Animal-sediment interactions: the effect of ingestion and excretion by worms on mineralogy

International audienceBy controlled experiments that simulate marine depositional environments, it is shown that accelerated weathering and clay mineral authigenesis occur during the combined process of ingestion, digestion and excretion of fine-grained sediment by two species of annelid worms. Previously characterized synthetic mud was created using finely ground, low-grade metamorphic slate (temperature approximately 300°C) containing highly crystalline chlorite and muscovite. This was added to experiment and control tanks along with clean, wind-blown sand. Faecal casts were collected at regular intervals from the experimental tanks and, less frequently, from the control tanks. Over a period of many months the synthetic mud (slate) proved to be unchanged in the control tanks, but was significantly different in faecal casts from the experimental tanks that contained the worms Arenicola marina and Lumbricus terrestris. Chlorite was preferentially destroyed during digestion in the gut of A. marina. Both chlorite and muscovite underwent XRD peak broadening with a skew developing towards higher lattice spacing, characteristic of smectite formation. A neoformed Fe-Mg-rich clay mineral (possibly berthierine) and as-yet undefined clay minerals with very high d-spacing were detected in both A. marina and L. terrestris cast samples. We postulate that a combination of the low pH and bacteria-rich microenvironment in the guts of annelid worms may radically accelerate mineral dissolution and clay mineral precipitation processes during digestion. These results show that macrobiotic activity significantly accelerates weathering and mineral degradation as well as mineral authigenesis. The combined processes of sediment ingestion and digestion thus lead to early diagenetic growth of clay minerals in clastic sediments

The Mg 2 h and k lines in a sample of dMe and dM stars

Both Mg II h and k line fluxes are presented for a sample of 4 dMe and 3 dM stars obtained with the IUE satellite in the long wavelength, low dispersion mode. The observed fluxes are converted to stellar surface flux units and the importance of chromospheric non radiative heating in this sample of M dwarf stars is intercompared. In addition, the net chromospheric radiative losses due to the Ca II H and K lines in those stars in the sample for which calibrated Ca II H and K line data exist are compared. Active region filling factors which likely give rise to the observed optical and ultraviolet chromospheric emission are estimated. The implications of the results for homogeneous, single component stellar model chromospheres analyses are discussed

Predicting Coupled Electron and Phonon Transport Using Steepest-Entropy-Ascent Quantum Thermodynamics

The current state of the art for determining thermoelectric properties is limited to the investigation of electrons or phonons without including the inherent electron-phonon coupling that is in all materials. This gives rise to limitations in accurately calculating base material properties that are in good agreement with experimental data. Steepest-entropy-ascent quantum thermodynamics is a general non-equilibrium thermodynamic ensemble framework that provides a general equation of motion for non-equilibrium system state evolution. This framework utilizes the electron and phonon density of states as input to compute material properties, while taking into account the electron-phonon coupling. It is able to span across multiple spatial and temporal scales in a single analysis. Any system's thermoelectric properties can, therefore, be attained provided the accurately determined density of states is available.Comment: Supplementary Materials Section is the last two pages of the manuscrip

Managing bereavement in the classroom: a conspiracy of silence?

The ways in which teachers in British schools manage bereaved children are under-reported. This article reports the impact of students' bereavement and their subsequent management in primary and secondary school classrooms in Southeast London. Thirteen school staff working in inner-city schools took part in in-depth interviews that focused on the impact of bereaved children on the school and how teachers responded to these children. All respondents had previously had contact with a local child bereavement service that aims to provide support, advice, and consultancy to children, their parents, and teachers. Interviews were audiotaped, transcribed verbatim, and analyzed using ATLAS-ti. Three main themes were identified from analysis of interview data. Firstly, British society, culture, local communities, and the family were significant influences in these teachers' involvement with bereaved students. Secondly, school staff managed bereaved students through contact with other adults and using practical classroom measures such as "time out" cards and contact books. Lastly, teachers felt they had to be strong, even when they were distressed. Surprise was expressed at the mature reaction of secondary school students to deaths of others. The article recommends that future research needs to concentrate on finding the most effective way of supporting routinely bereaved children, their families, and teachers

Marginal treatment benefit in anaplastic thyroid cancer

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/99665/1/cncr28187.pd

Validation of northern latitude Tropospheric Emission Spectrometer stare ozone profiles with ARC-IONS sondes during ARCTAS: sensitivity, bias and error analysis

We compare Tropospheric Emission Spectrometer (TES) versions 3 and 4, V003 and V004, respectively, nadir-stare ozone profiles with ozonesonde profiles from the Arctic Intensive Ozonesonde Network Study (ARCIONS, http://croc.gsfc.nasa.gov/arcions/ during the Arctic Research on the Composition of the Troposphere from Aircraft and Satellites (ARCTAS) field mission. The ozonesonde data are from launches timed to match Aura's overpass, where 11 coincidences spanned 44° N to 71° N from April to July 2008. Using the TES "stare" observation mode, 32 observations are taken over each coincidental ozonesonde launch. By effectively sampling the same air mass 32 times, comparisons are made between the empirically-calculated random errors to the expected random errors from measurement noise, temperature and interfering species, such as water. This study represents the first validation of high latitude (>70°) TES ozone. We find that the calculated errors are consistent with the actual errors with a similar vertical distribution that varies between 5% and 20% for V003 and V004 TES data. In general, TES ozone profiles are positively biased (by less than 15%) from the surface to the upper-troposphere (~1000 to 100 hPa) and negatively biased (by less than 20%) from the upper-troposphere to the lower-stratosphere (100 to 30 hPa) when compared to the ozonesonde data. Lastly, for V003 and V004 TES data between 44° N and 71° N there is variability in the mean biases (from −14 to +15%), mean theoretical errors (from 6 to 13%), and mean random errors (from 9 to 19%)

The Effects of Negative Legacies on the Adjustment of Parentally Bereaved Children and Adolescents

This is a report of a qualitative analysis of a sample of bereaved families in which one parent died and in which children scored in the clinical range on the Child Behavior Check List. The purpose of this analysis was to learn more about the lives of these children. They were considered to be at risk of developing emotional and behavioral problems associated with the death. We discovered that many of these “high risk” children had a continuing bond with the deceased that was primarily negative and troubling for them in contrast to a comparison group of children not at risk from the same study. Five types of legacies, not mutually exclusive, were identified: health related, role related, personal qualities, legacy of blame, and an emotional legacy. Coping behavior on the part of the surviving parent seemed to make a difference in whether or not a legacy was experienced as negative