Violation of causality in f(T)f(T) gravity

[Abridged] In its standard formulation, the $f(T)$ field equations are not invariant under local Lorentz transformations, and thus the theory does not inherit the causal structure of special relativity. A locally Lorentz covariant $f(T)$ gravity theory has been devised recently, and this local causality problem has been overcome. The nonlocal question, however, is left open. If gravitation is to be described by this covariant $f(T)$ gravity theory there are a number of issues that ought to be examined in its context, including the question as to whether its field equations allow homogeneous G\"odel-type solutions, which necessarily leads to violation of causality on nonlocal scale. Here, to look into the potentialities and difficulties of the covariant $f(T)$ theories, we examine whether they admit G\"odel-type solutions. We take a combination of a perfect fluid with electromagnetic plus a scalar field as source, and determine a general G\"odel-type solution, which contains special solutions in which the essential parameter of G\"odel-type geometries, $m^2$, defines any class of homogeneous G\"odel-type geometries. We extended to the context of covariant $f(T)$ gravity a theorem, which ensures that any perfect-fluid homogeneous G\"odel-type solution defines the same set of G\"odel tetrads $h_A^{~\mu}$ up to a Lorentz transformation. We also shown that the single massless scalar field generates G\"odel-type solution with no closed timelike curves. Even though the covariant $f(T)$ gravity restores Lorentz covariance of the field equations and the local validity of the causality principle, the bare existence of the G\"odel-type solutions makes apparent that the covariant formulation of $f(T)$ gravity does not preclude non-local violation of causality in the form of closed timelike curves.Comment: 10 pages, V2: Presentation of Sec.2 improved, references added, version published in Eur.Phys.J.

Conformal and gauge invariant spin-2 field equations

Using an approach based on the Casimir operators of the de Sitter group, the conformal invariant equations for a fundamental spin-2 field are obtained, and their consistency discussed. It is shown that, only when the spin-2 field is interpreted as a 1-form assuming values in the Lie algebra of the translation group, rather than a symmetric second-rank tensor, the field equation is both conformal and gauge invariant.Comment: 12 pages, no figures; accepted for publication in Gravitation & Cosmolog

Second Generation of 'Miranda Procedure' for CP Violation in Dalitz Studies of B (\& D \& \tau) Decays

The `Miranda Procedure' proposed for analyzing Dalitz plots for CP asymmetries in charged B and D decays in a model-independent manner is extended and refined. The complexity of CKM CP phenomenology through order $\lambda^6$ is needed in searches for New Dynamics (ND). Detailed analyses of three-body final states other great advantages: (i) They give us more powerful tools for deciding whether an observed CP asymmetry rep- resents the manifestation of ND and its features. (ii) Many advantages can already be obtained by the `Miranda Procedure' without construction of a detailed Dalitz plot de- scription. (iii) One studies CP asymmetries independent of production asymmetries. We illustrate the power of a second generation Miranda Procedure with examples with time integrated rates for $B_d/\bar B_d$ decays to final states $K_S\pi+\pi-$ as trial runs with comments on $B^{\pm} \to K^{\pm}\pi^+\pi^-/K^{\pm}K^+K^-$.Comment: 29 pages, 7 figure

Structure of concanavalin A at pH 8: bound solvent and crystal contacts

9 pages, 3 figures, 4 tables.Concanavalin A has been crystallized in the presence of the ligand (6-S-[beta]-D-galactopyranosyl-6-thio)-cyclomaltoheptaose. The crystals are isomorphous to those reported for ConA complexed with peptides at low resolution (3.00-2.75 Å). The structure was solved at 1.9 Å, with free R and R values of 0.201 and 0.184, respectively. As expected, no molecules of the ligand were bound to the protein. Soaking in the cryobuffer left its fingerprint as 25 molecules of glycerol in the bound solvent, most of them at specific positions. The fact that a glycerol molecule is located in the sugar-binding pocket of each of the four subunits in the asymmetric unit and another is located in two of the peptide-binding sites suggests a recognition phenomenon rather than a displacement of water molecules by glycerol. Crystal contact analysis shows that a relation exists between the residues that form hydrogen bonds to other asymmetric units and the space group: contact Asp58-Ser62 is a universal feature of ConA crystals, while Ser66-His121, Asn69-Asn118 and Tyr100-His205 contacts are general features of the C2221 crystal form.We thank Professor GarcõÂa-Ruiz for his constant support and helpful discussions and suggestions, Dr Cartwright for reviewing the manuscript and Professor Kabsch for providing XDS free of charge.We acknowledge EMBO/DESY for beam time, Professor Martinez Ripoll for his kind support in the preliminary X-ray characterization using the rotating-anode generator at the Instituto de QuõÂmica Fisica Roca Solano (CSIC) and the referees for valuable comments.Work in AA's laboratory is funded by Spanish Plan Nacional grant BMC- 2002-04011-C03.Peer reviewe

