Assessment of trace element contamination and effects on Paracentrotus lividus using several approaches: Pollution indices, accumulation factors and biochemical tools

Among the most common contaminants in marine ecosystems, trace elements are recognized as serious pollutants. In Corsica (NW Mediterranean Sea), near the old asbestos mine at Canari, trace elements from the leaching of mine residues have been discharged into the sea for several decades. The aim of this study was to assess the levels of contamination in this area and the potential effects on Paracentrotus lividus (Lamarck, 1816) using pollution indices, accumulation factors and biochemical tools. For this purpose, the concentration of 24 trace elements was measured in sea urchins (gonads and gut content), macroalgae, seawater column and sediment collected at 12 stations nearby the old asbestos mine and at a reference site. The bioaccumulation of trace elements occurs as follows: macroalgae > gut > gonads. TEPI contribute to highlight contamination gradients which are mainly due to the dominant marine currents allowing the migration of mining waste along the coastline. This hypothesis was supported by TESVI, which identified characteristic trace elements in the southern area of the mine. High hydrogen peroxide content, associated with elevated catalase and glutathione-S-transferase enzyme activities, were also identified at these sites and at the reference site. Trace elements contamination as well as several abiotic factors could explain these results (e.g. microbiological contamination, hydrodynamic events, etc.). The results obtained in this study suggest that oxidative stress induced by contamination does not affect the health of Paracentrotus lividus. This work has provided a useful dataset allowing better use of sea urchins and various tools for assessing trace element contamination in coastal ecosystems.

New recommendations for self-locking barriers to reduce skin injuries in dairy cows

The design of self-locking barriers can affect cows' skin injuries and impair welfare. This study aimed to propose and refine recommendations, expressed relatively to the cows' dimensions, for self-locking barrier design to reduce risks for skin injuries on the neck/shoulder/back and on carpus of dairy cows. We recorded individual body dimensions and the dimensions of self-locking barriers (e.g. top rail height) and assessed skin injuries on 3801 cows from 131 loose-housing dairy farms. We explored the significant associations between presence/absence of skin injuries and self-locking barrier dimensions using weighted multivariable logistic regression, taking into account the diversity of feeding barriers within each farm. The robustness of the models was assessed by cross-validation. Cows had skin injuries mainly on the neck/shoulder/back (29.0%) and, to a lesser extent, on the carpus (14.0%). The final multivariable logistic regression models comprised 13 factors for skin injuries on the neck/shoulder/back, and 11 factors for skin injuries on the carpus. Skin injuries were significantly reduced when the self-locking barriers were inclined (neck/shoulder/back) and when the cows used a feeding table (i.e. flat) instead of a feeding manger or cribs (i.e. hollow) (carpus). A top rail height >1.05 × cow height (measured at withers) was significantly associated with fewer skin injuries on the neck/shoulder/back and on carpus. Skin injuries on the neck/shoulder/back and carpus were significantly reduced when the bottom rail was on the food side relative to the wall, and at a height <0.39 of cow height. Skin injuries were significantly less frequent when the separation wall had no sharp edges on the food side (neck/shoulder/back), was >0.4 of cow height (carpus), was thinner than 15 cm (neck/shoulder/back and carpus) and when the height of the feeding step was 0.04 to 0.1 of cow height (neck/shoulder/back) and the length of the feeding step was <0.2 of cow length (carpus). A headlock articulation nut positioned between 0.62 and 0.78 of cow height significantly reduced skin injuries on the neck/shoulder/back. Here, by combining the diversity of on-farm self-locking barriers and their respective dimensions, we were able to refine the International Commission of Agricultural and Biosystems Engineering recommendations for self-locking barrier design and to propose new ones. This information now needs to be confirmed on other datasets, but can already help farmers and dairy industry stakeholders improve the design of self-locking barriers to improve dairy cow welfare.

Mineralogy and petrology of comet 81P/Wild 2 nucleus samples

The bulk of the comet 81P/Wild 2 (hereafter Wild 2) samples returned to Earth by the Stardust spacecraft appear to be weakly constructed mixtures of nanometer-scale grains, with occasional much larger (over 1 micrometer) ferromagnesian silicates, Fe-Ni sulfides, Fe-Ni metal, and accessory phases. The very wide range of olivine and low-Ca pyroxene compositions in comet Wild 2 requires a wide range of formation conditions, probably reflecting very different formation locations in the protoplanetary disk. The restricted compositional ranges of Fe-Ni sulfides, the wide range for silicates, and the absence of hydrous phases indicate that comet Wild 2 experienced little or no aqueous alteration. Less abundant Wild 2 materials include a refractory particle, whose presence appears to require radial transport in the early protoplanetary disk.

Impact Features on Stardust: Implications for Comet 81P/Wild 2 Dust

Particles emanating from comet 81P/Wild 2 collided with the Stardust spacecraft at 6.1 kilometers per second, producing hypervelocity impact features on the collector surfaces that were returned to Earth. The morphologies of these surprisingly diverse features were created by particles varying from dense mineral grains to loosely bound, polymineralic aggregates ranging from tens of nanometers to hundreds of micrometers in size. The cumulative size distribution of Wild 2 dust is shallower than that of comet Halley, yet steeper than that of comet Grigg-Skjellerup.

Comet 81P/Wild 2 Under a Microscope

The Stardust spacecraft collected thousands of particles from comet 81P/Wild 2 and returned them to Earth for laboratory study. The preliminary examination of these samples shows that the nonvolatile portion of the comet is an unequilibrated assortment of materials that have both presolar and solar system origin. The comet contains an abundance of silicate grains that are much larger than predictions of interstellar grain models, and many of these are high-temperature minerals that appear to have formed in the inner regions of the solar nebula. Their presence in a comet proves that the formation of the solar system included mixing on the grandest scales.

A comparison of breast self-examination and clinical examination

Twenty-six female college students were trained to examine their breasts using the Mammacare Method. After training, participants were asked to demonstrate their breast self-examination technique for a competency evaluation. On average, 85% of the components of the palpation technique were correctly included in the participants' self-examinations, indicating that they had been trained competently. Breast self-examiners then were asked to palpate three breast models in search of embedded lumps. Thirteen health professionals were asked to examine the same breast models for lumps. The examination of the models by self-examiners was compared to that by health professionals. Breast self-examiners took longer to examine each model, and on average correctly identified significantly more lumps than health professionals. The two groups did not differ in number of false-positive findings. These results indicate that women adequately trained to perform breast self-examination can perform breast examinations at least as accurately as health professionals.

An exploratory study on increases in masseteric muscle activity induced by caffeine

In a crossover double blind experimental design, the nocturnal masseteric activity of 14 selected volunteers was evaluated by means of a portable electromyograph recording unit. The recordings lasted for a period of 16 days following ingestion of caffeine or placebo for five specific days each. There were no significant differences between caffeine or placebo on masseteric activity associated with bruxism. But when the two periods were compared, there was a tendency towards reduction of masseteric area activity and increase of stress levels in the second period of ingestion.

Parent and child causal attributions related to the child's clinical problem

Parents and children were asked to give causal attributions related to the child's learning or behavior problems and an area of success. Actor-observer differences and tendencies of actors to make differential attributions for their positive and negative outcomes were examined. A significant number of parents and children were in disagreement regarding the cause of the child's problem. Parents made significantly more internal than external attributions for children's presenting problems. In contrast, children were evenly distributed in problem attributions. Both parents and children made significantly more internal success attributions. Research with clinical child populations is highlighted as a valuable way to validate, expand, and refine attribution theory while clarifying its practical applications.