What can we say about seed fields for galactic dynamos?

We demonstrate that a quasi-uniform cosmological seed field is a much less suitable seed for a galactic dynamo than has often been believed. The age of the Universe is insufficient for a conventional galactic dynamo to generate a contemporary galactic magnetic field starting from such a seed, accepting conventional estimates for physical quantities. We discuss modifications to the scenario for the evolution of galactic magnetic fields implied by this result. We also consider briefly the implications of a dynamo number that is significantly larger than that given by conventional estimates

Homelessness amongst Students in Higher Education: Time for a New Research Agenda?

The extent and causes of poverty and homelessness among students in UK Higher Education (HE) urgently require investigation and solutions, because the legacies of COVID-19 and the cost of living crisis have exacerbated pressures on students that have been growing for many years. The Higher Education Policy Institute (Hanna, 2023) reports that, in a website audit of the 140 Universities in the UK, 27% are operating a food bank, 11% are giving out vouchers, and over 50% offering discounts on food in recognition of rising poverty. A third of Russell Group universities – some of the most prestigious UK institutions – were found to be operating a food bank, compared with 26% of other universities. At their National Conference 2023, the NUS reiterated that there is a housing crisis for students across the UK who struggle to find affordable or suitable accommodation. While prices of rent and food have risen rapidly, student loans have remained the same. This means that more students are working long hours alongside their degrees, with international students, care leavers, and those estranged from family proving particularly vulnerable. Additionally, university study may be more challenging for students schooled during COVID-19, a greater number of whom are now reporting mental health difficulties. The impact of these conditions on students’ health and academic performance has not yet been examined. Since this demographic will make up a significant proportion of our country’s future workforce, their wellbeing, experiences, and abilities have far-reaching implications

Studies on the hill reaction activity of soluble chloroplast extracts final report

Hill reaction activity of soluble chloroplast extracts from spinac

Flip-flop phenomenon: observations and theory

In many active stars the spots concentrate on two permanent active longitudes which are 180 degrees apart. In some of these stars the dominant part of the spot activity changes the longitude every few years. This so-called flip-flop phenomenon has up to now been reported in 11 stars, both single and binary alike, and including also the Sun. To explain this phenomenon, a non-axisymmetric dynamo mode, giving rise to two permanent active longitudes at opposite stellar hemispheres, is needed together with an oscillating axisymmetric magnetic field. Here we discuss the observed characteristics of the flip-flop phenomenon and present a dynamo solution to explain them.Comment: 4 pages, 5 figures, contribution to the conference "Dynamos of the Sun, Stars and Planets", to be published in AN Volume 32

Phase transition in a mean-field model for sympatric speciation

We introduce an analytical model for population dynamics with intra-specific competition, mutation and assortative mating as basic ingredients. The set of equations that describes the time evolution of population size in a mean-field approximation may be decoupled. We find a phase transition leading to sympatric speciation as a parameter that quantifies competition strength is varied. This transition, previously found in a computational model, occurs to be of first order.Comment: accepted for Physica

RATES OF RETURN IN THE FARM AND NON-FARM SECTORS: A TIME SERIES COMPARISON

Financial Economics,

Rarefied flow past a flat plate at incidence

Results of a numerical study using the direct simulation Monte Carlo (DSMC) method are presented for the transitional flow about a flat plate at 40 deg incidence. The plate has zero thickness and a length of 1.0 m. The flow conditions simulated are those experienced by the Shuttle Orbiter during reentry at 7.5 km/s. The range of freestream conditions are such that the freestream Knudsen number values are between 0.02 and 8.4, i.e., conditions that encompass most of the transitional flow regime. The DSMC simulations show that transitional effects are evident when compared with free molecule results for all cases considered. The calculated results demonstrate clearly the necessity of having a means of identifying the effects of transitional flow when making aerodynamic flight measurements as are currently being made with the Space Shuttle Orbiter vehicles. Previous flight data analyses have relied exclusively on adjustments in the gas-surface interaction models without accounting for the transitional effect which can be comparable in magnitude. The present calculations show that the transitional effect at 175 km would increase the Space Shuttle Orbiter lift-drag ratio by 90 percent over the free molecule value

Impact of Capital Gains and Urban Pressure on Farmland Values: A Spatial Correlation Analysis

Farmland is a major component of wealth in the farm sector as well as wealth of farm households. This study contributes to our knowledge of variations in farmland prices by examining the extent to which farmland values are spatially correlated and to what extent that this spatial correlation can be explained by income to farmland.land values, spatial correlation, Land Economics/Use,

The Effect of US Energy Policy and Farm Program Payments on the Bio-Fuel Sector: A Regime-Switching Approach

Resource /Energy Economics and Policy,