and SDSS-DR12Q. GLADE is complete up to
dL=37+3−4Mpc in terms of the cumulative B-band luminosity of galaxies within luminosity distance dL, and contains all of the brightest galaxies giving half of the total B-band luminosity up to dL=91Mpc. As B-band luminosity is expected to be a tracer of binary neutron star mergers (currently the prime targets of joint GW+EM detections), our completeness measures can be used as estimations of completeness for containing all binary neutron star merger hosts in the local Universe
Remote Sensing D/H Ratios in Methane Ice: Temperature-Dependent Absorption Coefficients of CH3D in Methane Ice and in Nitrogen Ice
The existence of strong absorption bands of singly deuterated methane (CH3D)
at wavelengths where normal methane (CH4) absorbs comparatively weakly could
enable remote measurement of D/H ratios in methane ice on outer solar system
bodies. We performed laboratory transmission spectroscopy experiments,
recording spectra at wavelengths from 1 to 6 \mum to study CH3D bands at 2.47,
2.87, and 4.56 \mum, wavelengths where ordinary methane absorption is weak. We
report temperature-dependent absorption coefficients of these bands when the
CH3D is diluted in CH4 ice and also when it is dissolved in N2 ice, and
describe how these absorption coefficients can be combined with data from the
literature to simulate arbitrary D/H ratio absorption coefficients for CH4 ice
and for CH4 in N2 ice. We anticipate these results motivating new telescopic
observations to measure D/H ratios in CH4 ice on Triton, Pluto, Eris, and
Makemake.Comment: 17 pages, 7 figure
Integrated Strategy for Sustainable Cattle Fever Tick Eradication in USA is Required to Mitigate the Impact of Global Change
The ticks Rhipicephalus (Boophilus) annulatus and R. (B.) microplus, commonly known as cattle and southern cattle tick, respectively, impede the development and sustainability of livestock industries throughout tropical and other world regions. They affect animal productivity and wellbeing directly through their obligate blood-feeding habit and indirectly by serving as vectors of the infectious agents causing bovine babesiosis and anaplasmosis. The monumental scientific discovery of certain arthropod species as vectors of infectious agents is associated with the history of research on bovine babesiosis and R. annulatus. Together, R. microplus and R. annulatus are referred to as cattle fever ticks (CFT). Bovine babesiosis became a regulated foreign animal disease in the United States of America (U.S.) through efforts of the Cattle Fever Tick Eradication Program (CFTEP) established in 1906. The U.S. was declared free of CFT in 1943, with the exception of a permanent quarantine zone in south Texas along the border with Mexico. This achievement contributed greatly to the development and productivity of animal agriculture in the U.S. The permanent quarantine zone buffers CFT incursions from Mexico where both ticks and babesiosis are endemic. Until recently, the elimination of CFT outbreaks relied solely on the use of coumaphos, an organophosphate acaricide, in dipping vats or as a spray to treat livestock, or the vacation of pastures. However, ecological, societal, and economical changes are shifting the paradigm of systematically treating livestock to eradicate CFT. Keeping the U.S. CFT-free is a critical animal health issue affecting the economic stability of livestock and wildlife enterprises. Here, we describe vulnerabilities associated with global change forces challenging the CFTEP. The concept of integrated CFT eradication is discussed in reference to global change
A divergent heritage for complex organics in Isheyevo lithic clasts
Primitive meteorites are samples of asteroidal bodies that contain a high proportion of chemically complex organic matter (COM) including prebiotic molecules such as amino acids, which are thought to have been delivered to Earth via impacts during the early history of the Solar System. Thus, understanding the origin of COM, including their formation pathway(s) and environment(s), is critical to elucidate the origin of life on Earth as well as assessing the potential habitability of exoplanetary systems. The Isheyevo CH/CBb carbonaceous chondrite contains chondritic lithic clasts with variable enrichments in 15N believed to be of outer Solar System origin. Using transmission electron microscopy (TEM-EELS) and in situ isotope analyses (SIMS and NanoSIMS), we report on the structure of the organic matter as well as the bulk H and N isotope composition of Isheyevo lithic clasts. These data are complemented by electron microprobe analyses of the clast mineral chemistry and bulk Mg and Cr isotopes obtained by inductively coupled plasma and thermal ionization mass spectrometry, respectively (MC-ICPMS and TIMS). Weakly hydrated (A) clasts largely consist of Mg-rich anhydrous silicates with local hydrated veins composed of phyllosilicates, magnetite and globular and diffuse organic matter. Extensively hydrated clasts (H) are thoroughly hydrated and contain Fe-sulfides, sometimes clustered with organic matter, as well as magnetite and carbonates embedded in a phyllosilicate matrix. The A-clasts are characterized by a more 15N-rich bulk nitrogen isotope composition (δ15N = 200–650‰) relative to H-clasts (δ15N = 50–180‰) and contain extremely 15N-rich domains with δ15N 15N-rich domains show that the lithic clast diffuse organic matter is typically more 15N-rich than globular organic matter. The correlated δ15N values and C/N ratios of nanoglobules require the existence of multiple organic components, in agreement with the H isotope data. The combined H and N isotope data suggest that the organic precursors of the lithic clasts are defined by an extremely 15N-poor (similar to solar) and D-rich component for H-clasts, and a moderately 15N-rich and D-rich component for A-clasts. In contrast, the composition of