The Cosmological Bootstrap: Spinning Correlators from Symmetries and Factorization

We extend the cosmological bootstrap to correlators involving massless particles with spin. In de Sitter space, these correlators are constrained both by symmetries and by locality. In particular, the de Sitter isometries become conformal symmetries on the future boundary of the spacetime, which are reflected in a set of Ward identities that the boundary correlators must satisfy. We solve these Ward identities by acting with weight-shifting operators on scalar seed solutions. Using this weight-shifting approach, we derive three- and four-point correlators of massless spin-1 and spin-2 fields with conformally coupled scalars. Four-point functions arising from tree-level exchange are singular in particular kinematic configurations, and the coefficients of these singularities satisfy certain factorization properties. We show that in many cases these factorization limits fix the structure of the correlators uniquely, without having to solve the conformal Ward identities. The additional constraint of locality for massless spinning particles manifests itself as current conservation on the boundary. We find that the four-point functions only satisfy current conservation if the s, t, and u-channels are related to each other, leading to nontrivial constraints on the couplings between the conserved currents and other operators in the theory. For spin-1 currents this implies charge conservation, while for spin-2 currents we recover the equivalence principle from a purely boundary perspective. For multiple spin-1 fields, we recover the structure of Yang-Mills theory. Finally, we apply our methods to slow-roll inflation and derive a few phenomenologically relevant scalar-tensor three-point functions.Comment: 128 pages, 15 figures; V3: minor corrections and references adde

Reconnaissance of the HR 8799 Exosolar System. II. Astrometry and Orbital Motion

We present an analysis of the orbital motion of the four substellar objects orbiting HR 8799. Our study relies on the published astrometric history of this system augmented with an epoch obtained with the Project 1640 coronagraph with an integral field spectrograph (IFS) installed at the Palomar Hale telescope. We first focus on the intricacies associated with astrometric estimation using the combination of an extreme adaptive optics system (PALM-3000), a coronagraph, and an IFS. We introduce two new algorithms. The first one retrieves the stellar focal plane position when the star is occulted by a coronagraphic stop. The second one yields precise astrometric and spectrophotometric estimates of faint point sources even when they are initially buried in the speckle noise. The second part of our paper is devoted to studying orbital motion in this system. In order to complement the orbital architectures discussed in the literature, we determine an ensemble of likely Keplerian orbits for HR 8799bcde, using a Bayesian analysis with maximally vague priors regarding the overall configuration of the system. Although the astrometric history is currently too scarce to formally rule out coplanarity, HR 8799d appears to be misaligned with respect to the most likely planes of HR 8799bce orbits. This misalignment is sufficient to question the strictly coplanar assumption made by various authors when identifying a Laplace resonance as a potential architecture. Finally, we establish a high likelihood that HR 8799de have dynamical masses below 13 M_(Jup), using a loose dynamical survival argument based on geometric close encounters. We illustrate how future dynamical analyses will further constrain dynamical masses in the entire system

Bifurcations and Slow-Fast Analysis in a Cardiac Cell Model for Investigation of Early Afterdepolarizations

In this study, we teased out the dynamical mechanisms underlying the generation of arrhythmogenic early afterdepolarizations (EADs) in a three-variable model of a mammalian ventricular cell. Based on recently published studies, we consider a 1-fast, 2-slow variable decomposition of the system describing the cellular action potential. We use sweeping techniques, such as the spike-counting method, and bifurcation and continuation methods to identify parametric regions with EADs. We show the existence of isolas of periodic orbits organizing the different EAD patterns and we provide a preliminary classification of our fast-slow decomposition according to the involved dynamical phenomena. This investigation represents a basis for further studies into the organization of EAD patterns in the parameter space and the involved bifurcations

New peptides under the s(ORF)ace of the genome

Hundreds of previously unidentified functional small peptides could exist in most genomes, but these sequences have been generally overlooked. The discovery of genes encoding small peptides with important functions in different organisms, has ignited the interest in these sequences, and led to an increasing amount of effort towards their identification. Here, we review the advances, both, computational, and biochemical, that are leading the way in the discovery of putatively functional smORFs, as well as the functional studies that have been carried out as a consequence of these searches. The evidence suggests that smORFs form a substantial part of our genomes, and that their encoded peptides could have important functions in a variety of cellular function

Limitations of the removal of cyanide from coking wastewater by ozonation and by the hydrogen peroxideozone process

The purpose of this study is to compare the efficiency of ozonation and the hydrogen peroxide–ozone process for the removal of cyanide from coking wastewater. The most efficient oxidation process is combined with coagulation–flocculation–decantation and lime–soda ash softening pretreatments. The oxidation in aqueous solution and industrial wastewater (at pH 9.5–12.3) by O3 was carried out using a range of concentration of consumed O3 from 10 to 290 mg/L. A molar ratio of H2O2/O3 from 0.1 to 5.2 with different concentrations of O3 constants was used for the H2O2-O3 process. The maximum cyanide removal obtained in coking wastewater was 90% using a mass ratio of O3/CN– of 9.5. Using lower concentrations of O3, cyanide is not removed and can even be generated due to the presence of other cyanide precursor organic micropollutants in the industrial matrix. The concentration of O3 is reduced to half for the same cyanide removal efficiency if the pretreatments are applied to reduce the carbonate and bicarbonate ions. The cyanide removal efficiency in coking wastewater is not improved if the O3 is combined with the H2O2. However, the preliminary cyanide removal treatment in aqueous solution showed an increase in the cyanide removal efficiency for the H2O2-O3 process

