2,806 research outputs found
Morphological and molecular analysis of metacercariae of Diphtherostomum brusinae (Stossich, 1888) Stossich, 1903 from a new bivalve host Mytilus galloprovincialis
DOI: 10.1017/S0022149X10000428The digenean trematode Diphtherostomum brusinae (Stossich, 1888) Stossich, 1903 presents a complex life cycle that may involve more than one intermediate host. The present study represents the first description of the metacercariae from D. brusinae infecting the labial palps of a new intermediate host, Mytilus galloprovincialis, in the Aveiro estuary, Portugal. The morphology of this parasitic stage was studied by light (LM) and scanning electron microscopy (SEM) and some differences were reported (body and sucker sizes, and spine distribution and shape). In this work, the 18S partial region of the ribosomal DNA was sequenced from D. brusinae metacercariae isolated from M. galloprovincialis collected in different localities of the Aveiro estuary. In addition, sequences from the same region of the 18S rDNA were obtained from D. brusinae cercariae and metacercariae, hosted by Nassarius reticulatus and Cerastoderma edule, respectively. No intraspecific polymorphism was detected in the 18S partial region, since there was 100% homology among all the sequences analysed. The same comparison was made for the ITS1, and we observed intraspecific polymorphism in this region. To our knowledge, this is the first report of D. brusinae metacercariae infecting the mussel M. galloprovincialis with support from morphological and molecular data
An ultrafast outflow in the black hole candidate MAXI J1810-222?
The transient X-ray source MAXI J1810-222 was discovered in 2018 and has been
active ever since. A long combined radio and X-ray monitoring campaign was
performed with ATCA and Swift respectively. It has been proposed that MAXI
J1810-222 is a relatively distant black hole X-ray binary, albeit showing a
very peculiar outburst behaviour. Here, we report on the spectral study of this
source making use of a large sample of NICER observations performed between
2019 February and 2020 September. We detected a strong spectral absorption
feature at 1 keV, which we have characterised with a physical
photoionisation model. Via a deep scan of the parameters space, we obtained
evidence for a spectral-state dependent outflow, with mildly relativistic
speeds. In particular, the soft and intermediate states point to a hot plasma
outflowing at 0.05-0.15 . This speeds rule-out thermal winds and, hence,
they suggest that such outflows could be radiation pressure or (most likely)
magnetically-driven winds. Our results are crucial to test current theoretical
models of wind formation in X-ray binaries.Comment: 6 pages, 10 figures, accepted for publication in MNRAS Lette
The accretion/ejection link in the neutron star X-ray binary 4U 1820-30 I: A boundary layer-jet coupling?
The accretion flow / jet correlation in neutron star (NS) low-mass X-ray
binaries (LMXBs) is far less understood when compared to black hole (BH) LMXBs.
In this paper we will present the results of a dense multi-wavelength
observational campaign on the NS LMXB 4U 1820-30, including X-ray (Nicer,
NuSTAR and AstroSAT) and quasi-simultaneous radio (ATCA) observations in 2022.
4U 1820-30 shows a peculiar 170 day super-orbital accretion modulation, during
which the system evolves between "modes" of high and low X-ray flux. During our
monitoring, the source did not show any transition to a full hard state. X-ray
spectra were well described using a disc blackbody, a Comptonisation spectrum
along with a Fe K emission line at 6.6 keV. Our results show that the observed
X-ray flux modulation is almost entirely produced by changes in the size of the
region providing seed photons for the Comptonisation spectrum. This region is
large (about 15 km) in the high mode and likely coincides with the whole
boundary layer, while it shrinks significantly (<10 km) in low mode. The
electron temperature of the corona and the observed RMS variability in the hard
X-rays also exhibit a slight increase in low mode. As the source moves from
high to low mode, the radio emission due to the jet becomes about 5 fainter.
