bluuebunny/crossref_metadata_2025 huggingface dataset:
GENOTYPIC DIFFERENCES IN THE GROWTH OF BANANAS (MUSA SPP.) INFECTED WITH MIGRATORY ENDOPARASITIC NEMATODES. 1. ROOTS
Authors: KALORIZOU H. A. , GOWEN S. R. , WHEELER T. R.
Published: July 2007

The effects of nematodes on root morphology and the association of root characteristics with resistance to nematodes of seven banana varieties were investigated in two experiments. Banana plants were grown in controlled conditions within polytunnels and harvested on three occasions for the measurement of root morphology and biomass. Varieties differed in their resistance to nematodes, from resistant (Yg Km5, FHIA 17, FHIA 03) and partly resistant (FHIA 01, FHIA 25) to not resistant ((FHIA 23, Williams). Nematodes reduced the root dry weight of FHIA 01, FHIA 17 and FHIA 23 at some harvests. Primary root number was on average 9.5% lower in nematode-infected plants than controls, with no differences among the varieties. Thus, there was no simple association between the resistance of these varieties and their tolerance to nematodes. Varieties differed in root morphology. Root dry weight was greatest for resistant varieties Yg Km5 and FHIA 03, and least for non-resistant varieties FHIA 23 and Williams. Thus, resistance to nematodes was associated with varieties with greater root mass and more and larger primary roots.
CONTROLLING SUFETULA SPP.: A COCONUT INSECT PEST ON PEAT SOILS
Authors: BONNEAU X. , HUSNI M. , BEAUDOIN-OLLIVIER L. , SUSILO JOKO
Published: July 2007

We demonstrated experimentally that Sufetula, a root-mining insect, has a depressive effect on coconut yields on peat soils. The impact of the pest resulted in a shortfall in earnings that warranted taking control measures. We considered control methods suitable for rehabilitating infested mature coconut plantings and for preserving young coconut plantings. Currently, cultural control is the only effective method. It involves eliminating all identified shelters for the adult insect, i.e. fern cover and heaps of coconut waste (dry fronds and husks). The aim is to achieve totally bare soil, with moss cover that does not attract the pest, or planted with an unattractive intercrop such as pineapple.
Allies, Constituents or Myopic Investors: Marcus Garvey and Black Americans
Authors: PATSIDES NICHOLAS
Published: July 2007

Marcus Garvey's ideology had special meaning to West Indian migrants because it helped their economic adjustment in the United States. Despite the relocation of the Universal Negro Improvement Association to New York City, Garvey continued to speak predominantly to West Indians at home and abroad, since he shared their colonial mentality and understood their migrant ideology – the search for economic gain abroad in order to multiply options back home. Garvey scholars have argued that black Americans benefited from Garvey rhetoric as much as West Indian migrants, but tensions between the two communities suggest that black Americans did not think so. Garveyism served to accentuate economic rivalries as black Americans suspected that migrants wanted to transfer their material success back home – indeed, Garvey openly encouraged as much.
The Local and the Global: Gina Nahai and the Taking up of Serpents and Stereotypes
Authors: YOUSAF NAHEM
Published: July 2007

Region, home and transnational migration are explored in terms of the transcultural complexities that reverberate through Iranian American Gina Nahai's Sunday's Silence. Nahai grapples with stereotypes that attach to the Holiness churches in the east Tennessee region of Appalachia. This essay argues that the novel's politics rest on the intersubjectivity of strangers as bound into a metaphysics of desire. It is through this paradigm that Nahai writes against the reductive association of “minority” literature with discrete “national” models and through which she explores the local and the regional in a culturally complex narrative about the crisis of alterity.
Random-mood interpretation of determinants for major depression
Authors: KAPTEIN KIRSTEN I. , De JONGE PETER , KORF JAKOB , SPIJKER JAN , De GRAAF RON , VAN DER WERF SIEBREN Y.
Published: July 2007

Background

It has recently been proposed that major depression disorder (MDD) may, in a heterogeneous population-based cohort, be interpreted in terms of a random-mood model. Mood fluctuations are thought to result from stressors that occur randomly in time. We have investigated whether this concept also holds for more homogeneous groups, defined by known determinants for MDD, and whether the model's parameters, susceptibility (Z) and relaxation time (T), may be evaluated and used to differentiate between subcohorts.

Method

From a large epidemiological survey, the Netherlands Mental Health Survey and Incidence Study (NEMESIS), data on the duration of MDD were obtained for subcohorts, based on gender, severity of depression, recurrence and co-morbidity with dysthymia, anxiety and somatic disorder, and were compared with random-mood simulation calculations.

Results

Susceptibility,Z, is empirically found to be proportional to incidence and may be identified with a risk ratio. A second scaling rule states the proportionality of mean duration with the product ofZandT. ThisZ–Tclassification proves to be more sensitive than conventional significance tests. Notably for men/women and for co-morbid anxiety, differences are seen that have previously gone unnoticed.

Conclusions

Depression may be conceptualized as a disorder resulting from random-mood fluctuations, the response to which is influenced by a large variety of determinants or risk factors. The model's parameters can be evaluated and may be used in differentiating between risk factor-defined subgroups.
National fortification of staple foods can make a significant contribution to micronutrient intake of South African adults
Authors: Steyn Nelia P , Wolmarans Petro , Nel Johanna H , Bourne Lesley T
Published: July 2007

Background

A national survey found that micronutrient deficiencies are prevalent in South African children, particularly calcium, iron, zinc, riboflavin, niacin, vitamin B6, folate, vitamin A, E and C. Mandatory fortification of maize meal and wheat flour were introduced in 2003 to combat some of the deficiencies found in children. To date however, there has not been a national survey on dietary intake in adults.