Controls on space–time distribution of soft-sediment deformation structures: Applying palaeomagnetic dating to approach the apparent recurrence period of paleoseisms at the Concud Fault (eastern Spain)

This work describes soft-sediment deformation structures (clastic dykes, load structures, diapirs, slumps, nodulizations or mudcracks) identified in three sections (Concud, Ramblillas and Masada Cociero) in the Iberian Range, Spain. These sections were logged from boreholes and outcrops in Upper Pliocene-Lower Pleistocene deposits of the Teruel-Concud Residual Basin, close to de Concud normal fault. Timing of the succession and hence of seismic and non-seismic SSDSs, covering a time span between ~ 3.6 and ~ 1.9 Ma, has been constrained from previous biostratigraphic and magnetostratigraphic information, then substantially refined from a new magnetostratigraphic study at Masada Cociero profile. Non-seismic SSDSs are relatively well-correlated between sections, while seismic ones are poorly correlated except for several clusters of structures. Between 29 and 35 seismic deformed levels have been computed for the overall stratigraphic succession. Factors controlling the lateral and vertical distribution of SSDSs are their seismic or non-seismic origin, the distance to the seismogenic source (Concud Fault), the sedimentary facies involved in deformation and the observation conditions (borehole core vs. natural outcrop). In the overall stratigraphic section, seismites show an apparent recurrence period of 56 to 108 ka. Clustering of seismic SSDSs levels within a 91-ka-long interval records a period of high paleoseismic activity with an apparent recurrence time of 4.8 to 6.1 ka, associated with increasing sedimentation rate and fault activity. Such activity pattern of the Concud Fault for the Late Pliocene-Early Pliocene, with alternating periods of faster and slower slip, is similar to that for the most recent Quaternary (last ca. 74 ka BP). Concerning the research methods, time occurrence patterns recognized for peaks of paleoseismic activity from SSDSs in boreholes are similar to those inferred from primary evidence in trenches. Consequently, apparent recurrence periods calculated from SSDS inventories collected in borehole logs close to seismogenic faults are comparable to actual recurrence times of large paleoearthquakes

Nuevas modalidades de participación ciudadana en ciencia: hibridación, satelización y despatrimonialización

I La emergencia de los tecnocidanos 1. Legos, amateurs, nerds y tecnoácratas. 1.1 La construcción social de los públicos de la ciencia 1.2 La demanda social de participación en ciencia 1.3 Tecnoacracia: de los amateurs a los hackers 2. Criptopolíticas: activismo y tecnologías de despliegue 2.1 La ciencia como gestión de datos 2.2 La GPL como motor de Internet 2.3 Bien común y open access II La movilización de los tecnocidanos 3. Movilización de híbridos: nuevos actores y nuevos consensos 3.1 La irrupción de los híbridos 3.2 La política de los casos: tablas y comentarios 4. Satelización de e-sujetos: cálculo distribuido y popular power 4.1. Grid computing y wifi networks: la próxima revolución 4.2 La política de los casos: tablas y comentarios 5. Despatrimonialización de prácticas: open source y open access 5.1 La cultura hacker y el procomún 5.2 La política de los casos: tablas y comentarios III La promesa de los tecnocidanos 6. Las nuevas encrucijadas de la tecnociencia: ciudadanía y participación 6.1 Resumen 6.2 Recomendaciones 6.3 Bibliografía (resumen)La participación ciudadana en ciencia conoce en nuestra época una verdadera edad dorada. Hace apenas unas décadas era inimaginable la creciente influencia que la ciudadanía iba a tener en la marcha de la ciencia. Y, aunque algunos movimientos de activistas contra las nucleares lograron en los 80 situar en la agenda política de muchos gobiernos la resistencia popular al desarrollo de esta fuente de energía, lo cierto es que la presencia hoy de las ONG en la toma de decisiones comienza a ser algo habitual y, en algunos casos, alcanza la condición de estructural. Las sociedades modernas han necesitado explorar formas muy innovadoras de organización social que les permitan afrontar las nuevas encrucijadas a las que nos aboca la llamada sociedad del riesgo. Nadie discute que estamos hablando de asuntos de extrema gravedad, como lo manifiesta la experiencia adquirida durante las anteriores crisis del SIDA, de los alimentos y cultivos transgénicos y de las vacas locas. En su conjunto, los tres casos señalados (entre los muchos que podríamos mencionar) comparten algunos aspectos que aquí queremos subrayar. Quienes desde responsabilidades de gobierno o empresariales lamentaron el desbordamiento del tradicional sistema de expertos por los movimientos de agitación ciudadana, aprendieron que la gestión de estos conflictos tiene que ser menos vertical y más dialogante. Descubrieron también que no es fácil hacer frente a organizaciones que saben aprovechar muy bien las múltiples oportunidades que ofrecen las nuevas tecnologías de la información y de la comunicación (TIC).Fundación Española de Ciencia y Tecnología, FECYT (2004