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The Shearwater Field is a high-pressure–high-temperature (HPHT) gas condensate field located 180 km east of Aberdeen in UKCS Blocks 22/30b and 22/30e within the East Central Graben. Shell UK Limited operates the field on behalf of co-venturers Esso Exploration and Production UK Limited and Arco British Limited, via a fixed steel jacket production platform and bridge-linked wellhead jacket in a water depth of 295 ft. Sandstones of the Upper Jurassic Fulmar Formation constitute the primary reservoir upon which the initial field development was sanctioned; however, additional production has been achieved from intra-Heather Formation sandstones, as well as from the Middle Jurassic Pentland Formation. Following first gas in 2000, a series of well failures occurred such that by 2008 production from the main field Fulmar reservoir had ceased. This resulted in a shut-in period for the main field from 2010 before a platform well slot recovery and redevelopment drilling campaign reinstated production from the Fulmar reservoir in 2015. In addition to replacement wells, the redevelopment drilling also included the design and execution of additional wells targeting undeveloped reservoirs and near-field exploration targets, based on the lessons learned during the initial development campaign, resulting in concurrent production from all discovered reservoirs via six active production wells by 2018.

The Shearwater Field, located in Block 22/30b in the UK Central Graben, remains one of the best-known fields in the UK Continental Shelf (UKCS). At the time of the initial development, Shearwater represented one of the most complex and technically challenging high-pressure and high-temperature (HPHT) developments of its kind in the North Sea. During the early life of the field, pressure depletion resulted in compaction of the Fulmar reservoir, leading to mechanical failure of the development wells. The compaction also resulted in weakening of the overburden due to an effect known as stress arching. Over time, this resulted in in situ stress changes in the overburden which have been observed from 4D seismic datasets and are in line with geomechanical modelling. This is particularly true for the Hod Formation in the Chalk Group, and resulted in the need to make changes to infill well design, including the use of new drilling technologies, to ensure safe and effective well delivery. The insights presented here, which relate to the understanding of pore pressure and fluid fill in the overburden, and how the overburden has responded to stress changes over time, are of relevance to current and future HPHT field developments in both the UK North Sea and elsewhere.

Biological soil crusts (BSC) are an important multi-trophic component of arid ecosystems in the Mediterranean region, considered to have an important role in protecting the underlying soil from erosion and enhancing soil ecosystem functions. Using mesocosms in a 48 days glasshouse experiment, we investigated how previously hydrated (+W) and dried (-W) crust (+BSC) and uncrust (-BSC) -soil samples influenced microbial community structure, biomass and soil functionality of the underlying soils when exposed to two simulated extreme rain events. Community structure was assessed by phospholipid fatty acids analysis (PLFAs) and soil functionality by the activity of b-glucosidase, polyphenol oxidase, N-acetylglucosaminidase, acid phosphomoesterase and urease involve in C, P and N cycles. Crust increased the soil water content. In contrast, NH4 and NO3 were unaffected by the presence of the crust or its previous hydration status. N availability was affected by rain events; it declined from first to second event. Microbial biomasses were affected by the interaction crust x watering. Significant decline in biomasses was recorded in +BSC + W soils as a response to rain events. Little effects of treatments on soil enzymes were noticed; crust presence had a positive influence on the activity of phenol oxidase and a negative one on acid phosphomoesterase activity. The first rainfall had the greatest impact on microbial community structure, with communities in the previously hydrated crust affected most. These effects were less pronounced for the second rain event possibly due to microbial acclimation. Responses in enzyme profiles were consistent with those of communities, but delayed, with more marked responses following the second rainfall. We concluded that the effect of this lichen crust from the Mediterranean area on the response of soil microbial communities and enzymes to rainfall events depended strongly on the prior hydration status of the crust-soil complex.

