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Summary Three groups of 5 Welsh-Shetland crossbred pony foals each were infected with 450,000 third stage cyathostome larvae, given as either a single dose of freshly harvested larvae (Group A) or a single dose of larvae that had been cold conditioned for 6 weeks at 4°C (Group B) or as a trickle infection of 18 doses of 25,000 freshly harvested larvae administered on weekdays over 1 month (Group C). The mean pre-patent periods of Groups A and B were 53 days with shortest and longest individual values of 48 and 62 days. In Group C the mean pre-patent period was 65 days with a range from 60–77 days. The general patterns of faecal worm egg output were similar in Groups A and B, with rises in mean numbers of faecal worm eggs over about 3 weeks following patency, after which the mean worm egg counts in faeces remained between about 400 and 1,000 eggs/g. The mean faecal worm egg counts of Group C animals, at approximately 200–300 eggs/g, were lower than the mean values of Groups A and B. At post-mortem examinations 16 weeks post infection, the group mean total and mucosal cyathostome worm counts were: Group A, 60,898–14,806; Group B, 33,592–13,292; Group C, 30,794–14,714. Therefore, the relative proportions of total worm burdens present at mucosal stages were different between groups with values of 24%, 39% and 49% for Groups A, B and C respectively. It was concluded that both larval chilling and trickle larval dosing influenced the development of experimental cyathostome infections.

The geometric basis for the design of a new process to form sheet metal into a flat, corrugated product is described. The underlying principle is to determine a surface between entry of the sheet into the device and the exit of the formed product such that all points across the width of the sheet under go as nearly as possible similar deformation histories and also that longitudinal strain in the sheet is minimized. The surface for forming a product having a sinusoidal profile and also that for a trapezoidal profile are presented as examples. For the sinusoidal product, an empirical equation is developed that relates the strain during forming with the initial and final width, the forming length and the number of profile segments. A physical model shows that a sheet can be formed to such a surface without straining or buckling. Although this paper does not describe the type of tooling or forming machine that would be used to plastically deform steel sheet, the authors believe such a device can be constructed. The results suggest that the new approach would reduce defects such as edge-wave, oil-canning and splitting and that the overall length of the forming device could be an order of magnitude smaller than that for existing roll-forming lines.

Objective: The aim of this study was to determine the extent and the future of paediatric surgery performed in Scotland outside of the designated surgical paediatric centres. Materials and Methods: An anonymous questionnaire was sent to all 111 Scottish members of the Association of Surgeons of Great Britain and Ireland. There was a response rate of 69%. Results: Overall, 45% of responders operated on children. This was independent of the surgeon's age but was related to the type of hospital that the surgeon worked in. Eighty-four per cent of responders had a lower age limit under which they would not operate and 94% stated that there were specific circumstances where they would not operate. A mean of 18.5 elective procedures (range 0–250, median two) and six emergency procedures (range 0–30, median five) were carried out by each surgeon operating on children under the age of five per annum. Only 13% of responders thought that their successor would operate on children. Conclusions: Non-specialist paediatric surgery in Scotland is currently provided by a significant number of surgeons whose successors will not continue to provide a comparative paediatric service. This has implications for local provision of care, emergency management and capacity of existing children's hospitals in the future

In combined bending and stretching of aged steel sheet, an instability of an unusual kind is identified. Analysis of the behaviour of a sheet using a simplified material model shows that under certain conditions the maximum tension is less than the fully yielding tension and springback in the opposite direction to that normally observed could occur. Some of the sheet used industrially for panels of small curvature may age and there is considerable current interest in the prediction of springback in panels formed by combined bending and stretching.

