Characterisation of Gas Transport Properties of the Opalinus Clay, a Potential Host Rock Formation for Radioactive Waste Disposal

The Opalinus Clay in Northern Switzerland has been identified as a potential host rock formation for the disposal of radioactive waste. Comprehensive understanding of gas transport processes through this low-permeability formation forms a key issue in the assessment of repository performance. Field investigations and laboratory experiments suggest an intrinsic permeability of the Opalinus Clay in the order of 10(-20) to 10(-21) m(2) and a moderate anisotropy ratio < 10. Porosity depends on clay content and burial depth; values of similar to 0.12 are reported for the region of interest. Porosimetry indicates that about 10-30 of voids can be classed as macropores, corresponding to an equivalent pore radius > 25 nm. The determined entry pressures are in the range of 0.4-10 MPa and exhibit a marked dependence on intrinsic permeability. Both in situ gas tests and gas permeameter tests on drillcores demonstrate that gas transport through the rock is accompanied by porewater displacement, suggesting that classical flow concepts of immiscible displacement in porous media can be applied when the gas entry pressure (i.e. capillary threshold pressure) is less than the minimum principal stress acting within the rock. Essentially, the pore space accessible to gas flow is restricted to the network of connected macropores, which implies a very low degree of desaturation of the rock during the gas imbibition process. At elevated gas pressures (i.e. when gas pressure approaches the level of total stress that acts on the rock body), evidence was seen for dilatancy controlled gas transport mechanisms. Further field experiments were aimed at creating extended tensile fractures with high fracture transmissivity (hydro- or gasfracs). The test results lead to the conclusion that gas fracturing can be largely ruled out as a risk for post-closure repository performance.

Content of prenatal care and spontaneous preterm birth: Findings from the 1988 National Maternal and Infant Health Survey

The purposes of this study were to examine (1) the relationship between selected components of the content of prenatal care and spontaneous preterm birth; and (2) the degree of comparability between maternal and caregivers' responses regarding the number of prenatal care visits, selected components of the content of prenatal care, and gestational age, based on analyses of the 1988 National Maternal and Infant Health Survey conducted by the National Centers for Health Statistics. Spontaneous preterm birth was subcategorized into very preterm and moderately preterm births, with term birth as the controls. The study population was limited to non-Hispanic Anglo- and African-American mothers. The racial differences in terms of birth outcomes were also compared.^ This study concluded that: (1) there was not a high degree of comparability (less than 80%) between maternal and prenatal care provider's responses regarding the number of prenatal care visits and the content of prenatal care; (2) there was a low degree of comparability (less than 50%) between maternal and infant's hospital of delivery responses regarding gestational age at birth; (3) there were differences in selected components of the content of prenatal care between the cases and controls, overall and stratified by ethnicity (i.e., hemoglobin/hematocrit test, weight measurement, and breast-feeding counseling), but they were confounded with missing values and associated preterm delivery bias; (4) there were differences in selected components of the content of prenatal care between Anglo- and African-American cases (i.e., vitamin/mineral supplement advice, weight measurement, smoking cessation and drug abuse counseling), but they, too, were difficult to interpret definitively due to item nonresponse and preterm delivery biases; (5) no significant predictive association between selected components of the content of prenatal care and spontaneous preterm birth was found; and (6) inadequate/intermediate prenatal care and birth out of wedlock were found to be associated with moderately preterm birth.^ Future research is needed to examine the validity of maternal and prenatal care providers' responses and identify the sources of disagreement between their responses. In addition, further studies are needed to examine the relationship between the quality of prenatal care and preterm birth. Finally, the completeness and quality of patient and provider data on the utilization and content of prenatal care needs to be strengthened in subsequent studies. ^

The role of nitric oxide in Listeria encephalitis of ruminants and in rats intracisternally infected with Listeria monocytogenes

