Holography of Gravitational Action Functionals

Einstein-Hilbert (EH) action can be separated into a bulk and a surface term, with a specific ("holographic") relationship between the two, so that either can be used to extract information about the other. The surface term can also be interpreted as the entropy of the horizon in a wide class of spacetimes. Since EH action is likely to just the first term in the derivative expansion of an effective theory, it is interesting to ask whether these features continue to hold for more general gravitational actions. We provide a comprehensive analysis of lagrangians of the form L=Q_a^{bcd}R^a_{bcd}, in which Q_a^{bcd} is a tensor with the symmetries of the curvature tensor, made from metric and curvature tensor and satisfies the condition \nabla_cQ^{abcd}=0, and show that they share these features. The Lanczos-Lovelock lagrangians are a subset of these in which Q^{abcd} is a homogeneous function of the curvature tensor. They are all holographic, in a specific sense of the term, and -- in all these cases -- the surface term can be interpreted as the horizon entropy. The thermodynamics route to gravity, in which the field equations are interpreted as TdS=dE+pdV, seems to have greater degree of validity than the field equations of Einstein gravity itself. The results suggest that the holographic feature of EH action could also serve as a new symmetry principle in constraining the semiclassical corrections to Einstein gravity. The implications are discussed.Comment: revtex 4; 17 pages; no figure

The birth of a bacterial tRNA gene by large-scale, tandem duplication events

Organisms differ in the types and numbers of tRNA genes that they carry. While the evolutionary mechanisms behind tRNA gene set evolution have been investigated theoretically and computationally, direct observations of tRNA gene set evolution remain rare. Here, we report the evolution of a tRNA gene set in laboratory populations of the bacterium ̑extitPseudomonas fluorescens} SBW25. The growth defect caused by deleting the single-copy tRNA gene, ̑extit{serCGA}, is rapidly compensated by large-scale (45–290 kb) duplications in the chromosome. Each duplication encompasses a second, compensatory tRNA gene (̑extit{serTGA}) and is associated with a rise in tRNA-Ser(UGA) in the mature tRNA pool. We postulate that tRNA-Ser(CGA) elimination increases the translational demand for tRNA-Ser(UGA), a pressure relieved by increasing ̑extit{serTGA copy number. This work demonstrates that tRNA gene sets can evolve through duplication of existing tRNA genes, a phenomenon that may contribute to the presence of multiple, identical tRNA gene copies within genomes

Wormholes in 4D Einstein-Gauss-Bonnet Gravity

Recently Glavan and Lin [Phys. Rev. Lett. 124, 081301 (2020)] formulated the Einstein-Gauss-Bonnet (EGB) gravity by re-scaling GB coupling constant as $\alpha/(D-4)$ and taking limit $D \to 4$ at the level of field equations. The GB contribution, in the resulting novel 4D EGB theory, makes a nontrivial contribution and the theory preserves the number of degrees of freedom thereby free from the Ostrogradsky instability, and also bypasses the Lovelock theorem. We obtain an exact spherically symmetric wormhole solutions in the novel 4D EGB gravity for an isotropic and anisotropic matter sources. In this regard, we consider also a wormhole with a specific radial-dependent shape function, a power-law density profile as well as by imposing a particular equation of state. To this end, we analyze the flare-out conditions, embedding diagrams, energy conditions and the volume integral quantifier. In particular our $-$ve branch results, in the limit $\alpha \rightarrow 0$, reduced exactly to \emph{vis-$\grave{a}$-vis} 4D Moriss-Thorne wormholes of GR.Comment: 14 pages, 10 figures. Accepted for publication in The European Physical Journal

Building a Sentiment Corpus of Tweets in Brazilian Portuguese

The large amount of data available in social media, forums and websites motivates researches in several areas of Natural Language Processing, such as sentiment analysis. The popularity of the area due to its subjective and semantic characteristics motivates research on novel methods and approaches for classification. Hence, there is a high demand for datasets on different domains and different languages. This paper introduces TweetSentBR, a sentiment corpora for Brazilian Portuguese manually annotated with 15.000 sentences on TV show domain. The sentences were labeled in three classes (positive, neutral and negative) by seven annotators, following literature guidelines for ensuring reliability on the annotation. We also ran baseline experiments on polarity classification using three machine learning methods, reaching 80.99% on F-Measure and 82.06% on accuracy in binary classification, and 59.85% F-Measure and 64.62% on accuracy on three point classification.Comment: Accepted for publication in 11th International Conference on Language Resources and Evaluation (LREC 2018

