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A dedicated injector well, located in the Grane field in the Norwegian North Sea, was chosen as a candidate for application of a novel new sealant. The injector well, drilled for disposal of cuttings and produced water, was selected because of expected temperature and pressure cycling during the injection operation, and the risk of cement sheath integrity failure. This paper will discuss the design, execution, and evaluation of this injector well. Stress modeling indicated that as wellbore temperature decreased from bottomhole static to injection temperature and as bottomhole pressure cycled between static and dynamic conditions, conventional cement would fail in tension and create a microannulus. In view of these challenges, a redesigned the cement program, which incorporated stress analysis calculations and mechanical-properties testing provided a sealant material that would resist failure due to excessive wellbore stresses. The redesign required three steps;. Firstly, it was necessary to calculate temperature and pressure variations expected in the wellbore during injection. Next, temperature and pressure variations in the wellbore were evaluated using numerical analysis. Finally, a sealant was engineered so that its integrity would be maintained when exposed to repeated temperature and pressure cycles. The chosen sealant material incorporated flexible and expanding materials within an optimized particle size distribution blend. The sealant's mechanical properties were engineered in line with expected stresses to minimize the Young's modulus and improve bonding properties. The cuttings-disposal injector well was drilled, cased, and cemented using the new sealant material. Since placement, the well has been logged with sonic and ultrasonic tools and these data indicated an excellent bonding response. The well has now been used as an injector for more than two years with no indication of fluid communication in the annulus or loss of cement sheath integrity. Significantly, since this first application, which incorporated the successful of modeling of the expected stresses and the engineering of a sealant to manage these stresses, further injector wells have been cemented utilizing the same engineering approach.

We consider the small-volume dynamics of nonsupersymmetric orbifold and orientifold field theories defined on a three-torus, in a test of the claimed planar equivalence between these models and appropriate supersymmetric ``parent models". We study one-loop effective potentials over the moduli space of flat connections and find that planar equivalence is preserved for suitable averages over the moduli space. On the other hand, strong nonlinear effects produce local violations of planar equivalence at special points of moduli space. In the case of orbifold models, these effects show that the "twisted" sector dominates the low-energy dynamics., 20 pages, 3 figures; added references, minor changes

In the string holographic dual of large-N_c QCD with N_f flavours of Kruczenski et al, the eta' meson is massless at infinite N_c and dual to a collective fluctuation of N_f D6-brane probes in a supergravity background. Here we identify the string diagrams responsible for the generation of a mass of order N_f/N_c, consistent with the Witten-Veneziano formula, and show that the supregravity limit of these diagrams corresponds to mixings with pseudoscalar glueballs. We argue that the dependence on the theta-angle in the supergravity description occurs only through the combination theta + 2 \sqrt{N_f} eta' / f_pi, as dictated by the U(1) anomaly. We provide a quantitative test by computing the linear term in the eta' potential in two independent ways, with perfect agreement., Comment: 1+26 pages, 8 figures; V4: Appendix added, version published in JHEP

We present a spectroscopic study of four blue (B - V ≤ 0.6) compact (μB ≤ 21.0 mag arcsec-2) field galaxies with redshifts 0.095 ≤ z ≤ 0.438 and absolute magnitudes MB between -17.5 and -21.1. The spectra, taken with the Space Telescope Imaging Spectrograph on board the Hubble Space Telescope, show prominent emission lines whose spatial profiles reveal, at least in two cases, the existence of various star-forming regions and an underlying stellar population. The derived star formation rates from Hα luminosities in these star-forming regions range between 0.5 and 7 M⊙ yr-1. These regions are typically 10 times more luminous than and approximately twice as large as the well-known giant H II region 30 Doradus in the LMC. When compared with local starburst galaxies, the objects presented here turn out to be very similar to the brightest H II galaxies in terms of the areal star formation rate and in the ratio between the galactic half-light diameter to the line-emitting region half-light diameter (Deff/D0).

We study "multitrace" deformations of large N master fields in models with a mass gap. In particular, we determine the conditions for the multitrace couplings to drive tachyonic instabilities. These tachyons represent new local instabilities of the associated nonlocal string theories. In the particular case of Dp-branes at finite temperature, we consider topology-changing phase transitions and the effect of multitrace perturbations on the corresponding phase diagrams., harvmac. 28 pages. 9 eps figures

The aim of this study was to conduct an epidemiological analysis of quantitative dermatoglyphic traits as a marker of prenatal disturbance during the second trimester of life in schizophrenic patients. TFRC (Total Finger Ridge Count) and TABRC (Total a-b Ridge Count) were studied in a sample of 38 schizophrenic patients and 69 healthy individuals. A significant decrease of the a-b ridge count was found in patients compared to controls, with a significant linear trend across the population distribution (OR linear trend = 1.6; 95% CI = 1.0-2.4), indicating that the effect was not confined to a subgroup of cases with values in the lowest range. This finding was replicated in a second, larger sample (OR linear trend = 1.3; 95% CI = 1.0-1.8). The suggestion that a-b ridge count is associated with genetic risk for schizophrenia needs to be investigated further. TFRC did not distinguish between patients and controls. The a-b ridge count may be a continuous risk factor for later schizophrenia, pointing towards a disturbance occurring during the second trimester of prenatal life, a period of critical CNS growth.