Objectives

The main objectives of this study were to evaluate the micronutrient intake of the diet consumed by the average adult South African by means of secondary data analyses and secondly to evaluate the effects of fortification on selected nutrient intakes.

Study design

Secondary data analysis was carried out with numerous dietary surveys on adults to create a database that included sampling (and weighting) according to ethnic/urban–rural residence in line with the population census, of which 79% were black Africans and the majority resided in rural areas. The effect of fortification was evaluated by substituting fortified foods in the diet for the unfortified products.

Subjects

The combined database used in this study comprised 3229 adults.

Results

Mean calcium, iron, folate and vitamin B6 intakes were very low particularly in women. Mean intakes of most micronutrients were lower in rural areas. Fortification of maize meal and wheat flour (bread) raised mean levels of thiamine, riboflavin, niacin, vitamin B6 and folate above the recommended nutrient intakes (RNIs). In women, despite fortification, mean iron intakes remained below the RNIs, as did calcium since it was not in the fortification mix.

Conclusion

The average dietary intake of adults was of poor nutrient density, particularly in rural areas. Fortification of maize meal and wheat flour (bread) considerably improved mean vitamin B6, thiamine, riboflavin, niacin, folate and iron intakes as well as the overall mean adequacy ratio of the diet.
Childhood diet in relation to Sámi and Norwegian ethnicity in northern and mid-Norway – the SAMINOR study
Authors: Brustad M , Parr CL , Melhus M , Lund E
Published: July 2007

Objective

The purpose of this work was to identify dietary patterns in the past using cluster analysis of reported diet in childhood, and to assess predictors for dietary patterns in relation to ethnicity in the population in the Sámi core areas in Norway. The Sámis are an indigenous population living in the border areas of Norway, Sweden, Finland and Russia.

Design

Population-based, cross-sectional study, using self-administered questionnaires. A food-frequency questionnaire covering selected food items eaten in childhood was used. The questionnaire also provided data on ethnicity.

Subjects and setting

This study was based on data collected from 7614 subjects participating in The Population Based Study of Health and Living Conditions in Areas with a Mixed Sámi and Norwegian Population (the SAMINOR study) who grew up in the SAMINOR geographical areas, i.e. areas with mixed Sámi and Norwegian populations in Norway.

Results

Four dietary clusters were identified: a reindeer meat cluster; a cluster with high intakes of fish, traditional fish products and mutton, in addition to food sources from the local environment; a Westernised food cluster with high intakes of meat balls and sausages; and a cluster with a high intake of fish, but not any other foods in the questionnaire. The cluster distribution differed by ethnicity, but the effect of ethnicity on diet differed by coastal and inland residence.

Conclusion

Our study has shown that data gathered through the limited questionnaire could be used to group the study sample into different dietary clusters, which we believe will be useful for further research on relationships between diet in childhood and health in the Sámi core areas in Norway.
A school salad bar increases frequency of fruit and vegetable consumption among children living in low-income households
Authors: Slusser Wendelin M , Cumberland William G , Browdy Ben L , Lange Linda , Neumann Charlotte
Published: July 2007

Objective

To measure change in fruit and vegetable (F&V) consumption among elementary-school children after the introduction of a salad bar programme as a lunch menu option in the US Department of Agriculture’s (USDA) reimbursable lunch programme in Los Angeles Unified School District (LAUSD).

Design

A cross-sectional sample of children was interviewed before and after a salad bar intervention (1998 and 2000, respectively) utilising a 24-hour food recall questionnaire. Frequencies of F&V consumption were calculated.

Setting

The evaluation took place in three LAUSD elementary schools participating in the salad bar programme and the USDA reimbursable lunch programme.

Subjects

Three hundred and thirty-seven children in 2nd–5th grade (7–11 years old).

Results

After the salad bar was introduced, there was a significant increase in frequency (2.97 to 4.09,P< 0.001) of F&V consumed among the children studied. The increase in frequency of F&V consumed was almost all due to an increase during lunch (84%). Mean energy, cholesterol, saturated fat and total fat intakes were significantly lower in the children after the salad bar was introduced in the schools compared with the intakes in the children before the salad bar was introduced.

Conclusion

A salad bar as a lunch menu option in the USDA reimbursable lunch programme can significantly increase the frequency of F&V consumption by elementary-school children living in low-income households.
Emotionale Entwicklung und kunsttherapeutische Symbolisierung
Authors: Barth Gottfried Maria , Klosinski Gunther
Published: July 2007

Zusammenfassung. Anhand einer ausführlichen Kasuistik wird die sich entwickelnde Differenzierung des emotionalen Erlebens bei einer zu Beginn 12-jährigen Patientin während einer 2-jährigen stationären kinderpsychiatrischen Therapie dargestellt. Die von der Patientin in unterschiedlichen Settings angefertigten Bilder spiegeln verschiedene Entwicklungsstufen von einer Retardierung der emotionalen Entwicklung über eine depressive Phase bis hin zu einer Integration differenzierter Gefühle und Anerkennung von Beziehung mit Ausgestaltung von lebendiger Trauer. Diese Entwicklung wird in Beziehung gesetzt zu den Stufen emotionalen Erlebens (LEAS) nach Lane, die eine wichtige Ergänzung der seit Piaget konzeptualisierten Stufen kindlicher Entwicklung darstellen.
Tsallis distributions of magnetic field strength variations in the heliosphere: 5 to 90 AU
Authors: Burlaga L. F. , F‐Viñas A. , Wang C.
Published: July 2007

