Determining the relative sensitivity of benthic diatoms to atrazine using rapid toxicity testing: A novel method

Herbicides pose a potential threat to aquatic ecosystems, especially to phototrophic organisms such as benthic diatoms. Benthic diatoms may be a valuable indicator of the toxic impacts of herbicides in aquatic systems. However, this requires information on the herbicide sensitivity of a wide range of freshwater benthic diatom taxa. Unfortunately this information is only available for a limited number of species as current methods of developing new algae toxicity tests on individual taxa are lengthy and costly. To address this issue, we developed a new rapid toxicity test method to test natural benthic communities, from which the relative herbicide sensitivity of many individual taxa can be derived. This involved the collection of natural benthic communities from rocks in situ, which were placed directly into laboratory toxicity tests. Sensitivity data for several diatom genera in a 48hour exposure toxicity test were produced, without the need for cultures or multiple site visits. After exposure to the highest treatment of atrazine (500μgL-1) there were significant declines of healthy cells in the most sensitive genera: Gomphonema declined by 74%, Amphora by 62%, Cymbella by 54% and Ulnaria by 34% compared to control levels. In contrast, the genera, Eunotia, Achnanthidium and Navicula, had no statistically significant decline in cell health. This method can identify the diatom taxa most at risk of herbicide toxicity within the natural benthic diatom community. The rapid toxicity testing method presented is a simple and effective method to obtain sensitivity data for multiple taxa within a natural benthic diatom community in a relatively short period of time. © 2014 Elsevier B.V

Basking shark breaching behaviour observations West of Shetland

This is the author accepted manuscript. The final version is available from BioMed Central via the DOI in this record.This study reports observations of basking sharks (Cetorhinus maximus) sighted during an offshore geophysical survey conducted in July and August 2013, west of Shetland, UK. During the 38-day survey, trained and dedicated marine wildlife observers recorded 19 sightings of basking sharks (n=22 individuals). Of these observations, 17 were of single sharks, with one observation of two sharks and one observation of three sharks. All surface sightings occurred in water with depths between 129 and 199 m, predominantly prior to noon local time (79%), and were mostly of sharks 6-8 m in length, although a young (2 m) individual was also recorded. Breaching behaviour was observed on 14 occasions, by individuals or in small groups. Breaching has been proposed as a male-male competitive behaviour during courtship displays and female basking sharks may breach to signal their readiness for mating. Aggregations of basking sharks at frontal systems are well documented and linked to the occurrence of prey patches; however, these oceanographic features may also be of importance to courtship. The high number of sightings of sharks recorded during a relatively short time frame in addition to breaching behaviour and presence of young individuals, suggest that this area west of Shetland may be an important habitat for the basking shark

Angular needle tracker and stabilizer for image-guided interventions

Introduction Minimally invasive image-guided interventions have changed the face of procedural medicine. For these procedures, safety and efficacy depend on precise needle placement. Needle targeting devices help improve the accuracy of needle placement, but their use has not seen broad penetration. Some of these devices are costly and require major modifications to the clinical workflow. In this article, we developed a low-cost, disposable, and easy-to-use angulation tracking device, which was based on a redesigned commercial passive needle holder. Material and methods The new design provided real-time angulation information for needle tracking. In this design, two potentiometers were used as angulation sensors, and they were connected to two axes of the passive needle holder’s arch structure through a 3 D-printed bridge structure. A control unit included an Arduino Pro Mini, a Bluetooth module, and two rechargeable batteries. The angulation was calculated and communicated in real time to a novel developed smartphone app, where real-time angulation information was displayed for guiding the operator to position the needle to the planned angles. Results The open-air test results showed that the average errors are 1.03° and 1.08° for left–right angulation and head–foot angulation, respectively. The animal cadaver tests revealed that the novel system had an average angular error of 3.2° and a radial distance error of 3.1 mm. Conclusions The accuracy was comparable with some commercially available solutions. The novel and low-cost needle tracking device may find a role as part of a real-time precision approach to both planning and implementation of image-guided therapies

IBM 360 version of the neutron diffusion code CRAM.

The A.A.E.C. 360 CRAM program, written in FORTRAN IV and ASSEMBLER, is designed to run under the 360 operating system on a 256K model 50. The program can readily be changed to take advantage of additional storage that may be available on other 360 configurations. The code includes standard output routines as well as providing the user with the facility of including his own FORTRAN coded output routines. The code package includes sets of test problems for both one and two dimensional geometries

Earth science: Redox state of early magmas

International audienceA study of cerium in zircon minerals has allowed an assessment of the redox conditions that prevailed when Earth's earliest magmas formed. The results suggest that the mantle became oxidized sooner than had been though

Cadmium isotope fractionation during metal-silicate partitioning – Results and implications for Earth's volatile accretion

