1,876 research outputs found
Low fertility increases descendant socioeconomic position but reduces long-term fitness in a modern post-industrial society.
Adaptive accounts of modern low human fertility argue that small family size maximizes the inheritance of socioeconomic resources across generations and may consequently increase long-term fitness. This study explores the long-term impacts of fertility and socioeconomic position (SEP) on multiple dimensions of descendant success in a unique Swedish cohort of 14 000 individuals born during 1915-1929. We show that low fertility and high SEP predict increased descendant socioeconomic success across four generations. Furthermore, these effects are multiplicative, with the greatest benefits of low fertility observed when SEP is high. Low fertility and high SEP do not, however, predict increased descendant reproductive success. Our results are therefore consistent with the idea that modern fertility limitation represents a strategic response to the local costs of rearing socioeconomically competitive offspring, but contradict adaptive models suggesting that it maximizes long-term fitness. This indicates a conflict in modern societies between behaviours promoting socioeconomic versus biological success. This study also makes a methodological contribution, demonstrating that the number of offspring strongly predicts long-term fitness and thereby validating use of fertility data to estimate current selective pressures in modern populations. Finally, our findings highlight that differences in fertility and SEP can have important long-term effects on the persistence of social inequalities across generations
The Spectral Correlation Function -- A New Tool for Analyzing Spectral-Line Maps
The "spectral correlation function" analysis we introduce in this paper is a
new tool for analyzing spectral-line data cubes. Our initial tests, carried out
on a suite of observed and simulated data cubes, indicate that the spectral
correlation function [SCF] is likely to be a more discriminating statistic than
other statistical methods normally applied. The SCF is a measure of similarity
between neighboring spectra in the data cube. When the SCF is used to compare a
data cube consisting of spectral-line observations of the ISM with a data cube
derived from MHD simulations of molecular clouds, it can find differences that
are not found by other analyses. The initial results presented here suggest
that the inclusion of self-gravity in numerical simulations is critical for
reproducing the correlation behavior of spectra in star-forming molecular
clouds.Comment: 29 pages, including 4 figures (tar file submitted as source) See
also: http://cfa-www.harvard.edu/~agoodman/scf/velocity_methods.htm
Sibling configuration predicts individual and descendant socioeconomic success in a modern post-industrial society.
Growing up with many siblings, at least in the context of modern post-industrial low fertility, low mortality societies, is predictive of relatively poor performance on school tests in childhood, lower levels of educational attainment, and lower income throughout adulthood. Recent studies further indicate these relationships hold across generations, so that the descendants of those who grow up with many siblings are also at an apparent socioeconomic disadvantage. In this paper we add to this literature by considering whether such relationships interact with the sex and relative age of siblings. To do this we utilise a unique Swedish multigenerational birth cohort study that provides sibling configuration data on over 10,000 individuals born in 1915-1929, plus all their direct genetic descendants to the present day. Adjusting for parental and birth characteristics, we find that the 'socioeconomic cost' of growing up in a large family is independent of both the sex of siblings and the sex of the individual. However, growing up with several older as opposed to several younger siblings is predictive of relatively poor performance on school tests and a lower likelihood of progression to tertiary education. This later-born disadvantage also holds across generations, with the children of those with many older siblings achieving lower levels of educational attainment. Despite these differences, we find that while individual and descendant income is negatively related to the number of siblings, it is not influenced by the relative age of siblings. Thus, our findings imply that the educational disadvantage of later-born children, demonstrated here and in numerous other studies, does not necessarily translate into reduced earnings in adulthood. We discuss potential explanations for this pattern of results, and consider some important directions for future research into sibling configuration and wellbeing in modern societies
The Price-Earnings Relative as an Indicator of Investment Returns
The use of the price-earnings relative indicator (PER) is examined to assess its utility in evaluating stock returns for similarly performing firms. The measure does seem to be a valid predictor of investment returns and eliminate bias between firms within the same industry
The Effect of Projection on Derived Mass-Size and Linewidth-Size Relationships
Power law mass-size and linewidth-size correlations, two of "Larson's laws,"
are often studied to assess the dynamical state of clumps within molecular
clouds. Using the result of a hydrodynamic simulation of a molecular cloud, we
investigate how geometric projection may affect the derived Larson
relationships. We find that large scale structures in the column density map
have similar masses and sizes to those in the 3D simulation (PPP). Smaller
scale clumps in the column density map are measured to be more massive than the
PPP clumps, due to the projection of all emitting gas along lines of sight.
