bluuebunny/crossref_metadata_2025 huggingface dataset:
Estimates of surface ultraviolet radiation over north America using Geostationary Operational Environmental Satellites observations
Authors: Gadhavi H. , Pinker R. T. , Laszlo I.
Published: November 2008

Information on ultraviolet (UV) radiative fluxes is needed for public safety, understanding biodiversity, and for chemical transport modeling. Space‐based observations can provide homogeneous and systematic estimates of the UV flux over large regions. In the past, UV flux estimates have been made from polar orbiting satellites; such estimates lack information on diurnal variability that can result in significant errors in UV dose (diurnally integrated UV flux). An algorithm has been developed to estimate diurnally varying spectral UV flux at the surface based on information from geostationary satellites (cloud amount, surface albedo and aerosols) and from polar orbiting satellites (ozone). Algorithm evaluation is done by comparison with ground‐based observations made between January 1998 and December 2000 over eighteen stations of the United States Department of Agriculture (USDA)'s UV monitoring network. A good agreement between ground‐based observations and satellite estimates is found with a mean bias (satellite − ground) of +3.5% for all‐sky (cloudy + clear) cases. A negative mean bias of the same magnitude is found for clear‐sky cases. Root mean square (RMS) differences are 25% and 14% for all‐sky and clear‐sky cases, respectively. Using simulations, it is shown that when only one observation near noontime is used to estimate UV dose, errors in the range of −61% to 48% can result, depending on cloud conditions. The RMS difference is 9% and it increases to 13% when off‐noon hour (±2 hrs) observations are used to estimate the UV flux over Queenstown, MD.
Statistical downscaling of climate change impacts on ozone concentrations in California
Authors: Mahmud Abdullah , Tyree Mary , Cayan Dan , Motallebi Nehzat , Kleeman Michael J.
Published: November 2008

The statistical relationship between the daily 1‐hour maximum ozone (O3) concentrations and the daily maximum upper air temperature was explored for California's two most heavily polluted air basins: the South Coast Air Basin (SoCAB) and the San Joaquin Valley Air Basin (SJVAB). A coarse‐scale analysis of the temperature at an elevation of 850‐mbar pressure (T850) for the period 1980–2004 was obtained from the National Center for Environmental Prediction (NCEP)/National Center for Atmospheric Research (NCAR) Reanalysis data set for grid points near Upland (SoCAB) and Parlier (SJVAB). Daily 1‐hour maximum ozone concentrations were obtained from the California Air Resources Board (CARB) for these locations over the same time period. The ozone concentrations measured at any given value of the Reanalysis T850 were approximately normally distributed. The 25%, 50%, and 75% quartile ozone concentrations increased linearly with T850, reflecting the effect of temperature on emissions and chemical reaction rates. A 2D Lagrangian (trajectory) form of the UCD/CIT photochemical air quality model was used in a perturbation study to explain the variability of the ozone concentrations at each value of T850. Wind speed, wind direction, temperature, relative humidity, mixing height, initial concentrations for VOC concentrations, background ozone concentrations, time of year, and overall emissions were perturbed in a realistic fashion during this study. A total of 62 model simulations were performed, and the results were analyzed to show that long‐term changes to emissions inventories were the largest sources of ozone variability at a fixed value of T850. Projections of future T850 values in California were obtained from the Geophysical Fluid Dynamics Laboratory (GFDL) model under the Intergovernmental Panel on Climate Change (IPCC) A2 and B1 emissions scenarios for the years 2001 to 2100. The future temperature trends combined with the historical statistical relationships suggest that an additional 22–30 days year−1 in California would experience O3 ≥90 ppb under the A2 global emissions scenario, and an additional 6–13 days year−1 would experience O3 ≥ 90 ppb under the B1 global emissions scenario by the year 2050 (assuming the NOx and VOC emissions remained at 1990–2004 levels). These calculations help to quantify the climate “penalty” that must be overcome to improve air quality in California.
Sensitivity of three Mediterranean heavy rain events to two different sea surface fluxes parameterizations in high‐resolution numerical modeling
Authors: Lebeaupin Brossier C. , Ducrocq V. , Giordani H.
Published: November 2008

