Apparent Asymmetry Research Articles

An Actualist Explanation of the Procreation Asymmetry

AbstractWhile morality prohibits us from creating miserable children, it does not require us to create happy children. I offer an actualist explanation of this apparent asymmetry. Assume that for every possible world W, there is a distinct set of permissibility facts determined by the welfare of those who exist in W. Moral actualism says that actual-world permissibility facts should determine one's choice between worlds. But if one doesn't know which world is actual, one must aim for subjective rightness and maximize expected actual-world permissibility. So, because one should expect actual people to be worse off than they could have been if one creates a miserable child, creating a miserable child is subjectively impermissible. And because one should expect actual people to be at least as well off as they could have been if one fails to create a happy child, failing to create a happy child is subjectively permissible.

Recklessness and Uncertainty: Jackson Cases and Merely Apparent Asymmetry

Is normative uncertainty like factual uncertainty? Should it have the same effects on our actions? Some have thought not. Those who defend an asymmetry between normative and factual uncertainty typically do so as part of the claim that our moral beliefs in general are irrelevant to both the moral value and the moral worth of our actions (Weatherson 2014; Harman 2015). Here I use the consideration of Jackson cases to challenge this view, arguing that we can explain away the apparent asymmetries between normative and factual uncertainty by considering the particular features of the cases in greater detail. Such consideration shows that, in fact, normative and factual uncertainty are equally relevant to moral assessment.

Seeing events vs. entities: The processing advantage of Pseudo Relatives over Relative Clauses

Abstract We present the results of three offline questionnaires (one attachment preference study and two acceptability judgments) and two eye-tracking studies in French and English, investigating the resolution of the ambiguity between pseudo relative and relative clause interpretations. This structural and interpretive ambiguity has recently been shown to play a central role in the explanation of apparent cross-linguistic asymmetries in relative clause attachment (Grillo and Costa, 2014; Grillo et al., 2015). This literature has argued that pseudo relatives are preferred to relative clauses because of their structural and interpretive simplicity. This paper adds to this growing body of literature in two ways. First we show that, in contrast to previous findings, French speakers prefer to attach relative clauses to the most local antecedent once pseudo relative availability is controlled for. We then provide direct support for the pseudo relative preference: grammatically forced disambiguation to a relative clause interpretation leads to degraded acceptability and greater processing cost in a pseudo relative environment than maintaining compatibility with a pseudo relative.

Magmatic ocean-continent transitions

Abstract Continental extension may, or may not, be coeval with significant mantle melting, leading to the formation of distinct types of passive margins (respectively magma-poor or volcanic), with distinct crustal structures. Especially in inter-cratonic mobile areas, magmatic breakup and development of volcanic passive margins (VPMs) may postdate the early development of a non-magmatic continental rift system. The time-span between the amagmatic and the magmatic systems may be relatively short or, conversely, long (tens of millions years). Such evolution is often associated with a significant apparent asymmetry in the wideness of conjugate VPMs. In this paper, we attempt to re-interpret the structure of three paired VPMs which developed close to, but separately from, a previous amagmatic aborted rift system. Due to opposite dips in major crustal detachment faults accommodating extension from sedimentary to volcanic stages, those composite margins tend to individualize a fault-dissected continental block (here designed as L-Block) along one of the conjugate margins. In addition to the amount and distribution of amagmatic extension, the time-span between amagmatic and magmatic extension exerts a major structural and rheological control on the final structure of the ocean-continent transitions. The finite margin geometry may be erroneously interpreted as resulting from a continuous process from hyperextension to the final magmatic breakup. However, the early syn-sedimentary extension appears, in many cases, to be low-rate or episodic. Consequently, the VPM final breakup of the lithosphere may shift away from the original amagmatic stretched area to the rifted margin.

