Experiencing breast cancer at the workplace

We study unique data from a dynamic natural experiment involving more than 7,000 American women to understand how a woman’s propensity to perform an annual mammography changes over time after a co-worker is diagnosed with breast cancer. We find that in the year this event occurs the probability that a woman performs a mammography drops by about 8 percentage points, off a base level of about 70%. This impact effect is persistent during at least the following 2 years, is driven by cases of breast cancer diagnosed at non-early stages, and by the behavior of individuals who are less knowledgeable about health issues. This negative effect is confirm ed when we allow for serial correlation in screening behavior and when we estimate the effect of the treatment on the hazard of not screening, at the daily frequency. However, the effect vanishes in placebo experiments

Embedding of a non-Hermitian Hamiltonian to emulate the von Neumann measurement scheme

The problem of how measurement in quantum mechanics takes place has existed since its formulation. Von Neumann proposed a scheme where he treated measurement as a two-part process -- a unitary evolution in the full system-ancilla space and then a projection onto one of the pointer states of the ancilla (representing the "collapse" of the wavefunction). The Lindblad master equation, which has been extensively used to explain dissipative quantum phenomena in the presence of an environment, can effectively describe the first part of the von Neumann measurement scheme when the jump operators in the master equation are Hermitian. We have proposed a non-Hermitian Hamiltonian formalism to emulate the first part of the von Neumann measurement scheme. We have used the embedding protocol to dilate a non-Hermitian Hamiltonian that governs the dynamics in the system subspace into a higher-dimensional Hermitian Hamiltonian that evolves the full space unitarily. We have obtained the various constraints and the required dimensionality of the ancilla Hilbert space in order to achieve the required embedding. Using this particular embedding and a specific projection operator, one obtains non-Hermitian dynamics in the system subspace that closely follow the Lindblad master equation. This work lends a new perspective to the measurement problem by employing non-Hermitian Hamiltonians.Comment: 23 pages, 5 figure

Statistical Study of Plasmoids associated with post-CME Current Sheet

We investigate the properties of plasmoids observed in the current sheet formed after an X-8.3 flare followed by a fast CME eruption on September 10, 2017 using Extreme Ultraviolet (EUV) and white-light coronagraph images. The main aim is to understand the evolution of plasmoids at different spatio-temporal scales using existing ground- and space-based instruments. We identified the plasmoids in current sheet observed in the successive images of {\it Atmospheric Imaging Assembly} (AIA) and white-light coronagraphs, K-Cor and LASCO/C2. We found that the current sheet is accompanied by several plasmoids moving upwards and downwards. Our analysis showed that the downward and upward moving plasmoids have average width of 5.92 Mm and 5.65 Mm, respectively in the AIA field of view (FOV). However, upward moving plasmoids have average width of 64 Mm in the K-Cor which evolves to a mean width of 510 Mm in the LASCO/C2 FOV. Upon tracking the plasmoids in successive images, we observe that downward and upward moving plasmoids have average speeds of $\sim$272 km s$^{-1}$ and $\sim$191 km s$^{-1}$ respectively in the EUV passbands. We note that the plasmoids become super-Alfv\'enic when they reach at LASCO FOV. Furthermore, we estimate that the null-point of the current sheet at $\approx$ 1.15 R$_\odot$ where bidirectional plasmoid motion is observed. We study the width distribution of plasmoids formed and notice that it is governed by a power law with a power index of -1.12. Unlike previous studies there is no difference in trend for small and large scale plasmoids. The presence of accelerating plasmoids near the neutral point indicates a longer diffusion region as predicted by MHD models.Comment: Accepted for the publication in Astronomy & Astrophysics (A&A). 10 pages, 11 figures. Animations can be found at https://www.dropbox.com/sh/g0wjq2awxai1hy4/AAClkTHPFkTa5JU-Zulf9a75a?dl=

Correcting Projection Effects in CMEs Using GCS-Based Large Statistics of Multi-Viewpoint Observations

