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Search Results: 1 - 10 of 464680 matches for " Elisa A.;Ratcliffe "
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The distribution of agglutinins and lytic activity against Trypanosoma rangeli and erythrocytes in Rhodnius prolixus and Triatoma infestans tissue extracts and haemolymph
Gregório, Elisa A.;Ratcliffe, Norman A.;
Memórias do Instituto Oswaldo Cruz , 1991, DOI: 10.1590/S0074-02761991000200007
Abstract: haemolymph, heads, salivary glands, crops, midguts, hindguts, and malpighian tubules from rhodnius prolixus and triatoma infestans were extracted in phosphate or tris buffer saline with calcium, and tested for agglutination and lytic activities by microtitration against both vertebrateerythrocytes and cultured epimatigote forms of trypanosoma rangeli. haemagglutination activity against rabbit erythrocytes was found in the crop, midgut and hindgut extracts of t. infestans but only in the haemolymph of r. prolixus. higher titres of parasite agglutinins were found in r. prolixus haemolymph than t. infestans, whilst the converse occurred for the tissue extracts. in addition, the extracts of t. infestans salivary glands, but not those of r. prolixus, showed a trypanolytic activity that was heat-inactivated and was not abolished by pre-incubation with any of the sugars or glycoproteins tested. t. infestans, which is refractory to infection by t. rangeli, thus appears to contain a much wider distribution of agglutinating and trypanolytic factors in its tissues than the more susceptible species, r. prolixus
Aspects of birth history and outcome in diplegics attending specialised educational facilities
F Bischof, A Rothberg, I Ratcliffe
South African Medical Journal , 2012,
Abstract: Aim. We aimed to study functional mobility and visual performance in spastic diplegic children and adolescents attending specialised schools. Methods. Spastic diplegia (SD) was confirmed by clinical examination. Birth and related history were added to explore relationships between SD, birth weight (BW) and duration of pregnancy. Place of birth, BW, gestational age (GA) and length of hospital stay were obtained by means of parental recall. Outcome measures included the functional mobility scale (FMS) and Beery tests of visuomotor integration (VMI) and visual perception (VIS). Results. Forty participants were included (age 7 years 5 months – 19 years 6 months). Term and preterm births were almost equally represented. Functional mobility assessments showed that 20 were walking independently in school and community settings and the remainder used walking aids or wheelchairs. There were no significant correlations between BW or GA and outcomes (FMS, VIS-z-scores or VMI-z-scores) and z-scores were low. VIS scores correlated significantly with chronological age (p=0.024). There were also significant correlations between VIS and VMI scores and school grade appropriateness (p=0.004; p=0.027, respectively). Interpretation. Both term and preterm births were represented, and outcomes were similar regardless of GA. VIS and VMI were affected in both groups. Half of the group used assistive mobility devices and three-quarters were delayed in terms of their educational level. These problems require specialised teaching strategies, appropriate resources and a school environment that caters for mobility limitations.
A Review of Solar Type III Radio Bursts
Hamish A. S. Reid,Heather Ratcliffe
Physics , 2014, DOI: 10.1088/1674-4527/14/7/003
Abstract: Solar type III radio bursts are an important diagnostic tool in the understanding of solar accelerated electron beams. They are a signature of propagating beams of nonthermal electrons in the solar atmosphere and the solar system. Consequently, they provide information on electron acceleration and transport, and the conditions of the background ambient plasma they travel through. We review the observational properties of type III bursts with an emphasis on recent results and how each property can help identify attributes of electron beams and the ambient background plasma. We also review some of the theoretical aspects of type III radio bursts and cover a number of numerical efforts that simulate electron beam transport through the solar corona and the heliosphere.
