Functional dynamics of the folded ankyrin repeats of I kappa B alpha revealed by nuclear magnetic resonance.

Inhibition of nuclear factor kappaB (NF-kappaB) is mainly accomplished by IkappaB alpha, which consists of a signal response sequence at the N-terminus, a six-ankyrin repeat domain (ARD) that binds NF-kappaB, and a C-terminal PEST sequence. Previous studies with the ARD revealed that the fifth and sixth repeats are only partially folded in the absence of NF-kappaB. Here we report NMR studies of a truncated version of IkappaB alpha, containing only the first four ankyrin repeats, IkappaB alpha(67-206). This four-repeat segment is well-structured in the free state, enabling full resonance assignments to be made. H-D exchange, backbone dynamics, and residual dipolar coupling (RDC) experiments reveal regions of flexibility. In addition, regions consistent with the presence of micro- to millisecond motions occur periodically throughout the repeat structure. Comparison of the RDCs with the crystal structure gave only moderate agreement, but an ensemble of structures generated by accelerated molecular dynamics gave much better agreement with the measured RDCs. The regions showing flexibility correspond to those implicated in entropic compensation for the loss of flexibility in ankyrin repeats 5 and 6 upon binding to NF-kappaB. The regions showing micro- to millisecond motions in the free protein are the ends of the beta-hairpins that directly interact with NF-kappaB in the complex

New high-efficiency source of photon pairs for engineering quantum entanglement

We have constructed an efficient source of photon pairs using a waveguide-type nonlinear device and performed a two-photon interference experiment with an unbalanced Michelson interferometer. Parametric down-converted photons from the nonlinear device are detected by two detectors located at the output ports of the interferometer. Because the interferometer is constructed with two optical paths of different length, photons from the shorter path arrive at the detector earlier than those from the longer path. We find that the difference of arrival time and the time window of the coincidence counter are important parameters which determine the boundary between the classical and quantum regime. When the time window of the coincidence counter is smaller than the arrival time difference, fringes of high visibility (80$\pm$ 10%) were observed. This result is only explained by quantum theory and is clear evidence for quantum entanglement of the interferometer's optical paths.Comment: 4 pages, 4 figures, IQEC200

Finite resolution measurement of the non-classical polarization statistics of entangled photon pairs

By limiting the resolution of quantum measurements, the measurement induced changes of the quantum state can be reduced, permitting subsequent measurements of variables that do not commute with the initially measured property. It is then possible to experimentally determine correlations between non-commuting variables. The application of this method to the polarization statistics of entangled photon pairs reveals that negative conditional probabilities between non-orthogonal polarization components are responsible for the violation of Bell's inequalities. Such negative probabilities can also be observed in finite resolution measurements of the polarization of a single photon. The violation of Bell's inequalities therefore originates from local properties of the quantum statistics of single photon polarization.Comment: 15 pages, 5 figures and 1 table, new figure to illustrate results, improved explanation of statistical analysi

Coherent versus Incoherent Light Scattering from a Quantum Dot

We analyze the light scattered by a single InAs quantum dot interacting with a resonant continuous-wave laser. High resolution spectra reveal clear distinctions between coherent and incoherent scattering, with the laser intensity spanning over four orders of magnitude. We find that the fraction of coherently scattered photons can approach unity under sufficiently weak or detuned excitation, ruling out pure dephasing as a relevant decoherence mechanism. We show how spectral diffusion shapes spectra, correlation functions, and phase-coherence, concealing the ideal radiatively-broadened two-level system described by Mollow.Comment: to appear in PRB 85, 23531

33.8 GHz CCS Survey of Molecular Cores in Dark Clouds

We have conducted a survey of the CCS $J_N = 3_2-2_1$ line toward 11 dark clouds and star-forming regions at 30 arcsec spatial resolution and 0.054 km/s velocity resolution. CCS was only detected in quiescent clouds, not in active star-forming regions. The CCS distribution shows remarkable clumpy structure, and 25 clumps are identified in 7 clouds. Seven clumps with extremely narrow nonthermal linewidths < 0.1 km/s are among the most quiescent clumps ever found. The CCS clumps tend to exist around the higher density regions traced by NH_3 emission or submillimeter continuum sources, and the distribution is not spherically symmetric. Variation of the CCS abundance was suggested as an indicator of the evolutionary status of star formation. However, we can only find a weak correlation between N(CCS) and $n_{H_2,vir}$. The velocity distributions of CCS clouds reveal that a systematic velocity pattern generally exists. The most striking feature in our data is a ring structure in the position-velocity diagram of L1544 with an well-resolved inner hole of 0.04 pc x 0.13 km/s and an outer boundary of 0.16 pc x 0.55 km/s. This position-velocity structure clearly indicates an edge-on disk or ring geometry, and it can be interpreted as a collapsing disk with an infall velocity $\gtrsim$ 0.1 km/s and a rotational velocity less than our velocity resolution. Nonthermal linewidth distribution is generally coherent in CCS clouds, which could be evidence for the termination of Larson's Law at small scales, $\sim$ 0.1 pc.Comment: 21 pages, 25 ostscript figures, accepted for publication in the Supplement Series of the Astrophysical Journal (May 2000

Does Clauser-Horne-Shimony-Holt Correlation or Freedman-Clauser Correlation lead to the largest violation of Bell's Inequality?