The Kingfisher field is located in Blocks 16/8a and 16/8d in the South Viking Graben 278 km (173 mi) northeast of Aberdeen. The field was discovered in 1972 by Shell/Esso well 16/8-1, which targeted a faulted anticlinal structure and encountered thin-bedded and poor quality reservoir sandstones within a dip closure mapped at the Base Cretaceous unconformity (BCU) level. The field was first appraised in 1984 by well 16/8a-4, which encountered a better quality Brae sandstone member reservoir interval to the northwest of the discovery well. Further appraisal wells 16/8a-8, 16/8a-9, and 16/8a-9z confirmed the presence of good quality reservoir sands across the central and western parts of the field. The exploration and appraisal drilling established the fluid contacts in the field and also critically helped to delineate the transition from good quality axial to poorer quality distal facies within the outer part of the Brae submarine fan system. Furthermore, data from development well drilling and reservoir behavior during production of the field have provided insights into the static and dynamic connectivity within the Brae sandstone member reservoirs as well as provided additional insights into the controls on reservoir quality and productivity. This chapter aims to build on the previous published information on the field by providing further details on the geological characteristics of the Brae sandstone member reservoirs within the Kingfisher field and how the reservoir architecture and properties, in addition to aquifer connectivity, have determined well and reservoir production performance and behavior.

T. MCKIE1*, P. T. S. ROSE2, A. J. HARTLEY3, D. W. JONES1 & T. L. ARMSTRONG4 Shell UK Ltd, Altens Farm Road, Nigg, Aberdeen AB12 3FY, UK Apache North Sea, Caledonia House, Prime Four Business Park, Kingswells Causeway, Aberdeen AB15 8PU, UK Department of Geology & Petroleum Geology, School of Geosciences, University of Aberdeen, Aberdeen AB24 3UE, UK Talisman Sinopec Energy UK Ltd, Talisman House, 163 Holburn Street, Aberdeen AB10 6BZ, UK

Oestrus detection is an important part of maintaining efficient reproductive performance in dairy herds. Both lameness and mastitis are common diseases of dairy cows that may impact oestrus detection. A set of data from 28 herds identified as having good recording of clinical mastitis and lameness incidents was used for the study. Logistic regression was used to identify associations between disease episodes within 100 days of insemination and changes in the probability of reinsemination at either 18-24 or 19-26 days after an unsuccessful insemination. Population attributable risk was calculated to understand the impact these diseases may have at a herd level. Lameness 0-28 days after the first insemination of the interval decreased the odds of a reinsemination at an appropriate time by approximately 20 per cent. Clinical mastitis 1-28 days prior to the first insemination of the interval increased the odds of reinsemination at the expected time by approximately 20 per cent. The associations were similar for either interservice interval outcome. Population attributable risk suggested that the effect of these diseases on the probability of reinsemination at the expected time at a population level would likely be extremely small.

Highlights: Black-Right-Pointing-Pointer RNA structure is mapped by pyrite mediated {sup {center_dot}}OH footprinting. Black-Right-Pointing-Pointer Repetitive experiments can be done in a powdered pyrite filled cartridge. Black-Right-Pointing-Pointer High {sup {center_dot}}OH reactivity of nucleotides imply dynamic role in Diels-Alderase catalysis. -- Abstract: In RNA, function follows form. Mapping the surface of RNA molecules with chemical and enzymatic probes has revealed invaluable information about structure and folding. Hydroxyl radicals ({sup {center_dot}}OH) map the surface of nucleic acids by cutting the backbone where it is accessible to solvent. Recent studies showed that a microfluidic chip containing pyrite (FeS{sub 2}) can produce sufficient {sup {center_dot}}OH to footprint DNA. The 49-nt Diels-Alder RNA enzyme catalyzes the C-C bond formation between a diene and a dienophile. A crystal structure, molecular dynamics simulation and atomic mutagenesis studies suggest that nucleotides of an asymmetric bulge participate in the dynamic architecture of the ribozyme's active center. Of note is that residue U42 directly interacts with the product in the crystallized RNA/product complex. Here, we use powdered pyrite held in a commercially available cartridge to footprint the Diels-Alderase ribozyme with single nucleotide resolution. Residues C39 to U42 are more reactive to {sup {center_dot}}OH than predicted by the solvent accessibility calculated from themore » crystal structure suggesting that this loop is dynamic in solution. The loop's flexibility may contribute to substrate recruitment and product release. Our implementation of pyrite-mediated {sup {center_dot}}OH footprinting is a readily accessible approach to gleaning information about the architecture of small RNA molecules.« less

A detailed seismic stratigraphic interpretation of a previously unpublished, well-calibrated 3D seismic volume and regional 2D seismic lines in the Northern Porcupine Basin, west of Ireland has provided significant insights into the basin development, sedimentary fill and petroleum prospectivity within this area of the Irish Atlantic continental margin. The results of the seismic interpretation presented here provide a detailed description of the evolution of the Connemara discovery and have resulted in a revised model for the tectonic development and stratigraphic evolution of the fault block structure containing the oil accumulation. The new seismic stratigraphic analysis also provides the basis for an alternative interpretation of Early Cretaceous ‘clinoform’ features based on the results of the 3D seismic interpretation which supports a genesis through structural rotation of onlapping horizons rather than depositional downlap favoured by previous interpretations. This new-found structural and stratigraphic understanding not only has significant implications for determining the main controls on the Connemara discovery, but also provides a basis upon which to place other prospective structures in their regional context, including the identification and risking of exploration plays and prospects in the area.