These radio changes appear not to be strongly connected to the hard-to-soft
transitions as in BH systems, while they seem to be connected mostly to
variations observed in the boundary layer.Comment: 12 pages, 6 figures. Accepted for publication by MNRA
HST imaging of the dusty filaments and nucleus swirl in NGC4696 at the centre of the Centaurus Cluster
Narrow-band HST imaging has resolved the detailed internal structure of the
10 kpc diameter H alpha+[NII] emission line nebulosity in NGC4696, the central
galaxy in the nearby Centaurus cluster, showing that the dusty, molecular,
filaments have a width of about 60pc. Optical morphology and velocity
measurements indicate that the filaments are dragged out by the bubbling action
of the radio source as part of the AGN feedback cycle. Using the drag force we
find that the magnetic field in the filaments is in approximate pressure
equipartition with the hot gas. The filamentary nature of the cold gas
continues inward, swirling around and within the Bondi accretion radius of the
central black hole, revealing the magnetic nature of the gas flows in massive
elliptical galaxies. HST imaging resolves the magnetic, dusty, molecular
filaments at the centre of the Centaurus cluster to a swirl around and within
the Bondi radius.This is the accepted manuscript. It is currently embargoed pending publication
\u3cem\u3eHST\u3c/em\u3e Imaging of the Dusty Filaments and Nucleus Swirl in NGC4696 at the Centre of the Centaurus Cluster
Narrow-band HST imaging has resolved the detailed internal structure of the 10 kpc diameter H α+[N II] emission line nebulosity in NGC4696, the central galaxy in the nearby Centaurus cluster, showing that the dusty, molecular, filaments have a width of about 60 pc. Optical morphology and velocity measurements indicate that the filaments are dragged out by the bubbling action of the radio source as part of the active galactic nucleus feedback cycle. Using the drag force we find that the magnetic field in the filaments is in approximate pressure equipartition with the hot gas. The filamentary nature of the cold gas continues inwards, swirling around and within the Bondi accretion radius of the central black hole, revealing the magnetic nature of the gas flows in massive elliptical galaxies. HST imaging resolves the magnetic, dusty, molecular filaments at the centre of the Centaurus cluster to a swirl around and within the Bondi radius
Structural and temporal patterns of the first global trading market
Little is known about the structural patterns and dynamics of the first global trading market (FGTM), which emerged during the sixteenth century as a result of the Iberian expansion, let alone how it compares to today's global financial markets. Here we build a representative network of the FGTM using information contained in 8725 (handwritten) Bills of Exchange from that time-which were (human) interpreted and digitalized into an online database. We show that the resulting temporal network exhibits a hierarchical, highly clustered and disassortative structure, with a power-law dependence on the connectivity that remains remarkably robust throughout the entire period investigated. Temporal analysis shows that, despite major turnovers in the number and nature of the links-suggesting fast adaptation in response to the geopolitical and financial turmoil experienced at the time-the overall characteristics of the FGTM remain robust and virtually unchanged. The methodology developed here demonstrates the possibility of building and analysing complex trading and finance networks originating from pre-statistical eras, enabling us to highlight the striking similarities between the structural patterns of financial networks separated by centuries in time.This research was supported by FCT-Portugal through grant nos FCT-TECH/0002/2007 (A.S.R. and A.P.), SFRH/BD/77389/2011 (F.L.P.), SFRH/BPD/76278/2011 (A.S.R.), PTDC/MAT-STA/3358/2014 (F.L.P., F.C.S. and J.M.P.), PTDC/EEI-SII/5081/2014 (F.L.P., F.C.S. and J.M.P.), UID/BIA/04050/2013 (J.M.P.) and UID/CEC/50021/2013 (F.C.S.), and by the European Science Foundation through grant no. DynCoopNet-06-TECT-FP-004 (A.S.R. and A.P.)
Insights from two decades of the Student Conference on Conservation Science
Conservation science is a crisis-oriented discipline focused on reducing human impacts on nature. To explore how the field has changed over the past two decades, we analyzed 3245 applications for oral presentations submitted to the Student Conference on Conservation Science (SCCS) in Cambridge, UK. SCCS has been running every year since 2000, aims for global representation by providing bursaries to early-career conservationists from lower-income countries, and has never had a thematic focus, beyond conservation in the broadest sense. We found that the majority of projects submitted to SCCS were based on primary biological data collected from local scale field studies in the tropics, contrary to established literature which highlights gaps in tropical research. Our results showed a small increase over time in submissions framed around how nature benefits people as well as a small increase in submissions integrating social science. Our findings suggest that students and early-career conservationists could provide pathways to increase availability of data from the tropics and address well-known biases in the published literature towards wealthier countries. We hope this research will motivate efforts to support student projects, ensuring data and results are published and data made publicly available.The project was made possible through funding from: JG: EUs Horizon 2020 Marie SkĆodowska-Curie program (No 676108) and VILLUM FONDEN (VKR023371), HA-P; National Council for Scientific and Technological Development (CNPq) (203407/2017-2), TA: The Australian Research Council Future Fellowship (FT180100354), The Grantham Foundation for the Protection of the Environment and The Kenneth Miller Trust, APC: the Natural Environment Research Council (NERC DTP [NE/L002507/1]), LC: Cambridge International Scholarship from the Cambridge Trust, FH: the Newton International Fellowship of the Royal Society, DM: the Australian Government, Endeavor Postgraduate Scholarhip, HM: Branco Weiss Fellowship Administered by the ETH ZĂŒrich and Drapers' Company Fellowship, Pembroke College BIS: the Natural Environment Research Council (NERC DTP[NE/L002507/1 and NE/S001395/1]) and the Royal Commission for the Exhibition of 1851 Research Fellowship, HW: Cambridge Trust Cambridge-Australia Poynton Scholarship and Cambridge Department of Zoology J. S. Gardiner Scholarship
Astrophysically Triggered Searches for Gravitational Waves: Status and Prospects
In gravitational-wave detection, special emphasis is put onto searches that
focus on cosmic events detected by other types of astrophysical observatories.
The astrophysical triggers, e.g. from gamma-ray and X-ray satellites, optical
telescopes and neutrino observatories, provide a trigger time for analyzing
gravitational wave data coincident with the event. In certain cases the
expected frequency range, source energetics, directional and progenitor
information is also available. Beyond allowing the recognition of gravitational
waveforms with amplitudes closer to the noise floor of the detector, these
triggered searches should also lead to rich science results even before the
onset of Advanced LIGO. In this paper we provide a broad review of LIGO's
astrophysically triggered searches and the sources they target
- âŠ