the putative fluids is inferred to include D-poor but moderately to extremely 15N-rich H- and N-bearing components. The variable 15N enrichments in H- and A-clasts are associated with structural differences in the N bonding environments of their diffuse organic matter, which are dominated by amine groups in H-clasts and nitrile functional groups in A-clasts. We suggest that the isotopically divergent organic precursors in Isheyevo clasts may be similar to organic moieties in carbonaceous chondrites (CI, CM, CR) and thermally recalcitrant organic compounds in ordinary chondrites, respectively. The altering fluids, which are inferred to cause the 15N enrichments observed in the clasts, may be the result of accretion of variable abundances of NH3 and HCN ices. Finally, using bulk Mg and Cr isotope composition of clasts, we speculate on the accretion regions of the various primitive chondrites and components and the origin of the Solar System’s N and H isotope variability
Exochelin Production in Mycobacterium neoaurum
Mycobacterium neoaurum is a soil saprophyte and obligate aerobic bacterium. This group of mycobacterium is relatively fast-growing. They form colonies on nutrient agar at 37ºC within 3 – 4 days. In natural soil habitats, bioavailability of iron is limited. To facilitate iron uptake, most mycobacteria produce siderophores. One example is exochelin, which is extracellular and water-soluble. In this report, the production of exochelin in M. neoaurum was induced in iron-deficiency, but repressed under ironsufficiency growth conditions. It is however not induced under zinc-deficiency growth conditions. The growth of this mycobacterium was correlated with exochelin secretion under iron-deficiency culture conditions. When M. neoaurum was grown in defined medium containing 0.04 μg Fe(III)/mL (final concentration), the production of exochelin reached a maximum and the corresponding cell growth was comparable to that under iron-sufficiency conditions. In this study, exochelin was purified from spent supernatant of M. neoaurum by semi-preparative chromatography. When saturated ferric chloride solution was added into the purified exochelin, a ferri-exochelin complex was formed. It is proposed that iron uptake in M. neoaurum is exochelin-mediated
The shape and composition of interstellar silicate grains
We investigate the composition and shape distribution of silicate dust grains
in the interstellar medium. The effect of the amount of magnesium in the
silicate lattice is studied. We fit the spectral shape of the interstellar 10
mu extinction feature as observed towards the galactic center. We use very
irregularly shaped coated and non-coated porous Gaussian Random Field particles
as well as a statistical approach to model shape effects. For the dust
materials we use amorphous and crystalline silicates with various composition
and SiC. The results of our analysis of the 10 mu feature are used to compute
the shape of the 20 mu silicate feature and to compare this with observations.
By using realistic particle shapes we are, for the first time, able to derive
the magnesium fraction in interstellar silicates. We find that the interstellar
silicates are highly magnesium rich (Mg/(Fe+Mg)>0.9) and that the stoichiometry
lies between pyroxene and olivine type silicates. This composition is not
consistent with that of the glassy material found in GEMS in interplanetary
dust particles indicating that these are, in general, not unprocessed remnants
from the interstellar medium. Also, we find a significant fraction of SiC
(~3%). We discuss the implications of our results for the formation and
evolutionary history of cometary and circumstellar dust. We argue that the fact
that crystalline silicates in cometary and circumstellar grains are almost
purely magnesium silicates is a natural consequence of our findings that the
amorphous silicates from which they were formed were already magnesium rich.Comment: Accepted for publication in A&
Rescuing key native traits in cultured dermal papilla cells for human hair regeneration
Introduction: The dermal papilla (DP) represents the major regulatory entity within the hair follicle (HF), inducing hair formation and growth through reciprocal interactions with epithelial cells. However, human DP cells rapidly lose their hair inductive ability when cultured in an epithelium-deficient environment.
Objectives: To determine if the conditioned medium collected from interfollicular keratinocytes (KCs-CM) is capable of improving DP cell native properties and inductive phenotype.
Methods:DP cells were cultured with KCs-CM both in 2D and 3D culture conditions (spheroids). Further, the hair-inductive capacity of DP cells precultured with KCs-CM was tested in a hair reconstitution assay, after co-grafting with human keratinocytes in nude mice.
Results:We demonstrate that KCs-CM contributes to restore the inductivity of cultured human DP cells in a more effective mode than the conventional 3D-cultures. This is supported by the higher active alkaline phosphatase (ALP) levels in DP cells, the improved self-aggregative capacity and the reduced expression of α-SMA and the V1-isoform of versican. Moreover, DP cells cultured with KCs-CM displayed a secretome profile (VEGF, BMP2, TGF- β1, IL-6) that matches the one observed during anagen. KCs-CM also enhanced DP cell proliferation, while preventing cells to undergo morphological changes characteristic of high passage cells. In opposition, the amount of collagenous and non-collagenous proteins deposited by DP cells was lower in the presence of KCs-CM. The improvement in ALP activity was maintained in 3D spheroidal cultures, even after KCs-CM retrieval, being superior to the effect of the gold-standard culture conditions. Moreover, DP cells cultured with KCs-CM and grafted with human keratinocytes supported the formation of HF- and sebaceous gland-like structures in mice.