Osmolytes are small, chemically diverse, organic solutes that function as an essential component of cellular stress response. Protecting osmolytes enhance protein stability via preferential exclusion, and nonprotecting osmolytes, such as urea, destabilize protein structures. Although much is known about osmolyte effects on proteins, less is understood about osmolyte effects on nucleic acids and their counterion atmospheres. Nonprotecting osmolytes destabilize nucleic acid structures, but effects of protecting osmolytes depend on numerous factors including the type of nucleic acid and the complexity of the functional fold. To begin quantifying protecting osmolyte effects on nucleic acid interactions, we used small-angle X-ray scattering (SAXS) techniques to monitor DNA duplexes in the presence of sucrose. This protecting osmolyte is a commonly used contrast matching agent in SAXS studies of protein-nucleic acid complexes; thus, it is important to characterize interaction changes induced by sucrose. Measurements of interactions between duplexes showed no dependence on the presence of up to 30% sucrose, except under high Mg(2+) conditions where stacking interactions were disfavored. The number of excess ions associated with DNA duplexes, reported by anomalous small-angle X-ray scattering (ASAXS) experiments, was sucrose independent. Although protecting osmolytes can destabilize secondary structures, our results suggest that ion atmospheres of individual duplexes remain unperturbed by sucrose.

A cantilever-based uncooled IR imager was developed utilizing a novel optical readout scheme based on inter-pixel interference. A series of small arrays (approximately 100 × 100 pixels) were fabricated using 8-in. silicon MEMS processes. The array design and process development will be discussed and initial uniformity and imaging results presented. Future challenges in developing a direct-view IR imager will be addressed.

The adoption of large-scale distributed computing presents new opportunities and challenges for the physicists analyzing data from the Large Hadron Collider experiments. With petabytes of data to manage, effective use of provenance is critical to understanding the results.

OBJECTIVE: To investigate whether the favourable cardiovascular disease (CVD) risk factor profile of habitual exercisers is attributable to exercise or leanness. DESIGN: Cross-sectional study of 113 nonsmoking men aged 30-45 y. CVD risk factors were compared in exercisers (n=39) and sedentary men (n=74), and in subgroups of lean exercisers (n=37), lean sedentary men (n=46) and obese sedentary men (n=28). Waist girth was used to identify lean ( or =100 cm) subgroups. MEASUREMENTS: Blood pressure, physical activity (7-day recall), physical fitness (maximum oxygen consumption) and fasted lipoproteins, apolipoprotein (apo) B, triglycerides, glucose and fibrinogen. RESULTS: Exercisers were fitter and leaner than sedentary men and had a better CVD risk factor profile. Total cholesterol, LDL-cholesterol and apo B concentrations were lower in lean exercisers than in lean sedentary men, suggesting that exercise influences these risk factors. Indeed, time spent in vigorous activity was the only significant predictor of total cholesterol and LDL-cholesterol in multiple linear regression models. Exercise status had little influence on triglycerides and HDL-cholesterol (HDL-C), and unfavourable levels were only evident among obese sedentary men. Waist girth was the sole predictor of triglycerides and HDL-C, explaining 44 and 31% of the variance, respectively. CONCLUSIONS: These findings suggest that the CVD risk factor profile of habitual exercisers is attributable to leanness and exercise. Leanness is associated with favourable levels of HDL-C and triglycerides, while exercise is associated with lower levels of total cholesterol, LDL-cholesterol and apo B.

This paper demonstrates a new ion implantation and wet-etch technique for fabricating high-quality ridged optical waveguides for high-speed LiNbO/sub 3/-based optical modulators. In addition, the paper demonstrates the fabrication of optical waveguide ridges >3 /spl mu/m in height with 90/spl deg/, and even re-entrant sidewall angles for the first time. The modeling used indicates that 90/spl deg/ (and re-entrant) sidewall ridges can reduce the required modulator drive voltage by 10-20% over modulators with conventional trapezoidal ridge profiles fabricated with reactive ion etching. A 40-Gb/s modulator with a 30-GHz bandwidth, 5.1-V switching voltage at 1 GHz, and a 4.8-dB optical insertion loss is fabricated using the ion implantation/wet-etch process. Fabricated devices showed good stability against accelerated aging, indicating that this process could be used for commercial purposes.

