Time-Resolved Fuel Density Profiles of the Stagnation Phase of Indirect-Drive Inertial Confinement Implosions.

The implosion efficiency in inertial confinement fusion depends on the degree of stagnated fuel compression, density uniformity, sphericity, and minimum residual kinetic energy achieved. Compton scattering-mediated 50-200 keV x-ray radiographs of indirect-drive cryogenic implosions at the National Ignition Facility capture the dynamic evolution of the fuel as it goes through peak compression, revealing low-mode 3D nonuniformities and thicker fuel with lower peak density than simulated. By differencing two radiographs taken at different times during the same implosion, we also measure the residual kinetic energy not transferred to the hot spot and quantify its impact on the implosion performance.

First Observation of Cross-Beam Energy Transfer Mitigation for Direct-Drive Inertial Confinement Fusion Implosions Using Wavelength Detuning at the National Ignition Facility.

Cross-beam energy transfer (CBET) results from two-beam energy exchange via seeded stimulated Brillouin scattering, which detrimentally reduces ablation pressure and implosion velocity in direct-drive inertial confinement fusion. Mitigating CBET is demonstrated for the first time in inertial-confinement implosions at the National Ignition Facility by detuning the laser-source wavelengths (±2.3 Å UV) of the interacting beams. We show that, in polar direct-drive, wavelength detuning increases the equatorial region velocity experimentally by 16% and alters the in-flight shell morphology. These experimental observations are consistent with design predictions of radiation-hydrodynamic simulations that indicate a 10% increase in the average ablation pressure.

Order-of-magnitude increase in laser-target coupling at near-relativistic intensities using compound parabolic concentrators.

Achieving a high conversion efficiency into relativistic electrons is central to short-pulse laser application and fundamentally relies on creating interaction regions with intensities ≫10^{18}W/cm^{2}. Small focal length optics are typically employed to achieve this goal; however, this solution is impractical for large kJ-class systems that are constrained by facility geometry, debris concerns, and component costs. We fielded target-mounted compound parabolic concentrators to overcome these limitations and achieved nearly an order-of-magnitude increase to the conversion efficiency and more than tripled electron temperature compared to flat targets. Particle-in-cell simulations demonstrate that plasma confinement within the cone and formation of turbulent laser fields that develop from cone wall reflections are responsible for the improved laser-to-target coupling. These passive target components can be used to improve the coupling efficiency for all high-intensity short-pulse laser applications, particularly at large facilities with long focal length optics.

A dual high-energy radiography platform with 15 µm resolution at the National Ignition Facility.

To study matter at extreme densities and pressures, we need mega laser facilities such as the National Ignition Facility as well as creative methods to make observations during timescales of a billionth of a second. To facilitate this, we developed a platform and diagnostic to characterize a new point-projection radiography configuration using two micro-wires irradiated by a short pulse laser system that provides a large field of view with up to 3.6 ns separation between images. We used tungsten-carbide solid spheres as reference objects and inferred characteristics of the back-lighter source using a forward-fitting algorithm. The resolution of the system is inferred to be 15 µm (using 12.5 µm diameter wires). The bremsstrahlung temperature of the source is 70-300 keV, depending on laser energy and coupling efficiency. By adding the images recorded on multiple stacked image plates, the signal-to-noise of the system is nearly doubled. The imaging characterization technique described here can be adapted to most point-projection platforms where the resolution, spectral contrast, and signal-to-noise are important.

Production of relativistic electrons at subrelativistic laser intensities.

Relativistic electron temperatures were measured from kilojoule, subrelativistic laser-plasma interactions. Experiments show an order of magnitude higher temperatures than expected from a ponderomotive scaling, where temperatures of up to 2.2 MeV were generated using an intensity of 1×10^{18}W/cm^{2}. Two-dimensional particle-in-cell simulations suggest that electrons gain superponderomotive energies by stochastic acceleration as they sample a large area of rapidly changing laser phase. We demonstrate that such high temperatures are possible from subrelativistic intensities by using lasers with long pulse durations and large spatial scales.