Iceberg transport technologies in spatial competition. Hotelling reborn

Transport costs in address models of differentiation are usually modeled as separable of the consumption commodity and with a parametric price. However, there are many sectors in an economy where such modeling is not satisfactory either because transportation is supplied under oligopolistic conditions or because there is a difference (loss) between the amount delivered at the point of production and the amount received at the point of consumption. This paper is a first attempt to tackle these issues proposing to study competition in spatial models using an iceberg-like transport cost technology allowing for concave and convex melting functions

Laura ++ : a Dalitz plot fitter

The Dalitz plot analysis technique has become an increasingly important method in heavy flavour physics. The Laura fitter has been developed as a flexible tool that can be used for Dalitz plot analyses in different experimental environments. Explicitly designed for three-body decays of heavy-flavoured mesons to spinless final state particles, it is optimised in order to describe all possible resonant or nonresonant contributions, and to accommodate possible violation effects

Daily electrical activity in the master circadian clock of a diurnal mammal

From eLife via Jisc Publications RouterHistory: collection 2021, received 2021-03-08, accepted 2021-10-09, pub-electronic 2021-11-30Publication status: PublishedFunder: Biotechnology and Biological Sciences Research Council; FundRef: http://dx.doi.org/10.13039/501100000268; Grant(s): BB/P009182/1Funder: Biotechnology and Biological Sciences Research Council; FundRef: http://dx.doi.org/10.13039/501100000268; Grant(s): BB/S01764X/1Funder: Biotechnology and Biological Sciences Research Council; FundRef: http://dx.doi.org/10.13039/501100000268; Grant(s): BB/N014901/1Funder: Wellcome Trust; FundRef: http://dx.doi.org/10.13039/100004440; Grant(s): 210684/Z/18/ZFunder: National Science Foundation; FundRef: http://dx.doi.org/10.13039/100000001; Grant(s): DMS 155237Funder: Army Research Office; FundRef: http://dx.doi.org/10.13039/100000183; Grant(s): W911NF-16-1-0584Funder: US-UK Fulbright Commission; FundRef: http://dx.doi.org/10.13039/501100000592Funder: Engineering and Physical Sciences Research Council; FundRef: http://dx.doi.org/10.13039/501100000266; Grant(s): EP/N014391/1Circadian rhythms in mammals are orchestrated by a central clock within the suprachiasmatic nuclei (SCN). Our understanding of the electrophysiological basis of SCN activity comes overwhelmingly from a small number of nocturnal rodent species, and the extent to which these are retained in day-active animals remains unclear. Here, we recorded the spontaneous and evoked electrical activity of single SCN neurons in the diurnal rodent Rhabdomys pumilio, and developed cutting-edge data assimilation and mathematical modeling approaches to uncover the underlying ionic mechanisms. As in nocturnal rodents, R. pumilio SCN neurons were more excited during daytime hours. By contrast, the evoked activity of R. pumilio neurons included a prominent suppressive response that is not present in the SCN of nocturnal rodents. Our modeling revealed and subsequent experiments confirmed transient subthreshold A-type potassium channels as the primary determinant of this response, and suggest a key role for this ionic mechanism in optimizing SCN function to accommodate R. pumilio’s diurnal niche

On modeling transport costs

The interpretation of the loss of utility as transport costs in address models of differentiation poses a methodological difficulty. Transport costs implicitely amounts to assume that there is a good neither included in the differentiated sector nor in the composite (numeraire) good of the economy. We propose to use iceberg-type transport costs to solve this difficulty

A Non-parametric Approach to Measuring the \kpi{} Amplitudes in \dpkkpi{} Decay

Using a large sample of \dpkkpi{} decays collected by the FOCUS photoproduction experiment at Fermilab, we present the first non-parametric analysis of the \kpi{} amplitudes in \dpkkpi{} decay. The technique is similar to the technique used for our non-parametric measurements of the \krzmndk{} form factors. Although these results are in rough agreement with those of E687, we observe a wider S-wave contribution for the \ksw{} contribution than the standard, PDG \cite{pdg} Breit-Wigner parameterization. We have some weaker evidence for the existence of a new, D-wave component at low values of the $K^- \pi^+$ mass.Comment: 13 pages 3 figure