The Tsallis (q‐exponential) distribution function, derived from the entropy principle of nonextensive statistical mechanics, describes fluctuations in the magnetic field strength on many scales throughout the heliosphere. This paper shows that a one‐dimensional multifluid magnetohydrodynamic (MHD) model, with Advanced Composition Explorer (ACE) observations at 1 AU as input, predicts Tsallis distributions between 5 and 90 AU on scales from 1 to 128 days. At a scale of 1 day, the radial variation of the entropic indexqdecreases fromq≥ 5/3 atR≤ 50 AU toq≤ 5/3 atR≥ 60 AU, corresponding to a change from a divergent to a convergent second moment of the Tsallis distribution, suggesting the possibility of a “phase transition” and/or a relaxation effect at ≈60 AU. The Tsallis distribution derived from the time series of one‐dimensional MHD model is nearly identical to those observed by Voyager 1 at ∼80 AU over the scales from 1 to 64 days during the year 2000. The Tsallis distribution appears over a wide range of scales and distances despite the complex nonlinear dynamical evolution of the heliospheric magnetic field during 1999/2000.
Depth dependence of constitutive law parameters for shear failure of rock at local strong areas on faults in the seismogenic crust
Authors: Ohnaka Mitiyasu , Kato Aitato
Published: July 2007

In the framework of slip‐dependent constitutive formulation, which leads to a unifying law that governs not only frictional slip failure at precut interface areas on faults but also shear fracture of intact rock at local strong areas on the faults, a thorough investigation has been made about how the constitutive law (of dimensionless form) for rock failure at local strong areas on faults is affected by seismogenic crustal conditions of effective normal stress, pore pressure, and temperature, on the basis of laboratory data on the shear fracture of granite rock obtained by Kato et al. (2003a) under crustal conditions simulated in the laboratory. It has been revealed how dimensionless constitutive law parameters distinctively vary with depth, depending on the crustal conditions simulated; consequently, the constitutive behavior including the slip‐weakening phase also distinctively varies with depth. This behavior in the regime of suprahydrostatic pore pressure clearly differs from that in the regime of hydrostatic pore pressure. The results of this study are suited for implementation in a numerical code, and the constitutive properties of rock failure at local strong areas (called “asperites”) on faults will be easily assimilated into numerical models of earthquake ruptures for realistic computer simulation.
Measuring the heterogeneity of the coseismic stress change following the 1999 Mw7.6 Chi‐Chi earthquake
Authors: Marsan D. , Daniel G.
Published: July 2007

Seismicity quiescences are expected to occur in places where the stress has been decreased, in particular following large main shocks. However, such quiescences can be delayed by hours to years and be preceded by an initial phase of earthquake triggering. This can explain previous analyses arguing that seismicity shadows are rarely observed, since they can only be seen after this triggering phase is over. Such is the case of the main rupture zone, which experiences the strongest aftershock activity despite having been coseismically unloaded by up to tens of bars. The 1999 Mw7.6 Chi‐Chi, Taiwan earthquake is characterized by the existence of several such delayed quiescences, especially off the Chelungpu fault on which the earthquake took place. We here investigate whether these delays can be explained by a model of heterogeneous static‐stress transfer coupled with a rate‐and‐state friction law. We model the distribution of coseismic small‐scale stress change τ by a Gaussian law with mean and standard deviation στ. The latter measures the level of local heterogeneity of the coseismic change in stress. The model is shown to mimic the earthquake time series very well. Robust inversion of the and στ parameters can be achieved at various locations, although on‐fault seismicity has not been observed for a sufficiently long time to provide more than lower bounds on those estimates for the Chelungpu fault. Several quiescences have delays that can be well explained by local stress heterogeneity, even at relatively large distances from the Chi‐Chi earthquake.
Isopycnal deepening of an under‐ice river plume in coastal waters: Field observations and modeling
Authors: Li S. Samuel , Ingram R. Grant
Published: July 2007

The Great Whale River, located on the southeast coast of Hudson Bay in Canada, forms a large river plume under complete landfast ice during early spring. Short‐term fluctuations of plume depth have motivated the present numerical study of an under‐ice river plume subject to tidal motion and friction. We introduce a simple two‐layer model for predicting the vertical penetration of the under‐ice river plume as it propagates over a deepening topography. The topography is idealized but representative. Friction on the bottom surface of the ice cover, on the seabed, and at the plume interface is parameterized using the quadratic friction law. The extent of the vertical penetration is controlled by dimensionless parameters related to tidal motion and river outflow. Model predictions are shown to compare favorably with under‐ice plume measurements from the river mouth. This study illustrates that isopycnal deepening occurs when the ice‐cover vertical motion creates a reduced flow cross‐section during the ebbing tide. This results in supercritical flow and triggers the downward plume penetration in the offshore. For a given river discharge, the freshwater source over a tidal cycle is unsteady in terms of discharge velocity because of the variation in the effective cross‐sectional area at the river mouth, through which freshwater flows.
Incorporating water table dynamics in climate modeling: 2. Formulation, validation, and soil moisture simulation
Authors: Miguez‐Macho Gonzalo , Fan Ying , Weaver Christopher P. , Walko Robert , Robock Alan
Published: July 2007