The authors criticize the central place of belief-desire psychology in the theories-of-mind enterprise. They detail the merits of adopting a more agentive framework for conceptualizing human action and demonstrate how children's growing understanding of epistemic agency relates to advances in moral reasoning.

Antibodies to factor XII (FXII) have previously been identified in some patients who were lupus anti-coagulant-positive. The relationship between these antibodies and FXII levels appeared to be variable. The aim of the present study was to confirm the presence of antibodies to FXII in patients with well characterized antiphospholipid syndrome (APS) and to establish their potential effect on levels of FXII. Forty-two patients with APS were studied; 21 patients were found to have either immunoglobulin (Ig)G or IgM antibodies to FXII by enzyme-linked immunosorbent assay (ELISA) using a highly purified preparation of FXII (> 99% pure). Levels of FXII were statistically significantly lower (P = 0.02) in patients with antibodies to FXII when compared with patients without antibodies to FXII (median = 91 micro/dl, s.d. = 39.1, median = 122 micro/dl, s.d. = 41.1 respectively). Four of the 21 patients with antibodies to FXII were found to have FXII levels below the laboratory normal range. Antibodies to FXII are present in significant numbers of patients with APS and may lead to acquired FXII deficiency.

Ta2O5 is a candidate for use in metal–oxide–metal (MOM) capacitors in several areas of silicon device technology. Understanding and controlling leakage current is critical for successful implementation of this material. We have studied thermal and photoconductive charge transport processes in Ta2O5 MOM capacitors fabricated by anodization, reactive sputtering, and chemical vapor deposition. We find that the results from each of these three methods are similar if one compares films that have the same thickness and electrodes. Two types of leakage current are identified: (a) a transient current that charges the bulk states of the films and (b) a steady state activated process involving electron transport via a defect band. The transient process involves either tunneling conductivity into states near the Fermi energy or ion motion. The steady state process, seen most commonly in films

This communication demonstrates the combined use of two techniques for fabricating transistors that incorporate an organic semiconductor and that can operate at low voltages: anodization for thin (∼50 nm), high-capacitance gate dielectrics and microcontact printing on electroless silver for high-resolution (∼1 μm) source/drain electrodes. The techniques are attractive for use with organic active components because (i) they are carried out at or near room temperature in aqueous solutions, (ii) they are compatible with important organic semiconductors and flexible plastic substrates, and (iii) they are suitable for reel-to-reel processing. n- and p-Channel devices formed with the organic semiconductors dihexyl quinquethiophene and copper hexadecafluorophthalocyanine and anodized tantalum and silicon substrates illustrate the typical performance of transistors fabricated with these methods.

The interaction parameters that determine materials properties are generally sensitive to pressure. Thus, pressure tuning provides a means to rapidly explore a material's interaction parameter phase space to increase the rate of discovery of materials with improved properties. Here we report a significant improvement in the thermoelectric properties of the Kondo insulator NdxCe3-xPt3Sb4 upon pressure tuning to 2 GPa. This result provides a target for synthetic attempts at ambient pressure to duplicate the observed improved high-pressure behavior.

The temperature dependence of transport properties, including thermopower, electrical resistivity and thermal conductivity, were measured on a series of Nd substituted CePd 3 samples and Th substituted Nd x Ce 1− x Pd 3 samples ( x =0.6,0.7). The relatively large thermoelectric figure of merit ( ZT ) associated with the intermediate valence state of CePd 3 is reduced for all Nd x Ce 1− x Pd 3 samples and is primarily the result of reducing the thermopower at all temperatures. The ZT values of the Nd x Ce 1− x Pd 3 samples ( x =0.6,0.7) are increased, especially at low temperature ( K ), by replacing some of the Nd x Ce 1− x with the larger, tetravalent Th. However, the ZT values never exceed that of the pure CePd 3 . For all compounds, the Lorentz ratios ( L / L 0 ) are close to unity at room temperature and deviate to larger values as the temperature is lowered.

