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The first demonstration of laser action in ruby was made in 1960 by T. H. Maiman of Hughes Research Laboratories, USA. Many laboratories worldwide began the search for lasers using different materials, operating at different wavelengths. In the UK, academia, industry and the central laboratories took up the challenge from the earliest days to develop these systems for a broad range of applications. This historical review looks at the contribution the UK has made to the advancement of the technology, the development of systems and components and their exploitation over the last 60 years.
Psychotropic medication use and psychiatric symptoms during pregnancy each are associated with adverse neurodevelopmental outcomes in offspring. Commonly, studies considering medication effects do not adequately assess symptoms, nor evaluate children when the effects are believed to occur, the fetal period. This study examined maternal serotonin reuptake inhibitor and polypharmacy use in relation to serial assessments of five indices of fetal neurobehavior and Bayley Scales of Infant Development at 12 months in N = 161 socioeconomically advantaged, non-Hispanic White women with a shared risk phenotype, diagnosed major depressive disorder. On average fetuses showed the expected development over gestation. In contrast, infant average Bayley psychomotor and mental development scores were low (M = 84.10 and M = 89.92, range of normal limits 85–114) with rates of delay more than 2–3 times what would be expected based on this measure's normative data. Controlling for prenatal and postnatal depressive symptoms, prenatal medication effects on neurobehavioral development were largely undetected in the fetus and infant. Mental health care directed primarily at symptoms may not address the additional psychosocial needs of women parenting infants. Speculatively, prenatal serotonin reuptake inhibitor exposure may act as a plasticity rather than risk factor, potentially enhancing receptivity to a nonoptimal postnatal environment in some mother–infant dyads.
This study examines U.S. crop producers' perceptions of climate change, itseffects on crop agriculture, and likely ways farmers would adapt to weatherextremes. Based on a survey of crop producers in four states, we find that asignificant proportion of farmers do not perceive that climate change hasbeen scientifically proven and do not believe that it will adversely affectaverage crop yields and yield variability. Farmers are likely to diversifycrops, buy crop insurance, modify lease arrangements, and exit farming inresponse to extreme weather caused by climate change.
Rapid rebreeding of winter- and spring-lambing ewes is essential if ewes are to lamb more than once per year, but fertility of lactating ewes is often low and early weaning of lambs may be undesirable in forage-based production systems. Selection to improve fertility in spring matings has been successful and led to development of ewes with a reduced seasonal anestrus. Potential for rapid rebreeding of lactating out-of-season breeding (OOS) ewes was tested in three studies. In Experiment 1, effects of short-term lamb removal on rebreeding was evaluated over 2 years using 71 January-lambing OOS ewes. At an average of 63 days postpartum, 36 ewes had lambs removed for 72 h, and all ewes were joined with rams. Circulating progesterone levels indicated that 74% of ewes ovulated before lamb separation; 91% of ewes mated within 5 weeks of ram exposure, 85% were diagnosed as pregnant and 75% lambed. The average interval between lambings was 225 days. In contrast to results observed in cattle, none of the measured variables was affected by lamb separation (P>0.20). Experiment 2 compared rebreeding performance of 24 OOS and 23 St. Croix ewes that lambed in January and averaged 60 days postpartum at ram introduction. More OOS ewes ovulated, mated and became pregnant during the first 21 days of ram exposure (83.3%, 58.3%, and 41.7%, respectively; P<0.001) compared with St. Croix ewes (26.1%, 0%, and 0%, respectively). After 39 days of ram exposure, pregnancy rates still favored OOS ewes (66.7% v. 39.1%; P=0.06), but the percentage of ewes that lambed did not differ (P>0.20) between OOS (47.8%) and St. Croix ewes (34.8%). In the third study, 34 March-lambing OOS ewes were exposed to rams on May 3 at an average of 40 days postpartum to characterize their reproductive performance. After 39 days of ram exposure, 52.9±8.7% of the ewes had mated, and 38.2±8.5% were diagnosed as pregnant. However, only 20.6±7.0% of the ewes produced viable lambs, suggesting a high level of uterine insufficiency. Spring fertility of lactating OOS ewes in these studies was one of the highest reported in the literature and indicated that selection for fertility in spring mating would improve reproductive performance in accelerated lambing programs. However, exposure of lactating OOS ewes to rams at 30 to 50 days postpartum was associated with high prenatal lamb mortality.
