A Boundary-Local Mass Cocycle and the Mass of Asymptotically Hyperbolic Manifolds.

We construct a cocycle that, for a given n-manifold, maps a pair of asymptotically locally hyperbolic (ALH) metrics to a tractor-valued ( n - 1 ) -form field on the conformal infinity. This requires the metrics to be asymptotically related to a given order that depends on the dimension. It then provides a local geometric quantity on the boundary that is naturally associated to the pair and can be interpreted as a relative energy-momentum density. It is distinguished as a geometric object by its property of being invariant under suitable diffeomorphisms fixing the boundary, and that act on (either) one of the argument metrics. Specialising to the case of an ALH metric h that is suitably asymptotically related to a locally hyperbolic conformally compact metric, we show that the cocycle determines an absolute invariant c(h), which still is local in nature. This tractor-valued ( n - 1 ) -form field on the conformal infinity is canonically associated to h (i.e. is not dependent on other choices) and is equivariant under the appropriate diffeomorphisms. Finally specialising further to the case that the boundary is a sphere and that a metric h is asymptotically related to a hyperbolic metric on the interior, we show that the invariant c(h) can be integrated over the boundary. The result pairs with solutions of the KID (Killing initial data) equation to recover the known description of hyperbolic mass integrals of Wang, and Chrusciel-Herzlich.

Stress and Geometry for Isotropic Singularities.

We develop the mathematics needed to treat the interaction of geometry and stress at any isotropic spacetime singularity. This enables us to handle the Einstein equations at the initial singularity and characterize allowed general relativistic stress-energy tensors. Their leading behaviors are dictated by an initial hypersurface conformal embedding. We also show that an isotropic big bang determines a canonical nonsingular metric on and about the initial hypersurface as well as a cosmological time. This assigns a volume and energy to the initial point singularity.

Transient fetal hypertrichosis - Three cases.

We Summarize a three cases of transient fetal hypertrichosis in low risk preganant women. Hypertrichosis has been previously associated with over 140 different syndromes (OMIM); however this finding is rarely described in prenatal ultrasound. In this study we describe the finding of hypertrichosis which resolved later in gestation. CASE N1: A prominent unibrow (synophrys) and elongated eyelashes were noted at 24 weeks of gestation with no other abnormal features. CASE N 2: A prenatal ultrasound scan was performed at 24 weeks and revealed: horseshoe kidney and localized hypertrichosis on the lower back. CASE N 3: Ultrasound exam at 24 weeks of gestation demonstrated localized hypertrichosis on the chin. CONCLUSION: Transient localized hypertrichosis with no other major findings has a favorable prenatal outcome.

Broadband THz amplification and superradiant spontaneous emission in a guided FEL.

While significant progress has been made to fill the "THz gap", critical applications requiring powerful and energy efficient THz sources and amplifiers, from high frequency communications to medical and security imaging and nonlinear spectroscopy, continue to drive research on new methods of THz generation. Here we demonstrate a Free Electron Laser (FEL) THz source based on a novel interaction regime where broadband THz pulses can be phase and group velocity matched to the electron beam in a magnetic undulator via dispersion in a waveguide. Using < 10 pC, 6 MeV electron beams we show amplification of broadband THz pulses and demonstrate THz generation via both stimulated emission and spontaneous coherent superradiant emission, due to the short bunch length (< 200 fs rms) relative to resonant THz frequency (0.8 THz). A newly developed multifrequency simulation, designed to model the special case of guided FEL interaction, is benchmarked with the experiments and then used to extrapolate the capabilities of this "zero-slippage" FEL to efficient, tunable generation of > 100 µJ THz pulses when using higher (200 pC) beam charges and a tapered resonant condition.

Meter-Scale Terahertz-Driven Acceleration of a Relativistic Beam.

Terahertz (THz) radiation promises breakthrough advances in compact advanced accelerators due to the gigavolts-per-meter fields achievable, but the challenge of maintaining overlap and synchronism between beams and short laser-generated THz pulses has so far limited interactions to the few-millimeter scale. We implement a novel scheme for simultaneous group and phase velocity matching of nearly single-cycle THz radiation with a relativistic electron beam for meter-scale inverse free-electron laser interaction in a magnetic undulator, resulting in energy modulations of up to 150 keV using modest THz pulse energies (≤1 µJ). Using this scheme, we demonstrate for the first time the use of a laser-based THz source for bunch-length compression and time-stamping of a relativistic electron beam.

Diverse outcome following early prenatal diagnosis of pulmonary stenosis.

