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Notes: The Maxwell–Garnett class of effective medium model applies if a representative cell can be found whose polarization vanishes upon insertion in the effective medium. For an anisotropic composite with randomly distributed ellipsoidal particles aligned along the principal axis, this leads to electrostatic restraints on the shape of such cells. It is shown that the cell boundary must have different depolarization factors to the inclusion within the cell. Practice is to equate them. A new physically correct ellipsometric modeling routine still with only two fitting parameters is demonstrated. © 1997 American Institute of Physics.

Notes: Objectives To establish the relation between fetal abdominal circumference and birthweight in a large population of fetuses; to identify whether the error in estimating birthweight by abdominal circumference varied with the magnitude of abdominal circumference; and to establish whether adding femur length to abdominal circumference caused a clinically important reduction of error in predicting birthweight.Design A retrospective study.Setting The ultrasound department of a teaching maternity hospital offering a tertiary referral service.Sample From 3512 nondiabetic women with a normally formed singleton fetus, an abdominal circumference measurement of the infant was made within seven days of delivery; of these, 1213 had a femur length measurement performed at the same time.Results There was a linear relation between abdominal circumference and birthweight. There was a strong inverse correlation between the proportional error in predicting birthweight from the abdominal circumference and the magnitude of the abdominal circumference. Both the Campbell and Wilkin equation (abdominal circumference alone) and the Hadlock equation (abdominal circumference and femur length) were associated with systematic errors, especially with larger birthweight infants. The median absolute errors for the two equations were not significantly different overall (6.98% and 6.86% respectively), although the Hadlock equation was significantly more accurate in predicting birthweight in infants weighing greater than 4500 g. However, no threshold value of abdominal circumference or of estimated fetal weight using the Hadlock equation had a positive predictive value in estimating infants of 〉 4500 g of greater than 35%.Conclusions Prediction of birthweight should be by abdominal circumference alone. 〈link href="#t1"〉Table 1 presents robust estimates of the error of predicting birthweight using fetal abdominal circumference.〈tabular xml:id="t1"〉1〈title type="main"〉 The relation between fetal abdominal circumference (AC) and birthweight (BW). 〈table colsep="0" rowsep="0" frame="topbot" pgwide="0" orient="port"〉〈tgroup cols="5" align="left"〉〈colspec colnum="1" colname="col1" align="left"/〉〈colspec colnum="2" colname="col2" align="center"/〉〈colspec colnum="3" colname="col3" align="center"/〉〈colspec colnum="4" colname="col4" align="center"/〉〈colspec colnum="5" colname="col5" align="center"/〉〈thead valign="bottom"〉〈row rowsep="1"〉AC (mm)nMedian BW(g)10th-90th centile BW (g)Range BW(g)〈tbody valign="top"〉200-20913900750-1030740-1040210-219201040830-1370780-1400220–229201060750-1410650-1460230-239281255980-1470900-1860240-2493614351200-17901080-1950250-2593715801290-19251180-2260260-2695618351490-21901340-2400270-2798920001640-23201390-2620280-28913422651920-26601530-2910290-29921925302130-29001820-3100300-30935026852340-30802010-3420310-31938728502470-32902110-3650320-32948430602700-34702350-3770330-33943932602880-37002570-3980340-34942333803040-38602670-4240350-35931436153240-40402890-4460360-36924537503330-11903020-4610370-37911738403480-43603180-4790380-3896641403660-46403470-4820390-3993542903665-46753640-5000

Notes: During their upstream migration through the lower reaches of the Aberdeenshire Dee, Scotland, radio-tagged adult Atlantic salmon passed a Crump weir-based fish counter without substantial delay over a range of river flows and water temperatures. Tagged salmon were detected sequentially by automatic listening stations placed along the river and were detected at the counter site for a median time of 18 min, compared with a median time of 5 min before the weir was built. One fish out of 16 spent 6·7 h in the vicinity of the weir, but such migratory pauses also occurred before the weir existed. The results suggest that the number of salmon crossing the counter per unit time is a function of the number of fish present downstream and their tendency to migrate upstream, without being limited by their ability to surmount the weir. The apparent slight delay at the weir is probably insignificant in terms of the overall progress of riverine migration and in the context of using counter records to relate salmon movements to environmental Variables.