Data from black fly traps in Deep River over the past 5 years indicate that larvicides applied to breeding sites in streams surrounding the town have substantially reduced the numbers of this pest. Very high numbers occurred in 1972, the result of invasion associated with high westerly and northerly winds at a critical period of time or with heavy protective snow cover during the preceding winter. The lowest population levels occurred in 1975, when treatment included a stream near the town which had not been treated previously. The results indicate that with proper stream management it is possible to substantially reduce the nuisance value of black flies in a small northern town.
This is a two-year elementary college physics course for students majoring in science and engineering. The intention of the writers has been to present elementary physics as far as possible in the way in which it is used by physicists working on the forefront of their field. We have sought to make a course which would vigorously emphasize the foundations of physics. Our specific objectives were to introduce coherently into an elementary curriculum the ideas of special relativity, of quantum physics, and of statistical physics.
This course is intended for any student who has had a physics course in high school. A mathematics course including the calculus should be taken at the same time as this course.
There are several new college physics courses under development in the United States at this time. The idea of making a new course has come to many physicists, affected by the needs both of the advancement of science and engineering and of the increasing emphasis on science in elementary schools and in high schools. Our own course was conceived in a conversation between Philip Morrison of Cornell University and C. Kittel late in 1961. We were encouraged by John Mays and his colleagues of the National Science Foundation and by Walter C. Michels, then the Chairman of the Commission on College Physics. An informal committee was formed to guide the course through the initial stages.
The percentage composition and spatial distribution of embryogenic stages in the uteri of female Dirofilaria immitis were examined at various times after treatment with a microfilaricidal dose of ivermectin and compared to nontreated parasites. Worms sampled 42 days post-treatment (PT) exhibited an increased proportion of stretched microfilariae in the distal portion of the uterus. A decreased proportion of developed embryos was noted in the mid body region of worms sampled 42 days PT, and these forms were completely absent from the proximal area of the uterus. Relative numbers and spatial distribution of other stages remained virtually identical to controls. Radical changes in the composition and spatial distribution of embryogenic forms were noted in the uteri of a single worm sampled 80 days PT. Unlike nontreated parasites and worms sampled 42 days PT, stretched crofilariae constituted the predominant form in the distal uterus of this worm, and these stages were found in decreasing numbers throughout the proximal segments. Also, the intermediate embryogenic stages were either rare or absent.
In a factory population the occurrence of reactions to tetanus toxoid was recorded after 6740 injections. The incidence of general reactions was 0·3 % and of local reactions 2·6%. The local reaction rate to the first injection of the basic immunization course was 0·9%, to the second injection 2·7%, and to the third injection 7·4%. To booster injections the rate was 1·6%. The local reaction rate was appreciably higher in women than in men – 14·4 % and 5·7 % respectively in the case of the third injection – and the incidence among women increased with age.
Tetanus vaccine containing 10 Lf of toxoid caused fewer reactions than one containing 20 Lf, but a reduction in the content of aluminium adjuvant did not affect the reaction rate.
Almost all reactors were found to have a satisfactory serum antitoxin concentration at the time of the reaction or developed a satisfactory immunity within 1–6 months.
Skin tests were made in 32 hypersensitive patients. Neither the diluent, thiomersal preservative, nor the culture medium appeared to be responsible for hypersensitivity. The degree of hypersensitivity elicited by a special highly purified toxoid was only very slightly less than that elicited by the commercially pure toxoid. It is suggested that reactions are largely due to the toxoid antigen itself rather than to impurities or other components of the vaccine.
Spirorbis vitreus (Fab.), an arctic form, seems to be absent from Wales and most of England, but is generally abundant off the west coast of Scotland and also occurs in certain localities off Ireland, the Isle of Man, Cornwall and Brittany (which is probably its southern limit in Europe). Its range thus extends farthest down our western coasts, a distribution which is characteristic of various other northern and southern forms that are near the limits of their geographical ranges. Such species presumably benefit from the equable temperatures, adjoining deep water, and this winter-breeding species of Spirorbis also needs freedom from abrasion.