The Durham/UKST Galaxy Redshift Survey -III. Large Scale Structure via the 2-Point Correlation Function
A. Ratcliffe,T. Shanks,Q. A. Parker,R. Fong,.
Physics , 1997, DOI: 10.1046/j.1365-8711.1998.01329.x
Abstract: We have investigated the statistical clustering properties of galaxies by calculating the 2-point galaxy correlation function from the Durham/UKST Galaxy Redshift Survey. This survey is magnitude limited to bj = 17, contains 2500 galaxies sampled at a rate of one in three and surveys a 4 \times 10^6 (h^-1Mpc)^3 volume of space. We have empirically determined the optimal method of estimating the 2-point correlation function from just such a magnitude limited survey. Using this method, our correlation function results confirm the previously claimed detections of large scale power out to 40h^-1 Mpc scales. We compare with two common models of cosmological structure formation and find that our 2-point correlation function has power significantly in excess of the standard cold dark matter model in the 10-30h^-1 Mpc region, supporting the observational results of the APM galaxy survey.
The Durham/UKST Galaxy Redshift Survey - IV. Redshift Space Distortions via the 2-Point Correlation Function
A. Ratcliffe,T. Shanks,R. Fong,Q. A. Parker
Physics , 1997, DOI: 10.1046/j.1365-8711.1998.01330.x
Abstract: We have investigated the redshift space distortions in the optically selected Durham/UKST Galaxy Redshift Survey using the 2-point galaxy correlation function perpendicular and parallel to the observer's line of sight. We present results for the real space 2-point correlation function, by inverting the optimally estimated projected correlation function and find good agreement with other real space estimates. On small, non-linear scales we observe an elongation of the z-space corelation function contours in the line of sight direction. Our result for the 1-D pairwise rms velocity dispersion is sigma = 416 +- 36 kms^-1 which is consistent with those from recent redshift surveys and canonical values, but inconsistent with SCDM or LCDM models. On larger, linear scales we observe a compression of the z-space correlation function contours in the line of sight direction. This is due to the infall of galaxies into overdense regions and the Durham/UKST data favours a value of Omega^0.6/b = 0.5, where Omega is the mean mass density of the Universe and b is the linear bias factor which relates the galaxy and mass distributions. Comparison with other optical estimates yield consistent results, with the conclusion that the data does not favour an unbiased critical-density universe.
The Durham/UKST Galaxy Redshift Survey - II. The Field Galaxy Luminosity Function
A. Ratcliffe,T. Shanks,Q. A. Parker,R. Fong
Physics , 1997, DOI: 10.1046/j.1365-8711.1998.01137.x
Abstract: We present the results for the galaxy luminosity function as estimated from the Durham/UKST Galaxy Redshift Survey. This survey is magnitude limited to bj = 17, contains 2500 galaxies sampled at a rate of one in three and surveys a 4 x 10^6 Mpc^3 volume of space. The maximum likelihood parameters for a standard Schechter luminosity function are estimated to be M*bj = -19.72+-0.09, alpha = -1.14+-0.08 and phi* = (1.2 +- 0.2) x 10^-2 ( h^3Mpc^-3). A comparison with galaxy luminosity functions from other redshift surveys shows good agreement and the shape of the luminosity function now appears well-defined down to Mbj = -17. There are some discrepancies between the different surveys for galaxies fainter than this absolute magnitude. However, our estimate agrees well with that from the APM-Stromlo Galaxy Redshift Survey and we measure a fairly flat faint end slope.
Towards an understanding of the interactions of Trypanosoma cruzi and Trypanosoma rangeli within the reduviid insect host Rhodnius prolixus
Azambuja, Patrícia;Ratcliffe, Norman A.;Garcia, Eloi S.;
Anais da Academia Brasileira de Ciências , 2005, DOI: 10.1590/S0001-37652005000300004
Abstract: this review outlines aspects on the developmental stages of trypanosoma cruzi and trypanosoma rangeli in the invertebrate host, rhodnius prolixus. special attention is given to the interactions of these parasites with gut and hemolymph molecules and the effects of the organization of midgut epithelial cells on the parasite development. the vector insect's permissiveness to t. cruzi, which develops in the vector gut, largely depends on the host nutritional state, the parasite strain and the molecular interactions with trypanolytic compounds, lectins and resident bacteria in the gut. t. rangeli invades the hemocoel and once in the hemolymph, can be recognized and activates the defense system of its insect vector, i.e., the prophenoloxidase system, phagocytosis, hemocyte microaggregation, superoxide and nitric oxide activity and the eicosanoid biosynthesis pathway. taken together, these findings not only provide a better understanding of the interactions parasite - insect vector, but also offer new insights into basic physiological processes involved in the parasites transmission.
