Room temperature electron spin coherence in telecom-wavelength quaternary quantum wells

Time-resolved Kerr rotation spectroscopy is used to monitor the room temperature electron spin dynamics of optical telecommunication wavelength AlInGaAs multiple quantum wells lattice-matched to InP. We found that electron spin coherence times and effective g-factors vary as a function of aluminum concentration. The measured electron spin coherence times of these multiple quantum wells, with wavelengths ranging from 1.26 microns to 1.53 microns, reach approximately 100 ps at room temperature, and the measured electron effective g-factors are in the range from -2.3 to -1.1.Comment: 4 pages, 4 figure

Restoration of Sp4 in Forebrain GABAergic Neurons Rescues Hypersensitivity to Ketamine in Sp4 Hypomorphic Mice.

BackgroundKetamine produces schizophrenia-like behavioral phenotypes in healthy people. Prolonged ketamine effects and exacerbation of symptoms after the administration of ketamine have been observed in patients with schizophrenia. More recently, ketamine has been used as a potent antidepressant to treat patients with major depression. The genes and neurons that regulate behavioral responses to ketamine, however, remain poorly understood. Sp4 is a transcription factor for which gene expression is restricted to neuronal cells in the brain. Our previous studies demonstrated that Sp4 hypomorphic mice display several behavioral phenotypes relevant to psychiatric disorders, consistent with human SP4 gene associations with schizophrenia, bipolar disorder, and major depression. Among those behavioral phenotypes, hypersensitivity to ketamine-induced hyperlocomotion has been observed in Sp4 hypomorphic mice.MethodsIn the present study, we used the Cre-LoxP system to restore Sp4 gene expression, specifically in either forebrain excitatory or GABAergic inhibitory neurons in Sp4 hypomorphic mice. Mouse behavioral phenotypes related to psychiatric disorders were examined in these distinct rescue mice.ResultsRestoration of Sp4 in forebrain excitatory neurons did not rescue deficient sensorimotor gating nor ketamine-induced hyperlocomotion. Restoration of Sp4 in forebrain GABAergic neurons, however, rescued ketamine-induced hyperlocomotion, but did not rescue deficient sensorimotor gating.ConclusionsOur studies suggest that the Sp4 gene in forebrain GABAergic neurons regulates ketamine-induced hyperlocomotion

The CIV-MgII Kinematics Connection in <z>~0.7 Galaxies

We have examined Faint Object Spectrograph data from the Hubble Space Telescope Archive for CIV 1548,1550 absorption associated with 40 MgII 2796,2803 absorption-selected galaxies at 0.4 < z < 1.4. We report a strong correlation between MgII kinematics, measured in 6 km/s resolution HIRES/Keck spectra, and W_r(1548); this implies a physical connection between the processes that produce "outlying velocity" MgII clouds and high ionization galactic/halo gas. We found no trend in ionization condition, W_r(1548)/W_r(2796), with galaxy-QSO line-of-sight separation for 13 systems with confirmed associated galaxies, suggesting no obvious ionization gradient with galactocentric distance in these higher redshift galaxies. We find tentative evidence (2-sigma) that W_r(1548)/W_r(2796) is anti-correlated with galaxy color; if further data corroborate this trend, in view of the strong CIV-MgII kinematics correlation, it could imply a connection between stellar populations, star formation episodes, and the kinematics and ionization conditions of halo gas at z~1.Comment: Accepted to Astrophysical Journal Letters; 4 pages; 3 figures; emulateapj.st

Spitzer Mid-Infrared Spectroscopy of 70um-Selected Distant Luminous Infrared Galaxies