The tubes of juvenile S. vitreus are very different from those of adults. The distribution of uncini on the abdomen shows a remarkable bilateral asymmetry, as in S. spirillum.
Spirorbis corallinae sp.nov. is very similar to S. borealis but can be distinguished by its orange colour, small size, bifid opercular talon and particularly by the fact that the larvae choose to settle on Corallina officinalis rather than on Fucus serratus.
Other species dealt with, in a key to identification and notes on distribution, are S. granulatus, S. malardi, S. pagenstecheri, S. rupestris, S. spirillum and S. tridentatus.
Infection with Plasmodium vivax was established in splenectomized Callithrix jacchus marmosets by inoculation of parasitized blood from Aotus trivirgatus carrying the Vietnam Palo-Alto line of P. vivax. Subsequent blood passage through intact marmosets resulted in higher peak parasitaemias (about 1% of red cells infected) and the loss of stainable Schüffner's dots in infected cells. Primary infections with the adapted line were patent for 74 days or more, and induced both a substantial antibody response, as determined by indirect fluorescence, and some lymphocytosis, but no marked anaemia. Marmosets which had recovered from their primary infection (or in which it was drug-cured) suffered abbreviated patency with low-grade parasitaemia on re-infection.
In this study, 82 sex offenders incarcerated at the Massachusetts Treatment Center were administered a brief structured clinical interview focusing on caregiver and institutional history up to age 18. Interview data were examined along with archival information coded from the clinical files. Four factors were derived from principal components analysis and were entered into a series of multiple regression analyses. There were two noteworthy results. First, sexual and nonsexual aggression in adulthood each were related to distinct aspects of developmental history. Whereas caregiver inconstancy and sexual deviation in the family wére related to the severity of sexual aggression, childhood and juvenile institutional history and physical abuse and neglect were associated with severity of nonsexual aggression. Second, contrary to previous studies of other criminal populations, the severity of aggression rather than frequency of crimes was predicted by developmental history. The results of the study suggest that childhood experiences with and disruption of caregiver relationships may be important to understanding sexual aggression in adulthood.
An overview on current trends in stimulated Brillouin scattering and optical phase conjugation is given. This report is based on the results of the “Second International Workshop on stimulated Brillouin scattering and phase conjugation” held in Potsdam/Germany in September 2007. The properties of stimulated Brillouin scattering are presented for the compensation of phase distortions in combination with novel laser technology like ceramics materials but also for e.g., phase stabilization, beam combination, and slow light. Photorefractive nonlinear mirrors and resonant refractive index gratings are addressed as phase conjugating mirrors in addition.
Twelve spring-calving and twelve winter-calving cows were managed for extended lactation cycles of 18-months duration, with the former group then completing a second extended lactation. Half of the cows were fed according to standard management practice for the herd; the other half received supplementary concentrate from week 9 of lactation onwards. Commencing at the same time, half of the udder of each cow was subjected to increased milking frequency (thrice daily rather than twice daily). Lactation persistency (and hence total milk yield) was significantly increased by frequent milking. Winter calving cows and supplemented cows also exhibited better persistency, but this was only evident up until the point of re-breeding, at around lactation week 33. Milk composition was measured in the spring-calving cows in both their first and second extended lactations. Composition altered during the course of the lactation, protein and fat percentages increasing and lactose percentage decreasing, irrespective of treatment. The quality of the milk for processing into cheese, fermented products, heat-treated products and cream liqueurs was assessed by calculation of casein number (casein protein as a proportion of total protein). Processing quality declined across the course of lactation in those groups that showed poor persistency but not in those that maintained a persistent lactation. Milk hygienic quality (somatic cell counts) showed parallel changes. Body condition score increased during the course of lactation but was not affected by supplementation; none of the cows became excessively fat. All cows remained healthy throughout the extended lactations and the majority (33/36) re-bred successfully. By demonstrating that lactation persistency is plastic and can be improved by simple management interventions, the results lend support to the economic arguments in favour of extended lactation cycles. The likely welfare benefits of extended lactation are also discussed.