Background: the variability of venous reflux patterns complicate the management of venous disease. Our study investigates specific variations in venous anatomy and patterns of reflux in varying clinical situations. Methods: prospective analysis of 464 legs in 355 patients was performed by complete duplex venous mapping of both primary and recurrent varicose veins. Hand Held Doppler (HHD) and Duplex Ultrasonography (Duplex US) observations in the popliteal fossa were compared in a subgroup of 89 patients with primary varicose veins. Distribution of venous system disease was correlated with clinical severity in a subgroup of 117 affected legs which was representative of the overall study group. Results: sapheno-femoral junction (SFJ) incompetence predominated in both primary and recurrent varicose veins. Only 21% of primary legs and 25% of recurrent legs had sapheno-popliteal junction (SPJ) incompetence. SPJ incompetence was present in only 42% of cases where reflux in the popliteal region on HHD had been demonstrated. A proportion of both primary and recurrent varicose veins had evidence of deep venous incompetence (DVI). Sixty-four percent of primary leg ulcer patients had superficial incompetence alone. In patients with recurrent varicosities and ulceration, 57% had SPJ incompetence, 64% multiple sites and 50% DVI. Conclusion: the complex variations of varicose vein anatomy and functional pathology in the lower limb are currently best assessed by complete whole-leg venous duplex mapping. Eur J Vasc Endovasc Surg 25, 267–275 (2003)

These guidelines have been designed to assist in the planning, operation and interpretation of studies which would serve to assess the efficacy of drugs against internal parasites of horses. Although the term anthelmintic is used in the title and text, these guidelines include studies on drug efficacy against larvae of horse bot flies, Gasterophilus spp., which are non-helminth parasites commonly occurring in the stomach of horses. The advantages, disadvantages and application of critical and controlled tests are presented. Information is also provided on selection of animals, housing, feed, dose titration, confirmatory and clinical trials, record keeping and necropsy procedures. These guidelines should assist both investigators and registration authorities in the evaluation of compounds using comparable and standard procedures with the minimum number of animals.

In order to establish the infection pattern with gastrointestinal nematodes in ruminants in the central Kenya highlands, a study was carried out in 58 smallholder farms. The study involved monthly faecal examinations from sheep, goats and cattle and pasture sampling from eight communal grazing areas. Each month, six Dorper worm-free tracer lambs were introduced and four locally grazed cross-bred sheep were purchased for parasite recovery. The mean faecal egg counts ( FEC ) for cattle were low throughout the study period, whereas those for sheep and goats showed a seasonal pattern with high levels of infection occurring during the two main rainy seasons, especially in March, April and October. There were significant differences in egg counts over time and among farms. Haemonchus contortus was the most prevalent nematode in the tracer lambs whereas the previously exposed locally grazed sheep had significantly lower numbers of H contortus but significantly higher numbers of Trichostrongylus species The highest levels of infection in the tracer lambs occurred in November 1995 and January, May and June 1996. Based on this study, it is now possible to explore the possibility of using strategic treatments for the control of parasitic gastroenteritis in this area of Kenya.

The consequences for lambs of infection over the winter with Teladorsagia circumcincta were quantified by deliberate, trickle infection of selected animals at 7 months of age. Infected and control uninfected animals were each allocated into four groups, relatively resistant animals on a normal diet, relatively resistant animals on an isocaloric diet supplemented with urea, and relatively susceptible animals on the same two diets. Resistance and susceptibility was assessed by faecal egg counts following natural infection during the summer preceding the deliberate infection. During the deliberate infection egg counts remained low and most parasites recovered at necropsy were inhibited larvae. Nonetheless, infection reduced weight gain, decreased albumin and fructosamine concentrations and provoked a noticeable pepsinogen and eosinophil response. As most larvae were inhibited these responses may have been largely a consequence of immuno-inflammatory responses in the host rather than the direct action of parasites themselves. Relatively resistant animals on the supplemented diet allowed fewer larvae to establish and had higher fructosamine concentrations, higher albumin concentrations and decreased pepsinogen responses. Therefore, a combination of relatively resistant sheep and nutritional supplementation appears most efficient at controlling infection.

Previous research has shown that supplementing the diet of growing lambs with urea enhances their ability to withstand gastrointestinal infection with the nematode Haemonchus contortus. This study compared lambs given two different amounts (χ 1 and χ 1·5) of the same urea-supplemented diet. One dietary allowance was sufficient to allow uninfected lambs to gain approximately 400 g/week without adverse clinical signs. In contrast half of the H. contortus infected lambs on this dietary allowance had to be humanely killed before the end of the experiment due to severe anaemia and anorexia. All infected lambs on this dietary allowance showed decreased mean red cell volumes and decreased plasma albumin concentrations indicating inadequate replacement of red blood cells and plasma proteins lost during the infection. The remaining lambs were offered proportionately 0·5 more of the same dietary allowance. Among lambs on this dietary allowance, there were very few differences between uninfected and infected sheep in clinical signs and growth rate. Therefore, dietary allowances that are adequate for uninfected lambs are not necessarily sufficient for infected lambs. As nearly all grazing lambs are infected with nematodes, dietary recommendations should take parasitic infection and its nutritional demands into account.