An inequality is deduced from Einstein's locality and a supplementary assumption. This inequality defines an experiment which can actually be performed with present technology to test local realism. Quantum mechanics violate this inequality a factor of 1.5. In contrast, quantum mechanics violates previous inequalities (for example, Clauser-Horne-Shimony-Holt inequality of 1969, Freedman-Clauser inequality of 1972, Clauser-Horne inequality of 1974) by a factor of $\sqrt 2$. Thus the magnitude of violation of the inequality derived in this paper is approximately $20.7$ larger than the magnitude of violation of previous inequalities. This result can be particularly important for the experimental test of locality.Comment: 15 pages, LaTeX file, no figure

Relational autonomy in breast diseases care: A qualitative study of contextual and social conditions of patients' capacity for decision-making 17 Psychology and Cognitive Sciences 1701 Psychology

Background: A relational approach to autonomy refers to the way in which social conditions and relationships shape a person's self-identity and capacity in decision-making. This article provides an empirical account of how treatment choices for women undergoing breast diseases care are fostered within the dynamics of their relationships with clinicians, family members, and other aspects of their social environment. Methods: This qualitative study recruited ten women undergoing treatment at a breast programme, and eight clinicians supporting their care, in a private teaching hospital in New South Wales, Australia. Fourteen patient-clinician consultation observations and 17 semi-structured interviews were conducted. Schema analysis of interview transcripts were undertaken by a team of researchers and corroborated by observational fieldnotes. Results: Relational identities of patients influenced the rationale for treatment decision-making. Patients drew on supportive resources from family and medical advice from clinicians to progress with treatment goals. While clinicians held much social power over patients as the medical experts, patients highlighted the need for clinicians to earn their trust through demonstrated professionalism. Information exchange created a communicative space for clinicians and patients to negotiate shared values, promoting greater patient ownership of treatment decisions. As treatment progressed, patients' personal experiences of illness and treatment became a source of self-reflection, with a transformative impact on self-confidence and assertiveness. Conclusion: Patients' confidence and self-trust can be fostered by opportunities for communicative engagement and self-reflection over the course of treatment in breast disease, and better integration of their self-identity and social values in treatment decisions

Developmental Acquisition of Regulomes Underlies Innate Lymphoid Cell Functionality

Innate lymphoid cells (ILCs) play key roles in host defense, barrier integrity, and homeostasis and mirror adaptive CD4(+) T helper (Th) cell subtypes in both usage of effector molecules and transcription factors. To better understand the relationship between ILC subsets and their Th cell counterparts, we measured genome-wide chromatin accessibility. We find that chromatin in proximity to effector genes is selectively accessible in ILCs prior to high-level transcription upon activation. Accessibility of these regions is acquired in a stepwise manner during development and changes little after in vitro or in vivo activation. Conversely, dramatic chromatin remodeling occurs in naive CD4(+) T cells during Th cell differentiation using a type-2-infection model. This alteration results in a substantial convergence of Th2 cells toward ILC2 regulomes. Our data indicate extensive sharing of regulatory circuitry across the innate and adaptive compartments of the immune system, in spite of their divergent developing pathways

Dying Dyons Don't Count

The dyonic 1/4-BPS states in 4D string theory with N=4 spacetime supersymmetry are counted by a Siegel modular form. The pole structure of the modular form leads to a contour dependence in the counting formula obscuring its duality invariance. We exhibit the relation between this ambiguity and the (dis-)appearance of bound states of 1/2-BPS configurations. Using this insight we propose a precise moduli-dependent contour prescription for the counting formula. We then show that the degeneracies are duality-invariant and are correctly adjusted at the walls of marginal stability to account for the (dis-)appearance of the two-centered bound states. Especially, for large black holes none of these bound states exists at the attractor point and none of these ambiguous poles contributes to the counting formula. Using this fact we also propose a second, moduli-independent contour which counts the "immortal dyons" that are stable everywhere.Comment: 27 pages, 2 figures; one minus sign correcte