Analyses of geospace response to the geomagnetic storm in May 2017

Strong geomagnetic storm occurred since 15:37UT May 27th, 2017. The analysis result showed that, the corona mass ejection (CME) on May 23rd transformed into magnetic cloud while travelling towards the Earth, the B z component of which stayed continually below −10 nT, and reached minimum value of −20.71 nT. Under effect of the interaction between the B z component and the magnetic field in the magnetopause, the minimum value of SYM-H index reached −142 nT. Plenty of the global ionosonde stations observed ionospheric disturbances. Comprehensive study of the ionosonde, TIMED-GUVI observation and TEC assimilation data revealed that, such ionospheric storm showed apparent hemispheric asymmetries, neutral composition (N2, O2) disturbance may be the primary cause of the negative storm, while the positive storm may be caused by the upward effect of equatorward thermospheric wind or the increase of the neutral density ratio O/N2. The enhancement of the thermospheric atmosphere density during the geomagnetic storm caused the significant acceleration of the altitude decay speed of low orbit satellites, which was in good correspondence with the change of the HPI index.

P1 element morphological variability within the Late Pennsylvanian asymmetrical Idiognathodus clade from the Midcontinent, U.S.A. and implications for ontogeny, taxonomy, phylogeny, and function

Missourian-Virgilian asymmetrical Idiognathodus represent a distinct clade of species with strong dextral-sinistral P1 element asymmetry that exhibit a series of morphological events before the Late Pennsylvanian extinction of Idiognathodus. Previous taxonomic work and morphometric analyses were completed separately for the three major groups of the clade. From oldest to youngest, these are the I. magnificus, I. eudoraensis, and I. simulator groups. The dextral-sinistral P1 element asymmetry is more apparent in larger specimens and the asymmetry is caused by ontogenetic distortion of the dextral element, which widens in the ventral part of the rostral side. At smaller sizes, both sinistral and dextral elements grow predominately dorsal-ventral, and at larger sizes growth is predominately rostral-caudal. Lobe groups correspond with different platform shapes, suggesting that lobe groups are useful taxonomic identification criterion for classifying morphologically distinct species.There are four major morphological events that occur within the asymmetrical Idiognathodus clade: 1) the development of simulator-style P1 element asymmetry in the I. magnificus group; 2) the replacement of flat ungrooved platforms in the I. magnificus group with the grooved platforms of the I. eudoraensis group; 3) the shortening of the adcarinal ridges and development of stronger dextral-sinistral element P1 asymmetry in the I. simulator group; and 4) the replacement of the asymmetric Idiognathodus clade with the I. tersus group which have grooveless narrow platforms, long adcarinal ridges and no apparent dextral-sinistral P1 element asymmetry. These morphological events likely reflect significant biological and paleoecological changes that ultimately culminate with the extinction of Idiognathodus.

The two-dimensional kinetic ballooning theory for trapped electron mode in tokamak

The two-dimensional (2D) kinetic theory for a collisionless trapped electron mode is developed based on the Fourier-ballooning transform in an up-down symmetric equilibrium (illustrated via concentric circular magnetic surfaces). The system consists of two equations: the ballooning (integral) equation with a parameterized Floquet phase and a second order differential equation for the distribution of the Floquet phase. The coupled equations are, then, numerically solved as an eigenvalue problem yielding the 2D mode structure (in real space) as well as the global (phase-independent) eigenvalue for an L-mode parameter set. The 2D mode structure exhibits apparent radial-poloidal asymmetry; due to the poloidal coupling, the radial correlation length is found to be, at least, twice as large as the poloidal one. The global (phase-independent) eigenvalue of the mode differs considerably from the conventional local (phase-dependent) estimate. This paper shares many technical aspects with a published paper that works out the 2D kinetic theory for the ion temperature gradient mode [Xie et al., Phys. Plasmas 24, 102506 (2017)].

Functional characterization of the alanine-serine-cysteine exchanger of Carnobacterium sp AT7.