The measurement of the moment–curvature characteristic for thin sheet metal in the elastic–plastic range provides important information which is not readily obtained from the tensile test. Steel sheet which is roll-formed to products such as roofing typically contains a residual stress distribution and is subject to strain ageing; these conditions can be identified from bend tests. The accurate determination of the moment–curvature diagram is not easy as the limiting elastic curvature is large and the magnitude of the moment is small. Part I of this paper describes equipment and data processing which have been developed for this purpose and in Part II, results obtained in sheet which has been progressively aged and stress-relieved are presented.

The bending equipment described in Part I is used to study the behaviour of a sample of galvanised steel sheet. The sheet is known to have an internal stress distribution and to exhibit ageing. Tensile and bend behaviour is measured for the sheet in the “as-received” condition, after ageing at 170°C and 300°C and after ageing and stress relieving at 450°C. In the bend test, attention is focussed on the imposed outer fibre bending stress at the limit of linear, elastic bending. In the “as-received” condition, this is substantially less than the tensile yield stress, but increases rapidly with ageing and for ageing at 300 °C it is approximately 200 MPa greater than the lower yield stress in the tensile test. Samples treated at 300 and 450°C showed maxima in the moment/curvature characteristic and unstable “kinking” was observed in bending. The bending moment versus curvature diagrams presented indicate material characteristics of importance in technological forming processes which are not easily identified in tensile tests.

Attention is focused on the quantitative relationships between the parameters of the normal mode and the local mode effective Hamiltonian models of anharmonic stretching vibrations. R. G. Della Valle (1988, Molec. Phys., 63, 611) has demonstrated the general relationship between the harmonically coupled anharmonic (Morse) oscillators (HCAO) model and the normal mode model of X-H (or X-D or other weakly coupled) stretching vibrations of polyatomic molecules. Here we consider more fully the relationship between the normal mode and the anharmonically coupled local mode models for X-H stretching vibrations. The local mode Hamiltonian is expressed in terms of boson shift operators and these operators are then transformed into the corresponding normal mode model operators. Such relationships have already been derived for the special cases of H2X (Baggott, J. E., 1988, Molec. Phys., 65, 739), XH3 (C3v) and XH4 (Td) (Law, M. M., and Duncan, J. L., 1994, Molec. Phys., 83, 757) and here they are derived systematica...

Vibrational assignments for CH 2 D 2 are made from a detailed study of its gas-phase infrared spectrum below 17 000 cm −1 , up to six quanta of CH stretching excitation. Some 77 overtone and combination vibration levels are identified. These allow extraction of empirical values for approximately one-half of the 45 normal mode anharmonicity constants, and their comparison with recent ab initio predictions. Severe Fermi resonance perturbations at low excitation levels in both CD 2 stretching manifolds preclude the direct extraction of any of the 17 associated anharmonicity constants. However, observation of seven Fermi resonance diads below 4000 cm −1 permits the accurate definition of the corresponding cubic resonance parameters, and the determination of unperturbed CD 2 stretching fundamental wavenumbers. A simple local mode interpretation of the unperturbed stretching vibrational manifold in CH 2 D 2 is attempted. This then yields the 10 corresponding normal mode CH and CD stretching anharmonicity constants consistent with the model applied.

The response of Red Maasai sheep to natural and artificial Haemonchus contortus infections was compared with sheep of Blackheaded Somali, Dorper and Romney Marsh breeds. Significant breed differences in egg count, packed cell volume (PCV), and mortality rates showed that the Red Maasai sheep were more resistant to natural H. contortus infection than sheep from the other three breeds. Of the initial groups of 15 wethers of each breed, two animals from each of the Dorper and Blackheaded Somali groups and nine from the Romney Marsh group died with haemonchosis during a 12 month field study. Following artificial infection of the Red Maasai, Dorpers and Blackheaded Somalis, with 10000 H. contortus L3, the Red Maasai sheep maintained a lower egg output and a higher PCV than animals of the other two breeds. The results clearly showed that breed substitution with the Red Maasai is a control option in areas where sheep are kept for meat and H. contortus is endemic.