Auriculocephalic index: a new anthropometric index for syndrome delineation.

We describe a new anthropometric index, the "auriculocephalic index." It results from the ratio between the length of auricle and the corresponding preauricular head height. The index is independent of sex and of age. Normally it ranges between 0.25 (-2s) and 0.33 (+2s). In syndrome delineation it may help to diagnose more precisely large or small auricles as phenogenetic variants.

Informative morphogenetic and phenogenetic variants in children with cleft lip/cleft palate.

In 230 patients with nonsyndromic cleft lip/cleft palate (138 boys and 92 girls) and in 226 age related healthy children (137 boys and 89 girls) informative morphogenetic and phenogenetic variants (IMV and PHV, respectively) were investigated. There was no difference between the number of IMVs between both groups (chi 2 = 5.89; d.f. = 3; alpha > 0.70). This finding is in line with the hypothesis that facial cleft disorders occur during blastogenesis, whereas IMVs and PHVs are typical patterns of the embryo- and fetogenesis. The anthropometric findings are contradictory. In a few non-craniofacial phenogenetic variants significant differences were found between the patients and the healthy children. Intrinsic factors or secondary sequelae of the primary defect might additionally act in the morphological fine tuning of children with single cleft lip/cleft palate.

Delayed spontaneous pubertal growth spurt in girls with the Ullrich-Turner syndrome.

By means of an appropriate mathematical model (Sager's 2-components-concept) a delayed spontaneous pubertal growth spurt can be demonstrated in girls with 45,X Ullrich-Turner syndrome (UTS) (n1 = 45) as well as in those with 45,X/46,XX mosaicism (n2 = 14) never treated with any growth stimulating drug. On the average, this growth spurt begins later and its extent is smaller (mean growth rate = 3.10 and 2.79 cm, respectively, in the 15th year of chronological age) than in normal girls. The delay in acute growth spurt corresponds very well to the delay of skeletal maturation in the UTS (on the average 2 to 3 years of chronological age).

Greig syndrome in a large kindred due to reciprocal chromosome translocation t(6;7)(q27;p13).

We report on cases of Greig syndrome segregating in a large kindred over four generations due to reciprocal translocation t(6;7)(q27;p13) and on a patient from this pedigree with a severe malformation syndrome due to duplication 7(p13----pter). The clinical findings are discussed as possible consequence of a gene mutation due to the break at 7p13.

[Clinical evaluation of testicular size in boys and adolescents]. / Zur klinischen Beurteilung der Hodengrösse bei Knaben und Jugendlichen.

On 596 healthy boys and adolescents from 4 to 17 years of age measurements of the length and the width of the left testis as well as of the thickness of scrotal skin were carried out by means of a caliper, and the testis volume was secondarily calculated. Age specific mean values (means) and their +/- 2 s-limits are listed. Nonlinear s-shaped regression lines of the three main parameters clearly underline that the greatest increase is to be found in the length of testis. Consequently, as an indicator for gonadal developmental disturbances instead of testis volume measuring of testis length is recommended for routine in the physical examination of inpatients and outpatients as well as for the screening of schoolboys and male teenagers.

[Clinical assessment of ear size in children and adolescents]. / Zur klinischen Beurteilung der Ohrgrösse bei Kindern und Jugendlichen.

In 1271 children and adolescents of both sexes (596 boys and 675 girls) anthropometric measurements of the "physiognomic external ear length and ear width" were carried out by means of a caliper in order to make the clinical symptoms of macrotia and microtia, respectively, more objective than by clinical impression, only. In the mean ear lengths steadily and annually grow 0.66 mm in boys and 0.46 mm in girls, +/- 2s-border-lines based on a nonlinear regression model y = f(means +/- 2s) = a + b.ln x are calculated: For boys it is y + 2s = 47,9164 + 6,9539.ln x and y-2s = 36,7839 + 6,1172.ln x, respectively, for girls the regression equations are as follows: y + 2s = 49,1431 + 5,6002.ln x and y-2s = 41,3945 + 3,2266.ln x. The approximation of the regression model to the data observed is highly significant (alpha less than 0.0005). In contrast to the auricle length "physiognomic external ear width" is independent of age in both sexes, namely in boys means = 32.89 +/- 0.1176 mm and in girls means = 31.21 +/- 0.0876 mm. All sex differences are highly significant (alpha less than 0.0005).