We present mid-infrared spectroscopy obtained with the Spitzer Space Telescope of a sample of 11 optically faint, infrared luminous galaxies selected from a Spitzer MIPS 70um imaging survey of the NDWFS Bootes field. These are the first Spitzer IRS spectra presented of distant 70um-selected sources. All the galaxies lie at redshifts 0.3<z<1.3 and have very large infrared luminosities of L_IR~ 0.1-17 x 10^12 solar luminosities. Seven of the galaxies exhibit strong emission features attributed to polycyclic aromatic hydrocarbons (PAHs). The average IRS spectrum of these sources is characteristic of classical starburst galaxies, but with much larger infrared luminosities. The PAH luminosities of L(7.7) ~ 0.4 - 7 x 10^11 solar luminosities imply star formation rates of ~ 40 - 720 solar masses per year. Four of the galaxies show deep 9.7um silicate absorption features and no significant PAH emission features (6.2um equivalent widths < 0.03um). The large infrared luminosities and low f70/f24 flux density ratios suggests that these sources have AGN as the dominant origin of their large mid-infrared luminosities, although deeply embedded but luminous starbursts cannot be ruled out. If the absorbed sources are AGN-dominated, a significant fraction of all far-infrared bright, optically faint sources may be dominated by AGN.Comment: 8 Pages, ApJ accepte

Quantum Particles Constrained on Cylindrical Surfaces with Non-constant Diameter

We present a theoretical formulation of the one-electron problem constrained on the surface of a cylindrical tubule with varying diameter. Because of the cylindrical symmetry, we may reduce the problem to a one-dimensional equation for each angular momentum quantum number $m$ along the cylindrical axis. The geometrical properties of the surface determine the electronic structures through the geometry dependent term in the equation. Magnetic fields parallel to the axis can readily be incorporated. Our formulation is applied to simple examples such as the catenoid and the sinusoidal tubules. The existence of bound states as well as the band structures, which are induced geometrically, for these surfaces are shown. To show that the electronic structures can be altered significantly by applying a magnetic field, Aharonov-Bohm effects in these examples are demonstrated.Comment: 7 pages, 7 figures, submitted to J. Phys. Soc. Jp

Gravitational instability of Einstein-Gauss-Bonnet black holes under tensor mode perturbations

We analyze the tensor mode perturbations of static, spherically symmetric solutions of the Einstein equations with a quadratic Gauss-Bonnet term in dimension $D > 4$. We show that the evolution equations for this type of perturbations can be cast in a Regge-Wheeler-Zerilli form, and obtain the exact potential for the corresponding Schr\"odinger-like stability equation. As an immediate application we prove that for $D \neq 6$ and $\alpha >0$, the sign choice for the Gauss-Bonnet coefficient suggested by string theory, all positive mass black holes of this type are stable. In the exceptional case $D =6$, we find a range of parameters where positive mass asymptotically flat black holes, with regular horizon, are unstable. This feature is found also in general for $\alpha < 0$.Comment: 7 pages, 1 figure, minor corrections, references adde

Evidence from the first Shared Medical Appointments (SMAs) randomised controlled trial in India: SMAs increase the satisfaction, knowledge, and medication compliance of patients with glaucoma