The Ce8Pd24M compounds, with an ordered structure derived from CePd3, have been synthesized for various group 13 and 14 p-block elements. The electrical resistivities of the group 13 compounds have features that can be attributed to strong Kondo interactions while the group 14 compounds show typical metallic behavior. The thermopowers, or Seebeck coefficients, for each compound were measured at both 297 and 78 K, and are much smaller (|S

Factor XII levels were determined in plasma samples from 75 patients before undergoing aortocoronary bypass grafting and from 40 healthy age-matched donors by using a microtitre plate adaptation of a new chromogenic peptide substrate assay kit for factor XII. The chromogenic peptide substrate assay values for factor XII correlated well with those obtained in clotting (r=0.90; y= 15.811+0.8236x) and immunochemical (r=0.88; y=17.90+0.817x) assays in the normal donor samples. Factor XII levels in the patients were significantly lower than those in the normal donors (83.3+/-23.2% versus 103.4+/-23.1: p=0.004), and nine patients (12%) had factor XII values below 50% compared with only one of the normal donors (2.5%). Factor XII levels and kallikrein-like activities (a measure of contact system activation) were followed before, during, and one day after cardiopulmonary bypass in 20 patients. Factor XII levels were significantly reduced, and kallikrein-like activities significantly elevated after 5 and 30 minutes cardiopulmonary bypass. One day after cardiopulmonary bypass both factor XII levels and kallikrein-like activities were significantly lower than preoperation values.

The efficacy, tolerability, and safety of the potent angiotensin II receptor blocker candesartan cilexetil were evaluated in 217 adult patients (68% men, 41% black) with severe systemic hypertension on background therapy with hydrochlorothiazide (HCTZ) in a 4-week, multicenter, randomized, double-blind, placebo-controlled study. Patients with sitting diastolic blood pressure (BP) > or =110 mm Hg during the placebo run-in received HCTZ 12.5 mg once daily for 1 week. Those with sitting diastolic BP >95 mm Hg after the HCTZ run-in were randomized (2:1) to receive candesartan cilexetil 8 mg once daily (n = 141) or placebo (n = 76), plus HCTZ 12.5 mg. After 1 week of double-blind treatment, patients with sitting diastolic BP > or =90 mm Hg were uptitrated to candesartan cilexetil 16 mg once daily or matching placebo, plus HCTZ 12.5 mg; 84% required uptitration. Primary efficacy measurement was a change in trough (24+/-3 hours after treatment) sitting diastolic BP from the end of the HCTZ run-in to double-blind week 4. Mean changes in systolic and diastolic BP were significantly greater with candesartan cilexetil than with placebo, -11.3/-9.1 mm Hg versus -4.1/-3.1 mm Hg, p or =10 mm Hg decrease) and 32% were controlled (diastolic BP

Specific-heat measurements have been carried out to further elucidate the electronic and magnetic properties of ${\mathrm{Ce}}_{8}{\mathrm{Pd}}_{24}M$ ($M$=Ga, In, Sn, Sb, Pb, and Bi). The measurements show that a slight change in the chemical and electronic structure of ${\mathrm{CePd}}_{3}$, by forming the ordered ternary ${\mathrm{Ce}}_{8}{\mathrm{Pd}}_{24}M$-type compounds, induces an enhanced low-temperature electronic specific heat \ensuremath{\gamma}. This indicates the emergence of heavy-fermionic behavior with the loss of the intermediate valence nature of ${\mathrm{CePd}}_{3}$. All of the ${\mathrm{Ce}}_{8}{\mathrm{Pd}}_{24}M$-type compounds studied here exhibit a sharp peak in the specific heat at low temperature due to antiferromagnetic (AF) transitions. Below the transition temperature, the specific heat shows the heavy-fermionic behavior, i.e., \ensuremath{\gamma}( $T$\ensuremath{\rightarrow}0) equal to a finite value, rather than \ensuremath{\gamma}( $T$\ensuremath{\rightarrow}0)=0 in the paramagnetic AF ground state.

