Study of natural and induced tissue response in Macrobrachium rosenbergii de Man

The tissue response of the giant freshwater prawn Macrobrachium rosenbergii de Man, was studied histologically by investigating clinical cases of natural infectious and non-infectious diseases which occurred in cultured prawns and by carrying out the following experimental intramuscular injection of alcian blue dye, intramuscular injection of BCG vaccine (also using TEM), intramuscular injection of complete Freund’s adjuvant, intramuscular and systemic injection of heat-killed Aeromonas hydrophila, intramuscular and systemic injection of heat-killed and live Vibrio parahaemolyticus and Vibrio anguillarum, grafting or insertion of pieces of cuticle into the muscle of the same or different prawns and by cuticular traumatization or wounding of slight, moderate and severe degrees (also using SEM). Results demonstrated histologically the presence of a unified system of haemocytic cells participating in a range of defensive activities in varying degrees of intensity; viz. infiltration, aggregation, coagulation, melanization, phagocytosis, encapsulation, nodule formation and fibroplasia. More pronounced haemocytic activity occurred in the gills, hepatopancreas, heart and antennal gland, in addition to locally at the site of injection, wounding or grafting. Electron microscopy revealed that the haemocytes which participate in the tissue inflammatory response consist of cell types belonging to all three main classes, namely agranular, semi-granular and granular haemocytes, although semi-granular and granular haemocytes appeared to predominate. Findings of the experimentally induced tissue response were comparable to observations in the natural infectious and non-infectious disease conditions in Macrobrachium and in general, similar to those reported in natural infections and experimental challenges of other important wild and cultured crustaceans including penaeid shrimps, crabs and crayfish. A routine study of the haemocytic tissue response in cultured prawns can be recommended as a useful means of monitoring their health status and identifying the early stages of a disease process. This can prove of assistance in developing disease control strategies

Multi-particle Correlations in Quaternionic Quantum Systems

We investigate the outcomes of measurements on correlated, few-body quantum systems described by a quaternionic quantum mechanics that allows for regions of quaternionic curvature. We find that a multi-particle interferometry experiment using a correlated system of four nonrelativistic, spin-half particles has the potential to detect the presence of quaternionic curvature. Two-body systems, however, are shown to give predictions identical to those of standard quantum mechanics when relative angles are used in the construction of the operators corresponding to measurements of particle spin components.Comment: REVTeX 3.0, 16 pages, no figures, UM-P-94/54, RCHEP-94/1

Executive functioning and verbal fluency in children with language difficulties

This study provided a detailed analysis of verbal fluency in children with language difficulties, and examined the relative contributions of executive functioning (executive-loaded working memory, switching, inhibition) and language ability to verbal fluency performance. Semantic and phonemic fluency, language, and executive functioning tasks were completed by 41 children with specific language impairment (SLI) and 88 children with typical development. Children with SLI showed difficulties with most aspects of verbal fluency (rates of output, errors, switching) relative to typical children. Language ability predicted nearly every aspect of phonemic fluency performance and some aspects of semantic fluency performance. The relationships between verbal fluency and executive functioning were modest: inhibition was related to error scores on the phonemic fluency task, but relationships with executive-loaded working memory and switching were absent. Educationally, these results emphasise the underlying importance of language abilities in generation tasks like verbal fluency, but point to the importance of inhibition skills for error monitoring. Interventions to improve search and generation abilities have the potential to offer broader benefits in the classroom for children with language difficulties

Heritability of Clinical Mastitis Incidence and Relationships with Sire Transmitting Abilities for Somatic Cell Score, Udder Type Traits, Productive Life, and Protein Yield

The objective of this study was to determine the relationships among daughter clinical mastitis during first and second lactations and sire transmitting abilities for somatic cell score, udder type traits, productive life, and protein yield. Data on clinical mastitis during first lactation were available for 1795 daughters (in six Pennsylvania herds, one Minnesota herd, and one Nebraska herd) of 283 Holstein sires. Data on clinical mastitis during second lactation were available for 1055 of these daughters. A total of 479 cows had 864 clinical episodes during first lactation, and 230 cows had 384 clinical episodes during second lactation. Clinical mastitis incidence and the total number of clinical episodes during each lactation were regressed on herd-season of calving (a classification variable), age at first calving, lactation length, and sire transmitting abilities taken one at a time. Linear effects, nonlinear effects, and odds ratios were estimated for sire transmitting abilities. Separate analyses were conducted on dependent variables that considered clinical mastitis from: all organisms, coagulase-negative staphylococci, coliform species, streptococci other than Streptococcus agalactiae, and the most common environmental organisms (coliform species and streptococci other than Streptococcus agalactiae). Heritability of clinical mastitis ranged from 0.01 to 0.42. Daughters of sires that transmit the lowest somatic cell score had the lowest incidence of clinical mastitis and the fewest clinical episodes during first and second lactations. Daughters of sires that transmit longer productive life, shallower udders, deeper udder cleft, and strongly attached fore udders had either fewer clinical episodes or lower clinical mastitis incidence during first and second lactations. The incidence of clinical mastitis and the number of clinical episodes per lactation may be reduced by selection for lower somatic cell score, longer productive life, shallower udders, deeper udder cleft, or strongly attached fore udders