The southeast of France is prone to heavy rain events during the fall season. For these extreme precipitating events, the Mediterranean Sea supplies heat and moisture to the atmospheric boundary layer through the turbulent heat fluxes. In turn the low‐level jet, which frequently accompanies these events, induces a stress on the oceanic mixed layer. The aim of this study is to examine the sensitivity of short‐range (24 h) high‐resolution (2–3 km) forecasts to the sea surface fluxes parameterization for three representative torrential rainfall events. We consider in particular two sea surface fluxes bulk parameterizations: the original MESO‐NH model parameterization based on the Louis (1979) formulation and the iterative Coupled Ocean‐Atmosphere Response Experiment (COARE) bulk algorithm from Fairall et al. (2003). Results show that the two parameterizations produce very different air‐sea fluxes values, especially for strong winds; the largest differences are therefore found under the low‐level jets, where the COARE parameterization reduces the wind stress and the latent heat flux. The evaporation reduction results in a decrease of the low‐level humidity transport over the Mediterranean Sea in every case studied so that the convective activity, still intense, results in lower rainfall amounts. The impact of surface fluxes parameterization on the ocean mixed layer modeling is also examined by driving a one‐dimensional ocean model with the same set of atmospheric parameters but using the two parameterizations. Results show a significant impact on the mixed layer depth.
Overview of Mars surface geochemical diversity through Alpha Particle X‐Ray Spectrometer data multidimensional analysis: First attempt at modeling rock alteration
Authors: Tréguier Erwan , d'Uston Claude , Pinet Patrick C. , Berger Gilles , Toplis Michael J. , McCoy Timothy J. , Gellert Ralf , Brückner Johannes
Published: November 2008

Principal component analysis and a hierarchical clustering method have been employed to describe and quantify the compositional variability of Martian rocks and soils measured by the Alpha Particle X‐Ray Spectrometers onboard the Mars Exploration Rovers. A robust classification of samples emerges which defines distinct rock classes and sheds light on the petrogenetic relationships between rocks. This is particularly useful in the case of rocks from Gusev Crater, where significant chemical diversity is observed. This approach also highlights that compositional variability of rocks at Meridiani is dominated by variations in sulfur content; the relative proportions of other elements remaining approximately constant. For soils, variations in Fe concentration dominate because of the presence of hematite‐rich “berry”‐bearing samples. On the basis of this observation, a simple geochemical model of acid fog alteration of Martian basalts has been tested, assuming either equivalent alteration of all phases or preferential alteration of certain phases (thus taking into account kinetic considerations). The results show that for certain ranges of SO3/basalt, many of the compositional and mineralogical features measured at both sites may be explained. The secondary mineralogy and bulk rock compositions predicted by the model are broadly consistent with rock and soil compositions from Gusev and Meridiani, especially if the role of brine circulation and evaporation are considered. Although agreement is not perfect, comparison of observations and models argues in favor of variable interaction of the Martian surface with sour gas, explaining the high local abundance of sulfates, for example.
Nonlinear interaction of energetic electrons with large amplitude chorus
Authors: Bortnik J. , Thorne R. M. , Inan U. S.
Published: November 2008

The effect of large amplitude chorus on energetic, radiation‐belt electrons is evaluated using a general, relativistic, oblique, test‐particle code. Three specific cases are examined: (A) Low‐amplitude waves interacting at low‐latitudes exhibit the expected, linear scattering which leads to large‐scale diffusive behavior. (B) Large‐amplitude waves interacting at low‐latitudes result in monotonic decreases in pitch‐angle and energy due to a resonance dislocation effect, leading to large‐scale de‐energization and particle loss. (C) Large‐amplitude waves interacting obliquely at high latitudes result in a combination of the above behaviors, as well as nonlinear phase‐trapping which leads to rapid, dramatic increases in both energy and pitch‐angle of a small portion of the test‐particles. These results suggest that the intensity of individual, discrete wave elements is critical for quantifying the large‐scale dynamics of the radiation‐belts.
The deep magmatic system of the Campi Flegrei caldera (Italy)
Authors: Mangiacapra A. , Moretti R. , Rutherford M. , Civetta L. , Orsi G. , Papale P.
Published: November 2008