In this second part of the two‐part series, we discuss the formulation and implementation of groundwater processes into an existing climate model, by linking a groundwater reservoir and a rivers‐lakes reservoir with its land surface scheme. We present the parameterization and validation of these processes with river flow and soil moisture observations. We use the new scheme as a tool to investigate the role of the groundwater reservoir in controlling the spatial and temporal structure of large‐scale soil moisture fields. We find that where the water table is shallow, the groundwater reservoir is linked to the soil water reservoir through two‐way fluxes. At these locations, the role of the groundwater shifts from being primarily a sink to being primarily a source for the soil, as the season progresses from the wet spring to the dry autumn. Through the two‐way fluxes, groundwater exerts a certain degree of control on the root zone soil moisture fields; there is an apparent spatial correlation between the distribution of shallow water table and wet soil. Since the water table reflects long‐term climatic and topographic forcing and exhibits strong spatial organization, its link to the soil moisture gives the latter a certain degree of spatial organization as well. The slow changing nature of the water table acts to stabilize the temporal variations in soil water, giving the latter stronger seasonal persistence.
Diurnal cycle of precipitation in a climate model
Authors: Shin D. W. , Cocke S. , LaRow T. E.
Published: July 2007

An investigation is carried out to study the model capability in resolving the diurnal cycle of June–August rainfall using the Florida State University/Center for Ocean‐Atmospheric Prediction Studies (FSU/COAPS) climate model. The Tropical Rainfall Measuring Mission multisatellite precipitation analysis products are used as the verification data. In order to uncover which model components are more responsible for the diurnal cycle, a number of seasonal (3‐month‐long) integrations are performed by modifying the climate model configurations. It is found that the convective scheme employed is the most crucial component in properly capturing the diurnal cycle of rainfall. A detailed and improved signal of diurnal cycle is obtained in the experiments with a higher horizontal resolution. A negative influence is found when the Community Land Model version 2 as a land surface scheme is used. No additional improvement in the oceanic precipitation diurnal cycle is conferred even if a frequently coupled ocean model is used rather than prescribed weekly sea surface temperatures (SST). This is due to the weak SST diurnal cycle from the ocean model.
Subsurface structure of the “petit‐spot” volcanoes on the northwestern Pacific Plate
Authors: Fujiwara Toshiya , Hirano Naoto , Abe Natsue , Takizawa Kaoru
Published: July 2007

A seismic reflection survey was conducted in the northwestern Pacific to investigate subsurface structure of small volcanoes considered to be formed by the newly‐discovered “petit‐spot” intra‐plate volcanism. In contrast with an acoustically transparent sedimentary layer in the ambient northwestern Pacific, sedimentary layers are acoustically opaque with interbedded strong reflections beneath the volcanoes. These reflections are possibly caused by inhomogeneous structure due to intrusion of central vent. Subhorizontal strong reflections at base of the sedimentary layer, identified in the vicinity of volcanoes, are probably reflections from sills of dense lavas flowing out within the sedimentary layer. These volcanoes could be monogenetic volcanoes produced by small amount of magma intrusion,<1 km3 in volume. Although such small volcanoes have never been discovered unless through a high‐resolution bathymetric mapping, the “invisible” intra‐plate volcanism affects successive evolution/modification of the crustal architecture of old‐age oceanic plates.
Humoral immune responses in mice using gamma inulin preparations as adjuvants for hepatitis B vaccines
Authors: Leslie D. E. , Nicholson S. , Dimitrakakis M. , Johnston N. , Gust I. D.
Published: July 2007

There is an urgent need for new, powerful adjuvants suitable for use with sub‐unit and peptide vaccines in humans. We have measured the humoral immune response in BALB/c mice to vaccine formulations using recombinant HBsAg antigens, and gamma inulin and alum adjuvants. Using Merck, Sharpe & Dohme(MSD) HBsAg at 10 μg/mL, high levels of anti‐HBs were generated and geometric mean S/N ratios of 88, 133 and 107 were obtained for alum absorbed vaccine, gamma inulin, and a mixture of the two adjuvants, respectively. A dilution series produced ED50 values of 0·08, 0·15 and 0·22 μg/mL respectively. In a second series of experiments comparing alum and algamulin (a complex of gamma inulin and alum), MSD HBsAg induced anti‐HBs levels of 81 and 52, and ED50 values of 0·1 and 0·4 when used in conjunction with alum and algamulin, respectively. SKF HBsAg induced anti‐HBs levels of 126 and 111 with alum and algamulin, and ED50 values of 0·11 and 0·075. The class, subclass and level of antibody produced in mice boosted with a second dose of vaccine at 21 days was also examined. Both alum and gamma inulin induced higher levels of total antibody, IgGI and minor IgG subclasses than algamulin, or HBsAg alone. Overall, gamma inulin appears to be an equivalent adjuvant to alum, although their mechanisms of action arc different. Mixtures or complexes of the two adjuvants appear to be less effective in inducing humoral immune responses in mice than either alone.
Effect of exogenous prostaglandin E2 and actinomycin D on plasma leakage induced by neutrophil‐activating peptide‐1/interleukin‐8
Authors: Colditz I. G.
Published: July 2007