Aspects of classification of Hemiptera hemocytes from six triatomine species
Azambuja, Patricia de;Garcia, Eloi S.;Ratcliffe, Norman A.;
Memórias do Instituto Oswaldo Cruz , 1991, DOI: 10.1590/S0074-02761991000100002
Abstract: the objective of this work was to characterize, and compare different morphological types of hemocytes of rhodnius prolixus, rhodnius, rhodnius neglectus, triatoma infestans, panstrongylus megistus, and dipetalogaster maximus. this information provides the basis for studying the cellular immune systems of these insects. seven morphological hemocyte types wereidentified by phase-contrast microscopy: prohemocytes, plasmatocytes, granular cells, cytocytes, oenocytoids, adipohemocytes and giant cells. all seven types of hemocytes are not present in every species. for example, adipohemocytes and oenocytoids were not observed in p. megistus and p. infestans, and giant cells were rarely found in any of the species studied. the hemocytes of rhodnius and dipetalogaster are more similar to each other than those from triatoma and panstrongylus which in turn closely resemble each other. emphasis is placed on methodological problems arising in this work wicah are discussed in detail.
Separate lives, different interests: male and female reproduction in the Gambia
Ratcliffe,Amy A.; Hill,Allan G.; Walraven,Gijs;
Bulletin of the World Health Organization , 2000, DOI: 10.1590/S0042-96862000000500002
Abstract: we report the initial findings of a research programme on the fertility and reproductive health of both men and women in rural gambia. the reproductive experiences of men and women in the population studied were very different. during the period 1993-97, the total fertility rates were 12.0 for men and 6.8 for women. for men fertility began later, reached higher levels and continued into older ages than for women. through serial and polygynous marriages, men were able to extend their reproduction beyond what would be possible with one woman. of the married men interviewed, 40% were married polygynously. men?s fertility preferences indicated that they recognized their reproductive potentials to be greater than those of their individual wives. on average, married men desired 15.2 children for themselves and 7.3 for each wife. in this polygynous population the means available for attaining reproductive goals were different for the two sexes, depending on the separate lives and different interests of men and women.
Towards an understanding of the interactions of Trypanosoma cruzi and Trypanosoma rangeli within the reduviid insect host Rhodnius prolixus
Azambuja Patrícia,Ratcliffe Norman A.,Garcia Eloi S.
Anais da Academia Brasileira de Ciências , 2005,
Abstract: This review outlines aspects on the developmental stages of Trypanosoma cruzi and Trypanosoma rangeli in the invertebrate host, Rhodnius prolixus. Special attention is given to the interactions of these parasites with gut and hemolymph molecules and the effects of the organization of midgut epithelial cells on the parasite development. The vector insect's permissiveness to T. cruzi, which develops in the vector gut, largely depends on the host nutritional state, the parasite strain and the molecular interactions with trypanolytic compounds, lectins and resident bacteria in the gut. T. rangeli invades the hemocoel and once in the hemolymph, can be recognized and activates the defense system of its insect vector, i.e., the prophenoloxidase system, phagocytosis, hemocyte microaggregation, superoxide and nitric oxide activity and the eicosanoid biosynthesis pathway. Taken together, these findings not only provide a better understanding of the interactions parasite - insect vector, but also offer new insights into basic physiological processes involved in the parasites transmission.
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