Melt inclusions in phenocrysts of the Minopoli2 shoshonite and Fondo Riccio latite eruptive products (Campi Flegrei caldera; 10.2 to 9.5 ka BP) constrain the nature of deep Phlegraean magmatic fluids, their role in volcanism and give new insights into the magmatic plumbing system. The analyzed melt inclusions show that CO2 is an abundant gaseous species, confirming the results of geochemical studies on the magmatic gas fraction involved in present‐day fumarolic emissions. Volatile concentrations within the melt inclusions require gas‐melt equilibria between 8 and 9 km depth, and closed‐system degassing in presence of ascending CO2‐rich fluids of deep provenance. Magmas later re‐equilibrate at depths up to 3–2 km, i.e. above the top of the carbonate basement. These observations correlate well with independent geophysical and geochemical evidence and are useful constraints for volcanic hazards assessment at Campi Flegrei.
Energetic neutral atom occultation: New remote sensing technique to study the lunar exosphere
Authors: Futaana Y. , Nakano S. , Wieser M. , Barabash S.
Published: November 2008

We propose a new technique to investigate the lunar exosphere by measuring energetic neutral atoms (ENAs). The lunar exosphere is a typical exosphere of celestial bodies without a dense atmosphere and without a global magnetosphere, but our knowledge of it is incomplete because of a very limited number of observations. In this paper, we present a feasibility study for detecting the charge exchange solar wind ENAs in the vicinity of the Moon by developing a numerical model that simulates the interaction between the solar wind and the lunar exosphere. The calculated ENA flux reaches 107 cm−2 s−1, which corresponds to ∼3% of the solar wind flux. The flux is high enough to be measured by existing ENA sensors. We also conducted many runs with different exospheric parameters. The charge exchange ENA flux is then found to depend both on the positions of the satellite and on the exosphere parameters. This result indicates that inversion techniques can in principle be applied in the future to reconstruct the exosphere profile from the obtained ENA flux data.
Direct estimates of pedogenic magnetite as a tool to reconstruct past climates from buried soils
Authors: Geiss Christoph E. , Egli Ramon , Zanner C. William
Published: November 2008

Variations in magnetic properties of buried soils can be used to reconstruct past climatic conditions during paleosol formation. Most methods, however, are based on comparisons between the magnetically enriched upper soil horizons and the magnetically unaltered parent material. In thin loess‐paleosol sequences such a comparison can be problematic because all horizons, soil and underlying loess, may be affected to varying degrees by pedogenesis. We propose two direct estimates of pedogenic magnetite based on the analysis of anhysteretic remanent magnetization ratios (χARM/isothermal remanent magnetization) and coercivity distributions. These estimates are independent of any information regarding the parent material and are possible if pedogenic minerals have similar magnetic properties throughout the study region. This condition seems to be met throughout the Midwestern United States and a few loessic soils elsewhere. The remanence‐carrying part of pedogenic magnetite is composed of single‐domain particles with consistent, well‐constrained magnetic properties. These particles are extremely well dispersed in the soil matrix as indicated by the absence of noticeable magnetostatic interaction effects. Our analyses of over 70 modern loessic soil profiles demonstrate that the abundance of pedogenic magnetite correlates well with modern climate and that the method is suited for reconstruction of past climates from paleosols.
Enhancement of oceanic parameters associated with dust storms using satellite data
Authors: Singh Ramesh P. , Prasad Anup K. , Kayetha Vinay K. , Kafatos Menas
Published: November 2008