OBJECTIVE: To assess the natural history and outcome of fetal pulmonary stenosis (PS), particularly that detected at 14-17 weeks' gestation. METHODS: In this retrospective study we searched an electronic database of women from the general Israeli population attending a private ultrasound institute (Al-Kol ultrasound institute in Haifa) for routine complete early fetal ultrasound, including all fetal systems and a fetal echocardiogram, between 2004 and 2015. Ninety-seven percent of the women were at low risk of fetal malformations, and 3% had risk factors such as maternal Type-1 diabetes mellitus, exposure during pregnancy to teratogenic drugs, or anomalies in previous pregnancies or in other family members. At presentation at 14-17 weeks of gestation, color and pulsed Doppler imaging were performed across the four cardiac valves. We identified cases in which abnormal flow was detected, leading to suspicion of PS; in these cases, a follow-up examination was carried out at 17-19 weeks and then monthly until delivery or resolution of the finding, and postnatal echocardiography was performed at birth, 4-6 weeks thereafter, and yearly afterwards. Outcome data for suspicious cases, including postnatal diagnosis and general or specific symptoms, were collected by contacting the parents via email or telephone. RESULTS: Among 24 185 early prenatal transvaginal ultrasound screening examinations, 23 cases of suspected PS were identified. They were classified into three groups, according to their ultrasound findings. In Group A (n = 8), the ultrasound screen was normal except for high flow velocity across the pulmonary valve. In six cases, this finding had resolved by 20-21 weeks of gestation and all were found to be normal at postnatal follow-up, one case underwent termination of pregnancy at 19 weeks and PS was confirmed at autopsy and one case was lost to follow-up. In Group B (n = 12), there was aliasing across the pulmonary valve. Two of these cases were normal postnatally and eight had mild-to-moderate PS; the remaining two cases developed hypoplastic right ventricle and pulmonary atresia at 19-20 weeks and the pregnancies were terminated. In Group C (n = 3) PS was associated with other anomalies; all three pregnancies were terminated. There were an additional six cases (Group D) not identified in early gestation, in which PS was late-onset. One had tricuspid regurgitation at the early screen, but was subsequently diagnosed with Ebstein's anomaly and pulmonary atresia, at 22 weeks, and was terminated. The other cases had completely normal early ultrasound screening examinations: one case had Ebstein's anomaly and PS was diagnosed at birth; four had isolated mild PS, of which one was diagnosed at 22 weeks' gestation and the other three were diagnosed postnatally, before 3 months of age. The sensitivity for detection of the ascertained cases of PS was 64% (11/17) and the specificity was > 99%. CONCLUSION: There is a diverse spectrum of presentation of fetal PS in the early mid-trimester. A possible explanation for this could be different pathophysiological pathways. Further study is needed to explain the different prenatal sonographic presentations in an unselected population. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

High Efficiency Energy Extraction from a Relativistic Electron Beam in a Strongly Tapered Undulator.

We present results of an experiment where, using a 200 GW CO_{2} laser seed, a 65 MeV electron beam was decelerated down to 35 MeV in a 54-cm-long strongly tapered helical magnetic undulator, extracting over 30% of the initial electron beam energy to coherent radiation. These results, supported by simulations of the radiation field evolution, demonstrate unparalleled electro-optical conversion efficiencies for a relativistic beam in an undulator field and represent an important step in the development of high peak and average power coherent radiation sources.

Chest dynamics asymmetry facilitates earlier detection of pneumothorax.

Pneumothorax is usually diagnosed when signs of life-threatening tension pneumothorax develop. The case report describes novel data derived from miniature superficial sensors that continuously monitored the amplitude and symmetry of the chest wall tidal displacement (TDi) in a premature infant that suffered from pneumothorax. Off-line analysis of the TDi revealed slowly progressing asymmetric ventilation that could be detected 38 min before the diagnosis was made. The TDi provides novel and valuable information that can assist in early detection and decision making.

Prenatal and postnatal inflammation in relation to cortisol levels in preterm infants at 18 months corrected age.

