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Notes: A brief description of the most common encoding methods, and their relative merits, used with position sensitive proportional detectors at synchrotron facilities will be made. While some of these systems are reaching maturity, continued development is resulting in further improvements, especially in terms of linearity and resolution. The use of detectors with special geometries for specific experiments will be described. The microstrip gas chamber will be addressed, with particular emphasis on a comparison of its capabilities with those of the multiwire proportional chamber. The development of proportional detectors intended for dynamic studies at second- and third-generation sources, with counting rate capabilities well in excess of these generally available at present, will be described. The use of gas based detectors, albeit with modest energy resolution, for photon detection in the energy regime of a few hundred electron volts will be mentioned. © 1995 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: Some important characteristics are described of one- and two-dimensional gas proportional detectors with delay line position readout which are currently in use at beam line X12B of the National Synchrotron Light Source. The importance of careful choice of geometric design parameters is emphasized with respect to position linearity and electrical stability; position resolution of 100 μm FWHM and counting rates up to several times 105 s−1 are obtained in calibration studies. Results from some recent beam-line experiments further illustrate the excellent position resolution and linearity, and demonstrate the usefulness of these detector systems for small-angle scattering, particularly in dynamic studies. © 1995 American Institute of Physics.

Notes: The use of primary electron counting techniques as an alternative to the more usual parallel plate avalanche chamber that has been employed in soft x-ray scattering experiments is being investigated at the National Synchrotron Light Source. The theoretical aspects of primary electron counting and motivation behind building a primary electron counting detector are described, as well as characteristics and future improvements of the device constructed at the NSLS. The detector consists of a low electric field drift region and a low pressure multistep avalanche region which can be operated with two or three stages of electron multiplication. The device has worked well in extensive tests as a simple parallel plate avalanche chamber, providing energy resolutions of 58% and 43% at 277 and 500 eV, respectively. Operated as a primary electron counter, preliminary results show an energy resolution of 38% at 500 eV. © 1995 American Institute of Physics.

Notes: Subdivided samples of ground beef, pork sausage, and wieners were oven-dried at 102°C or extracted with diethyl ether at various time intervals from 1/4 to 8 h. Each moisture and fat extraction period correlated well with the standard 8 h analysis, although less variation tended to occur after 4 h of drying or extraction time. Results from reduced analysis time for moisture and fat determination were closely associated with the standard 8 h values and each other. These data suggest that modified moisture and fat determination methods which were evaluated gave suitably accurate and precise results for routine analyses use for quality control.

Notes: Four moisture and four fat determination methods requiring from 5 min to 12 h were performed on 664 ground beef samples to compare accuracy and precision of rapid fat and moisture determinations to the Association of Official Analytical Chemists (AOAC) procedures. The modified Babcock results were closer to the official ether extraction method than those obtained from the Banco and Univex methods. Moisturefuge moisture determinations were more highly correlated with AOAC percentages than either the Toluene or Ohaus methods. Correlations among moisture and fat determination methods studied with official results were 0.90 or higher and none of the fat and moisture values differed significantly from those using AOAC methods. These data suggest the modified rapid moisture and fat determination methods evaluated have adequate accuracy and precision for reliable control and analyses use.

Notes: The color of fresh meat is important to every aspect of the meat industry. The basic explanations for various colors and intensities of color need to be understood in order to minimize off-colors which ultimately result in product loss. This review discusses the various color forms of myoglobin in muscle and their relationship to species, atmospheric conditions, antemortem factors and storage characteristics.

Notes: Iron deficiency is a common nutritional anomaly encountered in surveys in diverse populations throughout the world. Etiological factors, including gastrointestinal disorders such as gastric ulcers or ulcerative colitis have a significant effect on and may cause this nutritional disorder.Research has indicated that dietary iron is found predominantly as either heme (absorbable) iron or as nonheme (less readily absorbable) iron. The absorption of nonheme iron is enhanced by the presence, in the diet, of certain factors, mainly ascorbic acid and meat, fish or poultry. Certain inhibitors and their effects have also been identified.Understanding the mechanism and regulation of intestinal iron absorption and the relationship to absorbable iron versus total iron intakes is of importance. This paper includes a review of the following information: food sources of both types of iron; factors affecting absorption — enhancers and inhibitors; and physiological states affecting iron absorption. Meats serve as a source of heme iron as well as having a promoting effect on absorption of nonheme iron.

Notes: Sides from 33 forage-fed steers were electrically stimulated and hotboned (ESHB) and muscles were vacuum-packaged either within 2 h (17 sides) or at 24 h (16 sides). Opposite sides were not electrically stimulated and were cold-boned (NESCB) and vacuum-packaged at 24 h. For ESHB muscles, packaging time did not affect (P〈0.05) palatability. Longissimus steaks from ESHB sides (pooled across packaging treatments) had lower (P〈0.05) shear force values than steaks from NESCB sides. As storage time of muscles increased from 7 to 21 days, shear force values generally decreased. Combining electrical stimulation with hot-boning enabled the removal of muscles without detrimental effects on beef palatability.