International Rotifer Symposia: prospects and retrospects from Rotifera XI

The XI International Rotifer Symposium was held during 11–18 March, 2006 at the National Autonomous University of Mexico Campus Iztacala located at the North Mexico City (Mexico). These triennial international meetings, first organized in Austria by Late Ruttner-Kolisko in September 1976, are gradually becoming the focal point of discussion and collaboration from rotifer workers across the world. The present XI symposium was attended by 125 participants from 20 nations. During this meeting, different themes of rotifer research from morphology to molecular biology were considered. In addition, there were four invited lectures and four workshops covering different themes of the symposium. During the last 30 years, rotifer research has witnessed gradual shift from the conventional morphological taxonomy to molecular and evolutionary systematics. While the basic rotifer ecological studies continue today, applied areas such as ecotoxicology and aquaculture have taken key roles in the recent meetings. The international rotifer meetings provide ample opportunities not only for exchange of ideas and recent research, but also for material and in establishing inter-personal relationships. Over the last 30 years, the number of participants attending the rotifer meetings has increased

Parental Participation in the Education of Female Students with Learning Difficulties: The Views of Saudi Elementary Teachers and Parents.

This study contributes to knowledge of parental involvement in education in Saudi Arabia by focusing on teachers’ and parents’ conceptualisations, attitudes and practices of parental involvement in the education of female students with learning difficulties in elementary inclusive schools. The specific location of the research is Riyadh, the capital city of Saudi Arabia. Three specific objectives informed the research: (1) to obtain teachers’ and parents’ views on their conceptualisations and current practices of parent involvement, (2) to document and analyse teachers’ and parents’ views about the importance of parental involvement, roles, and responsibilities, and (3) to identify the obstacles to implementing effective parental involvement practices. In this study, I used Bronfenbrenner’s bioecological system theory to provide a framework for the development of the questionnaire, data collection, analysis, and discussion. Based on the pragmatic research paradigm, I utilised a mixed-methods design with a purposive sampling strategy to collect data from 110 teachers and 105 parents. The particular design chosen for this study was a sequential explanatory type which is also referred to as the QUAN-qual research model or the explanatory mixed-method design. The research approach involved the collection and analysis of survey data followed by the collection and analysis of interview data for integration. A close-ended questionnaire and a semi-structured interview for teachers and parents were employed to collect data. At the interview stage, 10 parents and 10 teachers from those who responded to the questionnaire were interviewed. The survey data were transferred from the hard copy material into SPSS version 26. The data analyses included descriptive statistic of mean, standard deviations and rankings of mean scores. In addition, factor analysis, t-test, and ANOVA were performed to test the cluster of responses and variabilities in the results pertaining to teachers and parents. Further, framework analysis serves as a pragmatic approach to the analysis of the interview data. The results indicated that parental involvement conceptualisation varied among participants. Key among their conceptualisations were: the connection between the members of the school’s community; the activities that teachers and parents participate in together; a two-way communication that helps to improve the education of students; and a contractual agreement between teachers and parents that involved trust, respectful relationship, and positive cooperation. In terms of parental involvement practices, almost all the teachers indicated that they did not involve parents in making decisions about their children’s education. More than half of the teachers indicated that they communicated to parents regularly to provide information about their children’s education. However, parents contend that teachers only communicated to them about their children’s academic problems and behavioural challenges. Regarding the availability of school-level policy on parental involvement, most teachers and parents agreed these policies did not exist. In the absence of policy to guide teachers, parental involvement practice was arbitrary, demonstrating a dissonance in practice. However, parents’ support for their daughters’ learning at home achieved the highest mean score. A major concern of parents was that school meetings were organised without consulting them which may implicate some barriers to parents’ involvement, but teachers claimed that parents’ attitudes reduced their interest in working with them. Further, some teachers alluded that their school responsibilities and lack of time made it impossible for them to involve parents. The majority of teachers affirmed that training them on how to work with parents might improve parental involvement. All parents claimed that positive and effective communication that incorporates respectful relationships can improve their relationships with teachers to participate in the education of their children with learning difficulties in inclusive elementary schools in Saudi Arabia. Based on these findings, I provided recommendations that may help in developing a contextually relevant parental involvement practice in Saudi Arabia