Conclusion:The proposed strategy encourages future cell-based strategies for HF regeneration not only in the context of hair-associated disorders, but also in the management of wounds to aid in restoring critical skin regulatory appendages.he research reported in this publication was supported by FCT/
MCTES (Fundação para a Ciência e a Tecnologia/ Ministério da
Ciência, Tecnologia, e Ensino Superior) through the PD/59/2013,
PD/BD/113800/2015 (C. Abreu), CEECIND/00695/2017 (M. T. Cerqueira), IF/00347/2015 (R. Pirraco), IF/00945/2014 (A. P. Marques)
and UIDB/50026/2020 grants. We thank Manuela Lago for her sup port on experimental assays and to Emanuel Rognoni and Simon
Broad from King’s College London for their expert technical assis tance in the establishment of the in vivo chamber model in our
group
One Health – an Ecological and Evolutionary Framework for tackling Neglected Zoonotic Diseases
Understanding the complex population biology and transmission ecology of multihost parasites has been declared as one of the major challenges of biomedical sciences for the 21st century and the Neglected Zoonotic Diseases (NZDs) are perhaps the most neglected of all the Neglected Tropical Diseases (NTDs). Here we consider how multihost parasite transmission and evolutionary dynamics may affect the success of human and animal disease control programmes, particularly neglected diseases of the developing world. We review the different types of zoonotic interactions that occur, both ecological and evolutionary, their potential relevance for current human control activities, and make suggestions for the development of an empirical evidence base and theoretical framework to better understand and predict the outcome of such interactions. In particular, we consider whether preventive chemotherapy, the current mainstay of NTD control, can be successful without a One Health approach. Transmission within and between animal reservoirs and humans can have important ecological and evolutionary consequences, driving the evolution and establishment of drug resistance, as well as providing selective pressures for spill‐over, host switching, hybridizations and introgressions between animal and human parasites. Our aim here is to highlight the importance of both elucidating disease ecology, including identifying key hosts and tailoring control effort accordingly, and understanding parasite evolution, such as precisely how infectious agents may respond and adapt to anthropogenic change. Both elements are essential if we are to alleviate disease risks from NZDs in humans, domestic animals and wildlife
Systemic insecticide treatment of the canine reservoir of Trypanosoma cruzi induces high levels of lethality in Triatoma infestans, a principal vector of Chagas disease
BACKGROUND: Despite large-scale reductions in Chagas disease
prevalence across Central and South America, Trypanosoma cruzi
infection remains a considerable public health problem in the
Gran Chaco region where vector-borne transmission persists. In
these communities, peridomestic animals are major blood-meal
sources for triatomines, and household presence of infected dogs
increases T. cruzi transmission risk for humans. To address the
pressing need for field-friendly, complementary methods to
reduce triatomine infestation and interrupt T. cruzi
transmission, this study evaluated the systemic activity of
three commercial, oral, single dose insecticides Fluralaner
(Bravecto(R)), Afoxolaner (NexGard(R)) and Spinosad
(Comfortis(R)) in canine feed-through assays against Triatoma
infestans, the principal domestic vector species in the Southern
Cone of South America. METHODS: Twelve healthy, outbred dogs
were recruited from the Zoonosis Surveillance and Control
Program in Santa Cruz, Bolivia, and randomized to three
treatment groups, each containing one control and three treated
dogs. Following oral drug administration, colony-reared second
and third stage T. infestans instars were offered to feed on
dogs for 30 min at 2, 7, 21, 34 and 51 days post-treatment.
RESULTS: Eighty-five per cent (768/907) of T. infestans
successfully blood-fed during bioassays, with significantly
higher proportions of bugs becoming fully-engorged when exposed
to Bravecto(R) treated dogs (P < 0.001) for reasons unknown.
Exposure to Bravecto(R) or NexGard(R) induced 100% triatomine
mortality in fully- or semi-engorged bugs within 5 days of
feeding for the entire follow-up period. The lethality effect
for Comfortis(R) was much lower (50-70%) and declined almost
entirely after 51 days. Instead Comfortis(R) treatment resulted
in substantial morbidity; of these, 30% fully recovered whereas
53% remained morbid after 120 h, the latter subsequently unable
to feed 30 days later. CONCLUSIONS: A single oral dose of
Fluralaner or Afoxolaner was safe and well tolerated, producing
complete triatomine mortality on treated dogs over 7.3 weeks.
While both drugs were highly efficacious, more bugs exposed to
Fluralaner took complete blood-meals, and experienced rapid
knock-down. Coupled with its longer residual activity,
Fluralaner represents an ideal insecticide for development into
a complementary, operationally-feasible, community-level method
of reducing triatomine infestation and potentially controlling
T. cruzi transmission, in the Gran Chaco region
Hybridization in parasites: consequences for adaptive evolution, pathogenesis and public health in a changing world
[No abstract available
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