Maiden Red Maasai and Dorper ewes were kept indoors and artificially infected with a single oral dose of 5000 infective larvae of Haemonchus contortus. Their faecal egg counts (FEC) and packed red cell volumes (PCV) were monitored for 9 weeks. They were then treated with an anthelmintic and turned out to graze together on a pasture contaminated with H. contortus. They grazed this pasture for 14 months and were allowed to mate and lamb. While at pasture the ewes were monitored for FEC, PCV and peripheral eosinophilia. Red Maasai ewes had significantly lower FEC, and for certain periods, significantly higher PCV and peripheral eosinophilia. During the periparturient period, FEC were about twice as high in the Dorper breed as the Red Maasai. These results confirm and extend previous reports on the superiority of the Red Maasai breed in East Africa.

Six-month-old red Maasai lambs were more resistant than Dorper lambs to repeated infections at one to two week intervals with 1000 Haemonchus contortus infective larvae. Resistance after infection was assessed by means of faecal egg counts, packed cell volumes, eosinophil counts, total serum protein concentrations and mortality rates. The weight gains of the infected animals were only marginally lower than those of their uninfected controls, most probably because of their significantly higher feed consumption, and evidently the infected lambs were not utilising all of the extra feed for growth. This absence of anorexia in spite of the infection was probably due to the palatability of the high protein diet fed to the lambs.

The number of accumulated spectroscopic data sensitive to the harmonic force constants of methyl silane has been augmented recently through high resolution infrared gas-phase studies of 12 CH 3 SiH 3 , 13 CH 3 SiH 3 and 12 CH 3 SiD 3 species (J.L. Duncan, A.M. Ferguson and D.C. McKean, J. Mol. Spectrosc, 168 (1994) 522). This permits the determination of an empirical harmonic force field, in which 24 A, and E species force constants out of the total of 36 are independently defined in terms of 72 data across five isotopic species. The empirical constants are compared with those from a scaled ab initio force field using a basis set of double zeta plus polarization quality, where very good agreement is found throughout. Ultimately, a best estimate general harmonic force field is presented in which the 12 undermined and numerically small interaction force constants are constrained to their ab initio predicted scaled values.

Protein supplementation improves the resistance of sheep to haemonchosis. This experiment investigated the Scottish blackface breed to establish whether dietary protein supplementation is still beneficial in a genetically resistant breed. Lambs were given either a basal diet or a diet supplemented with soyabean meal to give an additional 80 g crude protein kg dry matter−1. The lambs were given an initial loading dose of Haemonchus contortus, followed by a trickle infection for 10 weeks. The weight gains of the lambs given the supplemented diet were greater and their carcases were leaner, irrespective of infection status. Infected animals on the basal diet were more anaemic and hypoalbuminaemic than animals receiving the supplemented diet, although there were no statistically significant differences in mean worm burdens or faecal egg counts.

The adult ES products of Dictyocaulus viviparus are a source of protective antigens against challenge in the guinea pig laboratory model. High levels of acetylcholinesterase (AChE) activity are present in these products and these enzymes are immunogenic in infected cattle. Here, the potential role of these enzymes in protective immunity was investigated using a fraction enriched for AChE to immunise guinea pigs. The antibody response stimulated by immunisation with AChE-enriched ES products and the worm burdens obtained following challenge with infective larvae were compared with those in animals immunised with whole ES products and challenge controls. The AChE-enriched preparation stimulated high levels of enzyme-specific antibody in immunised animals, which was not the case for those which received unfractionated ES products. Worm burdens of guinea pigs which received the AChE-enriched fraction were significantly lower than those obtained in adjuvant controls. The animals which received the unfractionated ES products were not significantly protected against challenge. These results suggest that AChEs may be potential candidates for incorporation in a sub-unit vaccine against D. viviparus .

