Magnetic heating across the cosmological recombination era: Results from 3D MHD simulations

The origin of cosmic magnetic fields is an unsolved problem and magnetogenesis could have occurred in the early Universe. We study the evolution of such primordial magnetic fields across the cosmological recombination epoch via 3D magnetohydrodynamic numerical simulations. We compute the effective or net heating rate of baryons due to decaying magnetic fields and its dependence on the magnetic field strength and spectral index. In the drag-dominated regime ($z \gtrsim 1500$), prior to recombination, we find no real heating is produced. Our simulations allow us to smoothly trace a new transition regime ($600 \lesssim z \lesssim 1500$), where magnetic energy decays, at first, into the kinetic energy of baryons. A turbulent velocity field is built up until it saturates, as the net heating rate rises from a low value at recombination to its peak towards the end of the transition regime. This is followed by a turbulent decay regime ($z \lesssim 600$) where magnetic energy dissipates via turbulent decay of both magnetic and velocity fields while net heating remains appreciable and declines slowly. Both the peak of the net heating rate and the onset of turbulent decay are delayed significantly beyond recombination, by up to 0.5 Myr (until $z\simeq 600-700$), for scale-invariant magnetic fields. We provide analytic approximations and present numerical results for a range of field strengths and spectral indices, illustrating the redshift-dependence of dissipation and net heating rates. These can be used to study cosmic microwave background constraints on primordial magnetic fields.Comment: Submitted to MNRAS, comments are welcome; 22 pages, 26 figures, 2 table

On the Dynamics of Near-Extremal Black Holes

We analyse the dynamics of near-extremal Reissner-Nordstr\"om black holes in asymptotically four-dimensional Anti-de Sitter space (AdS$_4$). We work in the spherically symmetric approximation and study the thermodynamics and the response to a probe scalar field. We find that the behaviour of the system, at low energies and to leading order in our approximations, is well described by the Jackiw-Teitelboim (JT) model of gravity. In fact, this behaviour can be understood from symmetry considerations and arises due to the breaking of time reparametrisation invariance. The JT model has been analysed in considerable detail recently and related to the behaviour of the SYK model. Our results indicate that features in these models which arise from symmetry considerations alone are more general and present quite universally in near-extremal black holes.Comment: 44 (=26+18) pages, 1 figure, 6 appendices; v2: references added; v3: minor changes made; v4: additional references added, version accepted in JHE

Primordial Magnetic Field Limits from Cosmic Microwave Background Bispectrum of Magnetic Passive Scalar Modes

Primordial magnetic fields lead to non-Gaussian signals in the cosmic microwave background (CMB) even at the lowest order, as magnetic stresses and the temperature anisotropy they induce depend quadratically on the magnetic field. In contrast, CMB non-Gaussianity due to inflationary scalar perturbations arises only as a higher order effect. Apart from a compensated scalar mode, stochastic primordial magnetic fields also produce scalar anisotropic stress that remains uncompensated till neutrino decoupling. This gives rise to an adiabatic-like scalar perturbation mode that evolves passively thereafter (called the passive mode). We compute the CMB reduced bispectrum ($b_{l_{_1}l_{_2}l_{_3}}$) induced by this passive mode, sourced via the Sachs-Wolfe effect, on large angular scales. For any configuration of bispectrum, taking a partial sum over mode-coupling terms, we find a typical value of $l_1(l_1+1)l_3(l_3+1) b_{l_{_1}l_{_2}l_{_3}} \sim 6-9 \times 10^{-16}$, for a magnetic field of $B_0 \sim 3$ nG, assuming a nearly scale-invariant magnetic spectrum . We also evaluate, in full, the bispectrum for the squeezed collinear configuration over all angular mode-coupling terms and find $l_1(l_1+1)l_3(l_3+1) b_{l_{_1}l_{_2}l_{_3}} \approx -1.4 \times 10^{-16}$. These values are more than $\sim 10^6$ times larger than the previously calculated magnetic compensated scalar mode CMB bispectrum. Observational limits on the bispectrum from WMAP7 data allow us to set upper limits of $B_0 \sim 2$ nG on the present value of the cosmic magnetic field of primordial origin. This is over 10 times more stringent than earlier limits on $B_0$ based on the compensated mode bispectrum.Comment: 9 page