Many key cell processes require prior cell uptake of amino acids from the environment, which is facilitated by cell membrane amino acid transporters such as those of the L-type amino acid transporter (LAT) subfamily. Alterations in LAT subfamily amino acid transport are associated with several human diseases, including cancer, aminoacidurias, and neurodegenerative conditions. Therefore, from the perspective of human health, there is considerable interest in obtaining structural information about these transporter proteins. We recently solved the crystal structure of the first LAT transporter, the bacterial alanine-serine-cysteine exchanger of Carnobacterium sp AT7 (BasC). Here, we provide a complete functional characterization of detergent-purified, liposome-reconstituted BasC transporter to allow the extension of the structural insights into mechanistic understanding. BasC is a sodium- and proton-independent small neutral amino acid exchanger whose substrate and inhibitor selectivity are almost identical to those previously described for the human LAT subfamily member Asc-1. Additionally, we show that, like its human counterparts, this transporter has apparent affinity asymmetry for the intra- and extracellular substrate binding sites-a key feature in the physiological role played by these proteins. BasC is an excellent paradigm of human LAT transporters and will contribute to our understanding of the molecular mechanisms underlying substrate recognition and translocation at both sides of the plasma membrane.

A gap in HD 92945’s broad planetesimal disc revealed by ALMA

In the last few years, multiwavelength observations have revealed the ubiquity of gaps/rings in circumstellar discs. Here we report the first ALMA observations of HD 92945 at 0.86 mm, that reveal a gap at about 73$\pm$3 au within a broad disc of planetesimals that extends from 50 to 140 au. We find that the gap is $20^{+10}_{-8}$ au wide. If cleared by a planet in situ, this planet must be less massive than 0.6 $M_\mathrm{Jup}$, or even lower if the gap was cleared by a planet that formed early in the protoplanetary disc and prevented planetesimal formation at that radius. By comparing opposite sides of the disc we also find that the disc could be asymmetric. Motivated by the asymmetry and the fact that planets might be more frequent closer to the star in exoplanetary systems, we show that the gap and asymmetry could be produced by two planets interior to the disc through secular resonances. These planets excite the eccentricity of bodies at specific disc locations, opening radial gaps in the planetesimal distribution. New observations are necessary to confirm if the disc is truly asymmetric, thus favouring the secular resonance model, or if the apparent asymmetry is due to a background galaxy, favouring the in-situ planet scenario. Finally, we also report the non-detection of CO and HCN gas confirming that no primordial gas is present. The CO and HCN non-detections are consistent with the destruction of volatile-rich Solar System-like comets.

Justice for guinea pigs

ABSTRACTInnovative medical treatments have an inescapable resemblance to medical experiments. They may prove to be of no help to those on whom they are performed but of great help to subsequent patients. The burdens suffered by those who undergo such treatments are, it seems, not reciprocated by those who benefit from their sacrifice. This apparent asymmetry of burden and benefit is the subject of the present paper, which views the issue through the prism of American law and the lenses of a theory which assigns pride of place to reciprocity among persons. Canonical treatments of medical mishaps in American law focus our attention on lesser harm, consent, and unavoidable injury as the distinctive issues raised by cases in this domain. This paper sets these values within a framework which holds that the proper liability regime for innovative treatments should depend primarily on the relationships between those who undergo the treatments and those who benefit from them, and not on considerations of aggregate welfare. Honouring the premise that innovative treatments should only be undertaken when they are in the ‘best interests’ of the patients on whom they are performed avoids the injustice of treating patients who are subjected to such treatments as mere guinea pigs, to be sacrificed to the general good. The subtler question of whether fairness not only forbids the sacrifice of some for the good of others but also requires those who benefit from the sacrifice of others to compensate their benefactors is the principal focus of this paper.

