Analytical approximation for the structure of differentially rotating barotropes

Approximate analytical formula for density distribution in differentially rotating stars is derived. Any barotropic EOS and conservative rotation law can be handled with use of this method for wide range of differential rotation strength. Results are in good qualitative agreement with comparison to the other methods. Some applications are suggested and possible improvements of the formula are discussed.Comment: 10 pages, 13 figures, accepted for publication in Monthly Notice

Fold and thrust belts : structural style, evolution and exploration – an introduction

Peer reviewedPublisher PD

Individual decision making and the evolutionary roots of institutions

Just as many aspects of individual decisions are sometimes called unconscious or automatic, we know that some institutions have evolved through unconscious, nondeliberative mechanisms. Their function can also be largely nondeliberative, as in the case of some institutions that may structure behavior without requiring any reflection on the part of the participants. On the other hand, political institutions exist for the purpose of bringing deliberative mechanisms to bear on institutions in the hope of changing them for the better. The immense project of building an integrated explanation of institutions from individual brains to nations-has only barely begun. In this chapter, we report on our discussions that attempted to sketch the mechanisms that connect individuals to large-scale institutions. We begin with a discussion of current thought on the design of individual decision making. If institutions regulate behavior, then presumably the mechanisms that have evolved to produce individual behavior will be relevant to the broader enterprise of integrating these two scales of explanation. Then we explore ways in which institutions may have evolved, both as a result of individual decision making and as a result of processes distinct from those that govern individual behavior. We approach this topic from two perspectives. Seen one way, unconscious psychological forces constrain the design of institutions, sometimes powerfully. Seen another way, unconscious population-level processes create functional institutional design that few social architects could conceive of with their individual deliberate faculties

Structural styles of the Camisea fold-and-thrust belt, southeast Peru

The Camisea multi-trillion cubic feet (tcf) gas and condensate fields are located at the southern edge of the Ucayali Basin of southeastern Peru. The Ordovician to Neogene sedimentary succession was deformed by late Miocene to Present Day contraction related to the Peruvian flat-slab subduction regime. This produced thin-skinned, north-northeast-vergent thrust-fault-related folds that form the traps of the Camisea fields. The architecture of the frontal thin-skinned thrust system is characterized by a faulted detachment fold system at Cashiriari and a gently dipping north-northeast-vergent thrust ramp system and associated kink-band hanging-wall anticlines and back-thrusts at San Martin. At San Martin, these form brittle thrust wedge systems that terminate in triangle zones in the Paleogene–Neogene strata of the foreland basin at the leading edge of the fold-and-thrust belt. The basal detachment of the thin-skinned system is located at the top of the Ordovician–Silurian synrift sequence and at the base of the Devono–Mississippian postrift units. Steep Ordovician–Silurian extensional faults offset the basement and form half-graben structures that influence the topography of the postrift strata and the basal detachment geometry. The Cashiriari Anticline is modeled as gentle inversion fault-propagation fold at the early stages of the Andean deformation and then was amplified forming a detachment fold during the late Miocene to Present Day phase of strong contraction. Small displacement limb-break thrusts displace the Cashiriari fold limbs. In contrast, the San Martin fault-fold system is modeled as a simple shear fault-bend fold that forms a wedge thrust and a triangle zone. The San Martin folds are hanging-wall kink-band-style fault-bend systems where the positions of the underlying thrust ramps were controlled by the basement fault systems and the topography of the postrift units. The hinterland of the Camisea frontal thinskinnedfold-and-thrust belt is interpreted to be a system of large inverted basement fault blocks that were uplifted and exhumed as the Andean deformation moved outboard from the hinterland to the foreland and transferred displacement onto the thin-skinned sedimentary wedge at the edge of the basin. This study shows how the underlying basement fault architectures and rift basin geometries can control the styles of the thin-skinned Andean deformation in the sub-Andean system

Helping in humans and other animals: a fruitful interdisciplinary dialogue.