Neutrophil accumulation and plasma leakage were measured in rabbit skin at sites stimulated with recombinant human neutrophil activating peptide‐1/interteukin‐8 (NAP‐1/IL‐8). Neutrophil accumulation occurred at doses equal to or greater than 10‐11 moles NAP‐1/IL‐8 per site. Co‐injection of prostaglandin E2 (PGE2) extended the threshold of inflammatory activity of NAP‐1/IL‐8 to less than 10‐13 moles/site and caused approximately three‐fold increases in neutrophil accumulation and ten‐fold increases in plasma leakage at the higher doses of NAP‐1/IL‐8 examined. Plasma leakage declined more rapidly than did neutrophil accumulation as lesions aged. It was postulated that an endothelial response may be initiated to limit plasma leakage during ongoing neutrophil emigration at sites stimulated with NAP‐1/IL‐8. The induction of vasodilatation by injection of PGE2 masked the decline of plasma leakage with time in lesions up to 120 min old. Co‐injection of the RNA synthesis inhibitor, actinomycin D, failed to abrogate the decline of plasma leakage with time, suggesting that de novo protein synthetic events such as production of the vasoconstrictor peptide, endothelin, are unlikely to contribute to the mechanism that restricts plasma leakage in older lesions. Although plasma leakage induced by NAP‐1/IL‐8 is dependent on the emigration of neutrophils, the results indicate that a mechanism, independent of de novo protein synthesis, restricts the rate of plasma leakage per neutrophil as lesions age.
Lymphocyte subpopulations in sheep with lymphosarcoma resulting from experimental infection with bovine leukaemia virus
Authors: Dimmock C. K. , Ward W. H. , Trueman K. F.
Published: July 2007

Sheep were experimentally infected with bovine leukaemia virus (BLV) and developed leukaemia and lymphosarcoma 30–88 weeks later. Ten sheep with lymphosarcoma were necropsied and lymphocyte subpopulations were evaluated in peripheral blood lymphocytes (PBL) and lymphocyte suspensions prepared from a range of lymph nodes, tumours and spleen. The leukaemic phase of BLV infection was characterized by an increase in the number of circulating B lymphocytes. The number of T lymphocytes was also increased with the CD8+ subpopulation proliferating at a much greater rate than the CD4+ subpopulation. In PBL the CD4:CD8 ratio fell rapidly as leukaemia developed, being 1·15 (±0·18) 5–8 weeks before necropsy and 0·38 (±0·09) at necropsy. During this period the number of B lymphocytes increased from 11·2 (± 0·7) to 379·4 (± 85·8)x 109/L. CD4: CD8 ratios were also low in all lymph nodes and spleens of leukaemic sheep at necropsy. Most of the cells in solid tumours were B lymphocytes but a small population of T lymphocytes with a low CD4: CD8 ratio was identified.
Prevention of adjuvant‐induced cachexia in rats by cyclosporin A
Authors: Rofe A. M. , Whitehouse M. W. , Bourgeois C. S. , Haynes D. R. , Vernon‐Roberts B.
Published: July 2007

The changes in food intake and biochemistry following Freund's adjuvant (AJ)‐induced inflammation in rats were investigated. Injection of AJ into rats resulted in a transient anorexia but a sustained decrease in body weight. Within 14 days, body weight decreased by 12% (P<0·05) and adipose tissue (retroperitoneal fat pads) decreased by more than 50%. Biochemical changes seen in association with the AJ‐induced wasting included decreased plasma concentrations of triglyceride and cholesterol. Injection of cyclosporin‐A (CS) (20 mg/kg) with the AJ decreased the anorexia, prevented the sustained loss of body weight and adipose tissue and reversed the effects on plasma triglyceride and cholesterol concentrations. Insulin concentrations were not significantly affected by the AJ or AJ/CS treatments. Peritoneal macrophages from AJ‐treated rats produced 3‐fold more tumour necrosis factor‐α (cachectin) than control rats. This effect was not observed in rats treated with AJ plus CS. The results are consistent with CS preventing the release of cytokines which have anorectic and catabolic actions (IL‐1, TNF), although there is also the possibility that CS has effects involving endocrine mechanisms.
The flow rate of whole and submandibular/sublingual gland saliva in patients receiving replacement complete dentures
Authors: Wolff A. , Ofer S. , Raviv M. , Helft M. , Cardash H. S.
Published: July 2007

summary  Provision of complete dentures to a new denture wearer increases the salivary flow rate is well known. The new dentures act as an additional mechanical stimulus to the salivary reflexes, thus increasing the flow rate. The purpose of this study was to determine whether replacing complete dentures would elicit the same response. Unstimulated and stimulated whole and submandibular/sublingual (SM/SL) saliva were collected before inserting complete replacement dentures and again after 2 days and after 3 weeks of denture wearing. Unstimulated whole salivary flow rate increased significantly 2 days after inserting replacement dentures, decreasing at 3 weeks but remaining significantly above the baseline. Stimulated whole salivary flow rate increased significantly after 2 days but decreased to normal after 3 weeks. Stimulated and unstimulated SM/SL salivary flow rate increased significantly after 2 days, decreasing at 3 weeks while remaining significantly above the values found before denture insertion.
Characterization of HfO2 films deposited on 4H-SiC by atomic layer deposition
Authors: Wolborski Maciej , Rooth Mårten , Bakowski Mietek , Hallén Anders
Published: July 2007

