NMR relaxation of quantum spin chains in magnetic fields

We investigate NMR relaxation rates 1/T_1 of quantum spin chains in magnetic fields. Universal properties for the divergence behavior of 1/T_1 are obtained in the Tomonaga-Luttinger-liquid state. The results are discussed in comparison with experimental results.Comment: 5 pages, 3 figure

ACCELERATIVE STABILIZATION OF SOLID WASTE IN ANAEROBIC/AEROBIC LAB-SCALE LANDFILL BIOREACTORS

Joint Research on Environmental Science and Technology for the Eart

Quantum Annealing: An Overview

In this review, after providing the basic physical concept behind quantum annealing (or adiabatic quantum computation), we present an overview of some recent theoretical as well as experimental developments pointing to the issues which are still debated. With a brief discussion on the fundamental ideas of continuous and discontinuous quantum phase transitions, we discuss the Kibble-Zurek scaling of defect generation following a ramping of a quantum many body system across a quantum critical point. In the process, we discuss associated models, both pure and disordered, and shed light on implementations and some recent applications of the quantum annealing protocols. Furthermore, we discuss the effect of environmental coupling on quantum annealing. Some possible ways to speed up the annealing protocol in closed systems are elaborated upon: We especially focus on the recipes to avoid discontinuous quantum phase transitions occurring in some models where energy gaps vanish exponentially with the system size.Comment: Final version; in pres

Three Lyα Emitting Galaxies within a Quasar Proximity Zone at z ~ 5.8

Quasar proximity zones at z > 5.5 correspond to overdense and overionized environments. Galaxies found inside proximity zones can therefore display features that would otherwise be masked by absorption in the intergalactic medium. We demonstrate the utility of this quasar-galaxy synergy by reporting the discovery of the first three “proximate Lyα emitters” (LAEs) within the proximity zone of quasar J0836+0054 at z = 5.795 (Aerith A, B, and C). Aerith A, located behind the quasar with an impact parameter D^{\perp} = 278 \pm 8 pkpc, provides the first detection of an Lyα transverse proximity effect. We model the transmission and show that it constrains the onset of J0836ʼs quasar phase to 0.2Myr < 28Myr < t in the past. The second object, Aerith B at a distance D < 912 pkpc from the quasar, displays a bright and broad double-peaked Lyα emission line. The peak separation implies a low ionizing f_{esc} \leqslant 1%. We fit the Lyα line with an outflowing shell model, finding a typical central density log N_{HI}/cm^{-2} = 19.3_{-0.2}^{+0.8}, outflow velocity v_{out} = 16_{-11}^{+4}km s^{-1}, and gas temperature log T/K = 3.8_{-0.7}^{+0.8} compared to 2 < z < 3 analog LAEs. We detect object Aerith C via an Lyα emission line at z = 5.726. This corresponds with the edge of the quasar’s proximity zone (Dz < 0.02), suggesting that the proximity zone is truncated by a density fluctuation. Via the analyses conducted here, we illustrate how proximate LAEs offer unique insight into the ionizing properties of both quasars and galaxies during hydrogen reionization

The role of galaxies and AGN in reionising the IGM -- III : IGM-galaxy cross-correlations at z~6 from 8 quasar fields with DEIMOS and MUSE

We present improved results of the measurement of the correlation between galaxies and the intergalactic medium transmission at the end of reionization. We have gathered a sample of 13 spectroscopically confirmed Lyman-break galaxies (LBGs) and 21 Lyman-α emitters (LAEs) at angular separations 20 arcsec ≲ θ ≲ 10 arcmin (∼0.1–4 pMpc at z ∼ 6) from the sightlines to eight background z ≳ 6 quasars. We report for the first time the detection of an excess of Lyman-α transmission spikes at ∼10–60 cMpc from LAEs (3.2σ) and LBGs (1.9σ). We interpret the data with an improved model of the galaxy–Lyman-α transmission and two-point cross-correlations, which includes the enhanced photoionization due to clustered faint sources, enhanced gas densities around the central bright objects and spatial variations of the mean free path. The observed LAE(LBG)–Lyman-α transmission spike two-point cross-correlation function (2PCCF) constrains the luminosity-averaged escape fraction of all galaxies contributing to reionization to ⟨fesc⟩MUV−20(2σ)⁠) is necessary to reproduce the observed 2PCCF and that reionization might be driven by different sub-populations around LBGs and LAEs at z ∼ 6

Planting the Seed : Perceived Benefits of and Strategies for Discussing Long-Term Prognosis with Older Adults

