Magnetic support of the optical emission line filaments in NGC 1275.

The giant elliptical galaxy NGC 1275, at the centre of the Perseus cluster, is surrounded by a well-known giant nebulosity of emission-line filaments, which are plausibly in excess of 10(8) years old. The filaments are dragged out from the centre of the galaxy by radio-emitting 'bubbles' rising buoyantly in the hot intracluster gas, before later falling back. They act as markers of the feedback process by which energy is transferred from the central massive black hole to the surrounding gas. The mechanism by which the filaments are stabilized against tidal shear and dissipation into the surrounding extremely hot (4 x 10(7) K) gas has been unclear. Here we report observations that resolve thread-like structures in the filaments. Some threads extend over 6 kpc, yet are only 70 pc wide. We conclude that magnetic fields in the threads, in pressure balance with the surrounding gas, stabilize the filaments, so allowing a large mass of cold gas to accumulate and delay star formation.

Antenatal diagnosis of fetal cardiac abnormalities.

Utilizing fetal electrocardiography, ultrasound, M-mode and two dimensional echocardiography, fetal cardiac function, structure, and rhythm were studied in pregnancies with obstetrical risk factors. Risk factors for fetal cardiac abnormalities were defined to include: maternal diabetes, connective tissue disorders; Rh hemolytic disease; fetal cardiac arrhythmias, ascites of hydrops; intrauterine growth retardation; maternal drug or teratogen exposure and a family history of congenital heart disease. Representative cases are presented and include fetal findings, management and neonatal outcome.

Serum copper concentrations in sick and well preterm infants.

In order to define the range of serum copper concentrations in preterm infants and to determine the effect of growth upon these values, serial serum copper concentrations were measured in 26 preterm infants over their first six weeks of life. Fourteen healthy, growing preterm infants (Group I) had mean serum copper concentrations below 32 microgram/dl throughout the study. Clinical and hematologic signs of copper deficiency which responded promptly to the oral administration of copper sulfate were noted in five of these 14 infants. Twelve ill preterm infants (Group II-A), who received parenteral nutrition without supplemental copper and had slow rates of growth, had mean serum copper concentrations above 50 micrograms/dl after the first week of life. Seven surviving from Group II-A (Group II-B) had a decrease in mean serum copper concentrations to values similar to those in Group I after two weeks of oral feedings and resumption of normal growth. Our findings suggest that preterm infants who have normal growth while receiving oral feedings are at significant risk for developing copper deficiency.

Anatomy and histology of the alimentary tract of the desert millipede Orthoporus ornatus (Girard) (Diplopoda: Spirostreptidae).

The alimentary tract of the desert millipede Orthoporus ornatus is essentially a straight tube consisting of a histologically distinct foregut, midgut, pylorus, hindgut, and rectum. Common to each region, but often different in regional appearance, are an outer sheath layer, longitudinal and circular muscle layers, a basement membrane, and an inner epithelial layer. Foregut and midgut lumina are lined by a cuticular intima, while a peritrophic membrane occurs in the midgut lumen. Gut structure is considered in the context of the known feeding habits and digestive efficiency of this long-lived, seasonally restricted detritivore.

Feeding-season production in the desert millipede Orthoporus ornatus (Girard) (Diplopoda).

Production during an assumed 131-day feeding season in 1974 was estimated for Orthoporus ornatus between 4.0 and 12.0 mm in midsegment width at Tornillo Flat, Big Bend National Park, Texas.A conservative density estimate in 1973 of 1,302 millipedes ha-1 involved daily specimen removal from three, 929-m2 plots for a month. Each plot typified a different aspect of local desert vegetation; most specimens came from the plot with greatest plant diversity and relatively high (20%) cover.Production calculations using 1973 density estimates were based on increase in size-class specific dry weight (minus gut contents) between 14 May and 21 September, 1974. Production ha-1 of cuticle and tissue was estimated at 0.85 kg (1972 kcal), while that of tissue alone came to 0.29 kg (1971 kcal). Orthoporus ornatus from Albuquerque, New Mexico increased in dry weight during 92 days in 1974 more rapidly and to a greater extent than comparable size classes at Tornillo Flat.An estimated feeding-season energy budget based on ash-free values of shrub food eaten at Tornillo Flat indicated ingestion ha-1 of 3,434 g (13,712 kcal) and defecation of 3,181 g (9,187 kcal). An independent estimate of ingestion based on known ingestion rates was 8,851 g ha-1.Considering probable net primary production at Tornillo Flat, local O. ornatus exert a trophic impact similar to that of other large invertebrate detritivores elsewhere.

Food, ingestion rates, and assimilation in the desert millipede Orthoporus ornatus (Girard) (Diplopoda).

Orthoporus ornatus feeds mostly on dead plant material and on superficia tissue of desert shrubs. Sand, small particles of rock, and parts of arthropods are also ingested. Millipedes could not be induced to feed in the absence of moist soil in the laboratory after an initial day of feeding.Field observations of apparent food preferences were made at several sites in the southwestern U.S. Millipedes at Big Bend National Park, Texas, fed regularly on bark of the following desert shrubs: cholla (Opuntia sp.), cresotebush (Larrea divaricata), and ocotillo (Fouqueria splendens). Millipedes on the West Mesa of Albuquerque, New Mexico, fed mostly on superficial tissues of dead Russian-thistle (Salsola kali). At the Jornada Validation Site, Dona Ana County, New Mexico, millipedes fed regularly on the bark of Mormon tea (two Ephedra spp.) and mesquite (Prosopis glandulosa). Otherwise, grazing on an assortment of surface litter was commonly observed.Ingestion rates and assimilation efficiencies were determined in the laboratory for millipedes feeding on Prosopis and Ephedra using an ash-free technique. Assimilation efficiencies and ingestion rates were temperature dependent, increasing with a rise in temperature. Ingestion rates for Ephedra ranged from 0.020 to 0.050 g ash-free dry wt per g dry wt tissue per day, with assimilation efficiencies ranging from 20-37%. Ingestion rates were lower for Prosopis than for Ephedra.Feeding experiments at 24° C were considered to depict feeding characteristics found in surface millipedes under field conditions. These millipedes ingested 0.034 g ash-free dry weight of Ephedra per g dry body weight per day with 31.4% of the food being assimilated.No significant differences occurred between assimilation efficiencies calculated by ash-free techniques and by using caloric values of food and feces.

Respiratory metabolism of the desert millipede Orthoporus ornatus (Girard) (Diplopoda).

Respiratory metabolism was measured each month for Orthoporus ornatus throughout a year. Respiratory rates were determined at a standard 20°C and at the mean ambient soil temperature at time of collection.No significant differences were noted between respiratory rates of reproductively mature males and females. A size relationship between live body weight and oxygen consumption per unit weight was found. The b values for 20°C and 25°C were-0.28 and-0.24, respectively. Premolt specimens had lower respiratory rates than postmolt individuals. There were significant differences between Q 10 values of animals exposed to temperatures above and below ambient field conditions.Seasonal changes in the use of metabolic reserves by O. ornatus were indicated by corresponding changes in RQ values.A "best estimate" of annual respiratory metabolism was 1332 cal g-1yr-1. Respiratory metabolism closely paralleled changes in ambient field temperature and was at its peak in July when animals were on the soil surface.