Atmospheric aerosols play a vital role on the dynamics of climate processes through direct and indirect effects. Dust storms originating over the world's arid regions contribute a large fraction of aerosols in the atmosphere. Using remote sensing data, an anomalous enhancement in the biological productivity of sea was observed in the Gulf of Oman which was attributed only to cold sea surface temperature (SST) eddies (during November to early December months of 1996–1999), whereas recent study has shown that during dust storms (June–July–August and October–November–December months of 1997–2004), major nutrient supply is from atmospheric dust deposition. We have carried out a study of individual cases of major dust storms over the Arabian Sea during the entire year (December 2003–December 2006) to quantify role of dust storms and changes in ocean surface due to chlorophyll bloom. Using Moderate Resolution Imaging Spectroradiometer (MODIS) Aqua, we have found that the deposition of dust along the passage of major dust storms (aerosol optical depth (AOD) ∼0.25–0.41) occuring over the Arabian Sea causes chlorophyll blooming (usually 10–22.43 mg/m3) within a period of 1–2 to up to 3–4 days. However, we have also found significant anomalous cooling of the ocean surface (SST) and relatively higher ocean wind speeds (QuikSCAT) during dust storms that may lead to favorable conditions for blooming. Exact nature and cause of chlorophyll bloom in the semienclosed northern Arabian Sea, surrounded by one of the world's major sources of dust storms (Africa, Middle East, Iran, and Afghanistan), are very important in understanding the productivity and the biogeochemical cycles of the marine ecosystem. The results have been validated using the Indian Remote Sensing Polar‐4 Ocean Color Monitor (IRS P4 OCM) data.
Surface processes recorded by rocks and soils on Meridiani Planum, Mars: Microscopic Imager observations during Opportunity's first three extended missions
Authors: Herkenhoff Ken E. , Grotzinger John , Knoll Andrew H. , McLennan Scott M. , Weitz Catherine , Yingst Aileen , Anderson Robert , Archinal Brent A. , Arvidson Raymond E. , Barrett Janet M. , Becker Kris J. , Bell James F. , Budney Charles , Chapman Mary G. , Cook Debbie , Ehlmann Bethany , Franklin Brenda , Gaddis Lisa R. , Galuszka Donna M. , Garcia Patricia A. , Geissler Paul , Hare Trent M. , Howington‐Kraus Elpitha , Johnson Jeffrey R. , Keszthelyi Laszlo , Kirk Randolph L. , Lanagan Peter , Lee Ella Mae , Leff Craig , Maki Justin N. , Mullins Kevin F. , Parker Timothy J. , Redding Bonnie L. , Rosiek Mark R. , Sims Michael H. , Soderblom Laurence A. , Spanovich Nicole , Springer Richard , Squyres Steve W. , Stolper Daniel , Sucharski Robert M. , Sucharski Tracie , Sullivan Rob , Torson James M.
Published: November 2008

The Microscopic Imager (MI) on the Mars Exploration Rover Opportunity has returned images of Mars with higher resolution than any previous camera system, allowing detailed petrographic and sedimentological studies of the rocks and soils at the Meridiani Planum landing site. Designed to simulate a geologist's hand lens, the MI is mounted on Opportunity's instrument arm and can resolve objects 0.1 mm across or larger. This paper provides an overview of MI operations, data calibration, and analysis of MI data returned during the first 900 sols (Mars days) of the Opportunity landed mission. Analyses of Opportunity MI data have helped to resolve major questions about the origin of observed textures and features. These studies support eolian sediment transport, rather than impact surge processes, as the dominant depositional mechanism for Burns formation strata. MI stereo observations of a rock outcrop near the rim of Erebus Crater support the previous interpretation of similar sedimentary structures in Eagle Crater as being formed by surficial flow of liquid water. Well‐sorted spherules dominate ripple surfaces on the Meridiani plains, and the size of spherules between ripples decreases by about 1 mm from north to south along Opportunity's traverse between Endurance and Erebus craters.
Southern Hemisphere forcing of Pliocene δ18O and the evolution of Indo‐Asian monsoons
Authors: Clemens Steven C. , Prell Warren L. , Sun Youbin , Liu Zhengyu , Chen Guangshan
Published: November 2008

