147 research outputs found
Key risk factors associated with fractal dimension based geographical clustering of COVID-19 data in the Flemish and Brussels region, Belgium
IntroductionCOVID-19 remains a major concern globally. Therefore, it is important to evaluate COVID-19's rapidly changing trends. The fractal dimension has been proposed as a viable method to characterize COVID-19 curves since epidemic data is often subject to considerable heterogeneity. In this study, we aim to investigate the association between various socio-demographic factors and the complexity of the COVID-19 curve as quantified through its fractal dimension.MethodsWe collected population indicators data (ethnic composition, socioeconomic status, number of inhabitants, population density, the older adult population proportion, vaccination rate, satisfaction, and trust in the government) at the level of the statistical sector in Belgium. We compared these data with fractal dimension indicators of COVID-19 incidence between 1 January â 31 December 2021 using canonical correlation analysis.ResultsOur results showed that these population indicators have a significant association with COVID-19 incidences, with the highest explanatory and predictive power coming from the number of inhabitants, population density, and ethnic composition.ConclusionIt is important to monitor these population indicators during a pandemic, especially when dealing with targeted interventions for a specific population
Nuclear Charge Radius of Be
The nuclear charge radius of Be was precisely determined using the
technique of collinear laser spectroscopy on the transition in the Be ion. The mean square charge radius increases
from Be to Be by \delta ^{10,12} = 0.69(5) \fm^{2}
compared to \delta ^{10,11} = 0.49(5) \fm^{2} for the
one-neutron halo isotope Be. Calculations in the fermionic molecular
dynamics approach show a strong sensitivity of the charge radius to the
structure of Be. The experimental charge radius is consistent with a
breakdown of the N=8 shell closure.Comment: 5 pages, 3 figure
DNA diet profiles with highâresolution animal tracking data reveal levels of prey selection relative to habitat choice in a crepuscular insectivorous bird
Given the global decline of many invertebrate food resources, it is fundamental to understand the dietary requirements of insectivores. We give new insights into the functional relationship between the spatial habitat use, food availability, and diet of a crepuscular aerial insectivore, the European Nightjar (Caprimulgus europaeus) by relating spatial use data with highâthroughput sequencing (HTS) combined with DNA metabarcoding. Our study supports the predictions that nightjars collect a substantial part of their daily nourishment from foraging locations, sometimes at considerable distance from nesting sites. Lepidopterans comprise 65% of nightjars' food source. Nightjars tend to select larger species of Lepidoptera (>19 mm) which suggests that nightjars optimize the efficiency of foraging trips by selecting the most energetically favorableâlargerâprey items. We anticipate that our findings may shed additional light on the interactions between invertebrate communities and higher trophic levels, which is required to understand the repercussions of changing food resources on individualâ and populationâlevel processes
Probing single electrons across 300 mm spin qubit wafers
Building a fault-tolerant quantum computer will require vast numbers of
physical qubits. For qubit technologies based on solid state electronic
devices, integrating millions of qubits in a single processor will require
device fabrication to reach a scale comparable to that of the modern CMOS
industry. Equally importantly, the scale of cryogenic device testing must keep
pace to enable efficient device screening and to improve statistical metrics
like qubit yield and process variation. Spin qubits have shown impressive
control fidelities but have historically been challenged by yield and process
variation. In this work, we present a testing process using a cryogenic 300 mm
wafer prober to collect high-volume data on the performance of
industry-manufactured spin qubit devices at 1.6 K. This testing method provides
fast feedback to enable optimization of the CMOS-compatible fabrication
process, leading to high yield and low process variation. Using this system, we
automate measurements of the operating point of spin qubits and probe the
transitions of single electrons across full wafers. We analyze the random
variation in single-electron operating voltages and find that this fabrication
process leads to low levels of disorder at the 300 mm scale. Together these
results demonstrate the advances that can be achieved through the application
of CMOS industry techniques to the fabrication and measurement of spin qubits.Comment: 15 pages, 4 figures, 7 extended data figure
High-precision quadrupole moment reveals significant intruder component in 13 33Al20 ground state
The electric quadrupole moment of the Al201333 ground state, located at the border of the island of inversion, was obtained using continuous-beam ÎČ-detected nuclear quadrupole resonance (ÎČ-NQR). From the measured quadrupole coupling constant ÎœQ=2.31(4) MHz in an α-Al2O3 crystal, a precise value for the electric quadrupole moment is extracted: |Qs(Al33)|=141(3) mb. A comparison with large-scale shell model calculations shows that Al33 has at least 50% intruder configurations in the ground state wave function, favoring the excitation of two neutrons across the N=20 shell gap. Al33 therefore clearly marks the gradual transition north of the deformed Na and Mg nuclei towards the normal Zâ„14 isotopesThis work was partly supported by the European Community FP6âStructuring the ERAâIntegrated Infrastructure Initiative Contract EURONS No. RII3-CT-2004-506065, by the FWO-Vlaanderen, by the IAP programme of the Belgium Science Policy under Grants No. P6/23 and No. P7/12, by a grant of the MICINN (Spain) (FPA2011-29854), by the Nupnet network SARFEN (PRI-PIMMNUP-2011-1361), by MINECO (Spain) Centro de Excelencia Severo Ochoa Programme under Grant No. SEV-2012-0249, and by JSPS KAKENHI (Japan) Grants No. 21740204 and No. 15K05094. The experiment was carried out under Experimental Program E437
Precision measurement of the electric quadrupole moment of 31Al and determination of the effective proton charge in the sd-shell
he electric quadrupole coupling constant of the 31Al ground state is measured
to be nu_Q = |eQV_{zz}/h| = 2196(21)kHz using two different beta-NMR (Nuclear
Magnetic Resonance) techniques. For the first time, a direct comparison is made
between the continuous rf technique and the adiabatic fast passage method. The
obtained coupling constants of both methods are in excellent agreement with
each other and a precise value for the quadrupole moment of 31Al has been
deduced: |Q(31Al)| = 134.0(16) mb. Comparison of this value with large-scale
shell-model calculations in the sd and sdpf valence spaces suggests that the
31Al ground state is dominated by normal sd-shell configurations with a
possible small contribution of intruder states. The obtained value for
|Q(31Al)| and a compilation of measured quadrupole moments of odd-Z even-N
isotopes in comparison with shell-model calculations shows that the proton
effective charge e_p=1.1 e provides a much better description of the nuclear
properties in the sd-shell than the adopted value e_p=1.3 e
Voltage scanning and technical upgrades at the Collinear Resonance Ionization Spectroscopy experiment
To optimize the performance of the Collinear Resonance Ionization
Spectroscopy (CRIS) experiment at CERN-ISOLDE, technical upgrades are
continuously introduced, aiming to enhance its sensitivity, precision,
stability, and efficiency. Recently, a voltage-scanning setup was developed and
commissioned at CRIS, which improved the scanning speed by a factor of three as
compared to the current laser-frequency scanning approach. This leads to faster
measurements of the hyperfine structure for systems with high yields (more than
a few thousand ions per second). Additionally, several beamline sections have
been redesigned and manufactured, including a new field-ionization unit, a
sharper electrostatic bend, and improved ion optics. The beamline upgrades are
expected to yield an improvement of at least a factor of 5 in the
signal-to-noise ratio by suppressing the non-resonant laser ions and providing
time-of-flight separation between the resonant ions and the collisional
background. Overall, the presented developments will further improve the
selectivity, sensitivity, and efficiency of the CRIS technique.Comment: 10 pages. Under review at NIM B as part of the proceedings of EMIS
2022 at RAON, South Kore
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