Listeria monocytogenes is a Gram-positive facultative intracellular bacteria which infects a wide range of hosts. In ruminants, infection with L. monocytogenes frequently causes encephalitis, which is usually fatal in sheep and goat, while cattle often recover with antibiotic therapy. Since the role of NO in the control of Listeria is controversial, we have studied the expression of iNOS in the brains of cattle, sheep and goats which had succumbed to listeria encephalitis. iNOS was demonstrated in decreasing intensity in the M phi of microabscesses from cattle, sheep and goat. iNOS expression was accompanied by NT in the microabscesses of cattle, but was only present to a low degree in sheep and was absent in goats. This is indirect evidence for differences in the ability to produce NO in the three species. Presence of iNOS and NT were inversely correlated with the numbers of bacteria. While microabscesses of goats contained high amounts of L. monocytogenes they occurred only rarely in cattle. To corroborate our hypothesis that NO is involved in the control of listeria encephalitis a new animal model was developed. Eleven day old infant rats were infected intracisternally with a low dose of L. monocytogenes. This resulted in a transient meningoencephalitis with moderate clinical signs and low mortality. Listeria proliferated strongly in the inflammatory lesions during the first days of infection, reached a peak at day 4 and were eliminated until day 7. The presence of bacteria was closely accompanied by high numbers of iNOS-expressing M phi and the formation of NT. Administration of the iNOS inhibitor L-NIL or the radical scavenger PBN resulted in rapid death of the treated animals. However, the increase in bacterial numbers was one order of magnitude higher for animals treated with PBN compared with L-NIL administration. This shows that NO plays an important role in the control of a brain infection with Listeria, but suggests that reactive oxidants other than NO are also involved. In conclusion, our findings point to a possible involvement of the differences in the ability to express iNOS and subsequent NO production in the different clinical outcome of listeria encephalitis in cattle and small ruminants.

Sheep macrophages express at least two distinct receptors for IgG which have similar affinity for homologous IgG1 and IgG2.

Ovine bone marrow-derived macrophages (BMM) may express several IgG receptor (Fc gamma receptor; FcR) subsets. To study this, model particles (opsonized erythrocytes; EA), which are selectively handled by certain FcR subsets of human macrophages were used in cross-inhibition studies and found to react in a similar manner with FcR subsets of sheep macrophages. In experiments with monoclonal antibodies against subsets of human FcR, human erythrocytes (E) treated with human anti-D-IgG (anti-D-EAhu) and sheep E treated with bovine IgG1 (Bo1-EAs) were handled selectively by human macrophage FcRI and FcRII, respectively. Rabbit-IgG-coated sheep E (Rb-EAs) were recognized by FcRI, FcRII and possibly also by FcRIII of human macrophages. Anti-D-EAhu, Bo1-EAs and Rb-EAs were also ingested by sheep BMM. Competitive inhibition tests, using various homologous and heterologous IgG isotypes as fluid phase inhibitors and the particles used as FcR-specific tools in man (anti-D-EAhu and Bo1-EAs), revealed a heterogeneity of FcR also in sheep BMM. Thus, ingestion of anti-D-EAhu by ovine BMM was inhibited by low concentrations of competitor IgG from rabbit or man in the fluid phase, but not at all by bovine IgG1, whereas ingestion of Bo1-EAs was inhibited by bovine IgG1. This suggested that anti-D-EAhu were recognized by a FcR subset distinct from that recognizing bovine-IgG1. It was concluded that sheep BMM express functional analogs of human macrophage FcRI and FcRII and that Bo1-EAs and anti-D-EAhu are handled by distinct subsets of BMM FcR. All EAhu tested (EAhu treated with anti-D, sheep IgG1 or sheep IgG2) were ingested to a lower degree than EAs. This inefficient phagocytosis could be enhanced by treatment of EAhu with antiglobulin from the rabbit, suggesting that it is caused by a low degree of activity of opsonizing antibodies rather than special properties of the erythrocytes themselves. Several lines of evidence suggested that both FcR subsets of ovine BMM recognize both ovine IgG1 and IgG2. In contrast, bovine IgG1 reacts with one FcR subset and bovine IgG2 interacts inefficiently with all FcR of ovine BMM.