Testing General Relativity with the Black Hole Shadow Size and Asymmetry of Sagittarius A*: Limitations from Interstellar Scattering

Abstract The Event Horizon Telescope, a global 230 GHz very-long-baseline interferometry array, achieves angular resolution of , sufficient to resolve the supermassive black hole Sagittarius A* (Sgr A*). This resolution may soon enable measurements of the black hole “shadow” size and asymmetry, predicted to be ≈50 and ≲3 μas, respectively. Measurements that depart from these values could indicate a violation of the “no-hair theorem.” However, refractive scattering by the turbulent ionized interstellar medium distorts the image of Sgr A*, affecting its apparent size and asymmetry. In this paper, we present a general analytic approach to quantify the expected image wander, distortion, and asymmetry from refractive scattering. If the turbulence in the scattering material of Sgr A* is close to Kolmogorov, we estimate the mean refractive image wander, distortion, and asymmetry to be 0.53, 0.72, and 0.52 μas at 230 GHz. However, alternative scattering models with flatter power spectra can yield larger values, up to 2.1, 6.3, and 5.0 μas, respectively. We demonstrate that these effects can be reduced by averaging images over multiple observations. For a small number of observations, the effects of scattering can be comparable to or greater than those from black hole spin, and they determine a fundamental limit for testing general relativity via images of Sgr A*.

Density Waves and Jet Emission Asymmetry in Bose Fireworks

A Bose condensate, subject to periodic modulation of the two-body interactions, was recently observed to emit matter-wave jets resembling fireworks [Nature (London) 551, 356 (2017)NATUAS0028-083610.1038/nature24272]. In this Letter, combining experiment with numerical simulation, we demonstrate that these "Bose fireworks" represent a late stage in a complex time evolution of the driven condensate. We identify a "density wave" stage which precedes jet emission and results from the interference of matter waves. The density waves self-organize and self-amplify without breaking long range translational symmetry. This density wave structure deterministically establishes the template for the subsequent patterns of the emitted jets. Moreover, our simulations, in good agreement with experiment, address an apparent asymmetry in the jet pattern, and show that it is fully consistent with momentum conservation.

Negotiating privacy. Athletes’ assessment and knowledge of the ADAMS

Elite athletes must comply with a complex system of controls in order to participate in international sports and competitions. The Anti-Doping Analysis Management System (ADAMS) is one of the control devices that subject athletes to a regime of control and surveillance. Anti-doping organisations (ADOs) and national and international sports federations, for example, make use of their whereabouts data for test planning and decision-making regarding test routines. Athletes’ participation is mandatory, otherwise they cannot take part in competitive sports. This, in return, means that they agree to have their privacy and that of others compromised. Thus, a tension exists between the fight against doping and the integrity of privacy. Through a qualitative study on doping, controls and control practices we have learned that athletes view ADAMS as a necessary nuisance, but we do not know what they actually know about the system. We conducted a survey among German elite athletes (summer and fall 2016) to further explore the usage routines of ADAMS, the athletes’ knowledge of the tool and their assessment of possible privacy infringements. A total of 523 German athletes registered in the Registered Testing Pool and National Testing Pool (N = 2,152) of the National Anti-Doping Agency of Germany, who provided us with a representative sample, took part. We found from the survey that athletes have rather contradictory views concerning ADAMS, and often little knowledge of the system as such and would (or know how to) engage in playing the system to avoid controls. Athletes generally voice strong feelings about privacy, while simultaneously accepting ADAMS despite the concerns raised. However, they want more transparency regarding the system and the fight against doping. We conclude our analysis with a discussion of ADAMS as a surveillance system that, by storing, processing and using data for the purpose of anti-doping measures, engages in social sorting among athletes and creates what we call spillover effects and apparent power asymmetries that have been established throughout the system. We argue for a new balance within the system of controls, in which athletes are to be treated as actors, i.e. equal stakeholders who take part in decision-making regarding the system, rather than simply users and clients of a control interface. It seems that ADAMS threatens athletes’ privacy and that of their social environment rather than guaranteeing fairness for them.