The influence of dietary protein supplementation on resistance to haemonchosis was examined in Hampshire down lambs fed either a basal diet or a diet supplemented with soyabean. At seven months of age the lambs were challenged with an initial loading dose of Haemonchus contortus, followed by a trickle infection three times a week. Blood and faecal samples were collected three times a week and bodyweights were recorded weekly. After 10 weeks the lambs were slaughtered and their worm burdens and carcase composition determined. Although their mean worm burdens were similar, the lambs given the basal diet had higher faecal egg counts, lower packed red cell volumes and lower concentrations of total plasma protein and plasma albumin than the lambs given the supplemented diet. The dietary supplementation also improved the carcase composition of the lambs.

Faecal egg counts, peripheral blood eosinophil counts and plasma pepsinogen concentrations were monitored during 2 successive, deliberate infections in 24 Scottish Blackface sheep. For all 3 techniques, the repeatability of replicate counts or of measurements made at short intervals were high which suggests that all 3 assays were reliable. Within an infection the repeatability of different samples from the same animal decreased as the interval between samples increased. The repeatability between infections was only moderate for faecal egg counts but high for peripheral eosinophil counts and plasma pepsinogen concentrations. Of the 3 variables, faecal egg count was the most strongly associated with the worm burden. Together, the three variables accounted for, in a statistical sense, one half of the variation in worm burden. The three variables, if measured concurrently, should provide a more effective identification of resistant and susceptible lambs.

Parasite preparations were examined for their ability to induce protective immunity against Dictyocaulus viviparus in guinea pigs. Dunkin-Hartley strain guinea pigs were immunised with somatic extracts of adult parasites, somatic extracts of third stage larvae or excretory/secretory (ES) products from adult parasites. The groups were immunised twice with Freund's adjuvant four weeks apart and challenged with 6000 infective L3. Significant levels of protective immunity were observed only in the adult ES-immunised animals. The antibody responses of the different groups were compared following analysis by ELISA and immunoprecipitation. To examine the protective role of antibody, guinea pigs were passively immunised with serum from animals immunised with adult ES products or serum from guinea pigs exposed to experimental D. viviparus infection. Following challenge with infective L3, lungworm burdens of these groups were significantly lower than in guinea pigs which received normal sera. The results suggest that D. viviparus adult ES products contain protective antigens and that antibody-mediated mechanisms contribute to immune protection.

Attention is focused on the relationship between the normal mode and the local mode descriptions of the stretching vibrations of polyatomic molecules. The harmonically coupled local mode model requires that the equivalent normal mode model parameter set obeys certain fixed interrelationships, the so called ‘x,K relations’. In this paper, a boson shift operator formalism is used, following J. E. Baggott (1988, Molec. Phys., 65, 739), to transform the unconstrained normal mode models for XH4 (Td) and XH3 (C3v) molecules to equivalent local mode effective Hamiltonians which include anharmonic as well as harmonic couplings between the bond modes. Relationships between the unconstrained normal mode and anharmonically coupled local mode models are established which allow for more reliable schemes for the relaxation of the x,K relations than those suggested hitherto for systems containing three or four equivalent stretching vibrations. The magnitudes of the anharmonic coupling terms in the local mode model are e...

The ν5 + ν9 A-type infrared combination band of C2D4 at 4627 cm-1 has the superficial appearance of an unperturbed absorption. Assignment, however, reveals the effects of Coriolis interaction with an inactive vibration level, ν2 + ν8 + ν9, which lies within 0·4 cm-1 of ν5 + ν9. Through the K dependence of the interaction, the K a = 0 subband J structure of ν5 + ν9 is completely unperturbed, while higher K a subband J structures assigned are displaced varyingly up to 3·5 cm-1. Due to almost exact degeneracy of interacting rovibration levels, for the K a = 3–7 subbands, two series of J structures are identified in the spectrum, and two series of subbands are identified in the overall Q branch for K a = 1–8, the ‘inactive’ transitions stealing intensity from those of ν5 + ν9 through the Coriolis interaction. Analysis of the assignments made yield unperturbed upper state parameters and the magnitude of the Coriolis interaction parameter.

Roll forming of sheet metal is considered in terms of four fundamental types of deformation: longitudinal stretching, longitudinal bending, transverse bending and shear. Strain and work expressions are developed for each deformation type. Three of the deformation types are associated with simple sectional properties and from these it is possible to predict their relative magnitudes. It is shown that shear strain is potentially far larger than the other deformation types. Some of the implications for practical roll design are discussed.

