Polybrominated diphenyl ether (PBDE) concentrations and resulting exposure in homes in California: relationships among passive air, surface wipe and dust concentrations, and temporal variability.

Polybrominated diphenyl ethers (PBDEs) are used as flame retardants in furniture foam, electronics, and other home furnishings. A field study was conducted that enrolled 139 households from California, which has had more stringent flame retardant requirements than other countries and areas. The study collected passive air, floor and indoor window surface wipes, and dust samples (investigator collected using an HVS3 and vacuum cleaner) in each home. PentaBDE and BDE209 were detected in the majority of the dust samples and many floor wipe samples, but the detection in air and window wipe samples was relatively low. Concentrations of each PBDE congener in different indoor environmental media were moderately correlated, with correlation coefficients ranging between 0.42 and 0.68. Correlation coefficients with blood levels were up to 0.65 and varied between environmental media and age group. Both investigator-collected dust and floor wipes were correlated with serum levels for a wide range of congeners. These two sample types also had a relatively high fraction of samples with adequate mass for reliable quantification. In 42 homes, PBDE levels measured in the same environmental media in the same home 1 year apart were statistically correlated (correlation coefficients: 0.57-0.90), with the exception of BDE209 which was not well correlated longitudinally.

Superparallel holographic correlator for ultrafast database searches.

We describe a superparallel holographic optical correlator that performs two-dimensional spatial and angular multiplexing simultaneously. The key step in this architecture is the use of a holographic multiplexer to split a query image into many copies before it applies them to the holographic database. A holographic demultiplexer, in conjunction with an aperture, is used to identify the location and the angle of the brightest correlation peak. This architecture uses only O(square root of N) detector elements to search through N unsorted images in a single query. We demonstrate the basic features of this architecture, using three spatial locations with eight angle-multiplexed images in each location.

Secondary organic aerosol formation from the irradiation of simulated automobile exhaust.

A laboratory study was conducted to evaluate the potential for secondary organic aerosol formation from emissions from automotive exhaust. The goal was to determine to what extent photochemical oxidation products of these hydrocarbons contribute to secondary organic aerosol (SOA) and how well their formation is described by recently developed models for SOA formation. The quality of a surrogate was tested by comparing its reactivity with that from irradiations of authentic automobile exhaust. Experiments for secondary particle formation using the surrogate were conducted in a fixed volume reactor operated in a dynamic mode. The mass concentration of the aerosol was determined from measurements of organic carbon collected on quartz filters and was corrected for the presence of hydrogen, nitrogen, and oxygen atoms in the organic species. A functional group analysis of the aerosol made by Fourier transform infrared (FTIR) spectroscopy indicated

Seasonal changes in energy and water use by verdins, Auriparus flaviceps.

We used the doubly labeled water (DLW) method to measure field metabolic rate (FMR) and water turnover during winter and summer in a very small (6.5 g) insectivorous desert passerine bird, the verdin (Auriparus flaviceps). Concurrently, we monitored weather conditions and used time-activity budget data of free-living birds and laboratory data on resting metabolic rate to construct time-activity laboratory (TAL) estimates of daily energy expenditure (DEE ) and to partition the verdins' energy budget into thermoregulatory, activity and basal components. The FMR of adult verdins was 33.6+/-0.9 kJ day(-)(1) (mean +/- s.e.m.; N=14) in winter and 22.8+/-0.45 kJ day(-)(1) (N=7) in summer. FMR correlated negatively with the mean standard operative environmental temperature (T(es)) prevailing during the measurement period. TAL analysis produced DEE estimates that corresponded on average to within -0.9+/-2.4 % of our DLW-measured FMR values (range of individual values -18.3 % to +14.3 %). Metabolic expeditures for cold defense were 19.5+/-2.1 % of DEE in winter (computed assuming substitution of exercise thermogenesis for thermoregulatory costs in active birds). In the summer, thermoregulatory costs amounted to 9.0+/-0.4 % of DEE for keeping warm and 1.0+/-0.1 % of DEE for keeping cool in the heat. Activity costs were 21.0+/-0.5 % of DEE in winter and 17.5+/-0.1 % of DEE in summer. The water efflux of nonbreeding adult verdins was 3.9+/-0.2 ml day(-)(1) (624+/-22 ml kg(-)(1 )day(-)(1)) in summer (N=5) and 3. 4+/-0.2 ml day(-)(1) (498+/-26 ml kg(-)(1 )day(-)(1)) in winter (N=14). The water economy index (WEI; water efflux per unit FMR) of verdins was higher in summer (0.17+/-0.01 ml kJ(-)(1)) than in winter (0.10+/-0.01 ml kJ(-)(1)) and correlated negatively with mean T(es).