Metal-silicate partitioning experiments were carried out at 1.5 GPa and 1508 to 1843 K to constrain Cd partitioning and isotope fractionation during core formation. At the studied conditions, there was no significant stable isotope fractionation during Cd partitioning between metal and silicate phases with a mean ∆114Cdmet-sil = −0.02 ± 0.09‰ (2SD, n = 7). Two experiments that investigated sulphide-silicate partitioning of Cd yielded fractionation factors of −0.04 ± 0.06‰ and − 0.23 ± 0.07‰ (2SE), whereby the latter result was obtained for a short run that may not represent full equilibrium. In summary, the findings suggest that Cd isotope fractionation during segregation of Earth's core was either absent or very minor. The Cd partitioning data of this and previous investigations were combined in multiple linear regression analyses to better constrain Cd metal-silicate partitioning during core formation. In accord with earlier work, the analyses reveal that Cd metal-silicate partitioning is not significantly impacted by temperature and pressure but affected by the S content of the metal phase. In addition, it is shown that the presence of C and Si in the metal reduce the siderophile character of Cd. Based on estimates for the composition of Earth's core, the data suggest a metal-silicate partition coefficient DCd of about 0.4 for a single-stage core formation event. However, given uncertainties about the light element composition of Earth's core, DCd values larger than 1 cannot be ruled out at present for core formation. The results of this study and data on the composition of the bulk silicate Earth and chondritic meteorites were applied in mass balance calculations to constrain the Cd signature of Earth's main stage accretion material prior to delivery of the late veneer. The modelling indicates Earth's main stage of accretion involved material with an average Cd isotope composition that was lighter than that of known carbonaceous and enstatite chondrites. Most likely, this reflects either poor characterisation of these meteorites by the few precise data currently available or that a significant fraction of the terrestrial volatile inventory was acquired from material not directly related to carbonaceous and enstatite chondrites. Furthermore, terrestrial accretion most likely did not encompass the addition of a volatile-rich late veneer exceeding 2% of Earth's mass, in accord with accretion models, which invoke that volatile delivery occurred primarily during main stage accretion, alongside core formation

The pyroxenite-diamond connection

Pieces of the Earth’s mantle occurring either as tectonic fragments or xenoliths in volcanic rocks are dominantly peridotites, assemblages of olivine, ortho- and clinopyroxene with minor garnet and/or spinel. They frequently contain pyroxene-rich inclusions which have compositions intermediate between peridotite and basalt. These pyroxenites typically contain varying amounts of more iron-rich (than peridotite) clinopyroxene, orthopyroxene, garnet and/or spinel and are commonly compositionally layered. Surprisingly, despite their subordinate abundance in mantle fragments, pyroxenitic compositions appear be the dominant sources of majoritic garnet inclusions in diamonds, the principal window into the mineralogy of the deep upper mantle and the transition zone (Kiseeva et al., 2013a). In this study we show that the pyroxenite-diamond association is a consequence of the interaction between basaltic and peridotitic compositions in the presence of carbonate melt and that layering of the pyroxenites is a natural consequence of this interaction. Reduction of carbonate to carbon at high pressures is responsible for the genetic connection between pyroxenite and diamond and the abundance of pyroxenitic inclusions reflects this connection rather than a high abundance of this rock type in the mantle

CONSISE statement on the reporting of Seroepidemiologic Studies for influenza (ROSES-I statement): an extension of the STROBE statement

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Effects of Cognitive Behavioral Therapy on Daily Living Skills in Children with High-Functioning Autism and Concurrent Anxiety Disorders

CBT is a promising treatment for children with autism spectrum disorders (ASD) and focuses, in part, on children’s independence and self-help skills. In a trial of CBT for anxiety in ASD (Wood et al. in J Child Psychol Psychiatry 50:224–234, 2009), children’s daily living skills and related parental intrusiveness were assessed. Forty children with ASD (7–11 years) and their primary caregiver were randomly assigned to an immediate treatment (IT; n = 17) or 3-month waitlist (WL; n = 23) condition. In comparison to WL, IT parents reported increases in children’s total and personal daily living skills, and reduced involvement in their children’s private daily routines. Reductions correlated with reduced anxiety severity. These results provide preliminary evidence that CBT may yield increased independence and daily living skills among children with ASD

Aerothermodynamic Analysis of a Reentry Brazilian Satellite

This work deals with a computational investigation on the small ballistic reentry Brazilian vehicle SARA (acronyms for SAt\'elite de Reentrada Atmosf\'erica). Hypersonic flows over the vehicle SARA at zero-degree angle of attack in a chemical equilibrium and thermal non-equilibrium are modeled by the Direct Simulation Monte Carlo (DSMC) method, which has become the main technique for studying complex multidimensional rarefied flows, and that properly accounts for the non-equilibrium aspects of the flows. The emphasis of this paper is to examine the behavior of the primary properties during the high altitude portion of SARA reentry. In this way, velocity, density, pressure and temperature field are investigated for altitudes of 100, 95, 90, 85 and 80 km. In addition, comparisons based on geometry are made between axisymmetric and planar two-dimensional configurations. Some significant differences between these configurations were noted on the flowfield structure in the reentry trajectory. The analysis showed that the flow disturbances have different influence on velocity, density, pressure and temperature along the stagnation streamline ahead of the capsule nose. It was found that the stagnation region is a thermally stressed zone. It was also found that the stagnation region is a zone of strong compression, high wall pressure. Wall pressure distributions are compared with those of available experimental data and good agreement is found along the spherical nose for the altitude range investigated.Comment: The paper will be published in Vol. 42 of the Brazilian Journal of Physic