1,134 research outputs found
Detecting stars, galaxies, and asteroids with Gaia
(Abridged) Gaia aims to make a 3-dimensional map of 1,000 million stars in
our Milky Way to unravel its kinematical, dynamical, and chemical structure and
evolution. Gaia's on-board detection software discriminates stars from spurious
objects like cosmic rays and Solar protons. For this, parametrised
point-spread-function-shape criteria are used. This study aims to provide an
optimum set of parameters for these filters. We developed an emulation of the
on-board detection software, which has 20 free, so-called rejection parameters
which govern the boundaries between stars on the one hand and sharp or extended
events on the other hand. We evaluate the detection and rejection performance
of the algorithm using catalogues of simulated single stars, double stars,
cosmic rays, Solar protons, unresolved galaxies, and asteroids. We optimised
the rejection parameters, improving - with respect to the functional baseline -
the detection performance of single and double stars, while, at the same time,
improving the rejection performance of cosmic rays and of Solar protons. We
find that the minimum separation to resolve a close, equal-brightness double
star is 0.23 arcsec in the along-scan and 0.70 arcsec in the across-scan
direction, independent of the brightness of the primary. We find that, whereas
the optimised rejection parameters have no significant impact on the
detectability of de Vaucouleurs profiles, they do significantly improve the
detection of exponential-disk profiles. We also find that the optimised
rejection parameters provide detection gains for asteroids fainter than 20 mag
and for fast-moving near-Earth objects fainter than 18 mag, albeit this gain
comes at the expense of a modest detection-probability loss for bright,
fast-moving near-Earth objects. The major side effect of the optimised
parameters is that spurious ghosts in the wings of bright stars essentially
pass unfiltered.Comment: Accepted for publication in A&
Brain stimulation techniques as novel treatment options for insomnia: A systematic review.
Despite the success of cognitive behavioural therapy for insomnia and recent advances in pharmacotherapy, many patients with insomnia do not sufficiently respond to available treatments. This systematic review aims to present the state of science regarding the use of brain stimulation approaches in treating insomnia. To this end, we searched MEDLINE, Embase and PsycINFO from inception to 24 March 2023. We evaluated studies that compared conditions of active stimulation with a control condition or group. Outcome measures included standardized insomnia questionnaires and/or polysomnography in adults with a clinical diagnosis of insomnia. Our search identified 17 controlled trials that met inclusion criteria, and assessed a total of 967 participants using repetitive transcranial magnetic stimulation, transcranial electric stimulation, transcutaneous auricular vagus nerve stimulation or forehead cooling. No trials using other techniques such as deep brain stimulation, vestibular stimulation or auditory stimulation met the inclusion criteria. While several studies report improvements of subjective and objective sleep parameters for different repetitive transcranial magnetic stimulation and transcranial electric stimulation protocols, important methodological limitations and risk of bias limit their interpretability. A forehead cooling study found no significant group differences in the primary endpoints, but better sleep initiation in the active condition. Two transcutaneous auricular vagus nerve stimulation trials found no superiority of active stimulation for most outcome measures. Although modulating sleep through brain stimulation appears feasible, gaps in the prevailing models of sleep physiology and insomnia pathophysiology remain to be filled. Optimized stimulation protocols and proof of superiority over reliable sham conditions are indispensable before brain stimulation becomes a viable treatment option for insomnia
Avian blood parasites in an endangered columbid: Leucocytozoon marchouxi in the Mauritian Pink Pigeon Columba mayeri
There is increasing evidence that pathogens can play a significant role in species decline. This study of a complete free-living species reveals a cost of blood parasitism to an endangered host, the Pink Pigeon Columba mayeri, endemic to Mauritius. We investigated the prevalence and effect of infection of the blood parasite, Leucocytozoon marchouxi, in the free-living Pink Pigeon population. Overall, L. marchouxi infection prevalence detected was 18·3%. Juveniles were more likely to be infected than older birds and there was geographical variation in infection prevalence. Survival of birds infected with L. marchouxi was lower than that of uninfected birds to 90 days post-sampling. This study suggests that while common haematozoa are well tolerated in healthy adults, these parasites may have greater pathogenic potential in susceptible juveniles. The study is unusual given its completeness of species sampling (96%) within a short time-period, the accurate host age data, and its focus on blood parasites in a threatened bird species. Species for which long-term life-history data are available for every individual serve as valuable models for dissecting the contribution of particular pathogens to species decline
A probabilistic approach to emission-line galaxy classification
