Human well-being and causality in social epidemiology

This paper discusses the work of Ballas and Dorling on life events and happiness. I believe epidemiologists have things they could learn from economists (and vice versa). Here I emphasize the issue of how to establish causality, and try to suggest some ways forward

Investigating the performance of simplified neutral‐ion collisional heating rate in a global IT model

The Joule heating rate has usually been used as an approximate form of the neutral‐ion collisional heating rate in the thermospheric energy equation in global thermosphere‐ionosphere models. This means that the energy coupling has ignored the energy gained by the ions from collisions with electrons. It was found that the globally averaged thermospheric temperature (Tn) was underestimated in simulations using the Joule heating rate, by about 11% when F10.7=110 solar flux unit (sfu, 1 sfu = 10−22 W m−2 Hz−1) in a quiet geomagnetic condition. The underestimation of Tn was higher at low latitudes than high latitudes, and higher at F region altitudes than at E region altitudes. It was found that adding additional neutral photoelectron heating in a global IT model compensated for the underestimation of Tn using the Joule heating approximation. Adding direct photoelectron heating to the neutrals compensated for the indirect path for the energy that flows from the electrons to the ions then to the neutrals naturally and therefore was an adequate compensation over the dayside. There was a slight dependence of the underestimation of Tn on F10.7, such that larger activity levels resulted in a need for more compensation in direct photoelectron heating to the neutrals to make up for the neglected indirect heating through ions and electrons.Key PointsUsing Joule heating rate as the neutral‐ion energy coupling led to a cooler thermosphereNeutral photoelectron heating efficiency compensates for the missing heatingA slight dependence of the underestimation of Tn on F10.7 existedPeer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/137627/1/jgra52323_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/137627/2/jgra52323.pd

A low-cost confocal microscope for the undergraduate lab

We demonstrate a simple and cost-efficient scanning confocal microscope setup for use in advanced instructional physics laboratories. The setup is constructed from readily available commercial products, and the implementation of a 3D-printed flexure stage allows for further cost reduction and pedagogical opportunity. Experiments exploring the thickness of a microscope slide and the surface of solid objects with height variation are presented as foundational components of undergraduate laboratory projects, and demonstrate the capabilities of a confocal microscope. This system allows observation of key components of a confocal microscope, including depth perception and data acquisition via transverse scanning, making it an excellent pedagogical resource

Climatic trends in E-region critical frequency and virtual height above Tromsø (70° N, 10° E)

International audienceWe have examined the long time series of observations of E-region virtual height (1948?2006) and critical frequency (1935-2006) hitherto made by the Tromsø ionosonde at 70° N, 19° E. Combining a simplistic trend analysis with a rigorous treatment of errors we identify a negative trend in critical frequency. While a similar analysis of the virtual height h'E also suggests a negative trend, a closer examination reveals a possible weak positive trend prior to ~1975 and a strong negative trend from ~1975 to present. These two metrics of essentially the same feature of the ionosphere do not exhibit the same signature since critical frequency is controlled by photochemistry within the E-layer while height is controlled by pressure level. We further find that the trend in critical frequency is a daylight/summer phenomenon, no significant trend being evident in the winter subset of the data. On the other hand, the trends in virtual height are independent of season/daylight

The Stellar-Disk Electric (Short) Circuit: Observational Predictions for a YSO Jet Flow

We discuss the star-disk electric circuit for a young stellar object (YSO) and calculate the expected torques on the star and the disk. We obtain the same disk magnetic field and star-disk torques as given by standard magnetohydrodynamic (MHD) analysis. We show how a short circuit in the star-disk electric circuit may produce a magnetically-driven jet flow from the inner edge of a disk surrounding a young star. An unsteady bipolar jet flow is produced that flows perpendicular to the disk plane. Jet speeds of order hundreds of kilometres per second are possible, while the outflow mass loss rate is proportional to the mass accretion rate and is a function of the disk inner radius relative to the disk co-rotation radius.Comment: 6 pages, 8 figures, Accepted for publication in Astrophysics & Space Scienc

Genomic data of different resolutions reveal consistent inbreeding estimates but contrasting homozygosity landscapes for the threatened Aotearoa New Zealand hihi

Inbreeding can lead to a loss of heterozygosity in a population and when combined with genetic drift may reduce the adaptive potential of a species. However, there is uncertainty about whether resequencing data can provide accurate and consistent inbreeding estimates. Here, we performed an in-depth inbreeding analysis for hihi (Notiomystis cincta), an endemic and nationally vulnerable passerine bird of Aotearoa New Zealand. We first focused on subsampling variants from a reference genome male, and found that low-density data sets tend to miss runs of homozygosity (ROH) in some places and overestimate ROH length in others, resulting in contrasting homozygosity landscapes. Low-coverage resequencing and 50 K SNP array densities can yield comparable inbreeding results to high-coverage resequencing approaches, but the results for all data sets are highly dependent on the software settings employed. Second, we extended our analysis to 10 hihi where low-coverage whole genome resequencing, RAD-seq and SNP array genotypes are available. We inferred ROH and individual inbreeding to evaluate the relative effects of sequencing depth versus SNP density on estimating inbreeding coefficients and found that high rates of missingness downwardly bias both the number and length of ROH. In summary, when using genomic data to evaluate inbreeding, studies must consider that ROH estimates are heavily dependent on analysis parameters, data set density and individual sequencing depth

Thermal Duality and Hagedorn Transition from p-adic Strings

We develop the finite temperature theory of p-adic string models. We find that the thermal properties of these non-local field theories can be interpreted either as contributions of standard thermal modes with energies proportional to the temperature, or inverse thermal modes with energies proportional to the inverse of the temperature, leading to a "thermal duality" at leading order (genus one) analogous to the well known T-duality of string theory. The p-adic strings also recover the asymptotic limits (high and low temperature) for arbitrary genus that purely stringy calculations have yielded. We also discuss our findings surrounding the nature of the Hagedorn transition.Comment: 4 pages and 4 figure