Time variable Earth’s gravity field from SLR satellites

The time variable Earth’s gravity field contains information about the mass transport within the system Earth, i.e., the relationship between mass variations in the atmosphere, oceans, land hydrology, and ice sheets. For many years, satellite laser ranging (SLR) observations to geodetic satellites have provided valuable information of the low-degree coefficients of the Earth’s gravity field. Today, the Gravity Recovery and Climate Experiment (GRACE) mission is the major source of information for the time variable field of a high spatial resolution. We recover the low-degree coefficients of the time variable Earth’s gravity field using SLR observations up to nine geodetic satellites: LAGEOS-1, LAGEOS-2, Starlette, Stella, AJISAI, LARES, Larets, BLITS, and Beacon-C. We estimate monthly gravity field coefficients up to degree and order 10/10 for the time span 2003–2013 and we compare the results with the GRACE-derived gravity field coefficients. We show that not only degree-2 gravity field coefficients can be well determined from SLR, but also other coefficients up to degree 10 using the combination of short 1-day arcs for low orbiting satellites and 10-day arcs for LAGEOS-1/2. In this way, LAGEOS-1/2 allow recovering zonal terms, which are associated with long-term satellite orbit perturbations, whereas the tesseral and sectorial terms benefit most from low orbiting satellites, whose orbit modeling deficiencies are minimized due to short 1-day arcs. The amplitudes of the annual signal in the low-degree gravity field coefficients derived from SLR agree with GRACE K-band results at a level of 77 %. This implies that SLR has a great potential to fill the gap between the current GRACE and the future GRACE Follow-On mission for recovering of the seasonal variations and secular trends of the longest wavelengths in gravity field, which are associated with the large-scale mass transport in the system Earth.

A Late-glacial and Holocene record of climatic change from a Swiss peat humification profile

Colorimetric measurements of alkaline extracts from two Swiss peat cores have provided a complete 14500-year-long record of peat humification, a proxy of effective precipitation. Peat from the cold Younger Dryas (11050–9550 cal. bc) was well preserved despite low levels of precipitation. A particularly dry period, peaking at c. 7100 cal. bc, is indicated by well-decomposed peat. Peat from c. 6750–4250 cal. bc shows a low degree of decomposition, indicating a wet bog surface despite relatively warm temperatures and therefore indicating high levels of precipitation. A sharp transition to higher levels of decomposition c. 4450–3750 cal. bc indicates a major transition to a drier bog surface. Subsequently, peat humification generally decreases towards the end of the deeper profile (c. cal. ad 1050), indicating a gradual return to wetter conditions. This gradual decrease is punctuated by periods of particularly low humification which appear to be due to shifts to higher levels of effective precipitation from c. 2500 to 1350 cal. bc, c. 1050 to 550 cal. bc, centered around 150 cal. bc, and from c. cal. ad 550 onwards. Anthropogenic influences appear to have affected peat humification at the site at least since the Middle Ages. This study indicates that humification in colder regions/time periods could be more affected by temperature than precipitation and vice versa.

Impact of a communication strategy on family satisfaction in the intensive care unit.

BACKGROUND Family satisfaction of critically ill patients has gained increased interest as important indicator to evaluate the quality of care in the intensive care unit (ICU). The family satisfaction in the ICU questionnaire (FS-ICU 24) is a well-established tool to assess satisfaction in such settings. We tested the hypothesis that an intervention, aiming at improved communication between health professionals and patients' next of kin in the ICU improves family satisfaction, as assessed by FS-ICU 24. METHODS Using a multicenter before-and-after study design, we evaluated medium-term effectiveness of VALUE, a recently proposed strategy aiming at improved communication. Satisfaction was assessed using the FS-ICU 24 questionnaire. Performance-importance plots were generated in order to identify items highly correlated with overall satisfaction but with low individual score. RESULTS A total of 163 completed family questionnaires in the pre-intervention and 118 in the post-intervention period were analyzed. Following the intervention, we observed: (1) a non-significant increase in family satisfaction summary score and sub-scores; (2) no decline in any individual family satisfaction item, and (3) improvement in items with high overall impact on satisfaction but quoted with low degree of satisfaction. CONCLUSION No significant improvement in family satisfaction of critically ill adult patients could be found after implementing the VALUE strategy. Whether these results are due to insufficient training of the new strategy or a missing effect of the strategy in our socio-economic environment remains to be shown.