We invoke a Gaussian mixture model (GMM) to jointly analyse two traditional
emission-line classification schemes of galaxy ionization sources: the
Baldwin-Phillips-Terlevich (BPT) and vs. [NII]/H
(WHAN) diagrams, using spectroscopic data from the Sloan Digital Sky Survey
Data Release 7 and SEAGal/STARLIGHT datasets. We apply a GMM to empirically
define classes of galaxies in a three-dimensional space spanned by the
[OIII]/H, [NII]/H, and EW(H), optical
parameters. The best-fit GMM based on several statistical criteria suggests a
solution around four Gaussian components (GCs), which are capable to explain up
to 97 per cent of the data variance. Using elements of information theory, we
compare each GC to their respective astronomical counterpart. GC1 and GC4 are
associated with star-forming galaxies, suggesting the need to define a new
starburst subgroup. GC2 is associated with BPT's Active Galaxy Nuclei (AGN)
class and WHAN's weak AGN class. GC3 is associated with BPT's composite class
and WHAN's strong AGN class. Conversely, there is no statistical evidence --
based on four GCs -- for the existence of a Seyfert/LINER dichotomy in our
sample. Notwithstanding, the inclusion of an additional GC5 unravels it. The
GC5 appears associated to the LINER and Passive galaxies on the BPT and WHAN
diagrams respectively. Subtleties aside, we demonstrate the potential of our
methodology to recover/unravel different objects inside the wilderness of
astronomical datasets, without lacking the ability to convey physically
interpretable results. The probabilistic classifications from the GMM analysis
are publicly available within the COINtoolbox
(https://cointoolbox.github.io/GMM\_Catalogue/).Comment: Accepted for publication in MNRA
The relationship between cognitive maturity and information about health problems among school age children
This study of urban, multi-ethnic children was undertaken to explore the relationships between age, cognitive developmental capability (termed âcognitive maturityâ) and accuracy of information about health problems. A total of 299 children in the first, second and third grades from six public and one private school hi New York City were individually interviewed using an open-ended set of questions. Findings indicated that having accurate health information is not the same as comprehending the abstract internal nature of the âfactsâ. Results supported Piaget\u27s levels of cognitive development applied to the area of health. Findings also showed that age is a better predictor of children\u27s accuracy about health information than their cognitive maturity. The findings underscore the need for those providing health education to place emphasis on the cognitive abilities of children and not to mistake recitation of factual information for understanding of conceptual elements of a health problem
Results of Sixteen Differential Absorption and Faraday Rotation Measurements with Nike-Apache Rockets
Coordinated Science Laboratory was formerly known as Control Systems LaboratoryJoint Services Electronics Program / DA 28 043 AMC 00073(E)NASA NGR 14 005 03
Recolonizing gray wolves increase parasite infection risk in their prey
The recent recolonization of Central Europe by the European gray wolf (Canis
lupus) provides an opportunity to study the dynamics of parasite transmission
for cases when a definitive host returns after a phase of local extinction. We
investigated whether a newly established wolf population increased the
prevalence of those parasites in ungulate intermediate hosts representing wolf
prey, whether some parasite species are particularly well adapted to wolves,
and the potential basis for such adaptations. We recorded Sarcocystis species
richness in wolves and Sarcocystis prevalence in ungulates harvested in study
sites with and without permanent wolf presence in Germany using microscopy and
DNA metabarcoding. Sarcocystis prevalence in red deer (Cervus elaphus) was
significantly higher in wolf areas (79.7%) than in control areas (26.3%) but
not in roe deer (Capreolus capreolus) (97.2% vs. 90.4%) or wild boar (Sus
scrofa) (82.8% vs. 64.9%). Of 11 Sarcocystis species, Sarcocystis taeniata and
Sarcocystis grueneri occurred more often in wolves than expected from the
Sarcocystis infection patterns of ungulate prey. Both Sarcocystis species
showed a higher increase in prevalence in ungulates in wolf areas than other
Sarcocystis species, suggesting that they are particularly well adapted to
wolves, and are examples of âwolf specialistsâ. Sarcocystis species richness
in wolves was significantly higher in pups than in adults. âWolf specialistsâ
persisted during wolf maturation. The results of this study demonstrate that
(1) predatorâprey interactions influence parasite prevalence, if both predator
and prey are part of the parasite life cycle, (2) mesopredators do not
necessarily replace the apex predator in parasite transmission dynamics for
particular parasites of which the apex predator is the definitive host, even
if mesoâ and apex predators were from the same taxonomic family (here:
Canidae, e.g., red foxes Vulpes vulpes), and (3) ageâdependent immune
maturation contributes to the control of protozoan infection in wolves
Monitoring contaminants, emerging infectious diseases and environmental change with raptors, and links to human health
CAPSULE:
Raptor research and monitoring informs issues of relevance to human health, including environmental contamination, emerging infectious diseases and environmental change.
