A
bstract
The
Neutrino Experiment with a Xenon TPC
(NEXT) searches for the neutrinoless double-beta (0
νββ
) decay of
136
Xe using high-pressure xenon gas TPCs with electroluminescent amplification. ...A scaled-up version of this technology with about 1 tonne of enriched xenon could reach in less than 5 years of operation a sensitivity to the half-life of 0
νββ
decay better than 10
27
years, improving the current limits by at least one order of magnitude. This prediction is based on a well-understood background model dominated by radiogenic sources. The detector concept presented here represents a first step on a compelling path towards sensitivity to the parameter space defined by the inverted ordering of neutrino masses, and beyond.
A new method to tag the barium daughter in the double-beta decay of ^{136}Xe is reported. Using the technique of single molecule fluorescent imaging (SMFI), individual barium dication (Ba^{++}) ...resolution at a transparent scanning surface is demonstrated. A single-step photobleach confirms the single ion interpretation. Individual ions are localized with superresolution (∼2 nm), and detected with a statistical significance of 12.9σ over backgrounds. This lays the foundation for a new and potentially background-free neutrinoless double-beta decay technology, based on SMFI coupled to high pressure xenon gas time projection chambers.
Introduction
Late-onset psychosis appears in people over the age of 40. Some preliminary studies show that LOP has fewer severe positive symptoms, more systematic persecutory delusions, more ...bizarre-type delusions, less affective flattening, and more social withdrawal than early onset psychosis.
There are some studies that consider late-onset and very late-onset psychosis as prodromes of neurodegenerative disease. There are some differences in neuropsychological profiles and specific cognitive function alterations discovered. More evidence, however, is required to make an accurate diagnosis.
Objectives
The objective of this study was to reflect the difficulties in differentiating between late-onset psychosis and dementia by reporting the case of a 77-year-old woman who presented with mystical-religious delusions and hallucinations during her hospitalization.
Methods
We present the case of a 77-year-old woman who was hospitalized because of a stroke. During her stay, she began receiving follow-up from the mental health team because she verbalized some mystical-religious delusional ideas. During the psychiatric interview, the patient verbalized mystical-religious ideas and oscillated between coherent, organized, and disaggregated speech. No problems were detected with orientation, or florid affective symptoms that could point to a delirium or affective disorder. The premorbid personality was extravagant, with interpersonal difficulties and magical thinking. Nonetheless, she had no prior contact with the mental health system or hospitalization. We could approximate the beginning of the symptomatology at around 60 years old, thanks to her relatives. Prior to this age, she maintained good function by working as a chef on a regular basis. She gradually isolated herself due to her lack of mobility. Similarly, she decreases her self-care activities, begins hoarding items around the house, and gradually develops more psychotic symptoms.A brain scan was performed, and no acute pathology was found. A neuropsychological test was not executed due to a lack of collaboration from the patient.
Results
-
Conclusions
This case reflects the complexity of differentiating between dementia and late-onset psychosis. Supplementary testing and follow-up are essential for establishing a diagnosis. Related to that, more research is needed to identify the differential characteristics between the two disorders and the temporal correlation between them.
Disclosure of Interest
None Declared
Long‐term observations of carbonaceous aerosols in the Austral Ocean are reported here for the first time from almost 5 years of continuous filter sampling performed at Amsterdam Island (37°48′S, ...77°34′E). Black carbon concentrations determined by optical method were among the lowest reported for marine atmosphere, with monthly mean levels ranging from 2–5 ng C/m3 during summer to 7–13 ng C/m3 during winter. A clear seasonal pattern was also observed for organic aerosols, but in opposite phase, with maximum values during the austral summer period (>250 ng C/m3) and minimum concentrations (100 ng C/m3) during winter. This seasonal variation of organic concentration was found to be almost entirely related to the water‐insoluble organic carbon fraction, suggesting a primary origin for these organics, most probably through bubble bursting processes. Moreover, this summer maximum observed for organic aerosols was found to be correlated with satellite‐derived chlorophyll a concentrations averaged over an oceanic region upwind of the sampling site and characterized by relatively high biogenic activity. This oceanic region being located at 1000–2000 km far away from the monitoring station, atmospheric ageing may have played a significant role on the levels and size‐resolved properties of marine organics collected at Amsterdam Island. This biogenic marine organic source of primary origin in the Austral Ocean is fully consistent with similar observations previously reported for the Northern Atlantic Ocean and brings further evidences of the major role of marine organic emissions over remote oceanic regions.
During the last years the atmosphere of the Great Athens Area (GAA) and other Greek cities is burdened from extended residential biomass burning for heating purposes. In this work, a series of near ...real-time and off-line biomass burning tracers are analyzed during intense wood burning events in Athens. The measurements were conducted at an urban background site located in the center of Athens, and in the heart of wood burning activities (winter 2013–2014). The measured tracers include high resolution measurements of non-sea salt potassium (nss-K+), wood burning black carbon (BCwb), the m/z 60 fragment associated with levoglucosan and monosaccharide anhydrides (levoglucosan, mannosan and galactosan) determined on selected filter samples. The suitability of these tracers was evaluated when the prevailing meteorological conditions with low dispersion and deposition mechanisms (low wind speed, absence of precipitation) were associated with high biomass burning emissions at nighttime. During the severe smog periods, the levels of K+, BCwb, m/z 60 and levoglucosan were up to 2.2 μg m−3, 12.5 μg m−3, 3.4 μg m−3 and 8.6 μg m−3, respectively, higher by a factor of at least two, relatively to the non smog periods due to biomass burning. Correlations between biomass burning tracers as well as between monosaccharide anhydrides provided information about the type of material and wood being burned.
