12,372 research outputs found
A Systematic Search for Corotating Interaction Regions in Apparently Single Galactic Wolf-Rayet Stars. II. A Global View of the Wind Variability
This study is the second part of a survey searching for large-scale
spectroscopic variability in apparently single Wolf-Rayet (WR) stars. In a
previous paper (Paper I), we described and characterized the spectroscopic
variability level of 25 WR stars observable from the northern hemisphere and
found 3 new candidates presenting large-scale wind variability, potentially
originating from large-scale structures named Co-rotating Interaction Regions
(CIRs). In this second paper, we discuss an additional 39 stars observable from
the southern hemisphere. For each star in our sample, we obtained 4-5
high-resolution spectra with a signal-to-noise ratio of ~100 and determined its
variability level using the approach described in Paper I. In total, 10 new
stars are found to show large-scale spectral variability of which 7 present
CIR-type changes (WR 8, WR 44, WR 55, WR 58, WR 61, WR 63, WR 100). Of the
remaining stars, 20 were found to show small-amplitude changes and 9 were found
to show no spectral variability as far as can be concluded from the data in
hand. Also, we discuss the spectroscopic variability level of all single
galactic WR stars that are brighter than v~12.5, and some WR stars with 12.5 <
v <= 13.5; i.e. all the stars presented in our two papers and 4 more stars for
which spectra have already been published in the literature. We find that 23/68
stars (33.8 %) present large-scale variability, but only 12/54 stars (~22.1 %)
are potentially of CIR-type. Also, we find 31/68 stars (45.6 %) that only show
small-scale variability, most likely due to clumping in the wind. Finally, no
spectral variability is detected based on the data in hand for 14/68 (20.6 %)
stars. Interestingly, the variability with the highest amplitude also have the
widest mean velocity dispersion.Comment: 14 pages, 24 figures, 2 tables, Accepted in Ap
A Sea - Grey House, the History of Renvyle House
Published by Renvyle House Hotel, Galway, Ireland, in 1995.
Printed in Ireland by The Connacht Tribune Ltd. Bound by Kenny\u27s Bookshop, Galway.
134 p. col. ill., 20 cm.https://arrow.tudublin.ie/irckbooks/1109/thumbnail.jp
A renormalization fixed point for Lorenz maps
A Lorenz map is a Poincar\'e map for a three-dimensional Lorenz flow. We
describe the theory of renormalization for Lorenz maps with a critical point
and prove that a restriction of the renormalization operator acting on such
maps has a hyperbolic fixed point. The proof is computer assisted and we
include a detailed exposition on how to make rigorous estimates using a
computer as well as the implementation of the estimates.Comment: 29 pages, 2 figure
Exploitation histories of pangolins and endemic pheasants on Hainan Island, China: baselines and shifting social norms
Overexploitation is a critical threat to the survival of many species. The global demand for wildlife products has attracted considerable research attention, but regional species exploitation histories are more rarely investigated. We interviewed 169 villagers living around seven terrestrial nature reserves on Hainan Island, China, with the aim of reconstructing historical patterns of hunting and consumption of local wildlife, including the globally threatened Chinese pangolin (Manis pentadactyla) and Hainan peacock-pheasant (Polyplectron katsumatae), from the mid-20th century onwards. We aimed to better understand the relationship between these past activities and current consumption patterns. Our findings suggest that eating pangolin meat was not a traditional behaviour in Hainan, with past consumption prohibited by local myths about pangolins. In contrast, local consumption of peacock-pheasant meat was a traditional activity. However, later attitudes around hunting pangolins and peacock-pheasants in Hainan were influenced by pro-hunting policies and a state-run wildlife trade from the 1960s to the 1980s. These new social norms still shape the daily lifestyles and perceptions of local people towards wildlife consumption in Hainan today. Due to these specific historical patterns of wildlife consumption, local-adapted interventions such as promoting substitute meat choices and alternative livelihoods might be effective at tackling local habits of consuming wild meat. Our study highlights the importance of understanding the local historical contexts of wildlife use for designing appropriate conservation strategies
Knowledge and attitudes about the use of pangolin scale products in Traditional Chinese Medicine (TCM) within China
1. All eight pangolin species are threatened with extinction, largely through demand
for their products including scales, meat and body parts. The demand for pangolin
scales has gained attention from many conservation groups due to the large volumes involved in illegal trade. Market demand in China is one of the major drivers
for international illegal trade according to confiscation reports, and many conservation interventions have been attempted to reduce this demand.
2. The Traditional Chinese Medicine (TCM) community plays a key role in regulating
legal trade and combating illegal trade in pangolin scales. However, this community has been largely overlooked by previous conservation interventions directed
at the pangolin scale trade. There has also been little research into the involvement of the TCM community in pangolin scale trade in China.