AIMS:
The paper examines the relevance of raptor research and monitoring to inform issues of relevance to human health, including environmental contamination, emerging vector-borne diseases and environmental change.
METHODS:
Reviews of European Union policy context and role of raptor research and monitoring in detection of and response to contaminants. Examples include lead ammunition in White-tailed Sea Eagles Haliaeetus albicilla in Europe, and impacts of diclofenac on Gyps vultures in the Indian subcontinent. Comments on the relevance of raptor research and monitoring to emerging infectious diseases and environmental change, and considers the links between raptors and humans.
RESULTS:
Biomonitoring of contaminants in raptors can perform useful purposes in relation to chemicals legislation. Raptors are useful sentinels of exposure to and effects of chemicals in the environment. Raptor research and monitoring can also elucidate environmental change and spread of emerging infectious diseases. Raptors are linked to humans through social, cultural and economic values.
CONCLUSION:
Raptors can be used to provide information relevant to human health and well-being. There are a number of challenges and opportunities in relating raptor research and monitoring to human health. Several areas with potential for development are outlined. The COST Action âEuropean Raptor Biomonitoring Facilityâ and the forthcoming LIFE APEX project will take forward relevant work
Bidirectional crosstalk between hypoxia-inducible factor and glucocorticoid signalling in zebrafish larvae
In the last decades in vitro studies highlighted the potential for crosstalk between Hypoxia-Inducible Factor-(HIF) and glucocorticoid-(GC) signalling pathways. However, how this interplay precisely occurs in vivo is still debated. Here, we use zebrafish larvae (Danio rerio) to elucidate how and to what degree hypoxic signalling affects the endogenous glucocorticoid pathway and vice versa, in vivo. Firstly, our results demonstrate that in the presence of upregulated HIF signalling, both glucocorticoid receptor (Gr) responsiveness and endogenous cortisol levels are repressed in 5 days post fertilisation larvae. In addition, despite HIF activity being low at normoxia, our data show that it already impedes both glucocorticoid activity and levels. Secondly, we further analysed the in vivo contribution of glucocorticoids to HIF activity. Interestingly, our results show that both glucocorticoid receptor (GR) and mineralocorticoid receptor (MR) play a key role in enhancing it. Finally, we found indications that glucocorticoids promote HIF signalling via multiple routes. Cumulatively, our findings allowed us to suggest a model for how this crosstalk occurs in vivo
Emergency care provided to refugee children in Europe: RefuNET: A cross-sectional survey study
Background Refugee children and young people have complex healthcare needs. However, issues related to acute healthcare provision for refugee children across Europe remain unexplored. This study aimed to describe the urgent and emergency healthcare needs of refugee children in Europe, and to identify obstacles to providing this care.Methods An online cross-sectional survey was distributed to European healthcare professionals via research networks between 1 February and 1 October 2017 addressing health issues of children and young people age
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