SummaryFactor XII (FXII) levels were determined in plasma samples from 29 normal donors, 10 patients with inherited FXII deficiency (all lupus anticoagulant [LA] negative) and 67 LA positive patients, using clotting (FXIIct), chromogenic substrate (FXIIcs) and immunochemical (FXIIag) assays. Excellent correlations were obtained in the three FXII assays with the LA negative samples and between the FXIIcs and FXIIag assays in the LA positive samples. Correlations between both the FXIIcs and FXIIag with FXIIct in the LA positive patients were poor. Of 67 LA positive samples studied, 25 (37.3%) showed lower values in the FXIIct assay; 13 (19.4%) of these patients were pseudo FXII deficient with values of FXII below the lower limit of normal.These results indicate that a diagnosis of FXII deficiency can be made inappropriately in the presence of phospholipid antibodies and that such a diagnosis should not be made by FXIIct assay alone.

The title compounds were prepared from the elemental components by arc-melting and subsequent annealing at 1020 K and 1170 K. Both CePd 0.63 Ge 1.37 and CeAu 0.75 Ge 1.25 crystallize in the AlB 2 structure type with a statistical distribution of the transition metal and germanium atoms on the boron site. The structure of CeAu 0.75 Ge 1.25 was refined from single crystal X-ray data: P6/mmm, a =433.5(1) pm, c =422.6(1) pm, V =0.0688(1) nm 3 , Z =1, wR 2=0.0504 for 157 F 2 values and 7 variables. Magnetic susceptibility data for both compounds show a full cerium moment and ferromagnetic ordering at 6.0(5) K for CeAu 0.75 Ge 1.25 and 3.0(5) K for CePd 0.63 Ge 1.37 . The crystal structure and properties of CeAu 0.75 Ge 1.25 are compared with those of equiatomic CeAuGe which adopts the NdPtSb structure type, an ordered variant of AlB 2 .

We have prepared and examined the resistivity and magnetic susceptibility of a series of ternary compounds with composition Ce 8 Pd 24 M, where M is one of Ga, In, Sn, Sb, Pb or Bi, and the related composition La 8 Pd 24 In. All members of this series are cubic with effective cerium moments consistent with trivalent cerium. The lanthanum compound behaves as a simple metal in resistivity and has a small, negative susceptibility at 295 K. All the cerium compounds but the gallide exhibit antiferromagnetic ordering below 10 K. Metallic behaviour is observed for all. The properties of the stannide, plumbide, antimonide and bismuthide reflect some weak interactions with crystal-field-split cerium states above 30 K and changes in slope at low temperature coincident with the second-order antiferromagnetic phase transitions. Resistivities for the gallide and indide display broad features near 15 and 50 K, respectively, suggesting that a strong Kondo interaction is present in these materials.

The effects of low-dose chronic scopolamine on measures of cerebral perfusion and muscarinic receptors were tested in eight Alzheimer's disease (AD) subjects and eight elderly controls. Single photon emission computed tomography (SPECT) scans using technetium-labelled hexamethypropylene amine oxide (99mTc-HMPAO) to measure cerebral perfusion before and after chronic scopolamine revealed a significant 12% increase in the normal controls (P0.01) while the AD subjects showed no significant change. In contrast, the controls showed decreased muscarinic binding as evidenced by 123I-quinuclidinyl-4-iodobenzilate (123I-QNB) labelling after chronic drug (-10%, P0.01) whereas the AD subjects showed increased 123I-QNB labelling (+8%, P0.05). The difference between AD and control subjects was even more marked when the ratio of I-QNB to HMPAO uptake was compared, pointing to a double dissociation in the SPECT results. These data cannot be explained by group differences in cerebral perfusion alone and suggest a differential sensitivity between AD and elderly controls to chronic cholinergic blockade.

We show that the solid-solution series Li x Cr y Co 1− y O 2 can be prepared as a single phase with x near 1 for 0≤ y ≤0.5 and y = 1.0. Using powder X-ray diffraction and Rietveld profile refinement, we show that these solid-solutions are isostructural with LiCoO 2 but with Cr and Co sharing the Co sites. Electrochemical measurements using Li/Li x Cr y Co 1− y O 2 cells show that as y increases the amount of Li which can be reversibly cycled in these materials decreases drastically, thus limiting the practical usefulness of these materials. We were unsuccessful at making single-phase solid-solutions of Li x Cr y Ni 1− y O 2 using similar methods.

Mode profiles of the light coming out of Ti diffused waveguides formed in LiNbO3 crystals were imaged using a near-field scanning optical microscope (NSOM). We find that the transverse magnetic mode has a smaller spatial dimension and is closer to the surface of the waveguide than the transverse electric mode. We also measured the phase and intensity distributions of the guided optical modes directly by incorporating the NSOM into an interferometer. The effective index (neff) is determined from the spacings of phase fronts, which equals λ/neff. The experimental results of mode profiles and neff are in good agreement with theoretical simulations. However, an unexpected nonuniform intensity distribution was observed, which could be linked to defects in the waveguide.

