A generalized non-Gaussian consistency relation for single field inflation

We show that a perturbed inflationary spacetime, driven by a canonical single scalar field, is invariant under a special class of coordinate transformations together with a field reparametrization of the curvature perturbation in co-moving gauge. This transformation may be used to derive the squeezed limit of the 3-point correlation function of the co-moving curvature perturbations valid in the case that these do not freeze after horizon crossing. This leads to a generalized version of Maldacena's non-Gaussian consistency relation in the sense that the bispectrum squeezed limit is completely determined by spacetime diffeomorphisms. Just as in the case of the standard consistency relation, this result may be understood as the consequence of how long-wavelength modes modulate those of shorter wavelengths. This relation allows one to derive the well known violation to the consistency relation encountered in ultra slow-roll, where curvature perturbations grow exponentially after horizon crossing.Comment: 16 pages, v3: matches published version (JCAP

Vanishing of local non-Gaussianity in canonical single field inflation

We study the production of observable primordial local non-Gaussianity in two opposite regimes of canonical single field inflation: attractor (standard single field slow-roll inflation) and non attractor (ultra slow-roll inflation). In the attractor regime, the standard derivation of the bispectrum's squeezed limit using co-moving coordinates gives the well known Maldacena's consistency relation $f_{NL} = 5(1-n_{s})/12$. On the other hand, in the non-attractor regime, the squeezed limit offers a substantial violation of this relation given by $f_{NL} = 5/2$. In this work we argue that, independently of whether inflation is attractor or non-attractor, the size of the observable primordial local non-Gaussianity is predicted to be $f_{NL}^{obs} = 0$ (a result that was already understood to hold in the case of attractor models). To show this, we follow the use of the so-called Conformal Fermi Coordinates (CFC), recently introduced in the literature. These coordinates parametrize the local environment of inertial observers in a perturbed FRW spacetime, allowing one to identify and compute gauge invariant quantities, such as $n$-point correlation functions. Concretely, we find that during inflation, after all the modes have exited the horizon, the squeezed limit of the 3-point correlation function of curvature perturbations vanishes in the CFC frame, regardless of the inflationary regime. We argue that such a cancellation should persist after inflation ends.Comment: 27 pages, v2:matches published version(JCAP

La plaza de mercado como espacio de hibridación cultural, sincretismo y creolización en el continente americano

Industrialization and globalization processes across the american continent, have led to cultural homogenization and hybridization, as traditional expressions are affected by global influences and tendencies. These globalizing effects tend to uniform and menace local identities and folklore, putting them on risk of disappearance. Facing these tendencies, traditional marketplaces have become a cultural reserve and resistance space against modernization and homogenization, as a collaborative and participatory effort by manufacturers, merchants, consumers and visitors, who collectively struggle to preserve their cultural expressions, including handcraft, alimentary heritage, religious and superstitious beliefs, medicine and other traditional practices. This paper is envisioned to recognize the value and importance of popular markets or marketplaces in the american context, as a preservation space for a series of traditional practices, customs and beliefs, evidencing assorted sociocultural phenomena, through a wide range of products, artifacts and paraphernalia. Based on direct experience, photographic record, and assorted theoretical perspectives, it is possible to develop a series of taxonomic approaches, regarding the products and practices available in these markets, facilitating the identification of diverse multicultural processes and phenomena. As a result, this research has allowed to identify particular and unifier aspects across a sample of markets in Colombia, with supplementary explorations in the USA, Panama and Ecuador. These continental referents help recognize a series of geographic, economic and sociocultural factors that get materialized through a wide offer of products and artifacts.Los procesos de globalización e industrialización en el continente americano, han llevado a la hibridación y homogeneización cultural, afectando con ello algunas expresiones tradicionales, debido a tendencias globales. Estos efectos globalizadores tienden a uniformar y amenazar el folclore y las identidades locales, al ponerlas en riesgo de desaparición. Enfrentando dichas tendencias, los mercados tradicionales se convierten en un espacio de preservación y resistencia cultural contra la modernidad y la globalización, en un esfuerzo compartido entre fabricantes, comerciantes, consumidores y visitantes, quienes luchan de manera colectiva para preservar sus expresiones culturales, incluidas la artesanía, la herencia alimentaria, las creencias religiosas y supersticiosas, la medicina y otras prácticas tradicionales. Este artículo busca reconocer la importancia y el valor de las plazas de mercado o mercados populares, como un espacio de conservación para una serie de prácticas tradicionales, costumbres y creencias, evidenciando con ello diversos fenómenos socioculturales mediante una amplia variedad de productos, artefactos y parafernalia. Con base en la experiencia directa, el registro fotográfico y distintas perspectivas teóricas, es posible desarrollar un conjunto de aproximaciones taxonómicas, frente a los productos y prácticas que se evidencian en estos lugares, facilitando así la identificación de diversos fenómenos y procesos multiculturales. Como resultado, este proyecto ha permitido identificar algunos aspectos unificadores y diferenciadores, a través de una muestra de mercados en Colombia, con exploraciones complementarias en EE. UU., Panamá y Ecuador. Finalmente, estos referentes continentales ayudan a reconocer una serie de factores geográficos, económicos y socioculturales, que se materializan a través de una amplia oferta de productos y artefactos, disponibles en estos contextos

