[1] The particle size distribution (PSD) plays a central role in understanding many facets of the aquatic ecosystem, yet it is rarely measured in field studies and no single method provides a complete description of the PSD. In this study, size distributions of diverse particle suspensions were measured using a laser diffractometer (LISST-100X), an electrical impedance particle sizer (Coulter Counter), and a particle imaging system (FlowCAM). All three instruments provided similar estimates of average particle size for suspensions of known standards. For broad polydisperse assemblages of particles a generally good agreement was found between the LISST and Coulter over a large portion of the size spectrum (from ∼1-3 mm to 50 mm), with the exception of suspensions exhibiting narrow features which were not accurately resolved with the LISST measurement. For featureless PSDs, however, the LISST provides an adequate proxy and has the capability for in situ measurements with high spatial and temporal resolution. We examined LISST field measurements from coastal regions within the context of a commonly used parameterization of the PSD. Analysis of nearly 5500 size distributions suggest that the average slope of the power law distribution for particles larger than 3 mm is −3.5. However, in many coastal waters this model provides a poor description of the PSD owing to the presence of significant peaks in the distribution. The combination of these data with Mie scattering calculations suggest that such departures from the idealized PSD can significantly impact the prediction of seawater optical properties.

[1] We examined optical variability of seawater in relation to particle concentration, composition, and size distribution in the nearshore marine environment at Imperial Beach, California, over a period of 1.5 years. Measurements included the hyperspectral inherent optical properties (IOPs) of seawater (particulate beam attenuation, particulate and CDOM absorption coefficients within the spectral range 300-850 nm), particle size distribution (PSD) within the diameter range 2-60 mm, and the mass concentrations of suspended particulate matter (SPM), particulate organic carbon (POC), and chlorophyll a (Chl). The particulate assemblage spanned a wide range of concentrations and composition, from the dominance of mineral particles (POC/SPM < 0.06) with relatively steep PSDs to the high significance or dominance of organic particles (POC/SPM > 0.25) with considerably greater contribution of larger-sized particles. Large variability in the particulate characteristics produced correspondingly large variability in the IOPs; up to 100-fold variation in particulate absorption and scattering coefficients and several-fold variation in the SPM-specific and POC-specific coefficients. Analysis of these data demonstrates that knowledge of general characteristics about the particulate composition and size distribution leads to improved interpretations of the observed optical variability. We illustrate a multistep empirical approach for estimating proxies of particle concentration (SPM and POC), composition (POC/SPM), and size distribution (median diameter) from the measured IOPs in a complex coastal environment. The initial step provides information about a proxy for particle composition; other particulate characteristics are subsequently derived from relationships specific to different categories of particulate composition. Cieplak (2010), Optical variability of seawater in relation to particle concentration, composition, and size distribution in the nearshore marine environment at

Objective To review antenatal and intrapartum assessment of pregnancies complicated by gastroschisis. Design Retrospective descriptive study. Setting University College Hospital, London. Subjects 24 consecutive cases of gastroschisis between 1986 and 1991. Results The gestational age at sonographic diagnosis was 20.3 weeks (SD 6.77) and at birth was 36.5 weeks (SD 2.06). There were 21 live births, all with good surgical outcome. There were 16 vaginal deliveries and eight caesarean sections. The elective sections were for oligohydramnios and dilated bowel (1) and clinically suspected growth retardation (1); the intrapartum caesarean sections were for fetal distress (4) and premature breech presentation (2). There were six with dilated gut on ultrasound; one of these ended in a stillbirth. There was a significant association between gut dilatation and caesarean section for fetal distress (P= 0.004). There was also a significant association between meconium staining and fetal distress (P= 0.021). Of these babies, 46% were ≤ third centile for corrected birth weight. Conclusions While half of the babies with gastroschisis were small for gestational age at birth, reliable antenatal prediction of birth weight is difficult. Gut dilatation may be an indicator of either antenatal or intrapartum fetal distress, but does not correlate with poor neonatal surgical outcome. We suggest close antenatal surveillance of fetal wellbeing in all cases of gastroschisis because, in addition to growth retardation, many show some evidence of fetal distress and 12.5% end in stillbirth, even when appropriately grown.

SUMMARY The importance of expectations has been assessed by giving 88 patients who had undergone total hip replacement surgery a series of visual analogue scales to provide a pain score, a 5-point rating scale to assess their remembered expectations, and an interview to establish clinical, functional, social, and psychological data. Patients generally had high expectations, but only 55 % had their expectations fulfilled. Despite this, 86% claimed the operation to be successful, though when questioned more closely patients noted a certain amount of displeasure about the outcome. Further analysis revealed that, when the sample was split into 2 groups of fulfilled and unfulfilled expectations, significant differences were noted in that the quality of life enjoyed by the former group was greater than that enjoyed by the latter group. This finding suggests that the notion of 'success' is not as effective as the notion of 'expectations' as a measure of the outcome of total hip replacement surgery.