716 research outputs found
Bolidomonas: a new genus with two species belonging to a new algal class, the Bolidophyceae (Heterokonta) 1.
International audienceA new algal class, the Bolidophyceae (Heterokonta), is described from one genus, Bolidomonas, gen, nov., and two species, Bolidomonas pacifica, sp, nov and Bolidomonas mediterranea, sp, nov., isolated from the equatorial Pacific Ocean and the Mediterranean Sea, respectively. Both species are approximately 1.2 mu m in diameter and have two unequal flagella; the longer flagellum bears tubular hairs, whereas the shorter is smooth. The flagellar basal apparatus is restricted to two basal bodies, and there is no transitional helix. Cells are naked, devoid of walls or siliceous structures. The internal cellular organization is simple with a single plastid containing a ring genophore and a girdle lamella, one mitochondrion with tubular cristae, and one Golgi apparatus close to the basal bodies. The Mediterranean and the Pacific species differ in the insertion angle between their flagella and their pattern of swimming, these differences possibly being linked to each other. Analyses of the SSU rDNA gene place the two strains as a sister group to the diatoms, Moreover, pigment analyses confirm this position, as fucoxanthin is found as the major carotenoid in both lineages. These data strongly suggest that the ancestral heterokont that gave rise to the diatom lineage was probably a biflagellated unicell
Preliminary results of the MIDTAL project: a microarray chip to monitor toxic dinoflagellates in the Orkney Islands, U.K.
Harmful algae can cause economic damage to fisheries and tourism. Additionally, toxins produced by harmful algae and ingested via contaminated shellfish can be potentially fatal to humans. Monitoring these harmful algae can be difficult as determining cell morphology by light microscopy may be insufficient to give definitive species attribution. The goal of the EU FP7 project MIDTAL (microarrays for the detection of toxic algae) was to achieve rapid species identification using species specific probes for rRNA genes in a microarray chip format. Field samples from the Orkney Islands, an area of the U.K. that has a number of nuisance and toxic species were tested with the second generation of the microarray chip. Species specific probes were looked at for the toxin producing dinoflagellates Alexandrium tamarense Group III (North American clade) and Dinophysis acuta and also general class probes for Dinophyta, Heterokontaphyta and Prymnesiophyta over the course of a year. These were compared with light microscopy cell counts. A good agreement in determining presence and absence between the methods was found. The second generation microarray is potentially more sensitive than cell counts. However, further work is needed to ensure that the microarray signal for each species provides an accurate quantitative assessment
Metallurgical and Corrosion Assessment of Submerged Tanker S.S. \u3ci\u3eMontebello\u3c/i\u3e
The Union Oil Tanker S.S. Montebello was torpedoed and sunk six miles (9.7 km) off the coast of Cambria, California by a Japanese submarine on December 23, 1941, two weeks after the attack on Pearl Harbor. With close proximity to the National Monterey Bay Marine Sanctuary, concern about possible crude oil contamination led to the most recent expedition to the site in October 2011. Assessment of the shell plate found that the average corrosion rate was very low and the structure will remain stable for many decades
Multi-digit Auto-amputation in Setting of Mixed Connective Tissue Disease
Raynaudâs disease is a cutaneous manifestation often present in various connective tissue and vascular diseases. Depending on the age of onset and acuity of symptoms, the phenomenon can provide clinicians with some insight as to the severity of underlying disease, including the distinction between primary and secondary Raynaudâs. However, this diagnostic approach seems to have its limitations regarding efficacy and timing of treatment. Traditionally, treatment of Raynaudâs has focused on reestablishing blood perfusion to affected tissue, which has previously been achieved with vasodilatory medications and site-specific surgical intervention. In lieu of the severe sequelae of Raynaudâs in the setting of mixed connective tissue disease, including autoamputation, preemptive treatment of Raynaudâs should be considered, as distinguishing between a primary and secondary etiology of Raynaudâs can often be difficult to discern. This case highlights the importance of conventional salvage therapies prior to establishing a definitive diagnosis or etiology of the phenomenon, as evidenced by our patient experiencing irreversible ischemic damage resulting in uncontrolled autoamputation of her digits
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 childrenâs 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 ÎŒAQUA 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 ÎŒAQUA 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
The Impacts of Microphysics and Planetary Boundary Layer Physics on Model Simulations of U. S. Deep South Summer Convection
Inspection of output from various configurations of high-resolution, explicit convection forecast models such as the Weather Research and Forecasting (WRF) model indicates significant sensitivity to the choices of model physics parameterizations employed. Some of the largest apparent sensitivities are related to the specifications of the cloud microphysics and planetary boundary layer physics packages. In addition, these sensitivities appear to be especially pronounced for the weakly-sheared, multicell modes of deep convection characteristic of the Deep South of the United States during the boreal summer. Possible ocean-land sensitivities also argue for further examination of the impacts of using unique ocean-land surface initialization datasets provided by the NASA Short-term Prediction Research and Transition (SPoRT Center to select NOAA/NWS weather forecast offices. To obtain better quantitative understanding of these sensitivities and also to determine the utility of the ocean-land initialization data, we have executed matrices of regional WRF forecasts for selected convective events near Mobile, AL (MOB), and Houston, TX (HGX). The matrices consist of identically initialized WRF 24-h forecasts using any of eight microphysics choices and any of three planetary boundary layer choices. The resulting 24 simulations performed for each event within either the MOB or HGX regions are then compared to identify the sensitivities of various convective storm metrics to the physics choices. Particular emphasis is placed on sensitivities of precipitation timing, intensity, and coverage, as well as amount and coverage of lightning activity diagnosed from storm kinematics and graupel in the mixed phase layer. The results confirm impressions gleaned from study of the behavior of variously configured WRF runs contained in the ensembles produced each spring at the Center for the Analysis and Prediction of Storms, but with the benefit of more straightforward control of the physics package choices. The design of the experiments thus allows for more direct interpretation of the sensitivities to each possible physics combination. The results should assist forecasters in their efforts to anticipate and correct for possible biases in simulated WRF convection patterns, and help the modeling community refine their model parameterizations
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