Somatic extracts and excretory/secretory (ES) products of the adult stage of the cattle nematode, Dictyocaulus viviparus, were examined for acetylcholinesterase (AChE) activity. Both were found to contain activity which had an optimum pH of 9.5, however, the adult ES products contained over 200 times more AChE activity per unit protein. Gel electrophoresis and specific enzyme staining revealed 5 migratory isoforms of AChE which were common to adult ES products and adult homogenates. Comparison of L3 with L4 and adult extracts indicated that the AChE were only produced by later developmental stages of this parasite. The antigenicity of D. viviparus AChE was demonstrated by binding to serum IgG from naturally and experimentally infected calves but the enzymes were not recognized by calves vaccinated twice with 400 Gy-irradiated larvae. This is the first report of helminth AChE release by a parasitic nematode in a pulmonary location. The presence of these enzymes in such high amounts in the ES products, along with their immunogenicity, suggests that they might have an important role to play in the immunobiology of D. viviparus in the lungs.

Second-order perturbation theory corrections to effective Fermi resonance coupling constants have been derived analytically within the framework of the traditional rectilinear normal coordinate approach to the analysis of anharmonic molecular vibrations. These corrections have been evaluated for a range of methyl halide molecules (including deuterated isotopomers) and are found to rationalise qualitatively discrepancies between the empirical effective Fermi resonance parameters and theoretical normal coordinate cubic force constants.

The IR spectra of C2H3D and C2HD3 have been studied up to 3 quanta of excitation of CH and CD stretching (

Previous studies of the CH (and CD) stretching vibration manifolds of the series of molecules H 2 CCH 2 , H 2 CCD 2 , H 2 CCCl 2 , and H 2 CCF 2 have been extended to cover all spectroscopic observations made to date on excited state vibration levels. From these, sets of normal mode anharmonicity constants have been assembled over the four molecules. These are individually incomplete, but exhibit a considerable degree of transferability of constants which relate to the normal vibrations associated with the moiety. In turn, this allows the vibrations of the group to be characterized in terms of a set of 24 averaged normal mode anharmonicity constants, which reproduce 77 spectroscopic observations for ethylene-H 4 up to 16 500 cm −1 with an rms error of 4.30 cm −1 .

The A 1 and E species fundamentals of 12 CH 3 SiH 3 , 13 CH 3 SiH 3 , and 12 CH 3 SiD 3 samples have been analyzed by gas-phase infrared spectroscopy at resolutions of up to 0.05 cm −1 . Precise vibrational and rovibrational parameters have been obtained for most fundamentals over all three isotopic species. The K structure of the E species fundamentals which was sufficiently resolved was readily assigned in most cases, rendering subsequent analyses straightforward. Analyses of the methyl group deformation fundamentals, ν 9 , previously misassigned to the more intense ν 11 + ν 12 combination band, are presented. Definitive vibrational band origins for the silyl group deformation fundamentals, ν 10 , are presented, partly from observations of the overtone ν 0 10 . Analyses of five perpendicular combination and overtone bands are also given. Evidence of localized perturbations are observed in most of the 37 bands studied.

Groups of animals of different ages and experience of previous parasite exposure were allowed to graze a single pasture for 5 weeks in autumn (7 October to 11 November). There was evidence that previous exposure modified cyathostome development, as acquired burdens in foals which had previously grazed were smaller and developed more slowly than those of helminth-naive animals of the same age. The burdens acquired by yearling and adult ponies were of a similar size to those of the previously grazed foals, but the incidence of arrested development was higher in the younger groups of foals and yearlings when compared with adults. Further evidence of an effect of age on cyathostome development was that the level of faecal egg output of the adult ponies was lower than in the groups of young animals.

The complete general harmonic force field of methyl flouride was recalculated using the most recent literature frequency, Coriolis ζ, and centrifugal distortion data for 12 CH 3 F, 13 CH 3 F, 12 CD 3 F, 12 CHD 2 F and 12 CH 2 DF. The anharmonic corrections applied to the observed frequency data and the adopted molecular geometry are considered to be more realistic than those used hitherto. There is excellent overall agreement between the fitted force constants and the highest quality ab initio force field currently available.

