Calorimetric Study of CeRu2Ge2 Under Continuously Swept Hydrostatic Pressure up to 8 GPa

We have implemented AC calorimetric measurements in diamond anvil pressure cells. The range of pressure (0–20 GPa), the excellent hydrostatic conditions of solid ⁴He used as the pressure transmitting medium associated with the possibility of continuously tuning the pressure at low temperature makes this experiment ideally suited for investigating phase diagrams under pressure and in particular for studying the thermodynamics of correlated metals around a Quantum Critical Point (QCP) where magnetic order is suppressed at absolute zero temperature. We present here results on the heavy fermion compound CeRu₂Ge₂ up to 8 GPa and down to 2 K. The specific heat anomalies associated with the different magnetic phase transitions are clearly resolved, allowing a precise determination of the magnetic phase diagram. On approaching the QCP close to 7 GPa, we observe a striking broadening of the antiferromagnetic transition associated with an anomalous behavior of the signal phase which could correspond to a change in the nature of this transition.     

An investigation of extraction procedures for assessing the phosphate rock residue in multicomponent fertilisers

Five chemical extractants-water, neutral ammonium acetate, neutral ammonium citrate (hot and cold) and alkaline ammonium citrate-have been assessed on their ability to efficiently isolate the residual phosphate rock present in multicomponent fertilisers without affecting the phosphate rock. Phosphoric acid-based partially acidulated phosphate rocks (PAPRs) were manufactured along with several LONGLIFE (LL, single superphosphate to which reactive phosphate rock is added ex-den) materials for the assessment of these extractants.Each extractant was assessed by analysing the resultant residual phosphate rock isolated from each multicomponent fertiliser and comparing its chemical properties with the original phosphate rock used to manufacture the products. An analysis of extractable phosphorus was also undertaken. X-ray diffraction analysis was performed on selected phosphate rock residues as an independent method of examining the extraction techniques.Water and neutral ammonium acetate were found to be unsatisfactory for use as extractants; neither removed calcium sulphate when present, while the latter also did not appear to extract all the monocalcium phosphate component. The remaining three extractants all removed soluble phosphorus components and impurity species from the fertiliser products, leaving the residual phosphate rock relatively unaffected. Residue analyses were only slightly modified to those of the original rocks, although there were some inconsistencies in results obtained using hot neutral ammonium citrate. X-ray diffraction analysis showed no significant differences between residues produced from neutral ammonium citrate or alkaline ammonium citrate extractions, but water and neutral ammonium acetate residues confirmed the presence of calcium sulphate in LL and the presence of monocalcium phosphate in a neutral ammonium acetate extracted PAPR.From this study, cold neutral ammonium citrate and alkaline ammonium citrate appear to be equally suitable for isolating the phosphate rock from a multicomponent fertiliser, leaving the residual rock substantially unmodified from the original phosphate rock. However, there was a slight preference for cold neutral ammonium citrate due to its ease of preparation and use.     

CONSTRAINTS ON DIAGENESIS AND RESERVOIR QUALITY IN THE FRACTURED HASDRUBAL FIELD, OFFSHORE TUNISIA

The hydrocarbon reservoir of the Hasdrubal field (offshore Tunisia) lies within the Eocene El Garia Formation. This formation was deposited on a shallow north- to NE-facing ramp in the Early Eocene and is composed of a belt of nummulitic wackestones-grainstones. The nummulitic fades occupies a range of depositional environments from outer to mid ramp. In addition to Hasdrubal, several other producing oil- and gasfields have been discovered in the variably dolomitised El Garia Formation offshore Tunisia. Cores from three Hasdrubal wells were examined. Reservoir quality shows a limited relationship to primary depositional fabric and has been influenced significantly by compaction and later diagenesis. The highest permeabilities are typically developed within a dolomitised zone which occurs near the middle of the reservoir interval across the entire field, and which may follow a primary wackestone lithofabric (typically 20–30% bulk volume dolomite, with porosities of 15–22% and permeabilities of l-30mD). Fractures, particularly in zones surrounding faults, have resulted in enhanced permeabilities. Combined results of isotope (δ¹⁸ O -5.0 to -7.3%oPDB) and fluid inclusion (Th 80–90d̀C) analyses of dolomites from this dolomitised zone indicate that matrix dolomites are burial diagenesis cements. Dolomitisation of the reservoir was a “closed system ” event and was not the result of major fluid flow or mixing. Magnesium ions for dolomitisation were derived from the transformation of high-Mg to low-Mg calcite in nummulite tests within the reservoir fades. Our analyses indicate that calcite cements were precipitated at temperatures of up to almost 150d̀C in primary and secondary pores and in variably-sealed fractures Fracture lining and filling cements show a range of δ¹⁸ O values, which suggests that the fractures acted as fluid conduits over a range of temperatures during burial diagenesis Fracture densities measured in core increase rapidly close to seismically-resolvable faults in the reservoir facies Fracturing probably resulted in the leakage of hydrocarbons through the Compact Micrite Member seal which overlies the accumulation, as well as facilitating the ingress of hot fluids from stratigraphically deeper levels in the basin     

Family life stress and insomnia symptoms in a prospective evaluation of young adults.