Medial claws from the right hind feet were obtained post mortem from four 19–20-month-old beef heifers and from four 28-month-old first-calving dairy heifers 3–4 days postpartum. X-ray diffraction (XRD) studies were undertaken on samples of soft and hard (cornified) integumental tissues of dorsal wall, sole and heel (bulb) for varying sites and planes of exposure. The measurements were interpreted as defining diffraction patterns and intermolecular spacings of cytoskeletal and extracellular fibrous structural proteins. The orientation of these proteins was examined in relation to physical characteristics and function including bearing of body weight by these tissues.
Physical measurements taken included impression hardness which showed typically greater values for wall than sole and variable differences between horn of dairy and beef origin and husbandry systems. Claws from dairy heifers had significantly smaller values for toe (dorsal wall) angle, claw height and heel height and thickness of solear horn and heel soft tissue. Although few were studied, the results reflected typical husbandry origins and indicated the susceptibility to the lesion formation well recognized in postpartum dairy cattle.
Typical XRD patterns for horn samples showed defined arcs of reflectance on the equatorial axis consistent with findings for the presence of α-helices in fibrils reported to occur in other hard-keratin-containing integumental tissues. However, reflectance on the meridional axis also reported for these other tissues was not detected. A similar defined pattern was obtained for less than 0·10 of samples of internal soft pre-cornified epidermal and attached dermal tissue although the values for intermolecular ‘d’ spacing for these were consistent with those reported for type I collagen. Diffuse reflection patterns were thus evident for the majority of samples of soft tissue epidermis and dermis and also for adipose tissue of the digital cushion.
The formation of defined arcs of reflectance allowed the determination of fibril alignment in wall and solear horn. For the orientated samples of dorsal wall horn tissue, the outer layer showed a longitudinal angle of orientation essentially maintained proximal to distal. This pattern was maintained throughout the depth of horn at the proximal site. In contrast, layers in mid-wall and towards the distal edge showed a greater circumferential (horizontal) orientation in sections collected anterior to posterior towards the inner corial, including laminar, tissues. The orientation of fibrils in inner wall horn appears to relate to the direction of load-bearing forces in connecting horn to the distal phalanx. Horizontal alignment of fibrils was observed in the sole. In presenting the long axis of cells to the ground surface this orientation may facilitate erosive forces and contribute to the thinning of cornified sole horn under adverse underfoot conditions.
The steady, laminar, incompressible flow over a periodic wavy surface with a prescribed surface-velocity distribution is found from the solution (via Newton's method) of the two-dimensional Navier–Stokes equations. Validation runs have shown excellent agreement with known analytical (Benjamin 1959) and analytico-numerical (Bordner 1978) solutions for small-amplitude wavy surfaces: For steeper waves, significant changes are observed in the computed surface-pressure distribution (and consequently in the nature of the momentum flux across the interface) when a surface orbital velocity distribution, of the type found in water waves, is included,
Forward pricing behavior of random samples of Indiana, Nebraska, andMississippi crop producers was analyzed using Heckman's two-step limitedinformation maximum likelihood estimation procedure. Producers who forwardpriced during the 1995–1998 period generally expected to forward price in1999 using similar techniques. Probit models were estimated for cash forwardcontracts and taking a direct position in futures or options separately andcombined. Results provide limited support for the hypothesis that forwardpricing should be analyzed as an adoption decision. Variables reflectingrisk attitudes do affect the decision to use forward pricing, whilevariables related to economic position affect the level of forwardpricing.
Cows managed for extended lactations of 16 months duration were milked on a half-udder basis twice or thrice daily, commencing in lactation week 9. Mammary epithelial integrity (assessed by milk sodium[ratio ]potassium ratio) was greater in the half-udder which was milked thrice daily. This difference was evident throughout the lactation but became greater after week 41. Milk protein composition was assessed during late lactation (52±3 weeks). Casein number (casein as a proportion of total protein) was significantly higher in half-udders milked thrice daily, as were the relative amounts of α- and β-caseins, whilst those of κ- and γ-caseins were reduced. Two days of inverted milking frequency (i.e. thrice-milked udder halves now milked twice, and vice versa) only partly reversed these differences. We concluded that thrice-daily milking will help to prevent or ameliorate the usual decline in milk processing quality associated with late lactation. Part of this effect is due simply to reduced exposure to proteolytic enzymes as a result of decreased storage time in the udder, but part is due to a better maintenance of epithelial tight junction integrity as lactation advances, which restricts leakage of proteolytic enzymes from serum into milk.