Red cell kinetics and plasma protein metabolism were investigated in two experiments using 20 adult sheep naturally infected with Dicrocoelium dendriticum, but free of other liver and gastrointestinal helminths. In the first experiment, where groups of animals with low to high Dicrocoelium burdens were injected with 51Cr-labelled red cells and 125I-labelled albumin, the results indicated that there were no significant differences in the turnover rate of labelled red cells or albumin between any of the groups. In the second experiment, two groups of sheep with low and high worm burdens were studied using the same radioisotope tracers; in addition, 59Fe-citrate was used to assess red cell iron incorporation rates in the two groups. Although the red cell half-lives of the infected sheep were just significantly longer, both were within normal limits and the difference was attributed to random variation within the two small groups of sheep. No significant differences were found in the other parameters. It was concluded that burdens of up to 4000 D. dendriticum do not cause significant blood or plasma protein loss in sheep.

This study was conducted to investigate the pathophysiology of Haemonchus placei infection in Friesian calves. Seven calves were divided into two groups, three uninfected calves (control group) and four infected animals. The latter group were infected orally with 500 H. placei larvae kg −1 body weight. Five weeks after infection they were all housed in metabolic crates and infected with 125 I-bovine albumin, 51 Cr-red cells and 59 Fe-transferrin, to study albumin metabolism, erythrokinetics and ferrokinetics. The results showed that there was a significant reduction in the mean haematocrit values and reduced weight gains in the infected calves compared with the controls. There was also a change in the distribution of albumin from the extravascular to the intravascular pool and a significant increase in the plasma and blood volumes of infected calves although the blood and albumin loss via the gastrointestinal tract recorded in this study was similar in both groups.

Previous studies of the CH (and CD) stretching vibration manifolds of the series of molecules H 2 CCH 2 , H 2 CCD 2 , H 2 CCCl 2 , and H 2 CCF 2 have been extended to cover all spectroscopic observations made to date on excited state vibration levels. From these, sets of normal mode anharmonicity constants have been assembled over the four molecules. These are individually incomplete, but exhibit a considerable degree of transferability of constants which relate to the normal vibrations associated with the moiety. In turn, this allows the vibrations of the group to be characterized in terms of a set of 24 averaged normal mode anharmonicity constants, which reproduce 77 spectroscopic observations for ethylene-H 4 up to 16 500 cm −1 with an rms error of 4.30 cm −1 .

The infrared spectrum of CH 3 Cl has been studied up to 16 500 cm −1 and vibrational assignments made for up to six quanta of excitation in CH stretching. Analysis of a total of 66 vibrational levels has been made in terms of a joint local mode and normal mode model, local with respect to CH stretching vibrations and normal with respect to other vibrations. Fermi resonance interactions with CH 3 deformation overtones must be included in the analysis. Reproduction of the observed vibration levels with a rms error of 2.61 cm −1 is achieved in terms of a 37-parameter model, with the four anharmonicity constants and two Darling-Dennison constants associated with CH 3 group stretchings constrained to be interrelated through local mode relations. The parameters obtained are in excellent accord with those available for the other methyl halides, and with established structural differences between the molecules.

The determination of strain in a deformed sheet from measurements of surface grid markings is improved by methods which take account of curvature and sheet thickness. Calculation of membrane strain is simplified without loss of rigour and examples are presented of different techniques for visualizing the strain distribution.

The CH stretching anharmonicity in CH 2 CF 2 and CH 2 CCl 2 has been investigated through application of the local mode model to vibration levels up to 14500 cm −1 . Good reproduction of observed data is achieved in each case, but whereas a “normal” anharmonicity constant of ≈−58 cm −1 is obtained for CH 2 CCl 2 , an anomalous value of ≈−52 cm −1 is determined for CH 2 CF 2 . By comparison of the spectra, the cause of the problem is traced to two critical misassignments due to the effects of Fermi resonances at different levels of excitation in CH 2 CF 2 . A “normal” anharmonicity constant is then obtained. The Fermi resonances cannot be quantified satisfactorily, due to lack of sufficient observations and their complexity. The local mode parameters determined for each molecule are supported by available structural information.