In Shared Medical Appointments (SMAs), patients with similar conditions meet the physician together and each receives one-on-one attention. SMAs can improve outcomes and physician productivity. Yet privacy concerns have stymied adoption. In physician-deprived nations, patients’ utility from improved access may outweigh their disutility from loss of privacy. Ours is to our knowledge the first SMA trial for any disease, in India, where doctors are scarce. In a 1,000-patient, single-site, randomized controlled trial at Aravind Eye Hospital, Pondicherry, we compared SMAs and one-on-one appointments, over four successive visits, for patients with glaucoma. We examined patients’ satisfaction, knowledge, intention-to-follow-up, follow-up rates, and medication compliance rates (primary outcomes) using intention-to-treat analysis. Of 1,034 patients invited between July 12, 2016 –July 19, 2018, 1,000 (96.7%) consented to participate, and were randomly assigned to either SMAs (NSMA = 500) or one-on-one appointments (N1-1 = 500). Patients who received SMAs showed higher satisfaction (MeanSMA = 4.955 (SD 0.241), Mean1-1 = 4.920 (SD 0.326); difference in means 0.035; 95% CI, 0.017–0.054, p = 0.0002) and knowledge (MeanSMA = 3.416 (SD 1.340), Mean1-1 = 3.267 (SD 1.492); difference in means 0.149; 95% CI, 0.057–0.241, p = 0.002) than patients who received one-on-one appointments. Across conditions, there was no difference in patients’ intention-to-follow-up (MeanSMA = 4.989 (SD 0.118), Mean1-1 = 4.986 (SD 0.149); difference in means 0.003; 95% CI, -0.006–0.012, p = 0.481) and actual follow-up rates (MeanSMA = 87.5% (SD 0.372), Mean1-1 = 88.7% (SD 0.338); difference in means -0.012; 95% CI, -0.039–0.015, p = 0.377). Patients who received SMAs exhibited higher medication compliance rates (MeanSMA = 97.0% (SD 0.180), Mean1-1 = 94.9% (SD 0.238); difference in means 0.020; 95% CI, 0.004–0.036, p = 0.013). SMAs improved satisfaction, learning, and medication compliance, without compromising follow-up rates or measured clinical outcomes. Peer interruptions were negatively correlated with patient satisfaction in early-trial SMAs and positively correlated with patient satisfaction in later-trial SMAs. Trial registration: The trial was registered with Clinical Trials Registry of India (https://ctri.nic.in/) with reference no. REF/2016/11/012659 and registration no. CTRI/2018/02/011998

Shared Service Delivery Can Increase Client Engagement: A Study of Shared Medical Appointments

Problem definition: Clients and service providers alike often consider one-on-one service delivery to be ideal, assuming, perhaps unquestioningly, that devoting individualized attention best improves client outcomes. In contrast, in shared service delivery, clients are served in batches and the dynamics of group interaction could lead to increased client engagement, which could improve outcomes. However, the loss of privacy and personal connection might undermine engagement. The engagement dynamics in one-on-one and shared delivery models have not been rigorously studied. To the extent that shared delivery may result in comparable or better engagement than one-on-one delivery, service providers in a broad array of contexts may be able to create more value for clients by delivering service in batches. Methodology/results: We conducted a randomized controlled trial with 1,000 patients who were undergoing glaucoma treatment over a three-year period at a large eye hospital. Using verbatim and behavioral transcripts from more than 20,000 minutes of video recorded during our trial, we examine how shared medical appointments (SMAs), in which patients are served in batches, impact engagement. On average, a patient who experienced SMAs asked 33.3% more questions per minute and made 8.6% more nonquestion comments per minute. Because there were multiple patients in an SMA, this increase in engagement at the individual patient level resulted in patients hearing far more comments in the group setting. Patients in SMAs also exhibited higher levels of nonverbal engagement across a wide array of measures (attentiveness, positivity, head wobbling, or “thalai aattam” in Tamil: a South Indian gesture to signal agreement or understanding, eye contact, and end-of-appointment happiness), relative to patients who attended one-on-one appointments. Managerial implications: These results shed light on the potential for shared service delivery models to increase client engagement and thus enhance service performance

Discovery of a z=4.93, X-ray selected quasar by the Chandra Multiwavelength Project (ChamP)

We present X-ray and optical observations of CXOMP J213945.0-234655, a high redshift (z=4.93) quasar discovered through the Chandra Multiwavelength Project (ChaMP). This object is the most distant X-ray selected quasar published, with an X-ray luminosity of L(X)=5.9x10^44 erg/s (measured in the 0.3-2.5 keV band and corrected for Galactic absorption). CXOMP J213945.0-234655 is a g' dropout object (>26.2), with r'=22.87 and i'=21.36. The rest-frame X-ray to optical flux ratio is similar to quasars at lower redshifts and slightly X-ray bright relative to z>4 optically-selected quasars observed with Chandra. The ChaMP is beginning to acquire significant numbers of high redshift quasars to investigate the unobscured X-ray luminosity function out to z~5.Comment: Published in ApJ Letters; 4 pages; 3 figures; http://hea-www.harvard.edu/CHAMP