Cosmic Microwave Background Trispectrum and Primordial Magnetic Field Limits

Primordial magnetic fields will generate non-Gaussian signals in the cosmic microwave background (CMB) as magnetic stresses and the temperature anisotropy they induce depend quadratically on the magnetic field. We compute a new measure of magnetic non-Gaussianity, the CMB trispectrum, on large angular scales, sourced via the Sachs-Wolfe effect. The trispectra induced by magnetic energy density and by magnetic scalar anisotropic stress are found to have typical magnitudes of approximately a few times 10^{-29} and 10^{-19}, respectively. Observational limits on CMB non-Gaussianity from WMAP data allow us to conservatively set upper limits of a nG, and plausibly sub-nG, on the present value of the primordial cosmic magnetic field. This represents the tightest limit so far on the strength of primordial magnetic fields, on Mpc scales, and is better than limits from the CMB bispectrum and all modes in the CMB power spectrum. Thus, the CMB trispectrum is a new and more sensitive probe of primordial magnetic fields on large scales.Comment: Published in Physical Review Letters on 5 June 201

A Meta Analysis of Different Herbs (Leaves, Roots, Stems) Used in Treatment of Cancer Cells

The initial step in the progression of cancer is the deformation of normal cells, which is caused by mutations in the DNA of the cell. This abnormal cell, during the process of it’s asexual reproduction, acquires invasion characteristics and causes alterations in the tissues that are around it, while at the same time ignoring signals linked to the regulation of cell growth that are present in its immediate environment. It would appear that a significant number of the chemical compounds that are created by plants do not play any direct role in the growth of plants. These kinds of molecules are referred to by the phrase "secondary metabolite," which is short for "secondary metabolites." Essential components include alkaloids, terpenoids, flavonoids, pigments, and tannins. Secondary metabolites are responsible for a wide variety of biological effects, including those on hematopoietic cells, lipids, and the cardiovascular system. Other biological effects can also be linked to secondary metabolites

GENDER DIFFERENCES IN COVID-19 EXPERIENCES OF OLDER FEMALE VETERANS USING THE PROSPECTIVE HERO CARE SURVEY DATA

Aging female Veterans faced unique experiences during the COVID-19 pandemic. We used self-reported experiences of older female Veterans during this time in comparison with male Veterans. We received responses for the HERO CARE survey from 2,080 (88 (4.2%) female, 1,992 (95.8%) male) community-dwelling Veterans from five geographically diverse Veterans Affairs Medical Centers. Veterans were prompted to self-report the impact of COVID-19 through an open-ended question asking to share anything they would like us to know about their experience. Open-ended responses were classified through inductive coding into emergent themes and chi-square tests. The most common emergent themes from female Veteran responses were social isolation (17.8%), negative effects on physical health (15.6%), and issues with accessing VA healthcare resources (15.6%). The most common emergent themes from male Veterans were social isolation (12.7%) and issues with accessing VA healthcare resources (8.2%). However, female Veterans were more likely to report experiencing a decline in their physical health compared to males (p< 0.01), more likely to report experiencing a negative change in their mental health (p< 0.01) and more likely to experience a decline in their general satisfaction with life (p< 0.002). They were also more likely to experience an issue with accessing VA healthcare resources (p< 0.02), and to experience financial problems (p< 0.0001). Female Veterans were more likely to report negative impacts of the COVID-19 pandemic to their mental and physical health, general satisfaction with life, and accessing VA healthcare resources. Routine assessment may be needed to adequately address their needs

UNMET NEEDS OF OLDER FEMALE VETERANS AND GENDER DIFFERENCES USING THE PROSPECTIVE HERO CARE SURVEY DATA

Abstract Aging female Veterans face unique healthcare needs which are yet to be well-described. We analyzed round one data from HERO CARE, a prospective survey, to describe the medical, psychological, and social unmet needs of female Veterans and compare them with those of male Veterans. We received survey responses from 8,056 community-dwelling Veterans (227 (2.8%) females and 7,829 (97.2%) males) from San Antonio, Palo Alto, Miami, Salt Lake City Veterans Affairs (VA) Medical Centers, and Veteran Integrated Service Network 8 in July 2021. We compared difference in needs between the female and male respondents using chi-square tests and difference in age in years using t-tests. Respondents were classified as having an unmet need if they responded that they needed “a little” or “a lot more help” for specific needs. Female respondents were 74.3 (SD: 14.5) years-old on average, and 7.9% Hispanic, 15.4% non-Hispanic Black, 72.7% non-Hispanic White. Male respondents were older 80.3 (SD: 9.8) years-old on average (p0.05). Among female Veterans, 20.1% screened positive for anxiety (GAD-2 score >2) and 22.8% for depression (PHQ-2 score >2), compared to male Veterans: 15.2% (p< 0.01) and 21.6% (p=0.41), respectively. Routine assessment of aging female Veterans, specifically focusing on mental health and IADLs, may better address their needs