Hafnium oxide films with a measured relative dielectric constant of 15.4 were deposited at room temperature on Si and 4H-SiC substrates, as well as on 4H-SiC p-i-n diodes. An 8 nm thick SiO2 interfacial layer on SiC increased the breakdown field of the HfO2∕SiO2 stack by 6%, while a 13 nm thick SiO2 layer reduced it by 35%. The evidence of different current conduction mechanisms in SiO2 is shown to be related to the oxide thickness. For the diodes, the breakdown voltage was extended by at least 20%, compared to nonpassivated devices. Annealing at 400 °C in a forming gas changed the crystallinity and increased the relative dielectric constant of the HfO2 layers. There is an indication of reaction between HfO2 and SiO2 in the stacked films after annealing.
Study and optimization of ion-irradiated high Tc Josephson junctions by Monte Carlo simulations
Authors: Sirena M. , Bergeal N. , Lesueur J. , Faini G. , Bernard R. , Briatico J. , Crete D. G. , Contour J. P.
Published: July 2007

High Tc Josephson junctions (HTc JJ) made by irradiation have remarkable properties for technological applications. However, the spread in their electrical characteristics increases with the ion dose. We present a simple model to explain the JJ inhomogeneities, which accounts quantitatively for experimental data. The spread in the slit’s width of the irradiation mask is the limiting factor. Monte Carlo simulations have been performed using different irradiation conditions to study their influence on the spread of the JJ characteristics. A “universal” behavior has been evidenced, which allows us to propose new strategies to optimize JJ reproducibility.
An improved discrete configuration of a cylinder magnet for portable nuclear magnetic resonance instruments
Authors: Chen Jizhong , Xu Chunyan
Published: July 2007

The continuous magnetization profile approximated by a discrete source is the main reason for the deteriorating magnetic field homogeneity in Halbach magnet. It is identified by comparing the two-dimensional (2D) field solutions of an ideal cylinder magnet with those of a cylinder magnet constructed from several segment magnets. To improve the magnetic field homogeneity, a cylinder magnet from several crescent-shaped magnets is therefore presented. The programed 2D field solutions of the magnet from the crescent-shaped segments verify that the configuration effectively improves the homogeneity inside the cylinder magnet compared to that of a magnet built from simpler segments. For a small magnet with a required field uniformity and magnitude, the configuration has more advantages than a configuration from typical segments. Hence, the magnet is more appropriate for a portable nuclear magnetic resonance instruments.
Semiempirical theory of Carver rates in alkali/noble-gas systems
Authors: Camparo J. C.
Published: July 2007

During an encounter between a noble-gas atom and an alkali-metal atom, the electron density at the alkali nucleus is altered, resulting in a collisional change in the alkali’s hyperfine coupling (i.e., AI∙S→(A+δA)I∙S). In the case of binary encounters, this process has been termed the Carver mechanism. The short-lived collisional change in hyperfine coupling can have very noticeable effects: it plays an important role in the loss of nuclear spin polarization in high magnetic fields, and it can be one of the dominant line broadening mechanisms for alkali hyperfine transitions (e.g., in atomic clocks). Unfortunately, though there have been measurements of the Carver relaxation rate, to date there has been little theoretical analysis of the Carver mechanism, in large part due to the very difficult problem of computing δA. In the present work, the author develops a theory of the Carver rate based on a semiempirical expression for δA(r)∕A, where r is the internuclear alkali/noble-gas separation, and validates the theory by comparing to experiment. This model is then used to compute Carver and Bouchiat relaxation rates (i.e., the three-body sticking-collision analog of the Carver rate) in diverse/alkali-noble gas systems. The main conclusion of this work is that Carver rates vary by orders of magnitude across the alkalies, and in general will likely only play a significant role for Rb and Cs noble-gas systems.
The stagnation point in Marangoni-thickened Landau-Levich type flows
Authors: Ramé Enrique
Published: July 2007

Experiments and analyses have shown that, when Marangoni stresses are present, the thickness of the Landau-Levich drawn-out film increases compared to the Marangoni-free classic case. As the Marangoni stress increases from zero, the stagnation point moves from where the interface height is three times the film thickness to infinity in the meniscus region when the film thickness is 22∕3 times the classic Landau-Levich value. In this Brief Communication, we examine the fate of the stagnation point as the film thickness increases past this value, and the stagnation point moves into the interior of the fluid.
Zero-variance zero-bias quantum Monte Carlo estimators of the spherically and system-averaged pair density
Authors: Toulouse Julien , Assaraf Roland , Umrigar C. J.
Published: July 2007

We construct improved quantum Monte Carlo estimators for the spherically and system-averaged electron pair density (i.e., the probability density of finding two electrons separated by a relative distance u), also known as the spherically averaged electron position intracule density I(u), using the general zero-variance zero-bias principle for observables, introduced by Assaraf and Caffarel. The calculation of I(u) is made vastly more efficient by replacing the average of the local delta-function operator by the average of a smooth nonlocal operator that has several orders of magnitude smaller variance. These new estimators also reduce the systematic error (or bias) of the intracule density due to the approximate trial wave function. Used in combination with the optimization of an increasing number of parameters in trial Jastrow-Slater wave functions, they allow one to obtain well converged correlated intracule densities for atoms and molecules. These ideas can be applied to calculating any pair-correlation function in classical or quantum Monte Carlo calculations.
Photoionization of C4 molecular beam: Ab initio calculations
Authors: Hochlaf Majdi , Nicolas Christophe , Poisson Lionel
Published: July 2007