Notes: The timing of salmon migration from the estuary of the Aberdeenshire Dee into the river in relation to tidal phase and time of day was studied by combined acoustic and radio-tracking of individual fish and by analysing records of untagged fish from a resistivity fish counter 0.8 km upstream from the tidal limit. Up-estuary movements that led to river entry were predominantly nocturnal and tended to occur during the ebb tide. Penetration into the non-tidal reaches of the river also tended to occur at night, but the timing of salmon movements was no longer significantly associated with tidal phase. The tracking data suggested that the reduction in the strength of the association between salmon migration and tidal phase resulted from variability in rates of progress from the estuary to the river. This variability may have been random, or related to changes in migratory behaviour during entry to fresh water. A simulation of upstream progress by groups of salmon illustrated the decay of the relationship between salmon movements and tidal phase and the advance of the average tidal phase of observed salmon movements with increasing distance of the observation point from where movements were initiated. The magnitude of these effects depended on the average rate of upstream progress and variability in the rate of progress, being greatest when upstream progress was slow and variable. These results highlight a limitation of point observations of migration with regard to identifying environmental stimuli for migration and quantifying their effects.

Notes: We report the case of a woman who had pain in both heels which was exacerbated by long periods of exercise. On examination, There were small flesh-coloured papules which appeared over the medial and lateral aspects of the heels only on weight bearing. Coincidentally. she was noted to have larger flesh-coloured papules over the anterior surface of the shins. The diagnoses of painful piezogenic pedal papules and bilateral tibialis anterior muscle herniation, respectively, were made. After many attempts to control the pain, a course of electro-acupuncture was commenced. A good subjective clinical response was achieved which has been maintained by fortnightly treatments. We discuss the prevalence, pathogenesis and treatment of painful piezogenic pedal papules. We believe that our patient is the first to have ‘herniations’ at both heel and shin sites and the first to have successful sustained pain relief for painful piezogenic pedal papules

Notes: Neutron reflectometry was used to investigate the density profiles of polymer brushes and an adsorbed polymer layer under shear. The brushes consisted of end-functionalized deuterated polystyrene. The adsorbed polymer was a random copolymer of deuterated styrene and 4-vinylpyridine. The brush and the adsorbed layer were sheared by the flowing of solvents over the polymer, with a maximum shear rate of 104s−1. Density profiles of the brush and the layer were determined before, during and after shear. The shear had no observable effect on the polymer profiles in any of the experiments. We discuss these results in the context of other experiments and a recent theory.

Notes: [Auszug] In sheep1-6 and goats7, polymorphisms of the PrP gene have been strongly associated with incidence of natural and experimental scrapie, the most common transmissible spongiform encephalopathy. However, it is still a matter of some debate whether natural scrapie is a genetic disease, arising from ...

Notes: The results from refinements with six different weighting schemes in PROFFT, SHELXL93 and X-PLOR show that experimental weights, and especially unit weights, tend to overweight the low-angle data at the expense of the higher resolution data. This suggests that the use of unit weights are inappropriate except during initial cycles of refinements. Two alternative weighting schemes, one-line and two-line empirical weights, are shown to produce a relatively even distribution of the weighted r.m.s. error [r.m.s. Err = (\sum w \Delta F {^2}/n) {^1} {^/} {^2})] as a function of sin θ/λ and result in linear δ(R) normal probability plots. Free R values and free weighted r.m.s. errors from the refinement of a scorpion toxin structure show that the alternative weighting schemes are superior to unit weights, and the r.m.s. deviations of bond distances and angles from the target values and G factors, as calculated by PROCHECK, confirm the superiority of the empirical weighting scheme. It was also observed that changing the value of WA, the contribution of the X-ray gradient to the total function minimized, produced little variation in R free but was directly proportional to the r.m.s. deviation of the bond distances from the target values.

Notes: The structure of toxin II from the scorpion Androctonus australis Hector has been determined ab initio by direct methods using SnB at 0.96 Å resolution. For the purpose of this structure redetermination, undertaken as a test of the minimal function and the SnB program, the identity and sequence of the protein was withheld from part of the research team. A single solution obtained from 1 619 random atom trials was clearly revealed by the bimodal distribution of the final value of the minimal function associated with each individual trial. Five peptide fragments were identified from a conservative analysis of the initial E-map, and following several refinement cycles with X-PLOR, a model was built of the complete structure. At the end of the X-PLOR refinement, the sequence was compared with the published sequence and 57 of the 64 residues had been correctly identified. Two errors in sequence resulted from side chains with similar size while the rest of the errors were a result of severe disorder or high thermal motion in the side chains. Given the amino-acid sequence, it is estimated that the initial E-map could have produced a model containing 99% of all main-chain and 81% of side-chain atoms. The structure refinement was completed with PROFFT, including the contributions of protein H atoms, and converged at a residual of 0.158 for 30 609 data with F ≥ 2σ(F) in the resolution range 8.0–0.964 Å. The final model consisted of 518 non-H protein atoms (36 disordered), 407 H atoms, and 129 water molecules (43 with occupancies less than unity). This total of 647 non-H atoms represents the largest light-atom structure solved to date.