Using coupled micropillar compression and micro-Laue diffraction to investigate deformation mechanisms in a complex metallic alloy Al13Co4

In this investigation, we have used in-situ micro-Laue diffraction combined with micropillar compression of focused ion beam milled Al13Co4 complex metallic alloy to study the evolution of deformation in Al13Co4. Streaking of the Laue spots showed that the onset of plastic flow occured at stresses as low as 0.8 GPa, although macroscopic yield only becomes apparent at 2 GPa. The measured misorientations, obtained from peak splitting, enabled the geometrically necessary dislocation density to be estimated as 1.1 x 1013 m-2

Optothermal Trapping of Fluorescent Nanodiamonds using a Drop-casted Gold Nanoparticle

Deterministic optical manipulation of fluorescent nanodiamonds (FNDs) in a fluid environment has emerged as an experimental challenge in multimodal biological imaging. The design and development of nano-optical trapping strategies to serve this purpose is an important task. In this letter, we show how a drop-casted gold nanoparticle (Au np) can facilitate optothermal potential to trap individual entities of FNDs using a low power density illumination (532nm laser, 0.1 mW/$\mu$m$^2$). We utilize the same trapping excitation source to capture the spectral signatures of single FNDs and track their position. Furthermore, by tracking the dynamics of FND, we measure the trapping stiffness as a function of laser power and surfactant concentration and emphasize their relevance as vital parameters for nano-manipulation. Our trapping configuration combines the thermoplasmonic fields generated by individual gold nanoparticles and the optothermoelectric effect facilitated by surfactants to realize a nano-optical trap down to a single FND 120 nm in size. We envisage that our drop-casting platform can be extrapolated to perform targeted, low-power trapping, manipulation, and multimodal imaging of FNDs inside biological systems such as cells.Comment: 17 pages, 4 figures, 3 tables. Supplementary videos may be found at: https://drive.google.com/drive/folders/1gkW9g5Z7Fhl4i3ZQUOBQYuUYAPrHykzY?usp=sharin

Study the impact of ketamine, clonidine and combination of ketamine-clonidine on cardiovascular system during pre and postoperatively: A double blind, placebo controlled study

Background: The use of ketamine as a sole anesthetic induces marked central sympathetic stimulation, causing increased heart rate, blood pressure (BP), and oxygen consumption (VO2). Both alpha 2-agonists and benzodiazepines have been used to attenuate these potentially harmful ketamine-induced responses.  Materials and Methods: After approval from institutional ethical committee and written informed consent, 120 adult patients, ASA physical status I and II, undergoing elective surgeries e.g. Open abdominal surgery, laparoscopic surgery, open urological surgery were included in this controlled, prospective, randomized, double-blind study. Patients were randomly (envelop randomization) allocated in 4 groups (n=30): Group K received IV ketamine (0.5mg/kg), Group C received IV clonidine (1.5μg/kg), Group KC received combination of IV ketamine (0.25mg/kg) and IV clonidine (0.75μg/kg) and Group P received IV normal saline (placebo). One envelop at a time was chosen by an anaesthesiologist, who was blinded to the preparation of study agents and administered the study drugs in the envelope one after the other, intravenously approximately 20 minutes before extubation. Results: Pre operative haemodynamic parameters like mean arterial pressure (MAP) and heart rate are comparable across the groups. There was statistically significant (two tailed p value < 0.001) rise in intra operative heart rate following intubation in groups K, KC and P. There was statistically significant increase in systolic blood pressure (SBP) in groups K and P (two tailed p value < 0.001). In group C and KC, there were significant fall in SBP, from the baseline values, following induction. Conclusion: The unwanted effects of the individual drugs like, haemodynamic alteration, hallucination or lower incidences of nausea and vomiting could be achieved by using half of the dose of each of the drugs in combination