This study addresses the limitations of single-viewpoint observations of Coronal Mass Ejections (CMEs) by presenting results from a 3D catalog of 360 CMEs during solar cycle 24, fitted using the Graduated Cylindrical Shell (GCS) model. The data set combines 326 previously analyzed CMEs and 34 newly examined events, categorized by their source regions into active region (AR) eruptions, active prominence (AP) eruptions, and prominence eruptions (PE). Estimates of errors are made using a bootstrapping approach. The findings highlight that the average 3D speed of CMEs is ∼1.3 times greater than the 2D speed. PE CMEs tend to be slow, with an average speed of 432 km s−1. AR and AP speeds are higher, at 723 and 813 km s−1, respectively, with the latter having fewer slow CMEs. The distinctive behavior of AP CMEs is attributed to factors like overlying magnetic field distribution or geometric complexities leading to less accurate GCS fits. A linear fit of projected speed to width gives a gradient of ∼2 km s−1 deg−1, which increases to 5 km s−1 deg−1 when the GCS-fitted ‘true’ parameters are used. Notably, AR CMEs exhibit a high gradient of 7 km s−1 deg−1, while AP CMEs show a gradient of 4 km s−1 deg−1. PE CMEs, however, lack a significant speed-width relationship. We show that fitting multi-viewpoint CME images to a geometrical model such as GCS is important to study the statistical properties of CMEs, and can lead to a deeper insight into CME behavior that is essential for improving future space weather forecasting

A CME Source Region Catalogue and their Associated Properties

The primary objective of this study is to connect the coronal mass ejections (CMEs) to their source regions, primarily creating a CME source region (CSR) catalogue, and secondly probing into the influence the source regions have on different statistical properties of CMEs. We create a source region catalogue for 3327 CMEs from 1998 to 2017, thus capturing the different phases of cycle 23 and 24. The identified source regions are segregated into 3 classes, Active Regions (ARs), Prominence Eruptions (PEs) and Active Prominences (APs), while the CMEs are segregated into slow and fast based on their average projected speeds. We find the contribution of these three source region types to the occurrences of slow and fast CMEs to be different in the above period. A study of the distribution of average speeds reveals different power-laws for CMEs originating from different sources, and the power-law is different during the different phases of cycles 23 and 24. A study of statistical latitudinal deflections showed equator-ward deflections, while the magnitude of deflections again bears an imprint of the source regions. An East-West asymmetry is also noted, particularly in the rising phase of cycle 23, with the presence of active longitudes for the CMEs, with a preference towards the Western part of the Sun. Our results show that different aspects of CME kinematics bear a strong imprint of the source regions they originate from, thus indicating the existence of different ejection and/or propagation mechanisms of these CMEs.Comment: 29 Pages, 18 Figures. Accepted in The Astrophysical Journal Supplement Series (APJS

Characterizing Spectral Channels of Visible Emission Line Coronagraph of Aditya-L1

Aditya-L1 is India’s first solar mission with the Visible Emission Line Coronagraph (VELC), which consists of three spectral channels taking high-resolution spectroscopic observations of the inner corona up to 1.5 Rʘ at 5,303, 7,892, and 10,747 Å. In this work, we present a strategy for the slit width optimization of the VELC using synthetic line profiles by taking into account the instrument characteristics and coronal conditions for log(T) varying from 6 to 6.5. The synthetic profiles are convolved with simulated instrumental scattered light and noise to estimate the signal-to-noise ratio (SNR), which will be crucial to designing the future observation plans. We find that the optimum slit width for VELC turns out to be 50 μm, providing sufficient SNR for observations in different solar conditions. We also analyzed the effect of plasma temperature on the SNR at different heights in the VELC field of view for the optimized slit width. We also studied the expected effect of the presence of a CME on the spectral channel observations. This analysis will help to plan the scientific observations of VELC in different solar conditions