Thermoregulation in Antarctic fulmarine petrels.

We measured resting metabolic rates at air temperatures between ca. -5 and 30 degrees C in snow petrels (Pagodroma nivea), cape petrels (Daption capense), Antarctic petrels (Thalassoica antarctica), and Antarctic fulmars (Fulmarus glacialoides). We measured seven age classes for each species: adults, and nestlings that were 3, 8, 15, 28, 35, and 42 days old. Basal metabolic rate (BMR) and thermal conductance (C) of adults averaged, respectively, 140% and 100% of values predicted allometrically for nonpasserine birds. Minimum metabolic rates of unfasted nestlings aged 15-42 days averaged, respectively, 97% and 98% of predicted adult BMR in Antarctic petrels and snow petrels, versus 119% and 126% of predicted in Antarctic fulmars and cape petrels. Nestlings of the southerly breeding snow petrel and Antarctic petrel were relatively well insulated compared with nestlings of other high-latitude seabirds. Adult lower critical temperature (T1c) was inversely related to body mass and averaged 9 degrees C lower than predicted allometrically. As nestlings grew, their T1c decreased with increasing body mass from ca. 14 to 22 degrees C (depending upon species) at 3 days of age, to -4 to 8 degrees C when nestlings attained peak mass. Nestling T1c subsequently increased as body mass decreased during pre-fledging weight recession. Nestling T1c was close to mean air temperature from the end of brooding until fledging in the three surface nesting species.

Cocaine use in women from a defined population: prevalence at delivery and effects on growth in infants.

Adverse health effects associated with intrauterine cocaine exposure (prematurity and its associated morbidity, intrauterine growth retardation, possible risk of sudden infant death syndrome) are based on studies from large urban hospitals, but few data exist from other sources. The current study, set in a community hospital, was designed to (1) estimate the prevalence of maternal cocaine use at delivery, (2) describe neonatal outcomes, and (3) evaluate physiological growth in exposed children. The study was conducted over 30 months (total births were 14,074) at The Children's Hospital of Greenville Memorial Hospital, the major source of neonatal care for Greenville County, South Carolina (1990 population: 320,000). A child was considered exposed to cocaine if there was documented evidence of use in the mother's medical record or if one member of the pair had a positive urine drug screen. Growth data were abstracted from clinical records. Overall prevalence of exposure was 1.0%. Of the 137 subjects (89, positive urine drug screen; 48 self-reported exposure), 21 (15%, 95% confidence interval, 9% to 21%) were premature (gestational age < 37 weeks) and 2 died of sudden infant death syndrome. Mean age- and sex-adjusted percentiles for weight, length, and head circumference increased from 23%, 29%, and 18%, respectively, at birth to 43%, 49%, and 54% in children followed for 12 months; however, 50% of the cohort were lost to follow-up, and these children were smaller at birth than those under active follow-up. Rates of prematurity and infant death were similar to those reported in urban hospitals.(ABSTRACT TRUNCATED AT 250 WORDS)

Validation of single-sample doubly labeled water method.

We have experimentally validated a single-sample variant of the doubly labeled water method for measuring metabolic rate and water turnover in a very small passerine bird, the verdin (Auriparus flaviceps). We measured CO2 production using the Haldane gravimetric technique and compared these values with estimates derived from isotopic data. Doubly labeled water results based on the one-sample calculations differed from Haldane values by less than 0.5% on average (range -8.3 to 11.2%, n = 9). Water flux computed by the single-sample method differed by -1.5% on average from results for the same birds based on the standard, two-sample technique (range -13.7 to 2.0%, n = 9).

Effects of heat stress on day-old broiler chicks.

