THINKING SKILLS, ACADEMIC INTRINSIC MOTIVATION, ACADEMIC SELF-CONCEPT, AND ACADEMIC INDEPENDENCE IN HOMESCHOOLED CHILDREN

The purpose of this study was to examine thinking skills, academic intrinsic motivation, academic self-concept, and academic independence in homeschooled children. Homeschooled children ages 6-12 years old (N=46) completed the Test of Problem Solving 3: Elementary (TOPS), which measured the following thinking skills: making inferences, sequencing, answering negative questions, problem solving, predicting, and determining causes. The Homeschool Motivation Scale measured academic intrinsic motivation, academic self-concept, and academic independence. Parents completed a brief questionnaire. The results showed that homeschooled children’s TOPS scores were significantly higher than those of the test standardization sample for all six subscales and for the total test. There were significant positive correlations between TOPS total test scores and both academic intrinsic motivation and academic self-concept scores. TOPS total test scores were not consistently related to parental teaching techniques. This research suggests that thinking skills may be more advanced in homeschooled children than in children attending public schools

New molecular tools: application of the μAQUA phylochip and concomitant FISH probes to study freshwater pathogens from samples taken along the Tiber River, Italy

Current knowledge about aquatic pathogens are scarce because bacteria, protozoans, algae and their toxins occur at low concentrations, making them difficult to measure directly or to filter sufficient volumes to facilitate detection. We developed and validated tools to detect pathogens in freshwater systems. To evaluate impacts on water quality, a phylogenetic microarray was developed in the EU project μAQUA to detect simultaneously numerous pathogens and was applied in MicroCoKit, to samples taken from four locations from two seasons for two years along the length of the Tiber River, Italy. The sites ranged from a pristine site near its source to ones contaminated by agricultural, industrial and anthropogenic waste moving downstream to near its mouth. Fifty litres were collected and concentrated using a hollow-fibre ultrafiltration, a rapid method with minimal cell loss to provide a concentrate for downstream analysis. The 60 Da cut-off ensures many organics, such as toxins, will be concentrated for analysis. Aliquots from the concentrate were preserved in TRI-Reagent and total RNA extracted, labelled and hybridised to the phylochip to detect pathogenic bacteria, protozoa and toxic cyanobacteria. The microarray results gave positive signals for all pathogens. Calibration curves enabled us to infer cell concentrations. Cross validation was performed using FISH probes for selected toxic cyanobacteria and hybridised to aliquots taken from the raw water prior to concentration by the hollow fibre filters

Mapping Selected Emergent Marine Toxin-Producing Organisms Using Historical Samples with Two Methods (Biosensors and Real-Time PCR): A Comparison of Resolution

The Continuous Plankton Recorder (CPR) survey is a valuable resource for mapping changes in plankton distribution and understanding harmful algal ecology because of its breadth and longevity. Preservation methods with formalin degrade DNA, making it difficult to use as a molecular tool for archived marine samples. DNA was extracted from CPR samples immediately after collection, seven months later and after nine years of storage from a cruise track along the Iberian Peninsula. PCR reactions performed from the nine-year timepoint were hybridized to probes in an electrochemical biosensor and compared to results obtained from RT-PCR performed at two earlier time points. The successful identification of Pseudo-nitzschia spp., Prorocentrum lima, Alexandrium minutum, Alexandrium ostenfeldii, Gambierdiscus spp. and Coolia spp. was documented. The biosensor analysis outperformed RT-PCR, allowing us to document certain tropical toxic dinoflagellates, viz., Gambierdiscus and Coolia, that produce human ciguatoxins and Coolia toxins, respectively. These non-native algal toxins can accumulate, pervade the food web and negatively impact human food security. This supports the northerly movement of microalgae with climate change in offshore Iberian peninsular waters. This study highlights biosensors as a cost-effective tool for the offshore monitoring of HAB species and advances molecular technologies for long-term CPR datasets that have limited records of harmful algae. DNA from formalin-preserved CPR samples is degraded, so the use of a short, multiprobe biosensor can augment historical plankton records with contemporary methods that also capture infrequently occurring benthic taxa carried in surface waters. The integration of probe-based biosensor technologies offers a promising avenue for exploring plankton dynamics in response to environmental changes.</jats:p