Diagenetic alteration of organic matter in DSDP Leg 57 Holes

I analyzed Leg 57 sediments organogeochemically and spectroscopically. Organic carbon and extractable organic matter prevail from the Pliocene to the Miocene. Humic acids occur widely from the Pleistocene to the lower Miocene and one portion of the Oligocene. The absence of humic acids in Oligocene and Cretaceous samples suggests that humic acids had changed to kerogen. Visible spectroscopic data reveal that humic acids in this study have a low degree of condensed aromatic-ring system, which is a feature of anaerobic conditions during deposition, and that chlorophyll derivatives that had at first combined with humic acids moved to the solvent- soluble fraction during diagenesis. The elemental compositions of humic acids show high H/C and O/C ratios, which seem appropriate to a stage before transformation to kerogen. The relation between the linewidths and g-values on the electron spin resonance data indicates that the free radicals in humic acids are quite different from those in kerogen. The low spin concentrations of kerogen and the yields of humic acids up to the lower Miocene demonstrate that organic matter in these sediments is immature. The foregoing indicate the necessity to isolate humic acids even in ancient rocks in the study of kerogen.

Propiedades químicas del suelo en bosques de Nothofagus antarctica y Austrocedrus chilensis afectados por fuego

Este estudio tuvo por objetivo caracterizar la fertilidad química del suelo superficial nueve meses después de la ocurrencia de fuegos en dos tipos de formaciones del bosque andino patagónico: Nothofagus antarctica y Austrocedrus chilensis. El área de estudio se centró en un sector de suelos de ceniza volcánica que fue afectado por el incendio denominado La Colisión (Chubut, Argentina, febrero 2008) y posteriormente cubierto por ceniza volcánica proveniente del volcán Chaitén (mayo 2008). Se tomaron muestras compuestas de suelo mineral a dos profundidades (0-5 cm y 5-10 cm) en un sector de bosque de N. antarctica y un sector de bosque de A. chilensis, considerando tres niveles de afectación por fuego (control no quemado, poco quemado, muy quemado). En las muestras más superficiales (i.e., 0-5 cm) hubo aumentos significativos de pH y conductividad eléctrica, y disminución de los contenidos de materia orgánica, nitrógeno total, CIC y sodio, como consecuencia del fuego. Las muestras de 5-10 cm evidenciaron disminución de materia orgánica y nitrógeno total y aumento de azufre. El mayor contenido de azufre en los bosques quemados y el aumento observado de fósforo en suelos alofanizados con bajo grado de afectación por fuego, podrían ser beneficiosos para la recuperación de la vegetación.

Physical properties and minerals of Leg 65 Holes basalts

Velocities and densities of submarine basalts obtained during Leg 65 are distinguished by their relatively high values (about 6.3 km/s and 2.9 g/cm/**3, respectively). This is consistent with their low degree of alteration. The range of velocities covered by these samples correlates well with porosity, and a comparison with in situ velocities from refraction data suggests maximum porosities ih the upper 100 meters of the crust of about 10%.

Magnetic properties of ODP Hole 109-670A

Magnetic fabrics of serpentinized peridotites are related to anisomorphic magnetite formed during serpentinization. In the less serpentinized facies they are, however, mainly mimetic of the high temperature deformation prior to serpentinization. In more serpentinized peridotites, the magnetic fabrics, related to magnetite veins which are more developed in this case, are superimposed on mimetic fabrics. Remanent properties, hysteresis loop parameters, and Curie temperatures were measured. Natural remanent magnetizations (NRM) have crystallization remanent magnetic (CRM) origin. Measured magnetic parameters suggest that pseudo-single domain (PSD) grains of magnetite are present in samples with low degree of serpentinization. The samples with high degree of serpentinization contain mainly multi-domain (MD) magnetite grains.