The Milankovitch paradigm links the timing (phase) of ice volume minima to summer insolation maxima in the hemisphere where ice volume dominates; consistent application of this paradigm dictates that Pliocene ice volume minima should lag Southern Hemisphere summer insolation maxima. We infer the magnitude of this lag on the basis of the phase relationship between equatorial sea surface temperature and benthic δ18O. We infer that Pliocene δ18O minima should lag obliquity maxima by 19° (2.2 ka), broadly consistent with the current global marine δ18O chronology, and precession maxima by 32° (2 ka), a difference of 160° (10.2 ka) relative to the current global marine δ18O chronology. Only in the context of this revision are Pliocene summer and winter monsoon phase relationships consistent with direct orbital forcing across the entire Indo‐Asian region, including marine and terrestrial proxies from the Chinese Loess Plateau, the South China Sea, and the Arabian Sea. Strong Pliocene summer and winter monsoons were in phase with one another, strengthened at obliquity minima and precession minima; the summer monsoon was also strengthened at precession maxima, yielding a semiprecession spectral signal. Strong Pliocene monsoons at orbital extremes indicate a direct response to fast physics processes including sensible heating and cooling of the Asian landmass and, for the summer monsoon, the export of latent heat from the southern Indian Ocean. As Northern Hemisphere ice volume grew into the Pleistocene, the timing of strong winter and summer monsoons drifted apart becoming influenced by the combined effects of fast physics and slow physics (ice volume) variables. The phase of strong winter monsoons shifted toward ice maxima, and the phase of strong summer monsoons shifted toward ice minima.
Diversity rankings among bacterial lineages in soil
Authors: Youssef Noha H , Elshahed Mostafa S
Published: November 2008

We used rarefaction curve analysis and diversity ordering-based approaches to rank the 11 most frequently encountered bacterial lineages in soil according to diversity in 5 previously reported 16S rRNA gene clone libraries derived from agricultural, undisturbed tall grass prairie and forest soils (n=26,140, 28 328, 31 818, 13 001 and 53 533). The Planctomycetes, Firmicutes and the δ-Proteobacteria were consistently ranked among the most diverse lineages in all data sets, whereas the Verrucomicrobia, Gemmatimonadetes and β-Proteobacteria were consistently ranked among the least diverse. On the other hand, the rankings of α-Proteobacteria, Acidobacteria, Actinobacteria, Bacteroidetes and Chloroflexi varied widely in different soil clone libraries. In general, lineages exhibiting largest differences in diversity rankings also exhibited the largest difference in relative abundance in the data sets examined. Within these lineages, a positive correlation between relative abundance and diversity was observed within the Acidobacteria, Actinobacteria and Chloroflexi, and a negative diversity–abundance correlation was observed within the Bacteroidetes. The ecological and evolutionary implications of these results are discussed.
The Association of Obesity and Cervical Cancer Screening: A Systematic Review and Meta‐analysis
Authors: Maruthur Nisa M. , Bolen Shari D. , Brancati Frederick L. , Clark Jeanne M.
Published: November 2008

Obese women are at an increased risk of death from cervical cancer, but the explanation for this is unknown. Through our systematic review, we sought to determine whether obesity is associated with cervical cancer screening and whether this association differs by race. We identified original articles evaluating the relationship between body weight and Papanicolaou (Pap) testing in the United States through electronic (PubMed, CINAHL, and the Cochrane Library) and manual searching. We excluded studies in special populations or those not written in English. Two reviewers sequentially extracted study data and independently extracted quality using standardized forms. A total of 4,132 citations yielded 11 relevant studies. Ten studies suggested an inverse association between obesity and cervical cancer screening. Compared to women with a normal BMI, the combined odds ratios (95% CI) for Pap testing were 0.91 (0.80–1.03), 0.81 (0.70–0.93), 0.75 (0.64–0.88), and 0.62 (0.55–0.69) for the overweight and class I, class II, and class III obesity categories, respectively. Three out of four studies that presented the results by race found this held true for white women, but no study found this for black women. In conclusion, obese women are less likely to report being screened for cervical cancer than their lean counterparts, and this does not hold true for black women. Less screening may partly explain the higher cervical cancer mortality seen in obese white women.
A Prospective Study of Overweight, Physical Activity, and Depressive Symptoms in Young Women
Authors: Ball Kylie , Burton Nicola W. , Brown Wendy J.
Published: November 2008

