Closed Strings and Moduli in AdS3/CFT2

String theory on AdS3×S3×T4 has 20 moduli. We investigate how the perturbative closed string spectrum changes as we move around this moduli space in both the RR and NSNS flux backgrounds. We find that, at weak string coupling, only four of the moduli affect the energies. In the RR background the only effect of these moduli is to change the radius of curvature of the background. On the other hand, in the NSNS background, the moduli introduce worldsheet interactions which enable the use of integrability methods to solve the spectral problem. Our results show that the worldsheet theory is integrable across the 20 dimensional moduli space

Unitary 4-point correlators from classical geometries

SCOAP

– Cardiodesfibrilador Implantável – Infecção em DCEI – Papel dos Fármacos Antiarrítmicos – Direção Veicular em Portadores de DCEI

Desde o primeiro implante, em 1980, até os dias atuais, ocorreram importantes avanços no cardiodesfibrilador implantável (CDI), tanto no tamanho como nas funções e programações. Atualmente esses dispositivos dispõem de terapia antitaquicardia (ATP), cardioversão com baixa energia, desfibrilação com alta energia e função antibradicardia de backup. Diversos estudos de grande porte demonstraram que o CDI trata efetivamente os eventos de taquicardia ventricular e fibrilação ventricular, reduzindo a mortalidade quando comparado com fármacos antiarrítmicos isoladamente.[...

– Terapia de Ressincronização Cardíaca

A insuficiência cardíaca é uma significante causa de morbidade e mortalidade em todo o mundo, com prevalência de 2,4% dos adultos 1 (A). Embora a sobrevivência após o diagnóstico de insuficiência cardíaca tenha melhorado nas duas últimas décadas, as taxas de morte e hospitalização por insuficiência cardíaca permanecem altas e aproximadamente 50% dos pacientes morrem dentro de 5 anos do diagnóstico 1 (A). Adicionalmente, a despeito do tratamento medicamentoso otimizado, muitos pacientes com insuficiência cardíaca permanecem sintomáticos e com redução da qualidade de vida 2 (D)

– Implante de Marcapasso nas Bradicardias e em Outras Situações Especiais – Estratificação de Risco de Morte Súbita na Cardiomiopatia Chagásica

A frequência cardíaca normal varia de 60 bpm a 100 bpm. Ritmos com frequência cardíaca < 60 bpm são definidos como bradicardia, que pode ser assintomática ou sintomática. As bradicardias sintomáticas têm características clínicas comuns, marcadas, sobretudo, pela síndrome do baixo fluxo cerebral e/ou sistêmico, cujos sintomas mais comuns são tontura, pré-síncope, síncope, fadiga, dispneia de esforço e bradipsiquismo, sendo comumente ocasionadas por doença do nó sinusal e bloqueio atrioventricular. As assintomáticas, geralmente, são de causas fisiológicas, representadas por bradicardia sinusal e ritmos de escape da junção atrioventricular

Physics, Astrophysics and Cosmology with Gravitational Waves

Gravitational wave detectors are already operating at interesting sensitivity levels, and they have an upgrade path that should result in secure detections by 2014. We review the physics of gravitational waves, how they interact with detectors (bars and interferometers), and how these detectors operate. We study the most likely sources of gravitational waves and review the data analysis methods that are used to extract their signals from detector noise. Then we consider the consequences of gravitational wave detections and observations for physics, astrophysics, and cosmology.Comment: 137 pages, 16 figures, Published version <http://www.livingreviews.org/lrr-2009-2

Protected string spectrum in AdS(3)/CFT2 from worldsheet integrability

We derive the protected closed-string spectra of AdS3/CFT2 dual pairs with 16 supercharges at arbitrary values of the string tension and of the three-form fluxes. These follow immediately from the all-loop Bethe equations for the spectra of the integrable worldsheet theories. Further, representing the underlying integrable systems as spin chains, we find that their dynamics involves length-changing interactions and that protected states correspond to gapless excitations above the Berenstein-Maldacena-Nastase vacuum. In the case of AdS3 × S3 × T4 the degeneracies of such operators precisely match those of the dual CFT2 and the supergravity spectrum. On the other hand, we find that for AdS3 × S3 × S3 × S1 there are fewer protected states than previous supergravity calculations had suggested. In particular, protected states have the same su(2) charge with respect to the two three-spheres

Interrogating and Predicting Tolerated Sequence Diversity in Protein Folds: Application to E. elaterium Trypsin Inhibitor-II Cystine-Knot Miniprotein

Cystine-knot miniproteins (knottins) are promising molecular scaffolds for protein engineering applications. Members of the knottin family have multiple loops capable of displaying conformationally constrained polypeptides for molecular recognition. While previous studies have illustrated the potential of engineering knottins with modified loop sequences, a thorough exploration into the tolerated loop lengths and sequence space of a knottin scaffold has not been performed. In this work, we used the Ecballium elaterium trypsin inhibitor II (EETI) as a model member of the knottin family and constructed libraries of EETI loop-substituted variants with diversity in both amino acid sequence and loop length. Using yeast surface display, we isolated properly folded EETI loop-substituted clones and applied sequence analysis tools to assess the tolerated diversity of both amino acid sequence and loop length. In addition, we used covariance analysis to study the relationships between individual positions in the substituted loops, based on the expectation that correlated amino acid substitutions will occur between interacting residue pairs. We then used the results of our sequence and covariance analyses to successfully predict loop sequences that facilitated proper folding of the knottin when substituted into EETI loop 3. The sequence trends we observed in properly folded EETI loop-substituted clones will be useful for guiding future protein engineering efforts with this knottin scaffold. Furthermore, our findings demonstrate that the combination of directed evolution with sequence and covariance analyses can be a powerful tool for rational protein engineering

Stochastic backgrounds of relic gravitons: a theoretical appraisal

Stochastic backgrounds or relic gravitons, if ever detected, will constitute a prima facie evidence of physical processes taking place during the earliest stages of the evolution of the plasma. The essentials of the stochastic backgrounds of relic gravitons are hereby introduced and reviewed. The pivotal observables customarily employed to infer the properties of the relic gravitons are discussed both in the framework of the $\Lambda$CDM paradigm as well as in neighboring contexts. The complementarity between experiments measuring the polarization of the Cosmic Microwave Background (such as, for instance, WMAP, Capmap, Quad, Cbi, just to mention a few) and wide band interferometers (e.g. Virgo, Ligo, Geo, Tama) is emphasized. While the analysis of the microwave sky strongly constrains the low-frequency tail of the relic graviton spectrum, wide-band detectors are sensitive to much higher frequencies where the spectral energy density depends chiefly upon the (poorly known) rate of post-inflationary expansion.Comment: 94 pages, 32 figure