105 research outputs found
VLBI Probes of Jet Physics in Neutrino-Candidate Blazars
In recent years, evidence has accumulated that some high-energy cosmic
neutrinos can be associated with blazars. The strongest evidence for an
individual association was found in the case of the blazar TXS 0506+056 in
2017. In July 2019, another track-like neutrino event (IC190730A) was found
spatially coincident with the well-known bright flat-spectrum radio quasar PKS
1502+106. PKS 1502+106 was not found to be in a particularly elevated gamma-ray
state, but exhibited a remarkably bright radio outburst at the time of the
neutrino detection, similar to TXS 0506+056. We have performed a
multi-frequency VLBI study from 15 GHz up to 86 GHz on TXS 0506+056, PKS
1502+106 and one additional neutrino-candidate blazar (PKS 0215+015) to study
the radio structure of neutrino candidate blazars in response to their neutrino
association. We have obtained target of opportunity observations with the VLBA
for all three sources within 1 month from their associated neutrino
events and are performing multi-epoch studies of the jet kinematics at 15 GHz
as part of the MOJAVE program. Here, we present first results on TXS 0506+056
at 86 GHz and one additional 43 GHz image obtained 27 days after IC170922A,
closer in time to the neutrino event than previously published images. We also
give an overview about our recent work on PKS 1502+106 and PKS 0215+015.Comment: 8 pages, 1 figure, 1 table, Proceedings of 38th International Cosmic
Ray Conference (ICRC2023
Predicting the Future of AI with AI: High-quality link prediction in an exponentially growing knowledge network
A tool that could suggest new personalized research directions and ideas by taking insights from the scientific literature could significantly accelerate the progress of science. A field that might benefit from such an approach is artificial intelligence (AI) research, where the number of scientific publications has been growing exponentially over the last years, making it challenging for human researchers to keep track of the progress. Here, we use AI techniques to predict the future research directions of AI itself. We develop a new graph-based benchmark based on real-world data -- the Science4Cast benchmark, which aims to predict the future state of an evolving semantic network of AI. For that, we use more than 100,000 research papers and build up a knowledge network with more than 64,000 concept nodes. We then present ten diverse methods to tackle this task, ranging from pure statistical to pure learning methods. Surprisingly, the most powerful methods use a carefully curated set of network features, rather than an end-to-end AI approach. It indicates a great potential that can be unleashed for purely ML approaches without human knowledge. Ultimately, better predictions of new future research directions will be a crucial component of more advanced research suggestion tools
Normal cervical changes in parous women during the second half of pregnancy - a prospective, longitudinal ultrasound study
OBJECTIVE: To determine what constitutes normal cervical changes during the second half of pregnancy in parous women delivering at term. DESIGN: The study comprises 21 healthy, pregnant parous women who all gave birth at term. They were examined with transvaginal ultrasound every two weeks from 24 gestational weeks until delivery. Cervical length and width were measured. The inner cervical os was assessed as being closed or open, the length and width of any opening were measured, and dynamic cervical changes (i.e. opening and closing of the inner cervical os during examination) were noted. RESULTS: Median cervical length was 41 mm (range 26-55) at the first examination and 29 mm (range 8-56) at the last examination. The corresponding figures for cervical width were 38 mm (range 29-47) and 46 mm (range 38-64). Cervical length decreased in 18 women but remained unchanged in three. Three patterns of change in cervical length were observed: in 12 women there was a steady, continuous decrease in cervical length (median decrease rate 1.1 mm/week, range 0.6-2.4); in four women the decrease rate accelerated towards the end of pregnancy, the median decrease rate after the change being 3.0 mm/week (range 1.5-4.8); and in two women there was a sudden drop in cervical length at term. Cervical width increased in 16 women but remained unchanged in five. Two patterns of change in cervical width were seen: 14 women manifested a steady continuous increase in cervical width (median 0.8 mm/week, range 0.4-1.8); in two women the increase rate accelerated from around 34 gestational weeks, the increase rate after the change being 4.1 and 5.9 mm/week, respectively. Opening of the internal cervical os was observed at least once in 11 (52%) women and was seen as early as at 24 and 25 gestational weeks in two women. The opening was always V-shaped (median length 6 mm, range 4-17; median width 7 mm, range 3-20). Dynamic changes of the internal cervical os were seen in three women (14%) at 25, 30 and 41 gestational weeks, respectively. CONCLUSION: The cervix of parous women decreases in length and increases in width from midpregnancy to term, but the pattern of change varies between individuals. Knowledge of the different patterns of normal change forms the basis of transvaginal ultrasound studies of pathological cervical changes during pregnancy
Gamow Shell Model Description of Weakly Bound Nuclei and Unbound Nuclear States
We present the study of weakly bound, neutron-rich nuclei using the nuclear
shell model employing the complex Berggren ensemble representing the bound
single-particle states, unbound Gamow states, and the non-resonant continuum.