The present study prospectively investigated the association between family life stress and insomnia symptoms among 115 undergraduates, ages 17-22 years. Participants completed the following questionnaires at 2 study time points, spaced 3 weeks apart: the Insomnia Severity Index, the Negative Life Events Questionnaire (NLEQ), and the Beck Depression Inventory. First, family life stress at baseline was hypothesized to predict elevated insomnia symptoms 3 weeks later, above and beyond depressive symptoms. Second, compared with academic stressors, negative family and social life events were expected to best predict increased insomnia. Regression analyses were conducted to test study predictions. Hypotheses were partially supported. Family life stress was significantly associated with increased insomnia symptomatology, even after controlling for depression. Results also revealed that negative family life events, together with academic stress, predicted the highest levels of insomnia. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A randomized clinical trial of a computer based preventive intervention: Replication and extension of ePREP.

This randomized clinical trial replicated the efficacy of the ePREP preventive intervention for mental health and relationship relevant outcomes in a sample of 77 college students. It extended previous research by demonstrating efficacy at a 10-month follow up. Participants in the ePREP condition experienced improved mental health and relationship relevant outcomes relative to those who received a placebo intervention. The impact of the ePREP intervention on these outcomes was durable to relationship dissolution with and without repartnering. The flexibility of this intervention empowers it to overcome key obstacles in the dissemination of relationship education. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Fast color grouping and slow color inhibition: Evidence for distinct temporal windows for separate processes in preview search.

The authors report 4 experiments that examined color grouping and negative carryover effects in preview search via a probe detection task (J. J. Braithwaite, G. W. Humphreys, & J. Hodsoll, 2003). In Experiment 1, there was evidence of a negative color carryover from the preview to new items, using both search and probe detection measures. There was also a negative bias against probes on old items that carried the majority color in the preview. With a short preview duration (150 ms) carryover effects to new items were greatly reduced, but probe detection remained biased against the majority color in the old items. Experiments 2 and 4 showed that the color bias effects on old items could be reduced when these items had to be prioritized relative to being ignored. Experiment 3 tested and rejected the idea that variations in the probability of whether minority or majority colors were probed were crucial. These results show that the time course of color carryover effects can be separated from effects of early color grouping in the preview display: Color grouping is fast, and inhibitory color carryover effects are slow. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Flight simulator evaluation of a novel flight instrument display to minimize the risks of spatial disorientation

BACKGROUND: Melanomas arising from the mucous membranes lining the respiratory, digestive, and genitourinary tracts are rare. Women are more commonly affected than are men, mainly because there is no male counterpart for vulvovaginal lesions. The mainstay of therapy is surgery, with little current use of adjuvant modalities in primary therapy. These lesions usually are advanced at initial presentation; consequently, the prognosis is poor, with 5-year survivals well below 50% in most series. METHODS: One hundred and nineteen patients with primary mucosal melanoma were reviewed. They represented 1.1% of the 10,393 melanoma patients seen at Duke University between 1970 and 1995. All data were obtained from the patients' clinic charts and computerized databases. RESULTS: There were 43 tumors arising from the head and neck region, 46 from the urogenital tract, and 30 from the anorectum. A female predominance was observed, with a female-to-male ratio of 2.7:1. All but five of the patients underwent resection with curative intent. Regional or distant metastases, or both, were encountered in 36 patients at the time of presentation. In patients with head and neck and urogenital tumors, local recurrences accounted for most of the treatment failures, whereas systemic recurrences were more common with tumors arising in the anorectum. The age and gender of the patient, anatomic site of origin of the tumor, clinical stage at initial presentation, and ulceration of the primary all clearly affected prognosis. Overall, the probabilities of being alive 1, 5, and 10 years after diagnosis were 80%, 29%, and 15%, respectively. CONCLUSIONS: Widely accepted classification systems are needed so that results from separate institutions can be compared adequately. Multi-institutional trials could help in delineating standardized therapeutic protocols and in establishing the potential roles of emerging modalities in the treatment of this subtype of melanoma.     

Influence of manufacturing variables on characteristics and the agronomic value of partially acidulated phosphate fertilizers

Partially acidulated phosphate fertilizers are manufactured either by direct partial acidulation of phosphate rocks (PRs) with sulphuric and/or phosphoric acid (directly acidulated PAPR) or indirectly by mixing reactive phosphate rocks (RPRs) with single superphosphate (SSP-RPR mixture). This form of low cost fertilizer manufacture is suitable for improving the agronomic value of unreactive PRs or production of high analysis fertilizers that can have agronomic values similar to fully acidulated phosphate fertilizers.The solubility characteristics of the directly acidulated PAPRs are affected by the type, composition and concentration of the acid used for acidulation, degree of acidulation, nature and fineness of PR and the method of manufacture. In general, partial acidulation with phosphoric acids which contain minimum amounts of metallic impurities acidulates more PR and results in more soluble P in the product. In the case of SSP-RPR mixtures made by adding RPR to immature SSP, the nature of PR used for SSP manufacture and the time of addition of RPR to ex-den SSP mixture affects the quality of the product. In order to minimize the selective reaction of the RPR with residual acid present in the ex-den SSP reaction mixture, RPR should not be added until PR acidulation (used for SSP) is essentially complete.The agronomic value of partially acidulated phosphate fertilizers is affected by the amount of water soluble P and the solubility of residual PR. None of the single extraction tests such as 2% citric acid, 2% formic acid and neutral ammonium citrate appear to be appropriate as indicators of plant available P in these fertilizers. Double extraction procedures which remove both the soluble P and the residual P have been investigated, but need to be correlated with agronomic data before they can be adopted as quality tests.