Large computations are performed on the C4+ cation in order to characterize its stable isomers and its lowest electronic excited states using configuration interaction methods and large basis sets. Several stable isomers are found including a linear C4+(l-C4+), a rhombic C4+(r-C4+) (or cyclic), and a branched (d-C4+) structure. Our calculations show a high density of electronic states for all of these isomers favoring their interactions. By combining the present ab initio data and those on neutral C4, the l-C4(X̃)+hν→l-C4+(X̃+)+e−, d-C4(X̃)+hν→d-C4+(X̃+)+e−, and r-C4(X̃)+hν→r-C4+(X̃+)+e− vertical photoionization transition energies are computed at 10.87, 10.92, and 10.77eV, respectively. Photoionizing a C4 molecular beam results on an onset at 10.4–10.5eV and then to a linear increase of the signal due to the opening of several ionization channels involving most of the C4 and C4+ isomers and electronic states.
Ultrahigh vacuum-compatible fabrication and electrical characterization systems for environmentally sensitive metal oxide semiconductor capacitors
Authors: Billman C. A. , Walker F. J.
Published: July 2007

We describe an integrated, ultrahigh vacuum system for metal oxide semiconductor (MOS) device fabrication and characterization. This system is advantageous for electrical property measurements on electronic devices with environmentally sensitive materials and is especially important as device dimensions approach the nanoscale. Without exposure to atmosphere, MOS capacitors were fabricated by evaporatively depositing gate metal on molecular-beam-epitaxy (MBE) grown dielectrics through a shadow mask in an UHV electrode-patterning chamber. Finished devices were transferred in UHV to an in situ UHV electrical characterization probe station. We obtained excellent agreement between air-ambient ex situ and in situ probe station measurements with less than 0.3% systemic error for frequencies from 20Hzto1MHz. We have successfully measured MOS capacitors with sensitivity to a density of interface states of 1×1010statescm−2eV−1. These measurements show 0.5% systematic error for measurement frequencies from 20Hzto1kHz and less than 0.1% from 1kHzto1MHz. The integrated system presented here is one where complex, MBE-grown MOS heterostructures can be synthesized and tested rapidly to explore new field-effect-device physics and functionality.
Ground and asymmetric CO-stretch excited state tunneling splittings in the formic acid dimer
Authors: Matanović I. , Došlić N. , Kühn O.
Published: July 2007

There has been some controversy concerning the assignment of measured tunneling splittings for the formic acid dimer in the vibrational ground state and the asymmetric CO-stretching excited state. The discussion is intimately related to the question whether the fundamental excitation of the CO-vibration promotes or hinders tunneling. Here we will address this issue on the basis of a five-dimensional reaction space Hamiltonian which includes three large amplitude coordinates as well as two harmonic modes whose linear superposition reproduces the asymmetric CO-vibrational mode. Within density functional theory using the B3LYP functional together with a 6-311++G(3df,3pd) basis set we obtain a ground state tunneling splitting which is about 2.4 larger than the one for the CO-stretching excited state.
Kinetic Monte Carlo simulations of the interaction of oxygen with Pt(111)
Authors: Sendner Christian , Groß Axel
Published: July 2007

The adsorption, dissociation, diffusion, and desorption of oxygen interacting with the Pt(111) surface have been studied using kinetic Monte Carlo simulations. This study has been motivated by uncertainties in the theoretical and the experimental derivations of O2∕Pt(111) reaction barriers. The simulations reproduce all known experimental data within basically one set of parameters, thus yielding microscopic insights into the elementary reaction steps occurring in the interaction of oxygen with Pt(111) and providing reliable estimates for adsorption energies and diffusion and desorption barriers. In particular, we confirm that the distance of oxygen atoms directly after dissociation is caused by ballistic hot atom motion rather than by diffusive motion. We address the equilibrium structure of oxygen atoms at high coverages. At low temperatures, chains of oxygen pairs are formed. We show that this mechanism can be explained by a lowered dissociation in the vicinity of already adsorbed atoms. Finally we discuss the role of the lateral interaction between the oxygen atoms in the oxygen desorption process.
A scalable distributed method for quantum-scale device simulation
Authors: Cauley Stephen , Jain Jitesh , Koh Cheng-Kok , Balakrishnan Venkataramanan
Published: July 2007

We present an algorithm for the fast and accurate simulation of nanoscale devices. The idea underlying the algorithm is a divide-and-conquer method based on the nonequilibrium Green’s function formalism. This formalism has provided a unifying conceptual framework for the analysis of quantum transport in nanodevices and the computations therein are of significant interest across many areas of research. We offer two applications, the atomistic level simulation of silicon nanowires and the two-dimensional simulation of nanotransistors, which highlight the benefits of the divide-and-conquer framework. The inherently parallel algorithm presented here allows for computing resources to be flexibly allocated toward either solving problems of larger sizes in comparable time or speeding up the solution of a problem for a given size. Our algorithm facilitates the solution of problems orders of magnitude larger and, in most cases, was able to achieve substantial speedup, as compared to the current state of the art algorithm. Thus, the method presented here allows for large-scale simulation problems that can now be realized without the use of special purpose hardware or approximation methods.
Low threshold voltage ZnO thin film transistor with a Zn0.7Mg0.3O gate dielectric for transparent electronics
Authors: Dhananjay  , Krupanidhi S. B.
Published: July 2007