Finite element analysis on the seismic behavior of fully prefabricated steel frames

This paper presents a method of finite element (FE) modeling and analysis of the seismic behavior of fully prefabricated steel frames with end-plate joints, flexible braces and composite slabs. The main idea and objectives of this paper is to develop a finite element model with high accuracy, good stabilization and acceptable computational costs for the simulation of the cyclic behavior of multi-story steel frames with bolted end-plate joints and concrete slabs. Because of the apparent tension-compression asymmetry of flexible braces, and the complex connection details between slabs and steel structures, as well as the huge number of contact interactions between interfaces, the cyclic behavior of this type of frame cannot be simulated accurately with commonly used line-element models, shell element models, or multi-scale models. A quasi-static test of a full-scale three-story fully prefabricated steel frame under cyclic horizontal loads by the present authors was simulated with the finite element model. Hollow section box columns, I-section beams, end-plates, inner diaphragms and stiffeners were modeled using shell elements; high strength bolts and concrete slab were modeled with solid elements; and flexible braces and rebar were modeled with truss elements. In order to develop a mesh skill to reduce computational costs while ensuring calculation accuracy, several FEM models were built and validated against previous experimental studies: static testing of bolted T-stub connections and bolted tension splices, static and cyclic testing of bolted end-plate steel joints, push-out tests of stud shear connectors, as well as static and cyclic testing of bolted end-plate composite joints. To simulate the “elastic-yield-hardening in tension, and buckling-without capacity in compression” behavior of the flexible braces, a simplified model in ABAQUS based on truss elements was developed and validated against previous tests. Results showed that the proposed FE modeling method could accurately simulate the static and cyclic performance of bolted T-stub connections, bolted tension splices, bolted end-plate steel joints, stud shear connectors, bolted end-plate composite joints and flexibly braced steel frames. Deformation capacity, cyclic behavior, horizontal loading performance, energy dissipation and stiffness degradation of steel frames with bolted end-plate joints, prefabricated slabs and flexible braces could be accurately simulated by this FEM model, providing a practical and accurate modeling method for similar structures. In addition, further research on the structural seismic performance simulation, parametric study and seismic design method could be carried out using the finite element model developed in this paper.

A study of the geomagnetic indices asymmetry based on the interplanetary magnetic field polarities

Data of geomagnetic indices (aa, Kp, Ap, and Dst) recorded near 1 AU over the period 1967–2016, have been studied based on the asymmetry between the interplanetary magnetic field (IMF) directions above and below of the heliospheric current sheet (HCS). Our results led to the following conclusions: (i) Throughout the considered period, 31 random years (62%) showed apparent asymmetries between Toward ( $\mathbf{T}$ ) and Away ( $\mathbf{A}$ ) polarity days and 19 years (38%) exhibited nearly a symmetrical behavior. The days of $\mathbf{A}$ polarity predominated over the $\mathbf{T}$ polarity days by 4.3% during the positive magnetic polarity epoch (1991–1999). While the days of $\mathbf{T}$ polarity exceeded the days of $\mathbf{A}$ polarity by 5.8% during the negative magnetic polarity epoch (2001–2012). (ii) Considerable yearly North–South (N–S) asymmetries of geomagnetic indices observed throughout the considered period. (iii) The largest toward dominant peaks for $aa$ and $Ap$ indices occurred in 1995 near to minimum of solar activity. Moreover, the most substantial away dominant peaks for $aa$ and $Ap$ indices occurred in 2003 (during the descending phase of the solar cycle 23) and in 1991 (near the maximum of solar activity cycle) respectively. (iv) The N–S asymmetry of $Kp$ index indicated a most significant away dominant peak occurred in 2003. (v) Four of the away dominant peaks of Dst index occurred at the maxima of solar activity in the years 1980, 1990, 2000, and 2013. The largest toward dominant peak occurred in 1991 (at the reversal of IMF polarity). (vi) The geomagnetic indices (aa, Ap, and $Kp$ ) all have northern dominance during positive magnetic polarity epoch (1971–1979), while the asymmetries shifts to the southern solar hemisphere during negative magnetic polarity epoch (2001–2012).