Humans are arguably unique in the extent and scale of cooperation with unrelated individuals. While pairwise interactions among non-relatives occur in some non-human species, there is scant evidence of the large-scale, often unconditional prosociality that characterizes human social behaviour. Consequently, one may ask whether research on cooperation in humans can offer general insights to researchers working on similar questions in non-human species, and whether research on humans should be published in biology journals. We contend that the answer to both of these questions is yes. Most importantly, social behaviour in humans and other species operates under the same evolutionary framework. Moreover, we highlight how an open dialogue between different fields can inspire studies on humans and non-human species, leading to novel approaches and insights. Biology journals should encourage these discussions rather than drawing artificial boundaries between disciplines. Shared current and future challenges are to study helping in ecologically relevant contexts in order to correctly interpret how payoff matrices translate into inclusive fitness, and to integrate mechanisms into the hitherto largely functional theory. We can and should study human cooperation within a comparative framework in order to gain a full understanding of the evolution of helping

Panic at the ISCO: the visible accretion disks powering optical variability in ZTF AGN

About 3-10% of Type I active galactic nuclei (AGN) have double-peaked broad Balmer lines in their optical spectra originating from the motion of gas in their accretion disk. Double-peaked profiles arise not only in AGN, but occasionally appear during optical flares from tidal disruption events and changing-state AGN. In this paper we identify 250 double-peaked emitters (DPEs) amongst a parent sample of optically variable broad-line AGN in the Zwicky Transient Facility (ZTF) survey, corresponding to a DPE fraction of 19%. We model spectra of the broad H alpha emission line regions and provide a catalog of the fitted accretion disk properties for the 250 DPEs. Analysis of power spectra derived from the 5 year ZTF light curves finds that DPEs have similar amplitudes and power law indices to other broad-line AGN, but have lower turnover frequencies. Follow-up spectroscopy of 12 DPEs reveals that ~50% display significant changes in the relative strengths of their red and blue peaks over long 10-20 year timescales, indicating that broad-line profile changes arising from spiral arm or hotspot rotation are common amongst optically variable DPEs. Analysis of the accretion disk parameters derived from spectroscopic modeling provides evidence that DPEs are not in a special accretion state, but are simply normal broad-line AGN viewed under the right conditions for the accretion disk to be easily visible. We compare the radio variability properties of the two samples and present radio jet imaging of 3 DPEs with disks of inclination angle 14-35 degrees. We discuss some objects with notable light curves or unusual broad line profiles which are outliers amongst the variable DPE population. We include inspiraling SMBH binary candidate SDSSJ1430+2303 in our analysis, and discuss how its photometric and spectroscopic variability is consistent with the disk-emitting AGN population in ZTF.Comment: Submitted to ApJ. 30 pages, 10 figures, 4 tables. Comments welcome

The evolution of cooperation and altruism--a general framework and a classification of models.

One of the enduring puzzles in biology and the social sciences is the origin and persistence of intraspecific cooperation and altruism in humans and other species. Hundreds of theoretical models have been proposed and there is much confusion about the relationship between these models. To clarify the situation, we developed a synthetic conceptual framework that delineates the conditions necessary for the evolution of altruism and cooperation. We show that at least one of the four following conditions needs to be fulfilled: direct benefits to the focal individual performing a cooperative act; direct or indirect information allowing a better than random guess about whether a given individual will behave cooperatively in repeated reciprocal interactions; preferential interactions between related individuals; and genetic correlation between genes coding for altruism and phenotypic traits that can be identified. When one or more of these conditions are met, altruism or cooperation can evolve if the cost-to-benefit ratio of altruistic and cooperative acts is greater than a threshold value. The cost-to-benefit ratio can be altered by coercion, punishment and policing which therefore act as mechanisms facilitating the evolution of altruism and cooperation. All the models proposed so far are explicitly or implicitly built on these general principles, allowing us to classify them into four general categories