OBJECTIVES: To characterize the goals and approaches of clinicians with experience discussing long-term prognostic information with older adults. DESIGN: We used a semistructured interview guide containing 2 domains of perceived benefits and strategies to explore why and how clinicians choose to discuss long-term prognosis, defined as life expectancy on the scale of years, with patients. SETTING: Clinicians from home-based primary care practices, community-based clinics, and academic medical centers across San Francisco. PARTICIPANTS: Fourteen physicians, including 11 geriatricians and 1 geriatric nurse practitioner, with a mean age of 40 and a mean 9 years in practice. MEASUREMENTS: Clinician responses were analyzed qualitatively using the constant comparisons approach. RESULTS: Perceived benefits of discussing long-term prognosis included establishing realistic expectations for patients, encouraging conversations about future planning, and promoting shared decision-making through understanding of patient goals of care. Communication strategies included adapting discussions to individual patient preferences and engaging in multiple conversations over time. Clinicians preferred to communicate prognosis in words and with a visual aid, although most did not know of a suitable visual aid. CONCLUSION: Engaging in customized longitudinal discussions of long-term prognosis aids clinicians in anchoring conversations about future planning and preparing patients for the end of life

Critical properties of S=1/2 Heisenberg ladders in magnetic fields

The critical properties of the $S=1/2$ Heisenberg two-leg ladders are investigated in a magnetic field. Combining the exact diagonalization method and the finite-size-scaling analysis based on conformal field theory, we calculate the critical exponents of spin correlation functions numerically. For a strong interchain coupling, magnetization dependence of the critical exponents shows characteristic behavior depending on the sign of the interchain coupling. We also calculate the critical exponents for the $S=1/2$ Heisenberg two-leg ladder with a diagonal interaction, which is thought as a model Hamiltonian of the organic spin ladder compound ${Cu}_2({1,4-diazacycloheptane})_2{Cl}_4$. Numerical results are compared with experimental results of temperature dependence of the NMR relaxation rate $1/T_1$.Comment: REVTeX, 10 pages, 8 figures, accepted for Phys. Rev.

In Vitro Microvessel Growth and Remodeling within a Three-Dimensional Microfluidic Environment

This paper presents in vitro microvascular network formation within 3D gel scaffolds made from different concentrations of type-I collagen, fibrin, or a mixture of collagen and fibrin, using a simple microfluidic platform. Initially, microvascular network formation of human umbilical vein endothelial cells was examined using live time-lapse confocal microscopy every 90 min from 3 h to 12 h after seeding within three different concentrations of collagen gel scaffolds. Among the three collagen gel concentrations, the number of skeletons was consistently the highest at 3.0 mg/mL, followed by those of collagen gel scaffolds at 2.5 mg/mL and 2.0 mg/mL. Results demonstrated that concentration of collagen gel scaffolds, which influences matrix stiffness and ligand density, may affect microvascular network formation during the early stages of vasculogenesis. In addition, the maturation of microvascular networks in monoculture under different gel compositions within gel scaffolds (2.5 mg/mL) was examined for 7 days using live confocal microscopy. It was confirmed that pure fibrin gel scaffolds are preferable to collagen gel or collagen/fibrin combinations, significantly reducing matrix retractions during maturation of microvascular networks for 7 days. Finally, early steps in the maturation process of microvascular networks for 14 days were characterized by demonstrating sequential steps of branching, expanding, remodeling, pruning, and clear delineation of lumens within fibrin gel scaffolds. Our findings demonstrate an in vitro model for generating mature microvascular networks within 3D microfluidic fibrin gel scaffolds (2.5 mg/mL), and furthermore suggest the importance of gel concentration and composition in promoting the maturation of microvascular networks.Singapore-MIT Alliance for Research and Technolog

The role of galaxies and AGNs in reionizing the IGM – II. Metal-tracing the faint sources of reionization at 5 ≲ z ≲ 6

We present a new method to study the contribution of faint sources to the ultraviolet background using the 1D correlation of metal absorbers with the intergalactic medium transmission in a quasi-stellar object (QSO) sightline. We take advantage of a sample of 25 high signal-to-noise ratio QSO spectra to retrieve 150 triply-ionized carbon (C IV) absorbers at 4.5 ≲ z ≲ 6.2, of which 37 systems whose expected H I absorption lie in the Lyman-α forest. We derive improved constraints on the cosmic density of C IV at 4.3 < z < 6.2 and infer from abundance matching that C IV absorbers trace MUV ≲ −16 galaxies. Correlation with the Lyman-α forest of the QSOs indicates that these objects are surrounded by a highly opaque region at r ≲ 5 cMpc h−1 followed by an excess of transmission at r ≳ 10 cMpc h−1 detected at 2.7σ. This is in contrast to equivalent measurements at lower redshifts where only the opaque trough is detected. We interpret this excess as a statistical enhancement of the local photoionization rate due to clustered faint galaxies around the C IV absorbers. Using the analytical framework described in Paper I of this series, we derive a constraint on the average product of the escape fraction and the Lyman continuum photon production efficiency of the galaxy population clustered around the C IV absorbers, log⟨fescξion⟩/[erg−1Hz]=25.01+0.30−0.19⁠. This implies that faint galaxies beyond the reach of current facilities may have harder radiation fields and/or larger escape fractions than currently detected objects at the end of the reionization epoch

Cardiovascular magnetic resonance tagging imaging correlates with myocardial dysfunction and T2 mapping in idiopathic dilated cardiomyopathy

To evaluate the details of myocardial dysfunction in dilated cardiomyopathy (DCM) patients using tagging images and the correlation of tagging imaging with tissue characteristics. C