Correlated Vascular Asymmetries in the Circle of Willis

The Circle of Willis (CoW) is a cranial vascular structure with documented anatomical variation. The variations of basic structure and collateral flow of the CoW are suggested to play a role in the development of, and protection against, ischemic stroke and injury. Patients with more extensive collateral flow pathways are less likely to suffer from ischemic injury. The internal carotid arteries, vertebral arteries, and basilar artery have been studied for impact of agenesis, aplasia, hypoplasia, and other congenital asymmetries on clinical outcomes. Previous studies have chosen to focus on specific vessels within CoW, particularly on the stenosis or compromise of certain vessels. Far less attention has been given to predictive models of vessel asymmetry. If anastomotic weaknesses and vessel asymmetries tend to co‐occur across different portions of the CoW, then some anatomical variants may carry higher risk of vascular injury than previously recognized. Our aim was to assess the correlations between missing or asymmetric vessels within the CoW, and to relate these to risk of vascular injury using a cadaveric population with known medical histories and causes of death.With permission from the Keck School of Medicine at the University of Southern California and the Anatomical Gift Program at USC, 33 cadavers managed by the Integrative Anatomical Sciences Department in the Keck School of Medicine were utilized in the study. As a part of the ongoing medical curriculum, the brains were removed and dissected from all 33 cadavers, with careful attention to preserving the CoW anatomy. We then used digital calipers to measure the diameter of vessels within the CoW, including the basilar artery, vertebral arteries (VA), posterior cerebral arteries (PCA), middle cerebral arteries (MCA), anterior cerebral arteries (ACA), anterior communicating arteries (Acomm), and posterior communicating arteries (Pcomm). Serial t‐tests with a Bonferroni Correction were employed to compare mean diameters. Reduced Major Axis regression was employed to determine if vessel size or left to right asymmetry in a specified area of the CoW could predict shape in other portions of the CoW.We found that ACA diameter significantly predicted a moderate proportion of the variation in Acomm diameter but that PCA diameters had no correlation with the diameter of the Pcomm vessels or Pcomm asymmetry. We found that the diameter of the right vertebral artery was significantly more predictive of basilar artery diameter than that of the left vertebral artery. Vertebral artery left to right asymmetry was also correlated with left to right asymmetry in the PCA. Unexpectedly, pairwise tests indicated that the difference in mean diameter was greater (and statistically significant) between left and right vessel pairs than in cross quadrant pairs (left ACA vs right PCA, for example). In fact, cross‐quadrant mean diameters did not differ significantly. This implies that right and left halves of the CoW tend to have opposing anteroposterior asymmetry. Our results suggest that the posterior CoW is particularly variable, and that vertebral artery asymmetry is dominated by variability of the left vertebral artery. The apparent counter‐directional asymmetry between left and right halves of the CoW may be an adaptive developmental pattern that promotes collateral flow potential in a highly variable system.Support or Funding InformationAccess to research material was provided by the Anatomical Gift Program at USCThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Cerebellar Hypoperfusion in Migraine Attack: Incidence and Significance.

Patients diagnosed with migraine with aura have an increased lifetime risk of ischemic stroke. It is not yet clear whether prolonged cortical hypoperfusion during an aura increases the immediate risk of cerebellar infarction because it may induce crossed cerebellar diaschisis and subsequent tissue damage. To address this question, we retrospectively analyzed potential relationships between cortical oligemia and cerebellar hypoperfusion in patients with migraine with aura and their potential relation to small infarct-like cerebellar lesions. One hundred six migraineurs who underwent MR imaging, including DSC perfusion, were included in the study. In patients with apparent perfusion asymmetry, we used ROI analysis encompassing 18 infra- and supratentorial ROIs to account for differences in regional cerebral blood flow and volume. The presence of cerebellar hypoperfusion was calculated using an asymmetry index, with values of >10% being considered significant. We observed perfusion asymmetries in 23/106 patients, 22 in patients with migraine with aura (20.8%). Cerebellar hypoperfusion was observed in 12/23 patients (52.2%), and crossed cerebellar diaschisis, in 9/23 patients (39.1%) with abnormal perfusion. In none of the 106 patients were DWI restrictions observed during migraine with aura. Cerebellar hypoperfusion and crossed cerebellar diaschisis are common in patients with migraine with aura and cortical perfusion abnormalities. Crossed cerebellar diaschisis in migraine with aura may be considered a benign phenomenon because we observed no association with DWI restriction or manifest cerebellar infarctions, even in patients with prolonged symptom-related perfusion abnormalities persisting for up to 24 hours.