Further, due to projection effects, structures in a synthetic spectral
observation (PPV) may not necessarily correlate with physical structures in the
simulation. In considering the turbulent velocities only, the linewidth-size
relationship in the PPV cube is appreciably different from that measured from
the simulation. Including thermal pressure in the simulated linewidths imposes
a minimum linewidth, which results in a better agreement in the slopes of the
linewidth-size relationships, though there are still discrepancies in the
offsets, as well as considerable scatter. Employing commonly used assumptions
in a virial analysis, we find similarities in the computed virial parameters of
the structures in the PPV and PPP cubes. However, due to the discrepancies in
the linewidth- and mass- size relationships in the PPP and PPV cubes, we
caution that applying a virial analysis to observed clouds may be misleading
due to geometric projection effects. We speculate that consideration of
physical processes beyond kinetic and gravitational pressure would be required
for accurately assessing whether complex clouds, such as those with highly
filamentary structure, are bound.Comment: 25 pages, including 7 Figures; Accepted for publication in Ap
Improving Patient Decision-Making in Health Care
Outlines regional variations within Minnesota in rates of patients with similar conditions receiving elective surgery, the concept of shared decision making, treatment choices for eight conditions, and steps for ensuring patients make informed decisions
Interferometric weak value deflections: quantum and classical treatments
We derive the weak value deflection given in a paper by Dixon et al. (Phys.
Rev. Lett. 102, 173601 (2009)) both quantum mechanically and classically. This
paper is meant to cover some of the mathematical details omitted in that paper
owing to space constraints
Central Nervous Control of Blood Pressure in Man; Preliminary Report
Electrical activity of the brain, eye movements, arterial pressure, heart rate, and respiratory rate and depth have been recorded continuously during a night of sleep not induced by drugs in 22 healthy subjects, two hypertensive patients, and one anephric man who was awaiting renal transplantation. Sleep was associated with reduction in arterial pressure averaging 50 mm Hg systolic and 30 mm Hg diastolic. Dreams, although occasionally associated with marked elevation of blood pressure, were usually accompanied by no change or a slight fall in pressure. The dramatic paroxysmal electroencephalographic alterations termed K complexes, occurring spontaneously or after a noise in sleep of moderate depth, were followed within two or three heart beats by abrupt elevation in arterial pressure, as much as 35 mm Hg, lasting 10 to 20 seconds. Blockade with propranolol of β-adrenergic receptors, which mediate cardio-excitatory effects of sympathetic nerve discharge, did not modify the hypertension following K complexes. Cerebral activity, transmitted by sympathetic peripheral vasoconstrictor pathways, is an important regulator of blood pressure during sleep in man
Prostaglandins A1 and E1 influence gene expression in an established insect cell line (BCIRL-HzAM1 cells)
Prostaglandins (PGs) and other eicosanoids exert important physiological actions in insects and other invertebrates, including influencing ion transport and mediating cellular immune defense functions. Although these actions are very well documented, we have no information on the mechanisms of PGs actions in insect cells. Here we report on the outcomes of experiments designed to test our hypothesis that PGs modulate gene expression in an insect cell line established from pupal ovarian tissue of the moth Helicoverpa zea (BCIRL-HzAM1 cells). We treated cells with either PGA1 or PGE1 for 12 or 24 h then analyzed cell lysates by 2-D electrophoresis. Analysis of the gels by densitometry revealed substantial changes in protein expression in some of the protein spots we analyzed. These spots were processed for mass spectrometric analysis by MALDI TOF/TOF, which yielded in silico protein identities for all 34 spots. The apparent changes in three of the proteins were confirmed by semi-quantative PCR, showing that the changes in mRNA expression were reflected in changes in protein expression. The 34 proteins were sorted into six categories, protein actions, lipid metabolism, signal transduction, protection, cell functions and metabolism. The findings support the hypothesis that one mechanism of PG action in insect cells is the modulation of gene expression
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