Broad snouted cladoselachian with sensory specialization at the base of modern chondrichthyans.

Unlabelled: Throughout the Silurian and Devonian, cartilaginous fish successively evolved their specialized skeletal and dental characteristics, and increasingly refined their sensory systems. The Late Devonian shark taxon gen. et sp.

Microwave-Assisted Fabrication of Mesoporous Silica-Calcium Phosphate Composites for Dental Application.

Herein, the microwave-assisted wet precipitation method was used to obtain materials consisting of mesoporous silica (SBA-15) and calcium orthophosphates (CaP). Composites were prepared through immersion of mesoporous silica in different calcification coating solutions and then exposed to microwave radiation. The composites were characterized in terms of molecular structure, crystallinity, morphology, chemical composition, and mineralization potential by Fourier-transform infrared spectroscopy (FTIR), powder X-ray diffraction (XRD), and scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy (SEM-EDX).

The early elasmobranch : phylogenetic relationships, ecomorphology and a new time-scale for shark evolution.

Anatomical knowledge of early chondrichthyans and estimates of their phylogeny are improving, but many taxa are still known only from microremains. The nearly cosmopolitan and regionally abundant Devonian genus has long been known solely from isolated teeth and fin spines. Here, we report the first skeletal remains of from the Famennian (Late Devonian) of the Maïder region of Morocco, revealing an anguilliform body, specialized braincase, hyoid arch, elongate jaws and rostrum, complementing its characteristic dentition and ctenacanth fin spines preceding both dorsal fins.

Thin-film filter, wavelength-locked, multi-laser cavity for dense wavelength beam combining of broad-area laser diode bars.

We report on individual wavelength locking of a multiplet of 100-μm broad-area laser diode emitters arranged on a 50% fill-factor bar by means of a single external multi-laser cavity using an ultra-narrowband thin-film filter as a dispersive optical element. The achieved wavelength-locked output power is 216 W, corresponding to an electrical-to-optical conversion efficiency of about 49.7%.

First shark from the Late Devonian (Frasnian) Gogo Formation, Western Australia sheds new light on the development of tessellated calcified cartilage.

Background: Living gnathostomes (jawed vertebrates) comprise two divisions, Chondrichthyes (cartilaginous fishes, including euchondrichthyans with prismatic calcified cartilage, and extinct stem chondrichthyans) and Osteichthyes (bony fishes including tetrapods). Most of the early chondrichthyan ('shark') record is based upon isolated teeth, spines, and scales, with the oldest articulated sharks that exhibit major diagnostic characters of the group--prismatic calcified cartilage and pelvic claspers in males--being from the latest Devonian, c. 360 Mya.

The effects of elevated carbon dioxide levels on a Vibrio sp. isolated from the deep-sea.

Introduction: The effect of oceanic CO2 sequestration was examined exposing a deep-sea bacterium identified as Vibrio alginolyticus (9NA) to elevated levels of carbon dioxide and monitoring its growth at 2,750 psi (1,846 m depth).

Findings: The wild-type strain of 9NA could not grow in acidified marine broth below a pH of 5. The pH of marine broth did not drop below this level until at least 20.

[Rieger's syndrome in a 12 year old girl].

The authors presented a case of Rieger syndrome with typical sings and symptoms. Genetic conditionings and differentiation, especially with Axenfeld syndrome, were shown. The therapeutic problems with secondary glaucoma and the applied methods of successful pharmacological and surgical treatment were described.

High resolution VUV spectroscopic facility at the SURF II electron storage ring.

Described in detail is a new high resolution spectroscopic facility which utilizes a 6.65-m off-plane Eagle spectrometer and synchrotron radiation from an electron storage ring light source. This facility has been constructed to provide a national capability for research in the atomic and molecular sciences which combines spectroscopic resolution in excess of 10(5) with a stable and calibrated VUV continuum light source.

Debris and VUV emission from a laser-produced plasma operated at 150 Hz using a krypton fluoride laser.

The output of a KrP laser (248 nm) operating at 150 Hz was focused onto metal targets to produce plasmas which emitted strongly in the VUV and XUV regions. Quantitative measurements of target debris produced in a laser-plasma light source show (1) that low pressures (~ 100 mTorr) of He buffer gas reduce the debris collected 150 mm from the target by more than an order of magnitude and (2) that the amount of debris collected rises faster than linearly with laser pulse energy in the 100-300-mJ range. This observed suppression of debris is explained in terms of a counterstreaming plasma mechanism.

Natural experiments and the educational context: the environment and effects of an alternative inner-city public school on adolescents.

The 1-year impact of attending a public alternative high school on two cohorts of adolescents who gained entrance to the school through a lottery was studied. Adolescents who had applied to the school but were not selected in the lottery served as a control group. The nature of the alternative high school environment is described, and the outcome of this natural experiment defined in terms of reactions to school, attitude change, and student achievement.

Primary prevention during school transitions: social support and environmental structure.

The nature and evaluation of a primary prevention project for students during the transition to high school are presented. In order to facilitate students' coping efforts during this transition, the project sought to increase the level of social support available as well as to reduce the degree of flux and complexity in the school setting. Midyear and end of ninth-grade assessments were done of Project and matched Control students' self-concepts.

Spectral-irradiance calibration of continuum emitted from rareearth plasmas.

The spectral irradiance of laser-produced plasmas of gadolinium and ytterbium have been determined in the 115-220-nm range for an incident 2.2-J, 30-nsec ruby-laser pulse. The effects of target geometry arnd variation of laser energy on the spectral irradiance were also studied.

Rare-earth plasma light source for VUV applications.

A compact versatile light source for producing VUV radiation from laser produced plasmas is described. Measurements of the spectral irradiance from CO(2) laser-produced plasmas on targets of gadolinium and ytterbium in the 115-220-nm range are given, and a comparison is made with analogous results obtained using a ruby laser.

Parental death or divorce and the school adjustment of young children.

This study examined the effects of two potentially crisis-producing experiences, parental divorce or death, on the school adjustment of young children. Children with such "crisis" histories were found to show greater overall school maladaptation than children without such histories. Children of divorce had significantly more acting-out problems than noncrisis controls or death children and those with histories of parental death more serious shy-anxious problems than the other groups.

Need for high resolution in VUV Rydberg state spectroscopy.

The necessity for high energy resolution (resolving powers > 100,000) in VUV spectroscopic determinations of atomic and molecular Rydberg electronic structures is emphasized. Examples include spectral observations of Rydberg levels in Ge I near the 4p(2)P( degrees )((1/2)) limit, in Sr I near the 4d(2)D(3/2) limit, and in the diatomic hydrogen halides (especially HI) below the X(2)II(3/2) limit.

High temperature furnace system for vacuum ultraviolet spectroscopic studies.

An improved furnace system for use in vacuum ultraviolet spectroscopic studies of atomic and molecular species stable at high temperatures (800-2500 degrees C) is described in detail. A new and improved high resolution spectrum of Mg I and several impurity spectra produced in the furnace are presented.