OBJECTIVE: To examine whether early inflammation is related to cortisol levels at 18 months corrected age (CA) in children born very preterm. STUDY DESIGN: Infants born ≤ 32 weeks of gestational age were recruited in the neonatal intensive care unit (NICU), and placental histopathology, magnetic resonance imaging (MRI) and chart review were obtained. At 18 months CA, developmental assessment and collection of three salivary cortisol samples were carried out. Generalized least squares was used to analyze data from 85 infants providing 222 cortisol samples. RESULT: Infants exposed to chorioamnionitis with funisitis had a significantly different pattern of cortisol across the samples compared with infants with chorioamnionitis alone or no prenatal inflammation (F(4, 139)=7.3996, P<0.0001). Postnatal infections, necrotizing enterocolitis and chronic lung disease were not significantly associated with the cortisol pattern at 18 months CA. CONCLUSION: In children born very preterm, prenatal inflammatory stress may contribute to altered programming of the hypothalamic-pituitary-adrenal (HPA) axis.

Collective-interaction control and reduction of optical frequency shot noise in charged-particle beams.

We present a theoretical model for longitudinal collective Coulomb interactions in a charged-particle beam. It suggests a possibility to control and reduce optical frequency shot-noise current in accelerated electron beams. For short interaction lengths, the model describes well coherent optical transition radiation effects observed in SLAC LCLS and in other laboratories. For longer interaction lengths (quarter plasma oscillation period) the model predicts the possibility to reduce the beam current noise below the classical shot-noise level, an effect not yet observed experimentally at optical frequencies.

Helical electron-beam microbunching by harmonic coupling in a helical undulator.

Microbunching of a relativistic electron beam into a helix is examined analytically and in simulation. Helical microbunching is shown to occur naturally when an e beam interacts resonantly at the harmonics of the combined field of a helical magnetic undulator and an axisymmetric input laser beam. This type of interaction is proposed as a method to generate a strongly prebunched e beam for coherent emission of light with orbital angular momentum at virtually any wavelength. The results from the linear microbunching theory show excellent agreement with three-dimensional numerical simulations.

Superradiant spin-flip radiative emission of a spin-polarized free-electron beam.

Radiative emission from the magnetic moments of the spins of an electron beam has never been observed directly, because it is fundamentally much weaker than the electric charge emission. We show that the detectivity of spin-flip and combined spin-flip-cyclotron-resonance-emission radiation can be substantially enhanced by operating with ultrashort spin-polarized electron beam bunches under conditions of superradiant (coherent) emission. The proposed superradiant spin-flip radiative emission scheme can be used for noninvasive diagnostics of polarized electron or positron beams. Such beams are of relevance in important scattering experiments off nucleons in nuclear physics and off magnetic targets in condensed matter physics.

Photoperiodism: the consistent use of CONSTANS.

Photoperiodic induction of flowering in the long-day plant Arabidopsis is mediated by the circadian regulated CONSTANS gene. New evidence suggests that CONSTANS-like genes have a similar role in short-day induction of flowering of rice and Pharbitis.

Superradiant and stimulated superradiant emission in a prebunched beam free-electron maser.

An electron beam, prebunched at the synchronous free-electron laser frequency and passing through a magnetic undulator, emits coherent (superradiant) synchrotron undulator radiation at the bunching frequency. If an external electromagnetic wave is introduced into the interaction region, at the same frequency and at a proper phase, the radiation process will be stimulated (stimulated prebunched beam radiation). We report first experimental measurements of stimulated superradiant emission in a prebunched free-electron maser. Measurements are in good agreement with theory.

Perceived conditions of confinement: a national evaluation of juvenile boot camps and traditional facilities.

In a national study of juvenile correctional facilities, the perceived environment of 22 juvenile boot camps was compared to the perceived environment of 22 traditional facilities. Self-report surveys completed by 4,121 juveniles recorded information on demographics, risk factors, and perceptions of the facility's environment. Compared to juveniles in traditional correctional facilities, boot camp residents consistently perceived the environment as significantly more controlled, active, and structured, and as having less danger from other residents. Boot camp juveniles also perceived the environment as providing more therapeutic and transitional programming. Overall, from the perspective of the juveniles, boot camps appear to provide a more positive environment conducive to effective rehabilitation considering almost all of the conditions measured. A major concern is that in both types of facilities, juveniles perceived themselves to occasionally be in danger from staff (rated as rarely to sometimes).

Albuquerque Target Cities: preliminary findings.

Overall, there appeared to be a decline in frequency of use in the substance patterns of the 46 cases investigated for this analysis. The rising frequency with which prescription drugs are reported may be explained by the fact that these clients are in treatment, a situation which frequently necessitates the prescription of various medications. Additionally, the rise in methadone use can also be explained by the fact that it is prescribed to individuals who are undergoing treatment for a heroin addiction. Finally, it is probable that polysubstance use is underreported in the intake data, thus explaining the apparent increase reported at follow-up.