In the proposed Gamow Shell Model, the Hamiltonian consists of a one-body
finite depth (Woods-Saxon) potential and a residual two-body interaction. We
discuss the basic ingredients of the Gamow Shell Model. The formalism is
illustrated by calculations involving {\it several} valence neutrons outside
the double-magic core: He and O.Comment: 19 pages, 20 encapsulated PostScript figure
TELAMON: Effelsberg Monitoring of AGN Jets with Very-High-Energy Astroparticle Emissions -- II. Polarization properties
We present recent results of the TELAMON program, which is using the
Effelsberg 100-m telescope to monitor the radio spectra of active galactic
nuclei (AGN) under scrutiny in astroparticle physics, namely TeV blazars and
neutrino-associated AGN. Our sample includes all known Northern TeV-emitting
blazars as well as blazars positionally coincident with IceCube neutrino
alerts. Polarization can give additional insight into the source properties, as
the polarized emission is often found to vary on different timescales and
amplitudes than the total intensity emission. Here, we present an overview of
the polarization properties of the TeV-emitting TELAMON sources at four
frequencies in the 20 mm and 7 mm bands. While at 7 mm roughly of all
observed sources are found to be significantly polarized, for 20 mm the
percentage is . We find that most of the sources exhibit mean
fractional polarizations of , matching the expectations of rather low
polarization levels in these sources from previous studies at lower radio
frequencies. Nevertheless, we demonstrate examples of how the polarized
emission can provide additional information over the total intensity.Comment: 9 pages, 2 figures, Proceedings of the 38th International Cosmic Ray
Conference (ICRC2023
Applying behavioural theory to the challenge of sustainable development: using hairdressers as diffusers of more sustainable hair-care practices
The challenges presented by sustainable development are broadly accepted, yet resource use increases unabated. It is increasingly acknowledged that while technical solutions may play a part, a key issue is behaviour change. In response to this there has been a plethora of studies into how behaviour change can be enabled, predominantly from psychological and sociological perspectives. This has resulted in a substantial body of knowledge into the factors that drive behaviour change and how they can be manipulated to achieve desired social goals. In this paper we describe a study that draws on this body of knowledge to design an intervention to drive behaviour change across the hairdressing sector, and by the process of diffusion, across the vast social networks of this occupational group to influence domestic hair-care practices. The intervention was successful: hairdressers indicated positive intentions to adopt more sustainable practices within their salons and pass them onto their customers. The customer survey (N=776) confirms this: customers surveyed after their hairdresser attended the Green-Salon-Makeover intervention were significantly more likely to report that environmental issues had been considered in their salon visit and that they themselves would consider such issues in their hair-care practices at home than customers who were surveyed before the intervention
Sub-10 a data reception with low latency using a 180-nm CMOS wake-up receiver at 868 MHz
This paper shows the benefits of a sub-10 A wake-up receiver circuit used for wireless data reception with reaction times down to 60 ms. The wake-up receiver is a wireless receiver which continuously scans the radio channel for particular pseudonoise sequences. Having received and decoded the sequence, the wake-up receiver triggers different actions in smart objects. The wake-up receiver offers a scalable current consumption between 2.4 A and 99 A and is very suitable for mobile battery-operated smart objects. Details on correlation codes and two proposed protocol schemes for radio channels with bit error rates above 10% are described
4-ÎŒW-WakeUp-Receiver als mögliche SchlĂŒsseltechnologie fĂŒr vernetzte intelligente Objekte
Wireless technologies such as Zigbee or Bluetooth Smart fail to entirely fulfil technical requirements towards lifetime and short latency. This contribution shows opportunities to implement wireless receivers for IoT applications at 2.4 GHz or 868 MHz in the WakeUp Receiver technology for intelligent mobile devices. Methods to achieve good tolerance against bit errors or dynamic interferers and the capability of selective wake-up enable a flexible application and service design with any network topologies in an Internet-of-Things context
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