23 research outputs found
Multi-Messenger Gravitational Wave Searches with Pulsar Timing Arrays: Application to 3C66B Using the NANOGrav 11-year Data Set
When galaxies merge, the supermassive black holes in their centers may form
binaries and, during the process of merger, emit low-frequency gravitational
radiation in the process. In this paper we consider the galaxy 3C66B, which was
used as the target of the first multi-messenger search for gravitational waves.
Due to the observed periodicities present in the photometric and astrometric
data of the source of the source, it has been theorized to contain a
supermassive black hole binary. Its apparent 1.05-year orbital period would
place the gravitational wave emission directly in the pulsar timing band. Since
the first pulsar timing array study of 3C66B, revised models of the source have
been published, and timing array sensitivities and techniques have improved
dramatically. With these advances, we further constrain the chirp mass of the
potential supermassive black hole binary in 3C66B to less than using data from the NANOGrav 11-year data set. This
upper limit provides a factor of 1.6 improvement over previous limits, and a
factor of 4.3 over the first search done. Nevertheless, the most recent orbital
model for the source is still consistent with our limit from pulsar timing
array data. In addition, we are able to quantify the improvement made by the
inclusion of source properties gleaned from electromagnetic data to `blind'
pulsar timing array searches. With these methods, it is apparent that it is not
necessary to obtain exact a priori knowledge of the period of a binary to gain
meaningful astrophysical inferences.Comment: 14 pages, 6 figures. Accepted by Ap
Invasive Plant Suppresses the Growth of Native Tree Seedlings by Disrupting Belowground Mutualisms
The impact of exotic species on native organisms is widely acknowledged, but poorly understood. Very few studies have empirically investigated how invading plants may alter delicate ecological interactions among resident species in the invaded range. We present novel evidence that antifungal phytochemistry of the invasive plant, Alliaria petiolata, a European invader of North American forests, suppresses native plant growth by disrupting mutualistic associations between native canopy tree seedlings and belowground arbuscular mycorrhizal fungi. Our results elucidate an indirect mechanism by which invasive plants can impact native flora, and may help explain how this plant successfully invades relatively undisturbed forest habitat
Multimessenger Gravitational-wave Searches with Pulsar Timing Arrays:Application to 3C 66B Using the NANOGrav 11-year Data Set
When galaxies merge, the supermassive black holes in their centers may form binaries and emit low-frequency gravitational radiation in the process. In this paper, we consider the galaxy 3C 66B, which was used as the target of the first multimessenger search for gravitational waves. Due to the observed periodicities present in the photometric and astrometric data of the source, it has been theorized to contain a supermassive black hole binary. Its apparent 1.05-year orbital period would place the gravitational-wave emission directly in the pulsar timing band. Since the first pulsar timing array study of 3C 66B, revised models of the source have been published, and timing array sensitivities and techniques have improved dramatically. With these advances, we further constrain the chirp mass of the potential supermassive black hole binary in 3C 66B to less than (1.65 ± 0.02) × 109 M o˙ using data from the NANOGrav 11-year data set. This upper limit provides a factor of 1.6 improvement over previous limits and a factor of 4.3 over the first search done. Nevertheless, the most recent orbital model for the source is still consistent with our limit from pulsar timing array data. In addition, we are able to quantify the improvement made by the inclusion of source properties gleaned from electromagnetic data over "blind"pulsar timing array searches. With these methods, it is apparent that it is not necessary to obtain exact a priori knowledge of the period of a binary to gain meaningful astrophysical inferences
The NANOGrav 15-year Data Set: Evidence for a Gravitational-Wave Background
We report multiple lines of evidence for a stochastic signal that is
correlated among 67 pulsars from the 15-year pulsar-timing data set collected
by the North American Nanohertz Observatory for Gravitational Waves. The
correlations follow the Hellings-Downs pattern expected for a stochastic
