The Phenomenology of Universal Extra Dimensions at Hadron Colliders

Theories with extra dimensions of inverse TeV size (or larger) predict a multitude of signals which can be searched for at present and future colliders. In this paper, we review the different phenomenological signatures of a particular class of models, universal extra dimensions, where all matter fields propagate in the bulk. Such models have interesting features, in particular Kaluza-Klein (KK) number conservation, which makes their phenomenology similar to that of supersymmetric theories. Thus, KK excitations of matter are produced in pairs, and decay to a lightest KK particle (LKP), which is stable and weakly interacting, and therefore will appear as missing energy in the detector (similar to a neutralino LSP). Adding gravitational interactions which can break KK number conservation greatly expands the class of possible signatures. Thus, if gravity is the primary cause for the decay of KK excitations of matter, the experimental signals at hadron colliders will be jets + missing energy, which is typical of supergravity models. If the KK quarks and gluons decay first to the LKP, which then decays gravitationally, the experimental signal will be photons and/or leptons (with some jets), which resembles the phenomenology of gauge mediated supersymmetry breaking models.Comment: review article, 39 pages, 10 figures, uses IJMPA style file

CATS: linearizability and partition tolerance in scalable and self-organizing key-value stores

Distributed key-value stores provide scalable, fault-tolerant, and self-organizing storage services, but fall short of guaranteeing linearizable consistency in partially synchronous, lossy, partitionable, and dynamic networks, when data is distributed and replicated automatically by the principle of consistent hashing. This paper introduces consistent quorums as a solution for achieving atomic consistency. We present the design and implementation of CATS, a distributed key-value store which uses consistent quorums to guarantee linearizability and partition tolerance in such adverse and dynamic network conditions. CATS is scalable, elastic, and self-organizing; key properties for modern cloud storage middleware. Our system shows that consistency can be achieved with practical performance and modest throughput overhead (5%) for read-intensive workloads

An evidence based guide to a safe intraoperative approach of avoiding iatrogenic lesions during difficult laparoscopic cholecystectomies

Introduction: Although there are many sources for iatrogenic lesions during laparoscopic cholecystectomy, only a few stand out as being one of the most difficult to predict due to their nature of being very hard to diagnose before surgery. Materials and Methods: a short guide of cases with an evidence-based approach to avoid laparoscopic iatrogenic lesions. Results: these cases have been classified and presented into 3 main groups: cases with abnormal arterial layout, cases with heavy alteration of the normal anatomy, and cases with anomalies of the main biliary pathway. Conclusions: while not a complete guide covering all aspects of intraoperative traps during laparoscopic cholecystectomy, this series of cases points out some dangerous situations and some simple solutions to avoid those fiercely iatrogenic lesions of the ductal and vascular landmarks associated with an otherwise simple surgical intervention that has become the golden standard of the gallbladder lithiasic pathology

Dirac-Coulomb scattering with plane wave energy eigenspinors on de Sitter expanding universe

The lowest order contribution of the amplitude of Dirac-Coulomb scattering in de Sitter spacetime is calculated assuming that the initial and final states of the Dirac field are described by exact solutions of the free Dirac equation on de Sitter spacetime with a given energy and helicity. We find that the total energy is conserved in the scattering process.Comment: 9 pages, no figure

Are we seeing the beginnings of Inflation?

Phantom Cosmology provides an unique opportunity to "connect" the phantom driven (low en- ergy meV scale) dark energy phase to the (high energy GUT scale) inflationary era. This is possible because the energy density increases in phantom cosmology. We present a concrete model where the energy density, but not the scale factor, cycles through phases of standard radiation/matter domi- nation followed by dark energy/inflationary phases, and the pattern repeating itself. An interesting feature of the model is that once we include interactions between the "phantom fluid" and ordinary matter, the Big rip singularity is avoided with the phantom phase naturally giving way to a near exponential inflationary expansion.Comment: 17 pages, 1 figur

Remarks on the spherical waves of the Dirac field on de Sitter spacetime

The Shishkin's solutions of the Dirac equation in spherical moving frames of the de Sitter spacetime are investigated pointing out the set of commuting operators whose eigenvalues determine the integration constants. It is shown that these depend on the usual angular quantum numbers and, in addition, on the value of the scalar momentum. With these elements a new result is obtained finding the system of solutions normalized (in generalized sense) in the scale of scalar momentum.Comment: 7 pages, no figure

The role of reactive astrocitose in the chronological evolution of traumatic brain injury

Introduction and objectives. This study aims to investigate whether the cerebral modifications of posttraumatic reactive astrocitose can be considered an objective criterion for determining the age of traumatic cranio-cerebral lesions. Materials and methods. The present study consists of a series of 23 medico-legal cases that underwent autopsy inTeleormanCounty(Romania) Department of Forensic Medicine during 2007–2016, with full immune-histochemical microscopic examination using GFAP staining. The study consists of two groups, a series of 13 cases with cranio-cerebral trauma with different posttraumatic survival periods and 9 cases as a control group. Results and discussions. We discovered GFAP+ reactive astrocytes even when death occurred immediately after the trauma event and up to 4 months after the traumatic incident. We also discovered an intense positive correlation between the density of the GFAP+ cell from the perilesional area and the posttraumatic survival period. The highest cerebral density of the GFAP+ astrocytes occurred with acute death prior (1 to 24 hours) and the lowest in the chronic period (over 2 weeks). Conclusions. The gradual and differentiated appearance of the reactive astrocytes in close relation with the cerebral posttraumatic interval, with specific lesional and perilesional distribution as well as in surrounding area, clearly demonstrates that the state of the reactive astrocitose may constitute an objective index for evaluation of the elapsed time after the posttraumatic event