•High temporal resolution measurements were deployed during wintertime in Athens to track and identify a number of different biomass burning tracers.•Biomass burning tracers such as non sea salt potassium (nss-K+), black carbon (BCwb), the organic fraction m/z 60 and levoglucosan were monitored.•The enhanced levels of chloride (Cl−) could provide evidence of combustion of inappropriate materials being used as fuel.•Sodium (Na+) was also shown to be an alternative combustion tracer.•The significant correlation between PM2.5 and levoglucosan, indicated that wood burning could be responsible for PM2.5 higher than 45 μg m−3.
A
bstract
Convolutional neural networks (CNNs) are widely used state-of-the-art computer vision tools that are becoming increasingly popular in high-energy physics. In this paper, we attempt to ...understand the potential of CNNs for event classification in the NEXT experiment, which will search for neutrinoless double-beta decay in
136
Xe. To do so, we demonstrate the usage of CNNs for the identification of electron-positron pair production events, which exhibit a topology similar to that of a neutrinoless double-beta decay event. These events were produced in the NEXT-White high-pressure xenon TPC using 2.6 MeV gamma rays from a
228
Th calibration source. We train a network on Monte Carlo-simulated events and show that, by applying on-the-fly data augmentation, the network can be made robust against differences between simulation and data. The use of CNNs offers significant improvement in signal efficiency and background rejection when compared to previous non-CNN-based analyses.
A
bstract
The NEXT experiment aims at the sensitive search of the neutrinoless double beta decay in
136
Xe, using high-pressure gas electroluminescent time projection chambers. The NEXT-White ...detector is the first radiopure demonstrator of this technology, operated in the Laboratorio Subterráneo de Canfranc. Achieving an energy resolution of 1% FWHM at 2.6 MeV and further background rejection by means of the topology of the reconstructed tracks, NEXT-White has been exploited beyond its original goals in order to perform a neu- trinoless double beta decay search. The analysis considers the combination of 271.6 days of
136
Xe-enriched data and 208.9 days of
136
Xe-depleted data. A detailed background modeling and measurement has been developed, ensuring the time stability of the radiogenic and cosmogenic contributions across both data samples. Limits to the neutrinoless mode are obtained in two alternative analyses: a background-model-dependent approach and a novel direct background-subtraction technique, offering results with small dependence on the background model assumptions. With a fiducial mass of only 3.50 ± 0.01 kg of
136
Xe-enriched xenon, 90% C.L. lower limits to the neutrinoless double beta decay are found in the
T
1
/
2
0
ν
> 5
.
5
×
10
23
−
1
.
3
×
10
24
yr range, depending on the method. The presented techniques stand as a proof-of-concept for the searches to be implemented with larger NEXT detectors.
Abstract
Core-collapse supernovae are among the most magnificent events in the observable universe. They produce many of the chemical elements necessary for life to exist and their remnants—neutron ...stars and black holes—are interesting astrophysical objects in their own right. However, despite millennia of observations and almost a century of astrophysical study, the explosion mechanism of core-collapse supernovae is not yet well understood. Hyper-Kamiokande is a next-generation neutrino detector that will be able to observe the neutrino flux from the next galactic core-collapse supernova in unprecedented detail. We focus on the first 500 ms of the neutrino burst, corresponding to the accretion phase, and use a newly-developed, high-precision supernova event generator to simulate Hyper-Kamiokande's response to five different supernova models. We show that Hyper-Kamiokande will be able to distinguish between these models with high accuracy for a supernova at a distance of up to 100 kpc. Once the next galactic supernova happens, this ability will be a powerful tool for guiding simulations toward a precise reproduction of the explosion mechanism observed in nature.
A
bstract
Natural radioactivity represents one of the main backgrounds in the search for neutrinoless double beta decay. Within the NEXT physics program, the radioactivity- induced backgrounds are ...measured with the NEXT-White detector. Data from 37.9 days of low-background operations at the Laboratorio Subterráneo de Canfranc with xenon depleted in
136
Xe are analyzed to derive a total background rate of (0.84
±
0.02) mHz above 1000 keV. The comparison of data samples with and without the use of the radon abatement system demonstrates that the contribution of airborne-Rn is negligible. A radiogenic background model is built upon the extensive radiopurity screening campaign conducted by the NEXT collaboration. A spectral fit to this model yields the specific contributions of
60
Co,
40
K,
214
Bi and
208
Tl to the total background rate, as well as their location in the detector volumes. The results are used to evaluate the impact of the radiogenic backgrounds in the double beta decay analyses, after the application of topological cuts that reduce the total rate to (0.25
±
0.01) mHz. Based on the best-fit background model, the NEXT-White median sensitivity to the two-neutrino double beta decay is found to be 3.5
σ
after 1 year of data taking. The background measurement in a Q
ββ
±
100 keV energy window validates the best-fit background model also for the neutrinoless double beta decay search with NEXT-100. Only one event is found, while the model expectation is (0.75
±
0.12) events.
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