3. To fill these knowledge gaps, we interviewed TCM doctors from 41 hospitals, shop
owners/assistants from 90 TCM shops, two TCM wholesalers, and 2,168 members
of the general public in Henan and Hainan provinces, China. Respondents' knowledge of and attitudes towards the pangolin scale trade were investigated using
semi-structured and structured questionnaires, with a total of 2,301 respondents.
4. Our results show that TCM practitioners generally have poor awareness of the illegal nature of their behaviours and pangolin scale products involved. Awareness is
particularly poor among participants at the end of the trade chain (i.e. end sellers).
The public also generally lacked understanding of pangolin products in markets.
5. Results also show that 20 (71%) of 28 doctors believed that the use of pangolin scales
in at least some, if not all, treatments could be substituted by other ingredients.
6. These findings suggest that raising awareness of the legality of pangolin scale products and petitioning TCM communities to use alternative substitutes for these products could constitute feasible and effective pangolin conservation interventions.
7. This study provides the first insights into the knowledge of and attitudes towards
the pangolin scale trade from the perspective of TCM practitioners, and suggests
that collaborating with the TCM community is necessary to combat this illegal trade
Mixture models for distance sampling detection functions
Funding: EPSRC DTGWe present a new class of models for the detection function in distance sampling surveys of wildlife populations, based on finite mixtures of simple parametric key functions such as the half-normal. The models share many of the features of the widely-used âkey function plus series adjustmentâ (K+A) formulation: they are flexible, produce plausible shapes with a small number of parameters, allow incorporation of covariates in addition to distance and can be fitted using maximum likelihood. One important advantage over the K+A approach is that the mixtures are automatically monotonic non-increasing and non-negative, so constrained optimization is not required to ensure distance sampling assumptions are honoured. We compare the mixture formulation to the K+A approach using simulations to evaluate its applicability in a wide set of challenging situations. We also re-analyze four previously problematic real-world case studies. We find mixtures outperform K+A methods in many cases, particularly spiked line transect data (i.e., where detectability drops rapidly at small distances) and larger sample sizes. We recommend that current standard model selection methods for distance sampling detection functions are extended to include mixture models in the candidate set.Publisher PDFPeer reviewe
The utility of micro-computed tomography for the non-destructive study of eye microstructure in snails
Molluscan eyes exhibit an enormous range of morphological variation, ranging from tiny pigment-cup eyes in limpets, compound eyes in ark clams and pinhole eyes in Nautilus, through to concave mirror eyes in scallops and the large camera-type eyes of the more derived cephalopods. Here we assess the potential of non-destructive micro-computed tomography (”-CT) for investigating the anatomy of molluscan eyes in three species of the family Solariellidae, a group of small, deep-sea gastropods. We compare our results directly with those from traditional histological methods applied to the same specimens, and show not only that eye microstructure can be visualised in sufficient detail for meaningful comparison even in very small animals, but also that ÎŒ-CT can provide additional insight into gross neuroanatomy without damaging rare and precious specimens. Data from ÎŒ-CT scans also show that neurological innervation of eyes is reduced in dark-adapted snails when compared with the innervation of cephalic tentacles, which are involved in mechanoreception and possibly chemoreception. Molecular tests also show that the use of ”-CT and phosphotungstic acid stain do not prevent successful downstream DNA extraction, PCR amplification or sequencing. The use of ”-CT methods is therefore highly recommended for the investigation of difficult-to-collect or unique specimens.Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the articleâs Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the articleâs Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.
The attached file is the published pdf
Localization, epidemic transitions, and unpredictability of multistrain epidemics with an underlying genotype network
Mathematical disease modelling has long operated under the assumption that
any one infectious disease is caused by one transmissible pathogen spreading
among a population. This paradigm has been useful in simplifying the biological
reality of epidemics and has allowed the modelling community to focus on the
complexity of other factors such as population structure and interventions.
However, there is an increasing amount of evidence that the strain diversity of
pathogens, and their interplay with the host immune system, can play a large
role in shaping the dynamics of epidemics. Here, we introduce a disease model
with an underlying genotype network to account for two important mechanisms.
One, the disease can mutate along network pathways as it spreads in a host
population. Two, the genotype network allows us to define a genetic distance
across strains and therefore to model the transcendence of immunity often
observed in real world pathogens. We study the emergence of epidemics in this
model, through its epidemic phase transitions, and highlight the role of the
genotype network in driving cyclicity of diseases, large scale fluctuations,
sequential epidemic transitions, as well as localization around specific
strains of the associated pathogen. More generally, our model illustrates the
richness of behaviours that are possible even in well-mixed host populations
once we consider strain diversity and go beyond the "one disease equals one
pathogen" paradigm
Static Trace-Based Deadlock Analysis for Synchronous Mini-Go
We consider the problem of static deadlock detection for programs in the Go
programming language which make use of synchronous channel communications. In
our analysis, regular expressions extended with a fork operator capture the
communication behavior of a program. Starting from a simple criterion that
characterizes traces of deadlock-free programs, we develop automata-based
methods to check for deadlock-freedom. The approach is implemented and
evaluated with a series of examples
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