A highly transparent all ZnO thin film transistor (ZnO-TFT) with a transmittance of above 80% in the visible part of the spectrum, was fabricated by direct current magnetron sputtering, with a bottom gate configuration. The ZnO-TFT with undoped ZnO channel layers deposited on 300 nm Zn0.7Mg0.3O gate dielectric layers attains an on/off ratio of 104 and mobility of 20 cm2∕V s. The capacitance-voltage (C−V) characteristics of the ZnO-TFT exhibited a transition from depletion to accumulation with a small hysteresis indicating the presence of oxide traps. The trap density was also computed from the Levinson’s plot. The use of Zn0.7Mg0.3O as a dielectric layer adds additional dimension to its applications. The room temperature processing of the device depicts the possibility of the use of flexible substrates such as polymer substrates. The results provide the realization of transparent electronics for next-generation optoelectronics.
In situ laser heating and radial synchrotron x-ray diffraction in a diamond anvil cell
Authors: Kunz Martin , Caldwell Wendel A. , Miyagi Lowell , Wenk Hans-Rudolf
Published: July 2007

We report a first combination of diamond anvil cell radial x-ray diffraction with in situ laser heating. The laser-heating setup of ALS beamline 12.2.2 was modified to allow one-sided heating of a sample in a diamond anvil cell with an 80W yttrium lithium fluoride laser while probing the sample with radial x-ray diffraction. The diamond anvil cell is placed with its compressional axis vertical, and perpendicular to the beam. The laser beam is focused onto the sample from the top while the sample is probed with hard x-rays through an x-ray transparent boron-epoxy gasket. The temperature response of preferred orientation of (Fe,Mg)O is probed as a test experiment. Recrystallization was observed above 1500K, accompanied by a decrease in stress.
Modeling plasma actuators with air chemistry for effective flow control
Authors: Singh Kunwar Pal , Roy Subrata
Published: July 2007

An asymmetric dielectric barrier discharge model is presented for real gas air chemistry using a self-consistent multibody system of plasma, dielectric, and neutral gas modeled together to predict the electrodynamic force imparted to the working gas. The equations governing the motion of charged and neutral species are solved with Poisson equation using finite element method using a Galerkin weak formulation. Electric field profile changes with the increase in grounded electrode and the density increases downstream. The electrodynamic force development mechanism is studied over a flat plate due to charge and neutral species production from adjacent air in a radio frequency driven barrier discharge. The time average of the force shows mostly acceleration above the actuator. Numerical simulation confirms that the magnitude of force increases very slightly with the increase in the length of grounded electrode.
Photostability of amino acids: Internal conversion versus dissociation
Authors: Lin Ming-Fu , Tzeng Cheng-Ming , Dyakov Yuri A. , Ni Chi-Kung
Published: July 2007

Photodissociation dynamics for various tryptophan chromophores was studied at 193 or 248nm using multimass ion imaging techniques. The competition between internal conversion to the ground electronic state and dissociation from the repulsive excited state reveals size-dependent photostability for these amino acid chromophores. As the size of chromophore increases, internal conversion to the ground state becomes the major nonradiative process. For tryptophan and larger chromophores, dissociation directly from the repulsive state is completely quenched.
Wet oxidation of nitride layer implanted with low-energy Si ions for improved oxide-nitride-oxide memory stacks
Authors: Ioannou-Sougleridis V. , Dimitrakis P. , Vamvakas V. Em. , Normand P. , Bonafos C. , Schamm S. , Cherkashin N. , Ben Assayag G. , Perego M. , Fanciulli M.
Published: July 2007

An alternative method for the formation of the top oxide in oxide-nitride-oxide dielectric stacks is proposed. This method combines low-energy (1keV) silicon ion implantation into a thin nitride-oxide stack and subsequent low-temperature wet oxidation (850°C for 15min). Transmission electron microscopy shows that for an implanted dose of 1.5×1016Sicm−2, an 8-nm-thick silicon oxide layer develops on the surface of the nitride-oxide stack. Time of flight secondary ion mass spectrometry reveals: (1) transformation of the implanted silicon nitride to an oxygen-rich-silicon nitride layer and (2) pilling up of nitrogen atoms at the bottom silicon/oxide-substrate interface. The resulting oxide-nitride-oxide stack exhibits strong charge storage effects and excellent charge retention properties leading to a 1.5V, 10yr extrapolated memory window at 125°C. These results suggest that the proposed fabrication route may lead to gate dielectric stacks of substantial potential impact for mainstream nitride-based memory devices.
Determination of the free exciton energy in ZnO nanorods from photoluminescence excitation spectroscopy
Authors: He H. P. , Ye Z. Z. , Lin S. S. , Tang H. P. , Zhang Y. Z. , Zhu L. P. , Huang J. Y. , Zhao B. H.
Published: July 2007

Temperature-dependent photoluminescence excitation (PLE) spectroscopy is used to study nominally undoped and indium-doped ZnO nanorods grown by thermal evaporation method. Clear differences in PLE features between the two samples are observed. We demonstrate that the first derivative of the PLE spectra can be used to determine the free exciton energy for both samples. The physics behind is understood either in terms of competing absorption and recombination to the green emission band being monitored, or based on the analogy between the first derivative of PLE and photoreflectance spectroscopy. Two residual donor levels located at about 37 and 120meV below the conduction band minimum are identified from the PLE spectra.