Short-term heat stress can occur when chicks are transported from the hatchery to growing facilities. Two experiments were conducted to determine the possible effects of short-term heat stress on growth and feed conversion of broiler (Hubbard X Hubbard) chicks. The heat stress was accomplished by placing chicks in Jamesway 252 incubators at dry bulb temperatures ranging from 40 to 45 C for variable times. Growth, feed consumption, and mortality were measured for 16 days following the heat stress. Short sublethal heat stress significantly reduced growth rate to 16 days in these experiments without any effect on feed conversion ratio. The results indicate that the hatchery industry should avoid overheating chicks even for periods as short as 1 hr.

Thermally induced peripheral blood flow changes in chickens.

Changes in wattle blood flow (Q) and vascular resistance (R) were examined during both local heating of the wattle and/or general body heating of unanesthetized, male White Leghorn chickens. Q increased and R decreased during both local and general heating. Termination of heating reversed the response. Beta stimulation with isoproterenol markedly reduced R and increased Q in normothermic birds, suggesting the presence of beta receptors in the wattle vasculature. Alpha blockade with phenoxybenzamine also resulted in pronounced vasodilatation, suggesting tonic alpha-sympathetic tone in the wattle vasculature under normothermic conditions. Neither cholinergic blockade with atropine sulfate nor beta-adrenergic blockade with propranolol altered the vascular response to general heating when administered near its peak. Release of alpha-sympathetic tone is believed to subserve the response to general heating.

Hemodynamics of the lesser mouse deer, Tragulus javanicus.

Mouse deer possess the smallest known erythrocytes. In contrast to the usual biconcave shape, mouse deer corpuscles are spherical which results in an appreciable increase in vitro blood viscosity. In the absence of compensation, increased viscosity should produce hemodynamic consequences. However, we find that cardiac output, arterial pressure, and total peripheral resistance are all within normal limits, while packed cell volume is considerably lower than normal. We suggest that reduced packed cell volume represents a compensation for the spherical shape of the corpuscles, serving to maintain blood viscosity and dependent hemodynamic parameters within normal limits. These results contrast markedly with the pattern observed in man where conditions which result in a high in vitro blood viscosity also have significant hemodynamic consequences. Mean values for three mouse deer were: body mass, 1.18 kg; packed cell volume, 29.8%; heart rate, 182 beats/min; cardiac output, 145 ml-(kg-min)-1., mean arterial pressure, 99 Torr; total peripheral resistance, 4.90 X 10(5) dyn-s-cm-5.

Hematology, viscosity, and respiratory functions of whole blood of the lesser mouse deer, Tragulus javanicus.

Blood samples from the lesser mouse deer were examined for hematology, viscosity, oxygen dissociation curve, and magnitude of the Bohr effect. Red corpuscle dimensions, determined under oil immersion with an ocular micrometer, averaged 2.2 micron while the cell counts averaged 53 million/micronl blood, and the packed cell volume averaged 31.2%. Blood hemoglobin concentration averaged 11.2 g/100 ml and the calculated mean cell hemoglobin concentration was 38 g/100 ml. The relative viscosity of the mouse deer plasma was 1.97 and increased in a nonlinear manner with hematocrit to 100 at 80% packed cell volume. Oxygen-hemoglobin equilibrium curves, determined with a mixing technique at 37 degrees C and 10, 36 and 71 Torr PCO2, have the same configuration observed in blood from mammals in general. The P50 of the mouse deer blood at pH = 7.40 is 34 Torr and the Bohr effect (deltalog P50/deltapH) is -0.483. The mouse deer have blood hematocrits which are well below the hematocrits observed in mammals with larger erythrocytes, but similar to the blood hematocrits observed in other mammals with small erythrocytes. We suggest that the low hematocrit is an adaptation which circumvents the hemodynamic problems associated with a high blood viscosity and that, in the mouse deer, the expected concomitantly low total blood hemoglobin concentration is compensated by a higher than average mean cell hemoglobin concentration.

Contribution of gular flutter to evaporative cooling in Japanese quail.

Oxygen consumption, body temperature (Tb), and evaporative water loss (mwe) were determined in intact Japanese quail (Coturnix coturnix), and in quail in which the hyoid musculature responsible for gular flutter had been surgically transected several days prior to study. Abolishing gular flutter reduced total mwe by an average of 20% at air temperatures (Ta) above 40 degrees C. Treated birds developed a significantly greater degree of hyperthermia during acute heat stress than the controls and, unlike the controls, were unable to maintain Tb less than Ta above 40 degrees C. These data demonstrate that gular flutter represents a significant cooling mechanism in heat-stressed quail.