Effect of salinity stress on the life history variables of Branchipus schaefferi Fisher, 1834 (Crustacea: Anostraca)

BACKGROUND: Freshwater anostracans inhabit ephemeral water bodies in which as the water level decreases due to evaporation the salt concentration increases. Thus, for most anostracans salinity becomes the major stress factor. RESULTS: We tested five concentrations of NaCl (0 to 8 g/l) on the life table demography of Branchipus schaefferi fed Chlorella (alga). Age-specific survivorship curves of male and female B. schaefferi showed nearly a similar pattern in that increased salt concentration resulted in decreased survivorship. The age-specific reproduction (m(x)) of females showed several peaks of cyst production at 0 and 1 g/l salinity while in treatments containing salt at 4 or 8 g/l, there were fewer peaks. Average lifespan, life expectancy at birth, gross and net reproductive rates, generation time and the rate of population increase were all significantly influenced by the salt concentration in the medium. The highest value of net reproductive rate (970 cysts/female) was in treatments containing 0 g/l of salt, while the lowest was 13 cysts/female at 8 g/l. The rate of population increase (r) varied from 0.52 to 0.32 per day depending on the salt concentration in the medium. CONCLUSION: The low survival and offspring production of B. schaefferi at higher salinity levels suggests that this species is unlikely to colonize inland saline water bodies. Therefore, the temporary ponds in which it is found, proper conservative measures must be taken to protect this species

Geochemistry of silicate-rich rocks can curtail spreading of carbon dioxide in subsurface aquifers.

Pools of carbon dioxide are found in natural geological accumulations and in engineered storage in saline aquifers. It has been thought that once this CO2 dissolves in the formation water, making it denser, convection streams will transport it efficiently to depth, but this may not be so. Here, we assess theoretically and experimentally the impact of natural chemical reactions between the dissolved CO2 and the rock formation on the convection streams in the subsurface. We show that, while in carbonate rocks the streaming of dissolved carbon dioxide persists, the chemical interactions in silicate-rich rocks may curb this transport drastically and even inhibit it altogether. These results challenge our view of carbon sequestration and dissolution rates in the subsurface, suggesting that pooled carbon dioxide may remain in the shallower regions of the formation for hundreds to thousands of years. The deeper regions of the reservoir can remain virtually carbon free.J. T. H. A. gratefully acknowledges the Schlumberger Foundation for financial support for her PhD study.This is the accepted manuscript. The final version is available from NPG at http://www.nature.com/ncomms/2014/141211/ncomms6743/full/ncomms6743.html

Mixing and reaction in turbulent plumes: The limits of slow and instantaneous chemical kinetics

We investigate the behaviour of a reactive plume in the two limiting cases of slow and instantaneous chemical reactions. New laboratory measurements show that, whereas the slow reaction between the source and entrained chemical species takes place within the whole volume of each eddy in the plume, the fast reaction develops preferentially at the periphery of the eddies. We develop a new model that quantifies the mixing of the reactive buoyant fluids at the Batchelor scale and thereby the progress of the fast reaction. We present a series of new experimental results that suggest that a critical distance from the source, $z_{crit}$, exists at which the volume of fluid that is entrained from the ambient is equal to that which is mixed within the plume at the Batchelor scale. For z>z_{crit}, only a fraction of the entrained fluid is rapidly mixed and reacts with the plume fluid. The results of the new experiments enable us to quantify the distance from the source at which an instantaneous reaction reaches completion, and show that it can be significantly larger than the distance $L_{s}$ at which the stoichiometric dilution of the plume fluid is achieved. In the limit of an instantaneous reaction, the longitudinal profiles of source chemical concentration in the plume depend on $(z_{crit}/L_{s})^{5/6}$. The predictions of the model are validated against the experimental results, and the profiles of source chemical concentration in the plume for slow and fast reactions are compared.</jats:p

Streptococcus pneumonia serotype 19A bacteremia in a child fully immunized with 10-valent pneumococcal conjugate vaccine

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