[The intermamillary index of newborn infants]. / Der Intermamillarindex bei Neugeborenen.

Using 500 healthy newly born babies age specific standard for intermamillary index was defined in order to improve objective criteria for the clinical features of 'widely spaced nipples' as it is to realize in connection with a variety of complex morphogenetic disturbances. Independent of sex and of post natalage the mean value is y mean = 23.31 and the standard deviation s = +/- 1.24. Consequently, the normal +/- 2s range is to be appraised between 21.0 and 26.0. In small-for-gestational-age infants and in babies born by breech presentation the + 2s limit is reduced to 25.0.

[Postnatal primary therapy of Morbus haemolyticus neonatorum in prematurely born infants, following intra-uterine foetal transfusion (author's transl)]. / Postnatale Primärtherapie Frühgeborener nach intrauteriner fetaler Transfusion bei schwerem Morbus haemolyticus neonatorum.

Intra-uterine foetal transfusion was applied in 63 instances to 44 patients with severe Rh incompatibility in the authors' hospital, between 1967 and 1976. Eighteen of 29 live-born children survived the neonatal period (41 per cent). - Nineteen live-born children with most severe M. h. n. received substitutions of O (d)-erythrocytes, immediately after birth. Ten children with moderate M. h. n. received exchange transfusions in a premature-birth ward not until four hours on average had elapsed from birth. - Comparison between the two groups would provide little consistent information on the effectiveness of such primary therapy, because of difference in severity. - The conclusion drawn by the authors is that the rare cases of severe M. h. n. should be transferred for treatment to a national therapeutic centre where adequate personnel and equipment are available for optimum intra-uterine or early postnatal treatment.

Sexual maturation in East German girls.

According to the internationally accepted classification (Tanner, 1962; van Wieringen, 1971), sexual maturation was investigated in 8703 healthy East German girls by means of the status quo method and probit regression analysis. The third, 50th and 97th centiles were calculated for the development of breasts, axillary and pubic hair, and the shape of the hips. The findings were compared with those of recent studies from different European countries. Special attention was paid to the stages at the beginning and at the end of sexual maturation, e.g. B2/B5, AH2/AH3, etc.

Robustness of spatial-coherence multiplexing under receiver misalignment.

It has been shown previously that the spatial coherence of a source can be modulated and demodulated; hence it can be used as the basis for a new dimension of multiplexing in high-speed optical communication links. We address the sensitivity of such a system to misalignments of the receiver with respect to the beam and examine how changing transverse modes affect the spatial coherence in the lateral direction. Specifically, we show that such a system is surprisingly robust for both lateral offsets, in which the receiver is not properly aligned on the beam center, and rotational offsets, in which the receiver is tilted with respect to the plane of the spatial coherence modulation. The presence of higher-order transverse modes or changes in the transverse-mode structure are also shown to have little effect on the system operation.

Spatial-coherence modulation for optical interconnections.

The spatial coherence of a laser beam depends on the number and the relative weights of the spatial modes supported by the laser waveguide. By electro-optic modulation of the cavity geometry, the spatial-coherence function can be modulated between zero and one at predictable locations across the beam and thus carry information. A simple integrated-optic interferometer is used to decode the signal. Spatial coherence can be modulated independently of the beam intensity and can be used as another level of multiplexing in addition to amplitude modulation, wavelength-division modulation, etc. One can implement a free-space optical interconnection scheme by carrying data on the intensity and address information on the spatial coherence.