Effects of service experience on customer responses to the hotel chain

This paper analyses customer experience in a hotel and its impact on the customer attitudes to both the individual hotel and the hotel chain. Specifically, the study focuses on the effects on emotions, satisfaction, attitude to hotel chain, intention to return, skepticism to negative information and WOM. In order to test the hypotheses, an empirical study was carried out in a sample of 300 individuals. Data was analysed through structural equation modelling, and results show that customer experiences in an individual hotel determine not only their responses to the hotel but also their responses to the hotel chain. Among all the considered outcomes, the stronger effects are found on WO

Unifying attractor and non-attractor models of inflation under a single soft theorem

We show that the observable squeezed limit of primordial curvature perturbations in canonical single-field inflation vanishes exactly, a result valid to all orders in slow-roll parameters. This result relies exclusively on the diffeomorphism invariance of canonical single-field inflation, and does not require taking into consideration de Sitter isometries or shift symmetries of the ultraviolet theory in which inflation is build upon. An important consequence of our result is the conclusion that a non-attractor phase (e.g. ultra slow-roll phase) cannot generate observable local non-Gaussianity at the end of inflation.Comment: 7 pages; v3: improved version, references added, critical mistake from Eq. (26) to (27) of v2 corrected. New section implementing conformal Fermi coordinates added. Main final conclusions still vali

Powering a Biosensor Using Wearable Thermoelectric Technology

Wearable medical devices such as insulin pumps, glucose monitors, hearing aids, and electrocardiograms provide necessary medical aid and monitoring to millions of users worldwide. These battery powered devices require battery replacement and frequent charging that reduces the freedom and peace of mind of users. Additionally, the significant portion of the world without access to electricity is unable to use these medical devices as they have no means to power them constantly. Wearable thermoelectric power generation aims to charge these medical device batteries without a need for grid power. Our team has developing a wristband prototype that uses body heat, ambient air, and heat sinks to create a temperature difference across thermoelectric modules thus generating ultra-low voltage electrical power. A boost converter is implemented to boost this voltage to the level required by medical device batteries. Our goal was to use this generated power to charge medical device batteries off-the-grid, increasing medical device user freedom and allowing medical device access to those without electricity. We successfully constructed a wearable prototype that generates the voltage required by an electrocardiogram battery; however, further thermoelectric module and heat dissipation optimization is necessary to generate sufficient current to charge the battery

MODEL-BASED QUALITY ASSESSMENT AND BASE-CALLING FOR SECOND-GENERATION SEQUENCING DATA

Second-generation sequencing (sec-gen) technology can sequence millions of short fragments of DNA in parallel, and is capable of assembling complex genomes for a small fraction of the price and time of previous technologies. In fact, a recently formed international consortium, the 1,000 Genomes Project, plans to fully sequence the genomes of approximately 1,200 people. The prospect of comparative analysis at the sequence level of a large number of samples across multiple populations may be achieved within the next five years. These data present unprecedented challenges in statistical analysis. For instance, analysis operates on millions of short nucleotide sequences, or reads—strings of A,C,G, or T’s, between 30-100 characters long—which are the result of complex processing of noisy continuous fluorescence intensity measurements known as base-calling. The complexity of the base-calling discretization process results in reads of widely varying quality within and across sequence samples. This variation in processing quality results in infrequent but systematic errors that we have found to mislead downstream analysis of the discretized sequence read data. For instance, a central goal of the 1000 Genomes Project is to quantify across-sample variation at the single nucleotide level. At this resolution, small error rates in sequencing prove significant, especially for rare variants. Sec-gen sequencing is a relatively new technology for which potential biases and sources of obscuring variation are not yet fully understood. Therefore, modeling and quantifying the uncertainty inherent in the generation of sequence reads is of utmost importance. In this paper we present a simple model to capture uncertainty arising in the base-calling procedure of the Illumina/Solexa GA platform. Model parameters have a straightforward interpretation in terms of the chemistry of base-calling allowing for informative and easily interpretable metrics that capture the variability in sequencing quality. Our model provides these informative estimates readily usable in quality assessment tools while significantly improving base-calling performance

Soil compaction and vegetation cover in a Scots pine stand at the Mediterranean rangelands

Right development of ROOT SYSTEMS is essential to ensure seedling survival in the initial stages of natural regeneration processes. Soil compaction determines this development both because of its influence on soil Tª & moisture dynamics and for its direct effect on soil mechanical impedance to root growth. All this effects can be assessed as a whole through soil penetration resistance (Soil Strength) measurements. SOIL STRENGTH has been usually evaluated in forest research in connection with severe disturbances derived from heavy machinery works during forest operations. Nevertheless, undisturbed soils are also expected to show different levels of compaction for root development. Organic matter modifies soil structure and so on porosity, compaction and resultant soil resistance to penetration. Its concentration in surface layers is rather related to vegetation cover composition and density. So within forest stands, a relationship is expected to be found between VEGETATION COVER density and compaction measured as resistance to penetration (soil strength