Community Perspective on Policy Options for Resettlement Management: A Case Study of Risk Reduction in Bududa, Eastern Uganda.

Introduction: Despite existing policy actions on Disaster Risk Reduction (DRR), many community members in Bududa still continue to settle in high-risk areas re-zoned for nonsettlement. There seems to be an apparent information asymmetry on expectations between the community and Government. The challenge then is ‘how to consult communities and seek their opinion in an adequately representative unbiased way’. This paper sets out to explore policy options on resettlement management as a DRR approach and how engaging with communities in a public discourse using the Deliberative Polling (DP) approach; to obtain their opinions and insights on these policy issues, revealed underlying challenges to policy implementation. Methods: A qualitative study was conducted in Bududa in eastern Uganda with fourteen group discussions; comprising 12-15 randomly assigned participants of mixed socio-economic variables. Trained research assistants and moderators collected data. All discussions were audio taped, transcribed verbatim before analysis. Data were analyzed using latent content analysis by identifying codes from which sub-themes were generated and grouped into main themes on policy options for resettlement management. Results and Discussion: We used Deliberative Polling, an innovative approach to public policy consultation and found that although the community is in agreement with most government policy options under resettlement management, they lacked an understanding of the rationale underlying these policy options leading to challenges in implementation. The community members seemed uncertain and had mistrust in government’s ability to implement the policies especially on issues of compensation for land lost. Key Words: Policy, Deliberative Polling, Climate change, risk-reduction, landslides, Uganda

Coevolutionary arms race versus host defense chase in a tropical herbivore–plant system

Coevolutionary models suggest that herbivores drive diversification and community composition in plants. For herbivores, many questions remain regarding how plant defenses shape host choice and community structure. We addressed these questions using the tree genus Inga and its lepidopteran herbivores in the Amazon. We constructed phylogenies for both plants and insects and quantified host associations and plant defenses. We found that similarity in herbivore assemblages between Inga species was correlated with similarity in defenses. There was no correlation with phylogeny, a result consistent with our observations that the expression of defenses in Inga is independent of phylogeny. Furthermore, host defensive traits explained 40% of herbivore community similarity. Analyses at finer taxonomic scales showed that different lepidopteran clades select hosts based on different defenses, suggesting taxon-specific histories of herbivore-host plant interactions. Finally, we compared the phylogeny and defenses of Inga to phylogenies for the major lepidopteran clades. We found that closely related herbivores fed on Inga with similar defenses rather than on closely related plants. Together, these results suggest that plant defenses might be more evolutionarily labile than the herbivore traits related to host association. Hence, there is an apparent asymmetry in the evolutionary interactions between Inga and its herbivores. Although plants may evolve under selection by herbivores, we hypothesize that herbivores may not show coevolutionary adaptations, but instead "chase" hosts based on the herbivore's own traits at the time that they encounter a new host, a pattern more consistent with resource tracking than with the arms race model of coevolution.

Alignments of parity even/odd-only multipoles in CMB

We compare the statistics of parity even and odd multipoles of the cosmic microwave background (CMB) sky from PLANCK full mission temperature measurements. An excess power in odd multipoles compared to even multipoles has previously been found on large angular scales. Motivated by this apparent parity asymmetry, we evaluate directional statistics associated with even compared to odd multipoles, along with their significances. Primary tools are the \emph{Power Tensor} and \emph{Alignment Tensor} statistics. We limit our analysis to the first sixty multipoles i.e., $l=[2,61]$. We find no evidence for statistically unusual alignments of even parity multipoles. More than one independent statistic finds evidence for alignments of anisotropy axes of odd multipoles, with a significance equivalent to $\sim 2 \sigma$ or more. The robustness of alignment axes is tested by making galactic cuts and varying the multipole range. Very interestingly, the region spanned by the (a)symmetry axes is found to broadly contain other parity (a)symmetry axes previously observed in the literature.