Global effects in quaternionic quantum field theory

We present some striking global consequences of a model quaternionic quantum field theory which is locally complex. We show how making the quaternionic structure a dynamical quantity naturally leads to the prediction of cosmic strings and non-baryonic hot dark matter candidates.Comment: 11 pages, no figures, revte

A variational principle for volume-preserving dynamics

We provide a variational description of any Liouville (i.e. volume preserving) autonomous vector fields on a smooth manifold. This is obtained via a ``maximal degree'' variational principle; critical sections for this are integral manifolds for the Liouville vector field. We work in coordinates and provide explicit formulae

Hot dense capsule implosion cores produced by z-pinch dynamic hohlraum radiation

Hot dense capsule implosions driven by z-pinch x-rays have been measured for the first time. A ~220 eV dynamic hohlraum imploded 1.7-2.1 mm diameter gas-filled CH capsules which absorbed up to ~20 kJ of x-rays. Argon tracer atom spectra were used to measure the Te~ 1keV electron temperature and the ne ~ 1-4 x10^23 cm-3 electron density. Spectra from multiple directions provide core symmetry estimates. Computer simulations agree well with the peak compression values of Te, ne, and symmetry, indicating reasonable understanding of the hohlraum and implosion physics.Comment: submitted to Phys. Rev. Let

Perturbation Theory and Control in Classical or Quantum Mechanics by an Inversion Formula

We consider a perturbation of an ``integrable'' Hamiltonian and give an expression for the canonical or unitary transformation which ``simplifies'' this perturbed system. The problem is to invert a functional defined on the Lie- algebra of observables. We give a bound for the perturbation in order to solve this inversion. And apply this result to a particular case of the control theory, as a first example, and to the ``quantum adiabatic transformation'', as another example.Comment: Version 8.0. 26 pages, Latex2e, final version published in J. Phys.

Do measures of memory, language, and attention predict eyewitness memory in children with and without autism?

Background & aims. There are few investigations of the relationship between cognitive abilities (memory, language and attention) and children’s eyewitness performance in typically developing children (TD), and even fewer in children on the autism spectrum. Such investigations are important to identify key cognitive processes underlying eyewitness recall, and assess how predictive such measures are compared to non-verbal IQ, diagnostic group status (autism or TD) and age. Methods. A total of 272 children (162 boys; 110 girls) of age 76 months to 142 months (M = 105 months) took part in this investigation: 71 children with autism and 201 TD children. The children saw a staged event involving a minor mock crime and were asked about what they had witnessed in an immediate Brief Interview. This focused on free recall, included a small number of open-ended questions, and was designed to resemble an initial evidence gathering statement taken by police officers arriving at a crime scene. Children were also given standardised tests of intelligence, memory, language and attention. Results & conclusions. Despite the autism group recalling significantly fewer items of correct information than the TD group at Brief Interview, both groups were equally accurate in their recall: 89% of details recalled by the TD group and 87% of the details recalled by the autism group were correct. To explore the relationship between Brief Interview performance and the cognitive variables, alongside age, diagnostic group status and non-verbal IQ, multiple hierarchical regression analyses were conducted, with Brief Interview performance as the dependant variable. Age and diagnostic group status were significant predictors of correct recall, whereas non-verbal IQ was less important. After age, non-verbal IQ and diagnostic group status had been accounted for, the only cognitive variables that were significant predictors of Brief Interview performance were measures of memory (specifically, memory for faces and memory for stories). There was little evidence of there being differences between the autism and TD groups in the way the cognitive variables predicted the Brief Interview. Implications. The findings provide reassurance that age – the most straightforward information to which all relevant criminal justice professionals have access – provides a helpful indication of eyewitness performance. The accuracy of prediction can be improved by knowing the child’s diagnostic status (i.e., whether the child is on the autism spectrum), and further still by using more specific assessments (namely memory for faces and memory for stories), possibly via the input of a trained professional. Importantly, the findings also confirm that whilst children with autism may recall less information than TD children, the information they do recall is just as accurate

Global embedding of the Kerr black hole event horizon into hyperbolic 3-space

An explicit global and unique isometric embedding into hyperbolic 3-space, H^3, of an axi-symmetric 2-surface with Gaussian curvature bounded below is given. In particular, this allows the embedding into H^3 of surfaces of revolution having negative, but finite, Gaussian curvature at smooth fixed points of the U(1) isometry. As an example, we exhibit the global embedding of the Kerr-Newman event horizon into H^3, for arbitrary values of the angular momentum. For this example, considering a quotient of H^3 by the Picard group, we show that the hyperbolic embedding fits in a fundamental domain of the group up to a slightly larger value of the angular momentum than the limit for which a global embedding into Euclidean 3-space is possible. An embedding of the double-Kerr event horizon is also presented, as an example of an embedding which cannot be made global.Comment: 16 pages, 13 figure