Interacting spin-2 fields in three dimensions

Using the frame formulation of multi-gravity in three dimensions, we show that demanding the presence of secondary constraints which remove the Boulware-Deser ghosts restricts the possible interaction terms of the theory and identifies invertible frame field combinations whose effective metric may consistently couple to matter. The resulting ghost-free theories can be represented by theory graphs which are trees. In the case of three frame fields, we explicitly show that the requirement of positive masses and energies for the bulk spin-2 modes in AdS$_3$ is consistent with a positive central charge for the putative dual CFT$_2$.Comment: 26 pages, 3 figures, v2: minor changes, matches published versio

First report on natural Leishmania infection of Phlebotomus sergenti due Leishmania tropica by high resolution melting curve method in Southeastern Iran

Objective: To identify the Leishmania species in infected sand flies by Real-time PCR coupled with HRM analysis. Methods: Real-time PCR coupled with HRM analysis targeting the first iidnetenrtnifayl atrnadn sdcirsitbinegdu sispha cLeeri s(hITmSa1n) ioaf snpueccleieasr irnib soasnodm aflli eDsN sAp eacsi mtheen sg.e Rneetsiuc ltms:a rTkherre we aosu tu soef d1 1to5 females of Phlebotomus sergenti (P. sergenti) (2.6%) were positive to Leishmania tropica (L. tropica). Conclusions: This is the first report on P. sergenti as the main and proven vector of anthroponitic cutaneous leishmaniasis in Dehbakri County using Real-time PCR coupled with HRM analysis. Tidheias l mfoert hlaordg eis s craapleid g,e sneontsyiptiivneg apnrodj escptesc.ifi

On Non-Linear Actions for Massive Gravity

In this work we present a systematic construction of the potentially ghost-free non-linear massive gravity actions. The most general action can be regarded as a 2-parameter deformation of a minimal massive action. Further extensions vanish in 4 dimensions. The general mass term is constructed in terms of a "deformed" determinant from which this property can clearly be seen. In addition, our formulation identifies non-dynamical terms that appear in previous constructions and which do not contribute to the equations of motion. We elaborate on the formal structure of these theories as well as some of their implications.Comment: v3: 22 pages, minor comments added, version to appear in JHE

Critical solutions in topologically gauged N=8 CFTs in three dimensions

In this paper we discuss some special (critical) background solutions that arise in topological gauged ${\mathcal N}=8$ three-dimensional CFTs with SO(N) gauge group. These solutions solve the TMG equations (containing the parameters $\mu$ and $l$) for a certain set of values of $\mu l$ obtained by varying the number of scalar fields with a VEV. Apart from Minkowski, chiral round $AdS_3$ and null-warped $AdS_3$ (or Schr\"odinger(z=2)) we identify also a more exotic solution recently found in $TMG$ by Ertl, Grumiller and Johansson. We also discuss the spectrum, symmetry breaking pattern and the supermultiplet structure in the various backgrounds and argue that some properties are due to their common origin in a conformal phase. Some of the scalar fields, including all higgsed ones, turn out to satisfy three-dimensional singleton field equations. Finally, we note that topologically gauged ${\mathcal N}=6$ ABJ(M) theories have a similar, but more restricted, set of background solutions.Comment: 34 pages, v2: minor corrections, note about a new solution added in final section, v3: two footnotes adde

Limits of JT gravity

We construct various limits of JT gravity, including Newton-Cartan and Carrollian versions of dilaton gravity in two dimensions as well as a theory on the three-dimensional light cone. In the BF formulation our boundary conditions relate boundary connection with boundary scalar, yielding as boundary action the particle action on a group manifold or some Hamiltonian reduction thereof. After recovering in our formulation the Schwarzian for JT, we show that AdS-Carroll gravity yields a twisted warped boundary action. We comment on numerous applications and generalizations.Comment: 41 pages, 3 figures, 1 table; v2: Matches published version + Footnote 11; v3: Corrected typo in Carrollian/Galilean generalized dilaton potentia

Quantitative fractographic analysis of impact fracture surfaces of steel R73

Macroscopic images offracture surfaces of Charpy test specimens of steel R73 were studied, where bright spots in images represent cleavage facets or ductile dimples, respectively, both in special orientations. Within image analysis, they may be taken for the most significant textural element. Being the brightest patches in the image, they can be extracted by thresholding. Their counts and area distribution are closely related to temperature and impact energy.Выполнены исследования макроизображений поверхностей разрушений образцов Шарпи из стали R73. При специальных условиях ориентации поверхностей разрушения видны яркие участки на изображениях, соответствующие граням скола или ямкам вязкого разрушения. Эти участки могут быть использованы в качестве основного элемента текстуры для обработки изображения. Поскольку эти участки на изображениях являются наиболее яркими, их можно отсеять путем настройки порогового уровня освещенности. Результаты расчета относительной доли их площади тесно коррелируют с температурой и энергией ударного разрушения