This paper describes the development and preliminary testing of a unique air mattress system for the prevention of decubiti and the enhancement of circulation in bedridden and elderly individuals. The mattress body is constructed of an array of small air cells contained within a foam matrix. The pattern and duty cycle for pressurization of the individual cells is microprocessor controlled, allowing the uset to adjust the mattress for immediate comfort, to stimulate circulation in selected body regions, or to alternate the contact of various body regions with the mattress. The capability of varying the amount of pressure to various body parts will prevent the constant pressure against tissue that causes bed sores and impedes circulation in long-term, bedridden patients.

The effect of supplementing the diet of scavenging chickens with housefly larvae on productivity was studied. Birds on supplement received 30-50 g of live housefly larvae from the age of 2 weeks until they laid and hatched their first clutch of eggs. Monthly body weight, age at first lay. egg weight. number of eggs hatched, and weight of chicks hatched by the supplemented birds were compared with those of the control group of birds which did not receive any supplement. There were significant differences (P < 0.05) in clutch size, egg weight, number of eggs hatched. and chick weight between supplemented birds and the control. Mean clutch size, egg weight, number of eggs hatched. and chick weight were 11.5 ± 2.57, 43.5 ± 25.53,9.8 ± 2.21. and 34.2 ± 0.78; and 9.5 ± 1.14,33.6 ± 2.72,7.1 ± 0.70. and 29.8 ± 1.89 for supplemented and control birds. respectively. The beneficial effects of supplementing the diets of local scavenging chickens with housefly larvae are discussed.

Bending along a straight line is the most common of all sheet-forming processes; it can be done in various ways, such as forming along the complete bend in a die, or by wiping, folding or flanging in special machines, or sliding the sheet over a radius in a die. A very large amount of sheet is roll formed where it is bent progressively under shaped rolls. Failure by splitting during a bending process is usually limited to high-strength, less ductile sheet, and a more common cause of unsatisfactory bending is the lack of dimensional control in terms of spring back and thinning. If the line of bending is curved, the adjacent sheet is usually deformed in the process and the sheet is either stretched, which may lead to splitting, or compressed with the possibility of buckling. There are special cases where sheet can be bent along curved lines without stretching or shrinking adjacent areas, but these require special geometric design. In this chapter, simple cases of bending along straight lines are examined for the elastic, plastic, and fully plastic regimens.

Many sheet-forming operations can be modeled as the deformation of circular (axisymmetric) shells, for example, stretching a sheet over a domed punch, drawing a circular disc to form a cylindrical cup and tube-forming processes such as flaring and necking. Detailed analyses usually require numerical methods, but by making certain simplifying assumptions, useful information about forming loads and strains can obtained from approximate analytical models. This chapter introduces the basic simplifying assumptions and some applications to typical forming processes.

In the analysis of a sheet-metal-forming operation, different regions of the sheet have a particular forming path that can often be considered as proportional, and represented by a line in the stress and strain diagrams. These diagrams are the charts in which the course of the process can be plotted. This chapter presents these diagrams and their utility in uniform sheet deformation processes. In this process, membrane stresses and strains are equal and opposite, and the sheet deforms without change in thickness. It is called drawing as it is observed when sheet is drawn into a converging region. The process is also called pure shear and occurs in the flange of a deep-drawn cup. Engineering strain diagrams are still widely used and it is advisable to be familiar with both forms. In this work, true strain diagrams will be used unless specifically stated.

The purpose of this chapter is to indicate how the true stress-strain curve derived from a tensile test can be applied to other deformation processes that may occur in typical sheet-forming operations. A common feature of many sheet-forming processes is that compared with the stresses in the plane of the sheet (the membrane stresses), the stress perpendicular to the surface of the sheet is small. If this normal stress is assumed zero, a major simplification is possible. Such a process is called plane stress deformation and the theory of yielding for this process is described in the chapter. There are cases in which the through-thickness or normal stress cannot be neglected and the theory of yielding in a three-dimensional stress state is described in an Appendix. In the chapter, it is shown that for simple (monotonic, proportional) plane stress processes, it is possible to determine at any instant the principal membrane stresses required for deformation, provided that the current flow stress σ f is known and also that either the stress ratio α or strain ratio β are known. The theory given in the chapter applies only for an instantaneous state in which the strain increment is small and the flow stress constant.