Solid deuterium surface degradation at ultracold neutron sources

Solid deuterium (sD_2) is used as an efficient converter to produce ultracold neutrons (UCN). It is known that the sD_2 must be sufficiently cold, of high purity and mostly in its ortho-state in order to guarantee long lifetimes of UCN in the solid from which they are extracted into vacuum. Also the UCN transparency of the bulk sD_2 material must be high because crystal inhomogeneities limit the mean free path for elastic scattering and reduce the extraction efficiency. Observations at the UCN sources at Paul Scherrer Institute and at Los Alamos National Laboratory consistently show a decrease of the UCN yield with time of operation after initial preparation or later treatment (`conditioning') of the sD_2. We show that, in addition to the quality of the bulk sD_2, the quality of its surface is essential. Our observations and simulations support the view that the surface is deteriorating due to a build-up of D_2 frost-layers under pulsed operation which leads to strong albedo reflections of UCN and subsequent loss. We report results of UCN yield measurements, temperature and pressure behavior of deuterium during source operation and conditioning, and UCN transport simulations. This, together with optical observations of sD_2 frost formation on initially transparent sD_2 in offline studies with pulsed heat input at the North Carolina State University UCN source results in a consistent description of the UCN yield decrease.Comment: 15 pages, 22 figures, accepted by EPJ-

A new fluorescent oligonucleotide probe for in-situ identification of Microcystis aeruginosa in freshwater.

contaminated water bodies (freshwater, brackish and marine areas). Among 150 known cyanobacteria genera,>40 species are able to produce toxins, which are natural compounds that differ from both a chemical and toxicological point of view and are responsible for acute and chronic poisoning in animals and humans. Among the main classes of cyanotoxins, microcystins are frequently found in the environment. Fast and accurate methods for unequivocally identifying microcystin-producing cyanobacteria, such as Microcystis aeruginosa in water bodies, are necessary to distinguish them from other non-toxic cyanobacteria and to manage and monitor algal blooms. For this purpose, we designed, developed and validated an oligonucleotide probe for FISH (Fluorescence In Situ Hybridization) analysis to detect Microcystis aeruginosa at the species level even at relatively low concentrations in freshwater. The FISH probe, MicAerD03, was designed using the ARB software with the Silva database within the framework of the MicroCoKit project, also with the intention of adding it to the microarray from the EU project, μAQUA, for freshwater pathogens, which had only genus level probes for Microcystis. We tested various fixative methods to minimize the natural autofluorescence from chlorophyll-a and certain accessory pigments (viz., phycobilins and carotenoids). The FISH probe was tested on pure cultures of Microcystis aeruginosa, and then successfully applied to water samples collected from different sampling points of the Tiber River (Italy), using a laser confocal microscope. Subsequently, the probe was also conjugated at the 5′ end with horse-radish peroxidase (HRP-MicAerD03) to apply the CAtalysed Reported Deposition-FISH (CARD-FISH) for increasing the fluorescence signal of the mono-fluorescently labelled probe and make it possible to detect M. aeruginosa using an epifluorescence microscope. Samples taken within the EU MicroCokit project indicated thatmicroarray signals for Microcystis were coming from single cells and not colonial cells. We confirmed this with the CARD-FISH protocol used here to validate the microarray signals for Microcystis detected at the genus level in MicroCokit. This paper provides a new early warning tool for investigating M. aeruginosa at the species level even at low cell concentrations in surface water, which can be added to the μAqua microarray for all freshwater pathogens to complete the probe hierarchy for Microcystis aeruginosa

Advances in the Detection of Toxic Algae Using Electrochemical Biosensors

Harmful algal blooms (HABs) are more frequent as climate changes and tropical toxic species move northward, especially along the Iberian Peninsula, a rich aquaculture area. Monitoring programs, detecting the presence of toxic algae before they bloom, are of paramount importance to protect ecosystems, aquaculture, human health and local economies. Rapid, reliable species identification methods using molecular barcodes coupled to biosensor detection tools have received increasing attention as an alternative to the legally required but impractical microscopic counting-based techniques. Our electrochemical detection system has improved, moving from conventional sandwich hybridization protocols using di�erent redox mediators and signal probes with di�erent labels to a novel strategy involving the recognition of RNA heteroduplexes by antibodies further labelled with bacterial antibody binding proteins conjugated with multiple enzyme molecules. Each change has increased sensitivity. A 150-fold signal increase has been produced with our newest protocol using magnetic microbeads (MBs) and amperometric detection at screen-printed carbon electrodes (SPCEs) to detect the target RNA of toxic species. We can detect as few as 10 cells

Pseudo-cryptic speciation in coccolithophores

Coccolithophores are a group of calcifying unicellular algae that constitute a major fraction of oceanic primary productivity, play an important role in the global carbon cycle, and are key biostratigraphic marker fossils. Their taxonomy is primarily based on the morphology of the minute calcite plates, or coccoliths, covering the cell. These are diverse and include widespread fine scale variation, of which the biological/taxonomic significance is unknown. Do they represent phenotypic plasticity, genetic polymorphisms, or species-specific characters? Our research on five commonly occurring coccolithophores supports the hypothesis that such variation represents pseudocryptic speciation events, occurring between 0.3 and 12.9 million years ago from a molecular clock estimation. This finding suggests strong stabilizing selection acting on coccolithophorid phenotypes. Our results also provide strong support for the use of fine scale morphological characters of coccoliths in the fossil record to improve biostratigraphic resolution and paleoceanographic data retrieval