We describe a microfluidic device containing a mineral matrix capable of rapidly generating hydroxyl radicals that enables high-resolution structural studies of nucleic acids. Hydroxyl radicals cleave the solvent accessible backbone of DNA and RNA; the cleavage products can be detected with as fine as single nucleotide resolution. Protection from hydroxyl radical cleavage (footprinting) can identify sites of protein binding or the presence of tertiary structure. Here we report preparation of micron sized particles of iron sulfide (pyrite) and fabrication of a microfluidic prototype that together generate enough hydroxyl radicals within 20 ms to cleave DNA sufficiently for a footprinting analysis to be conducted. This prototype enables the development of high-throughput and/or rapid reaction devices with which to probe nucleic acid folding dynamics and ligand binding.

Osmolytes, which function as a vital component of the cellular stress response, are small, chemically diverse, intracellular organic solutes. Protecting osmolytes enhance protein stability via preferential exclusion, where denaturation of the protein in the presence of the osmolyte is less favorable than in an aqueous environment. Thus, the correct ratios of protecting to non-protecting osmolytes and protecting osmolytes to ions are critical to maintain protein structure and protein-nucleic acid interactions. In contrast to the effects of osmolytes on protein stability, structure, and function, there is much less understood concerning the effects of osmolytes on nucleic acids. Although non-protecting osmolytes can destabilize both protein and nucleic acid structures, protecting osmolytes have different effects depending on the complexity of the nucleic acid structure. Furthermore, the influence of osmolytes on the ion atmosphere surrounding nucleic acids is not well understood. As a first step in quantifying the effects of osmolytes on nucleic acid electrostatics we used small angle x-ray scattering (SAXS) techniques to monitor 25-bp DNA duplexes and their interactions in the presence and absence of sucrose, a protecting osmolyte and important contrast matching agent in SAXS studies of protein-nucleic acid complexes. Results will be discussed.

Different types of graphs are widely used to represent many types of management science models. Examples include vehicle routing, production planning, simulation and decision trees. In previous work, the author has developed tools and techniques based on graph-grammars to provide interfaces for such models. In this paper, we explore several such models with particular emphasis on integrating different graph-based models within a single environment. It is shown how the environment can combine a variety of visual models in different ways.

The solid solution series LiFe y Ni 1- y O 2 (0.1≤ y ≤0.5) has been prepared from various starting materials. Using powder X-ray diffraction and Rietveld profile refinement, we show that this solid solution is only iso-structural with hexagonal LiNiO 2 in the conposition range 0≤ y ≲0.23. For 0.23≲ y ≲0.48 phase coexistence occurs between hexagonal LiFe 0.23 Ni 0.77 O 2 and cubic (NiO structure) LiFe 0.48 Ni 0.52 O 2 . For all samples in the hexagonal phase, cation mixing between transition metal and lithium layers, was observed. Using anomalous X-ray techniques we were able to determine that the cation mixing was primarily between Fe and Li. The cation mixing and the presence of the cubic phase for y >0.2, profoundly affects the electrochemical de-intercalation of Li from these materials. Electrochemical measurements using Li/Li 1− x Fe y Ni 1− y O 2 cells show that as y increases the amount of Li which can be reversibly cycled, Δ x , decreases, thus limiting the practical usefulness of these materials.

thermal parameters for the H atoms were fixed throughout all subsequent refinements. Least-squares refinement converged to final R = 0.044, wR = 0.048, S = 1.416. At this point all subsequent shifts were found to be < 0.001tr. A single prominent peak is evident on the difference electron density map measuring 0.67 e A -3 in the immediate vicinity of Br. Otherwise, all remaining difference peaks were found to be < 0.39 e A -3. Anomalous scattering of Br anti S atoms was employed for verification of the proper choice of enantiomeric configuration, following the statistical criterion proposed by Hamilton (1965). The opposite enantiomorph refined to final reliability indices of R = 0.051, wR = 0.057. Scattering factors for neutral atoms and anomalous-scattering parameters for Br and S atoms were taken from International Tables for X-ray Crystallography (1974, Vol. IV). All calculations were performed on a PDP 11/60 utilizing the SDP-Plus package (Frenz, 1978). Discussion. Refined positional parameters for all atoms and equivalent isotropic B values are supplied in Table 1. Atom numbering follows the scheme indicated in Fig. 1. Fig. 2 shows a stereo OR TEP (Johnson, 1976) representation of the molecule. Interatomic bonding distances and angles are supplied in Table 2.* Bond distances and angles are, generally, as expected. The one exception to this is * Lists of structure factors, complete bond distances and angles, and anisotropic thermal parameters have been deposited with the British Library Document Supply Centre as Supplementary Publication No. SUP 55634 (18 pp.). Copies may be obtained through The Technical Editor, International Union of Crystallography, 5 Abbey Square, Chester CH1 2HU, England. [CIF reference: CRI012]