gravitational-wave background. The presence of such a gravitational-wave
background with a power-law-spectrum is favored over a model with only
independent pulsar noises with a Bayes factor in excess of , and this
same model is favored over an uncorrelated common power-law-spectrum model with
Bayes factors of 200-1000, depending on spectral modeling choices. We have
built a statistical background distribution for these latter Bayes factors
using a method that removes inter-pulsar correlations from our data set,
finding (approx. ) for the observed Bayes factors in the
null no-correlation scenario. A frequentist test statistic built directly as a
weighted sum of inter-pulsar correlations yields (approx. ). Assuming a fiducial
characteristic-strain spectrum, as appropriate for an ensemble of binary
supermassive black-hole inspirals, the strain amplitude is (median + 90% credible interval) at a reference frequency of
1/(1 yr). The inferred gravitational-wave background amplitude and spectrum are
consistent with astrophysical expectations for a signal from a population of
supermassive black-hole binaries, although more exotic cosmological and
astrophysical sources cannot be excluded. The observation of Hellings-Downs
correlations points to the gravitational-wave origin of this signal.Comment: 30 pages, 18 figures. Published in Astrophysical Journal Letters as
part of Focus on NANOGrav's 15-year Data Set and the Gravitational Wave
Background. For questions or comments, please email [email protected]
In vitro Expression von Osteoporose modifizierenden Mediatoren und proinflammatorischen Zytokinen in karpalem Synovialgewebe von Patienten mit Rheumatoider Arthritis unter dem Einfluss von Bisphosphonaten
Synovialgewebe von Patienten mit Rheumatoider Arthritis (RA) wurde 24 vs 48h mit Alendronat (Al) (Amino-Bisphosphonat (BP)), und Clodronat (Cl) (Non-Amino-BP) inkubiert, die Genexpression mit real-time RT-PCR, die Proteinfreisetzung mit ELISA (Enzyme-linked-immuno-sorbent-assay) gemessen.
Die Induktion von TNF und IL-1 nach 24h kann als proinflammatorischer Effekt gesehen werden, tendenziell in der Proteinfreisetzung unter Al erhalten. Die Inkubation nach 48h weist auf einen antiinflammatorischen Effekt, für Cl in der Proteinfreisetzung reflektiert. Die Diskrepanz zwischen Genexpression und Proteinfreisetzung deutet auf eine posttranskriptionelle Modifikation.
Die Induktion von OPG (Osteoprotegerin) konnte die von OPGL (OPG-Ligand) kompensieren. Die erniedrigte OPG-Freisetzung nach 24h kann auf einen posttranskriptionellen Effekt deuten, wobei die Ergebnisse nach 48h die Genexpression reflektieren. Keine eindeutigen Unterschiede zwischen Al und Cl
Design, development and field evaluation of row-cleaners for strip tillage in conservation farming
A concept for integrated care pathways for atopic dermatitis-A GA 2 LEN ADCARE initiative
The integrated care pathways for atopic dermatitis (AD-ICPs) aim to bridge the gap between existing AD treatment evidence-based guidelines and expert opinion based on daily practice by offering a structured multidisciplinary plan for patient management of AD. ICPs have the potential to enhance guideline recommendations by combining interventions and aspects from different guidelines, integrating quality assurance, and describing co-ordination of care. Most importantly, patients can enter the ICPs at any level depending on AD severity, resources available in their country, and economic factors such as differences in insurance reimbursement systems. The GA 2 LEN ADCARE network and partners as well as all stakeholders, abbreviated as the AD-ICPs working group, were involved in the discussion and preparation of the AD ICPs during a series of subgroup workshops and meetings in years 2020 and 2021, after which the document was circulated within all GAL 2 EN ADCARE centres. The AD-ICPs outline the diagnostic procedures, possible co-morbidities, different available treatment options including differential approaches for the pediatric population, and the role of the pharmacists and other stakeholders, as well as remaining unmet needs in the management of AD. The AD-ICPs provide a multidisciplinary plan for improved diagnosis, treatment, and patient feedback in AD management, as well as addressing critical unmet needs, including improved access to care, training specialists, implementation of educational programs, assessment on the impact of climate change, and fostering a personalised treatment approach. By focusing on these key areas, the initiative aims to pave the way for a brighter future in the management of AD