We study using gauge-gravity duality the transport properties of charge carriers in a strongly-coupled theory with nonrelativistic symmetry, which were obtained via an irrelevant deformation that breaks the initial relativistic conformal group down to the Schodinger group. We compute the associated DC and AC conductivities in the dual gravity description of probe D7-branes in an asymptotically Schrodinger spacetime. We find generically that the conductivities exhibit nonrelativistic scaling with dynamical exponent z = 2 in the ultraviolet, while in the infrared the scaling is relativistic.

It is a challenge to describe the non-Fermi liquid behavior that appears in strongly interacting systems of fermions using traditional field theory techniques. A proposal to model the associated strange metal phenomenology is to use a strongly coupled critical point with non-relativistic scale invariance, dual to a Lifshitz geometry, coupled to a finite density of probe charged carriers dual to D-branes. We use this model to study the thermodynamic and transport properties of charge carriers at finite and zero temperature. At zero temperature we show that the large wavelength behavior is dominated by a single mode whose properties are similar to the zero sound of Fermi liquids.

14 pages, 2 figures.-- Submitted on 15 Jul 2008 (v1), last revised 23 Jul 2008 (this version, v2) by adding reference., We use the identification between null singularities of correlators in the bulk with time singularities in the boundary correlators to study the analytic structure of time-dependent thermal Green functions using the eikonal approximation for classical solutions in the AdS black hole background. We show that the location of singularities in complex time can be understood in terms of null rays bouncing on the boundaries and singularities of the eternal black hole, giving the picture of a 'reflecting cavity'. We can then extract the general analytic expression for the asymptotic values of the frequencies of quasinormal modes in large AdS black holes., I.A. is supported by grant BES-2007-16830 and by the Plan Nacional de Altas Energías FPA-2006-05485, FPA-2006-05423 and EC Commission under grant MRTN-CT-2004-005104.

The plasma phase at high temperatures of a strongly coupled gauge theory can be holographically modelled by an AdS black hole. Matter in the fundamental representation and in the quenched approximation is introduced through embedding D7-branes in the AdS-Schwarzschild background. Low spin mesons correspond to the fluctuations of the D7-brane world volume. As is well known by now, there are two different kinds of embeddings, either reaching down to the black hole horizon or staying outside of it. In the latter case the fluctuations of the D7-brane world volume represent stable low spin mesons. In the plasma phase we do not expect mesons to be stable but to melt at sufficiently high temperature. We model the late stages of this meson melting by the quasinormal modes of D7-brane fluctuations for the embeddings that do reach down to the horizon. The inverse of the imaginary part of the quasinormal frequency gives the typical relaxation time back to equilibrium of the meson perturbation in the hot plasma. We briefly comment on the possible application of our model to quarkonium suppression., 25+1 pages, 6 figures; v4: references added

We construct the first order hydrodynamics of quantum critical points with Lifshitz scaling and a spontaneously broken symmetry. The fluid is described by a combination of two flows, a normal component that carries entropy and a super-flow which has zero viscosity and carries no entropy. We analyze the new transport effects allowed by the lack of boost invariance and constrain them by the local second law of thermodynamics. Imposing time-reversal invariance, we find eight new parity even transport coefficients. The formulation is applicable, in general, to any superfluid/superconductor with an explicit breaking of boost symmetry, in particular to high $T_c$ superconductors. We discuss possible experimental signatures., 18 pages, 1 figure; added comments about time reversal invariance and the choice of time direction; updated referee comments according to published version

We compute the bulk viscosity in holographic models dual to theories with Lifshitz scaling and/or hyperscaling violation, using a generalization of the bulk viscosity formula derived in arXiv:1103.1657 from the null focusing equation. We find that only a class of models with massive vector fields are truly Lifshitz scale invariant, and have a vanishing bulk viscosity. For other holographic models with scalars and/or massless vector fields we find a universal formula in terms of the dynamical exponent and the hyperscaling violation exponent., 24 pages

This paper proposes a new cough detection system based on audio signals acquired from conventional smartphones. The system relies on local Hu moments to characterize cough events and a k-NN classifier to distinguish cough events from non-cough ones (speech, laugh, sneeze, etc.) and noisy sounds. To deal with the unbalance between classes, we employ Distinct-Borderline2 Synthetic Minority Oversampling Technique and a bespoke cost matrix. The system additionally features a post-processing module to avoid isolated false negatives and, this way, increases sensitivity. Evaluation has been carried out using a database comprising a variety of cough and non-cough events and different types of background noise. In this study, we specifically focused on noise likely to appear when the user is carrying the smartphone in daily activities. Different Signal to Noise Ratio values were tested ranging between -15 and 0 dB. Our experiments confirm that local Hu moments are suitable not only for characterizing cough events but also for coping with noisy environments. Results show a sensitivity of 94.17% and a specificity of 92.16% at -15 dB. Thus, our system shows potential as a reliable and place-ubiquitous monitoring device that helps patients self-manage their own respiratory diseases and avoids unreported or fabricated symptoms.