This paper contains a study of the response of shifting agriculture to several social and environmental changes in circumstances in which farmers form in a relatively sophisticated manner their expectations of the future values of key economic variables. Farmers are 'given' a model of expectations formation in which the expected future value of variables interact in the same manner as in the current period. With this structure of expectations, the responses of the length of fallow period (the inverse of the percentage of available land cultivated in the initial period), the total area of land under cultivation and lying fallow in the initial period of a rotational cycle, and the initial-period wage rate and spatial structure of land rent to changes in several social and environmental parameters are examined. Several salient characteristics commonly attributed to shifting, or rotational, agriculture are replicated. Higher crop prices and increased population shorten fallow periods. Those same changes also increase the total area of land under shifting agriculture. Higher interest rates also shorten fallow periods. Fallows are longer at locations farther from central markets. Less commonly recognized is that social feedbacks operate to reduce pressure on more fragile land, although this does not imply that, other things being equal, fragile tropical land will not be 'overused' in an ecological sense.

The dielectric loss in amorphous, thin-film oxide insulators produces a real part of the ac conductivity σ′(ω) that scales as ωs with s∼1. Conventional models explain this frequency dependence by hopping or tunneling of charge between neighboring defect sites. These models fail at low temperatures since they predict that σ′ should vanish at T=0. We observe that the ac conductivity of Ta2O5, ZnO, and SiO2 has a nonzero extrapolated value at T=0. We propose that this behavior is consistent with the predictions of a Coulomb glass, an insulator with a random distribution of charged defects.The dielectric loss in amorphous, thin-film oxide insulators produces a real part of the ac conductivity σ′(ω) that scales as ωs with s∼1. Conventional models explain this frequency dependence by hopping or tunneling of charge between neighboring defect sites. These models fail at low temperatures since they predict that σ′ should vanish at T=0. We observe that the ac conductivity of Ta2O5, ZnO, and SiO2 has a nonzero extrapolated value at T=0. We propose that this behavior is consistent with the predictions of a Coulomb glass, an insulator with a random distribution of charged defects.

Forty female patients with either primary anti-phospholipid syndrome (n = 26) or systemic lupus erythematosus (anti-phospholipid syndrome positive) (n = 14) were investigated for levels of factor XII, the presence of lupus anticoagulant and antibodies to cardiolipin, beta 2-glycoprotein I and factor XII. Twenty-one patients had a history of recurrent fetal loss (> 2, mean = 2.6). Lupus anticoagulant positivity showed a weak association with recurrent fetal loss (odds ratio = 1.1). While there was no association between the presence of antibodies to cardiolipin or beta 2-glycoprotein I with recurrent fetal loss, antibodies to factor XII showed a strong and statistically significant association (odds ratio = 5.4, P = 0.025).

The majority of charge-compensating ions around nucleic acids form a diffuse counterion “cloud” that is not amenable to investigation by traditional methods that rely on rigid structural interactions. Although various techniques have been employed to characterize the ion atmosphere around nucleic acids, only anomalous small-angle X-ray scattering (ASAXS) provides information about the spatial distribution of ions. Here we present an experimentally straightforward extension of ASAXS that can be used to count the number of ions around nucleic acids.

C 19 H 14 cristallise dans P2 1 /c avec a=5,994, b=23,482, c=18,367 A, β=90,57 o , Z=8; affinement jusqu'a R=0,053. Les deux molecules independantes possedent des orienttions differentes a l'interieur de la maille et sont presque planes, mais les angles diedres de 3,4 et 6,2 o entre les cycles les plus en dehors A et D sont plus grands que dans les benzo [a] anthracenes les moins substitues en position «baie»