Geochemistry of Walvis Ridge basalts

The proposed origins for the Enriched Mantle I component are many and various and some require an arbitrary addition of an exotic component, be it pure sediment or an enriched melt from the subcontinental lithosphere. With Pitcairn, Walvis Ridge is the 'type-locality' for the Enriched Mantle I (EMI) component. We analyzed basalts from DSDP Site 525A, Site 527 and Site 528 on the Walvis Ridge with the aim to constrain the history of its source. The isotopic compositions we measured for the three sites overlap with the values obtained by Richardson et al. (1982a) and extend towards less radiogenic Sr and more radiogenic Pb and Nd isotopic compositions. We used our new trace element and radiogenic isotope (Hf, Nd, Pb and Sr) characterization in combination with the literature data to produce the simplest possible model that satisfies the trace element and isotopic constraints. Although the elevated 207Pb/204Pb with respect to 206Pb/204Pb predicts an ancient origin for EMI, none of the proposed origins had modeled it as such. The data is consistent with the EMI composition being formed by the addition of a melt to a mantle with bulk Earth-like composition followed by melt extraction of a low degree melt. The timing of these two events is such that the metasomatism has to have taken place prior to 4 Ga and the subsequent melt removal before 3.5 Ga. This confirms the expectation of an ancient character for the EMI component. The Walvis Ridge data shows two distinct two component mixing trends: one formed by the less enriched Site 527 and Site 528 basalts and one formed by the Site 525A basalts. The two trends have the EMI endmember in common. The less depleted end of the Site 527-Site 528 basalts is FOZO-like and can be explained by the addition of a recycled component (basaltic oceanic crust plus sediment). This recycled component was altered during subduction. The sense and magnitude of the chemical fractionation resulting from the subduction alteration are in agreement with dehydration experiments on basalts and sediment. Compared to other EMI like basalts the Walvis Ridge basalts have flatter REE patterns and show less fractionation between large ion lithophile and heavy REE elements. Using the isotopic compositions as constrains for the parent-daughter ratios we were able to model the trace element patterns of the basalts as melting between 5 and 10% for Site 525A and between 10 and 15% for the depleted end of the Site 528-Site 527 array. In all cases a significant portion of melting takes place in the garnet stability field.

14C ages, grain size distribution and foraminifer abundance of sediments from the Barents Sea shelf

The origin of friable sediments blanketing the Barents Sea shelf is considered. It is shown that their characteristic seismoacoustic record patterns reflect low degree of diagenetic transformations and indicates continuous sedimentation. According to traditional views, this single sedimentary complex also includes diamicton, and the section is interpreted as a three-unit structure: diamicton, which is considered a till; the overlying friable sediments accumulated under different conditions of deglaciation in glaciomarine settings; and the postglacial marine sediments. It is demonstrated that such views are inconsistent with geomorphologic features (datings by physical methods included) indicating a prolonged hiatus that separates epochs of the diamicton accumulation and formation of friable sediments. The analysis revealed that the composition, vertical succession, and lateral distribution of different lithological types of friable sediments are related to the regular spatiotemporal replacements of different facies settings in the transgressing Arctic sea rather than by the glacial process. This inference is confirmed by the composition of foraminiferal assemblages.

Strontium isotope geochemistry of ODP Leg 113 sites

The concentration of dissolved Sr and the distribution of 87Sr/86Sr isotope ratios in Leg 113 interstitial waters may be interpreted in terms of mixing of Sr from four different reservoirs: indigenous seawater, marine carbonate minerals, and basaltic and siliceous detrital material. The input to the pore water from these reservoirs is determined by the reactivity of the reservoir rather than its size. The presence of strontium derived from siliceous detrital material is unequivocally demonstrated in the pore waters of the hemipelagic deposits, and is also significant in the calcareous Maud Rise sediments due to the unusually low degree of carbonate recrystallization. Also, alteration of basic volcanic material is important at several sites.

Organic chemistry of sediments of the Peru margin

Organic-carbon-rich anoxic sediments from the continental shelf (Site 680) and the lower continental slope (Site 688) off Peru were studied to determine factors controlling the accumulation of reduced sulfur. High concentrations of organic matter in diatomaceous muds, its thermal immaturity, and the presence of abundant hydrogen-containing organic compounds lead to the conclusion that organic matter is not limiting for reduced sulfur formation. Rather, high degrees of iron pyritization at Site 680 limit pyrite accumulation in sediments from this shelf site. The low degree of iron pyritization and nearly complete reduction of dissolved sulfate at Site 688 suggest that a lack of interstitial sulfate is limiting pyrite formation there. Although factors that limit the formation of sedimentary iron sulfide are different at each site, the resulting average reduced-sulfur concentrations are remarkably similar (0.85 wt.% at Site 680 and 0.86 wt.% at Site 688). Carbon to sulfur (C/S) ratios are higher in samples containing in excess of 3 wt.% organic carbon than the average of 2.8 in normal marine sediments and have been primarily influenced by variations in organic matter concentrations.