Finding Direct-Collapse Black Holes at Birth

Direct-collapse black holes (DCBHs) are currently one of the leading contenders for the origins of the first quasars in the universe, over 300 of which have now been found at $z >$ 6. But the birth of a DCBH in an atomically-cooling halo does not by itself guarantee it will become a quasar by $z \sim$ 7, the halo must also be located in cold accretion flows or later merge with a series of other gas-rich halos capable of fueling the BH's rapid growth. Here, we present near infrared luminosities for DCBHs born in cold accretion flows in which they are destined to grow to 10$^9$ M$_{\odot}$ by $z \sim$ 7. Our observables, which are derived from cosmological simulations with radiation hydrodynamics with Enzo, reveal that DCBHs could be found by the James Webb Space Telescope at $z \lesssim$ 20 and strongly-lensed DCBHs might be found in future wide-field surveys by Euclid and the Wide-Field Infrared Space Telescope at $z \lesssim$ 15.Comment: 5 pages, 2 figures, accepted by ApJ

A computational tool to predict the evolutionarily conserved protein-protein interaction hot-spot residues from the structure of the unbound protein

Identifying hot-spot residues – residues that are critical to protein–protein binding – can help to elucidate a protein's function and assist in designing therapeutic molecules to target those residues. We present a novel computational tool, termed spatial-interaction-map (SIM), to predict the hot-spot residues of an evolutionarily conserved protein–protein interaction from the structure of an unbound protein alone. SIM can predict the protein hot-spot residues with an accuracy of 36–57%. Thus, the SIM tool can be used to predict the yet unknown hot-spot residues for many proteins for which the structure of the protein–protein complexes are not available, thereby providing a clue to their functions and an opportunity to design therapeutic molecules to target these proteins.Novartis (Firm)Singapore-MIT Alliance for Research and Technolog

Absolute structures and conformations of the spongian diterpenes spongia-13(16), 14-dien-3-one, epispongiadiol and spongiadiol

The absolute configurations of spongia-13(16),14-dien-3-one [systematic name: (3bR,5aR,9aR,9bR)-3b,6,6,9a-tetra-methyl-4,5,5a,6,8,9,9a,9b,10,11-deca- hydro-phenanthro[1,2-c]furan-7(3bH)-one], C20H28O2, (I), epispongiadiol [systematic name: (3bR,5aR,6S,7R,9aR,9bR)-7-hydr-oxy-6-hydroxy-methyl-3b,6,9a- trimethyl-3b,5,5a,6,7,9,9a,9b,10,11-deca-hydro-phenanthro[1,2-c]furan-8(4H)-one] , C20H28O4, (II), and spongiadiol [systematic name: (3bR,5aR,6S,7S,9aR,9bR)-7- hydr-oxy-6-hy-droxy-methyl-3b,6,9a-trimethyl-3b,5,5a,6,7,9,9a,9b,10, 11-deca-hydro-phenanthro[1,2-c]furan-8(4H)-one], C20H28O4, (III), were assigned by analysis of anomalous dispersion data collected at 130 K with Cu K radiation. Compounds (II) and (III) are epimers. The equatorial 3-hydroxyl group on the cyclo-hexa-none ring (A) of (II) is syn with respect to the 4-hydroxy-methyl group, leading to a chair conformation. In contrast, isomer (III), where the 3-hydroxyl group is anti to the 4-hydroxy-methyl group, is conformationally disordered between a major chair conformer where the OH group is axial and a minor boat conformer where it is equatorial. In compound (I), a carbonyl group is present at position 3 and ring A adopts a distorted-boat conformation

Selection for inpatient rehabilitation after severe stroke: What factors influence rehabilitation assessor decision making?

Objectives: This study aimed to identify factors that assessors considered important in decision-making regarding suitability for inpatient rehabilitation after acute severe stroke.Design: Multi-site prospective observational cohort study. Subjects: Consecutive acute, severe stroke patients and their assessors for inpatient rehabilitation. Methods: Rehabilitation assessors completed a questionnaire, rating the importance (10 point visual analogue scale) and direction (positive, negative or neutral) of 15 patient related and 2 organisational items potentially affecting their decision regarding patients’ acceptance to rehabilitation. Results: Of the 75 patients referred to rehabilitation and included in this study 61 (81.3%) were accepted for inpatient rehabilitation. The items considered to be most important in the decision to accept the patient for rehabilitation were pre-morbid cognition, pre-morbid mobility and pre-morbid communication. For those not accepted the most important items were current mobility, social support and current cognition. Factor analysis revealed 3 underlying factors, interpreted as post-stroke status, pre-morbid status, and social attributes, accounting for 61.8% of the total variance. All were independently associated with acceptance for rehabilitation (p < 0.05). Conclusions: This study highlights the importance of pre-morbid function and social factors in addition to post-stroke function in the decision making process for acceptance to rehabilitation following severe stroke. Future models for selection for rehabilitation should consider inclusion of these factors

Effects of atomic diffraction on the Collective Atomic Recoil Laser

We formulate a wave atom optics theory of the Collective Atomic Recoil Laser, where the atomic center-of-mass motion is treated quantum mechanically. By comparing the predictions of this theory with those of the ray atom optics theory, which treats the center-of-mass motion classically, we show that for the case of a far off-resonant pump laser the ray optics model fails to predict the linear response of the CARL when the temperature is of the order of the recoil temperature or less. This is due to the fact that in theis temperature regime one can no longer ignore the effects of matter-wave diffraction on the atomic center-of-mass motion.Comment: plain tex, 10 pages, 10 figure

An Early Mobilization Protocol Successfully Delivers More and Earlier Therapy to Acute Stroke Patients: Further Results From Phase II of AVERT.

Background: The optimal physical therapy dose in acute stroke care is unknown. The authors hypothesized that physical therapy would be significantly different between treatment arms in a trial of very early and frequent mobilization (VEM) and that immobility-related adverse events would be associated with therapy dose. Methods: This study was a single-blind, multicenter, randomized control trial. Patients admitted to a stroke unit <24 hours of stroke randomized to standard care (SC) or intervention, SC plus additional early out-of-bed therapy (VEM). Timing, amount, and type of therapy recorded throughout the trial. Adverse events were recorded to 3 months. Results: A total of 71 patients (SC n = 33, VEM n = 38) received 788 therapy sessions in the first 2 weeks of stroke. Schedule (hours to first mobilization, dose per day, frequency and session duration) and nature (percentage out-of-bed activity) of therapy differed significantly between groups (P ≤ .001 for all components). Mobilization was earlier, happened on average 3 times per day in those receiving VEM, with the proportion of out-of-bed activity double in VEM session (median SC 42.5%, VEM 85.5%). SC consisted of 17 minutes of occupational and physiotherapy per day and was the same between groups. Number of immobility-related adverse events 3 months poststroke was not associated with therapy dose or frequency. Conclusions: The authors detailed usual care and intervention therapy provided to patients from admission to 14 days after stroke. The therapy schedule was markedly different in the intervention arm, but whether this schedule reduces complications or improves outcome is unknown

Influence of damping on the excitation of the double giant resonance

We study the effect of the spreading widths on the excitation probabilities of the double giant dipole resonance. We solve the coupled-channels equations for the excitation of the giant dipole resonance and the double giant dipole resonance. Taking Pb+Pb collisions as example, we study the resulting effect on the excitation amplitudes, and cross sections as a function of the width of the states and of the bombarding energy.Comment: 8 pages, 3 figures, corrected typo