Short-term exposure sequences and anxiety symptoms: A time series clustering of smartphone-based mobility trajectories

Background Short-term environmental exposures, including green space, air pollution, and noise, have been suggested to affect health. However, the evidence is limited to aggregated exposure estimates which do not allow the capture of daily spatiotemporal exposure sequences. We aimed to (1) determine individuals’ sequential exposure patterns along their daily mobility paths and (2) examine whether and to what extent these exposure patterns were associated with anxiety symptoms. Methods We cross-sectionally tracked 141 participants aged 18–65 using their global positioning system (GPS) enabled smartphones for up to 7 days in the Netherlands. We estimated their location-dependent exposures for green space, fine particulate matter, and noise along their moving trajectories at 10-min intervals. The resulting time-resolved exposure sequences were then partitioned using multivariate time series clustering with dynamic time warping as the similarity measure. Respondents’ anxiety symptoms were assessed with the Generalized Anxiety Disorders-7 questionnaire. We fitted linear regressions to assess the associations between sequential exposure patterns and anxiety symptoms. Results We found four distinctive daily sequential exposure patterns across the participants. Exposure patterns differed in terms of exposure levels and daily variations. Regression results revealed that participants with a “moderately health-threatening” exposure pattern were significantly associated with fewer anxiety symptoms than participants with a “strongly health-threatening” exposure pattern. Conclusions Our findings support that environmental exposures’ daily sequence and short-term magnitudes may be associated with mental health. We urge more time-resolved mobility-based assessments in future analyses of environmental health effects in daily life

Interpreting time-integrated polarization data of gamma-ray burst prompt emission

Aims. With the accumulation of polarization data in the gamma-ray burst (GRB) prompt phase, polarization models can be tested. Methods. We predicted the time-integrated polarizations of 37 GRBs with polarization observation. We used their observed spectral parameters to do this. In the model, the emission mechanism is synchrotron radiation, and the magnetic field configuration in the emission region was assumed to be large-scale ordered. Therefore, the predicted polarization degrees (PDs) are upper limits. Results. For most GRBs detected by the Gamma-ray Burst Polarimeter (GAP), POLAR, and AstroSat, the predicted PD can match the corresponding observed PD. Hence the synchrotron-emission model in a large-scale ordered magnetic field can interpret both the moderately low PDs ($\sim10\%$) detected by POLAR and relatively high PDs ($\sim45\%$) observed by GAP and AstroSat well. Therefore, the magnetic fields in these GRB prompt phases or at least during the peak times are dominated by the ordered component. However, the predicted PDs of GRB 110721A observed by GAP and GRB 180427A observed by AstroSat are both lower than the observed values. Because the synchrotron emission in an ordered magnetic field predicts the upper-limit of the PD for the synchrotron-emission models, PD observations of the two bursts challenge the synchrotron-emission model. Then we predict the PDs of the High-energy Polarimetry Detector (HPD) and Low-energy Polarimetry Detector (LPD) on board the upcoming POLAR-2. In the synchrotron-emission models, the concentrated PD values of the GRBs detected by HPD will be higher than the LPD, which might be different from the predictions of the dissipative photosphere model. Therefore, more accurate multiband polarization observations are highly desired to test models of the GRB prompt phase.Comment: 6 pages, 5 figures, with updated AstroSat data, accepted by A

Normalizing Weak Boson Pair Production at the Large Hadron Collider

The production of two weak bosons at the Large Hadron Collider will be one of the most important sources of SM backgrounds for final states with multiple leptons. In this paper we consider several quantities that can help normalize the production of weak boson pairs. Ratios of inclusive cross-sections for production of two weak bosons and Drell-Yan are investigated and the corresponding theoretical errors are evaluated. The possibility of predicting the jet veto survival probability of VV production from Drell-Yan data is also considered. Overall, the theoretical errors on all quantities remain less than 5-20%. The dependence of these quantities on the center of mass energy of the proton-proton collision is also studied.Comment: 11 pages; added references, minor text revisions, version to appear in Phys. Rev.

Quantitative characterisation of the layered structure within lithium-ion batteries using ultrasonic resonance

Lithium-ion batteries (LIBs) are becoming an important energy storage solution to achieve carbon neutrality, but it remains challenging to characterise their internal states for the assurance of performance, durability and safety. This work reports a simple but powerful non-destructive characterisation technique, based on the formation of ultrasonic resonance from the repetitive layers within LIBs. A physical model is developed from the ground up, to interpret the results from standard experimental ultrasonic measurement setups. As output, the method delivers a range of critical pieces of information about the inner structure of LIBs, such as the number of layers, the average thicknesses of electrodes, the image of internal layers, and the states of charge variations across individual layers. This enables the quantitative tracking of internal cell properties, potentially providing new means of quality control during production processes, and tracking the states of health and charge during operation

Probing the magnetic ground state of the molecular Dysprosium triangle

We present zero field muon spin lattice relaxation measurements of a Dysprosium triangle molecular magnet. The local magnetic fields sensed by the implanted muons indicate the coexistence of static and dynamic internal magnetic fields below $T^* ~35$ K. Bulk magnetization and heat capacity measurements show no indication of magnetic ordering below this temperature. We attribute the static fields to the slow relaxation of the magnetization in the ground state of Dy3. The fluctuation time of the dynamic part of the field is estimated to be ~0.55 $\mu$s at low temperaturesComment: 5 pages, 5 figures, accepted for publication in Phys. Rev.

Entanglement of remote atomic qubits

We report observations of entanglement of two remote atomic qubits, achieved by generating an entangled state of an atomic qubit and a single photon at Site A, transmitting the photon to Site B in an adjacent laboratory through an optical fiber, and converting the photon into an atomic qubit. Entanglement of the two remote atomic qubits is inferred by performing, locally, quantum state transfer of each of the atomic qubits onto a photonic qubit and subsequent measurement of polarization correlations in violation of the Bell inequality |S| <2. We experimentally determine S =2.16 +/- 0.03. Entanglement of two remote atomic qubits, each qubit consisting of two independent spin wave excitations, and reversible, coherent transfer of entanglement between matter and light, represent important advances in quantum information science.Comment: 5 pages, 3 figure

Controlling the spin orientation of photoexcited electrons by symmetry breaking

We study reflection of optically spin-oriented hot electrons as a means to probe the semiconductor crystal symmetry and its intimate relation with the spin-orbit coupling. The symmetry breaking by reflection manifests itself by tipping the net-spin vector of the photoexcited electrons out of the light propagation direction. The tipping angle and the pointing direction of the net-spin vector are set by the crystal-induced spin precession, momentum alignment and spin-momentum correlation of the initial photoexcited electron population. We examine non-magnetic semiconductor heterostructures and semiconductor/ferromagnet systems and show the unique signatures of these effects.Comment: 4 pages, 3 figures, resubmitte