This study examined the prospective associations of BMI, physical activity (PA), changes in BMI, and changes in PA, with depressive symptoms. Self‐reported data on height, weight, PA, selected sociodemographic and health variables and depressive symptoms (CESD‐10) were provided in 2000 and 2003 by 6,677 young adult women (22–27 years in 2000) participating in the Australian Longitudinal Study on Women's Health (ALSWH). Results of logistic regression analyses showed that the odds of developing depressive symptoms at follow‐up (2003) were higher in women who were overweight or obese in 2000 than in healthy weight women, and lower in women who were active in 2000 than in sedentary women. Changes in BMI were significantly associated with increased odds of depressive symptoms at follow‐up. Sedentary women who increased their activity had lower odds of depressive symptoms at follow‐up than those who remained sedentary. Increases in activity among initially sedentary young women were protective against depressive symptoms even after adjusting for BMI changes. These findings indicate that overweight and obese young women are at risk of developing depressive symptoms. PA appears to be protective against the development of depressive symptoms, but does not attenuate the depressive symptoms associated with weight gain. However, among initially sedentary young women, even small increases in PA over time may reduce the odds of depressive symptoms, regardless of weight status.
Capacity for Physical Activity Predicts Weight Loss After Roux‐en‐Y Gastric Bypass
Authors: Hatoum Ida J. , Stein Heather K. , Merrifield Benjamin F. , Kaplan Lee M.
Published: November 2008

Despite its overall excellent outcomes, weight loss after Roux‐en‐Y gastric bypass (RYGB) is highly variable. We conducted this study to identify clinical predictors of weight loss after RYGB. We reviewed charts from 300 consecutive patients who underwent RYGB from August 1999 to November 2002. Data collected included patient demographics, medical comorbidities, and diet history. Of the 20 variables selected for univariate analysis, 9 with univariatePvalues ≤ 0.15 were entered into a multivariable regression analysis. Using backward selection, covariates withP< 0.05 were retained. Potential confounders were added back into the model and assessed for effect on all model variables. Complete records were available for 246 of the 300 patients (82%). The patient characteristics were 75% female, 93% white, mean age of 45 years, and mean initial BMI of 52.3 kg/m2. One year after surgery, patients lost an average of 64.8% of their excess weight (s.d. = 20.5%). The multivariable regression analysis revealed that limited physical activity, higher initial BMI, lower educational level, diabetes, and decreased attendance at postoperative appointments had an adverse effect on weight loss after RYGB. A model including these five factors accounts for 41% of the observed variability in weight loss (adjustedr2= 0.41). In this cohort, higher initial BMI and limited physical activity were the strongest predictors of decreased excess weight loss following RYGB. Limited physical activity may be particularly important because it represents an opportunity for potentially meaningful pre‐ and postsurgical intervention to maximize weight loss following RYGB.
Hyperreactio Luteinalis Associated with Pregnancy: A Case Report and Review of the Literature
Authors: Schnorr John A. , Miller Hugh , Davis John R. , Hatch Kenneth , Seeds John
Published: November 2008

Hyperreactio luteinalis is a condition associated with bilateral and, in rare cases, unilateral ovarian enlargement due to theca lutein cysts. Hyperreactio luteinalis is a benign condition, usually found incidentally at cesarean section, which can appear anaplastic and lead to unnecessary ovarian resection. A 21-year-old Hispanic woman, G2P1, presented at 19 weeks with a singleton pregnancy, bilaterally enlarged ovaries, and a normal βhCG. Over the next four months, her ovaries increased 75% in size with the right ovary becoming entrapped in the pelvis. The patient underwent a primary low transverse cesarean section. The ovaries had an anaplastic appearance and on frozen section revealed multiple benign theca lutein cysts. There are 51 reported cases of hyperreactio luteinalis associated with a normal pregnancy in the literature. It is estimated that approximately 60% of the cases of hyperreactio luteinalis unassociated with trophoblastic disease occur with normal singleton pregnancy. There are multiple benign ovarian lesions including hyperreactio luteinalis that can mimic ovarian neoplasms. Accordingly, it is important to exclude these from the differential diagnosis via a wedge biopsy and frozen section to avoid unnecessary surgical excision.
Intraoperative Embolization for Pelvic Hemorrhage Following Termination of Pregnancy
Authors: Kerr Andrew , Karlin David , Mikhail Magdy , Rashbaum William , Anyaegbunam Akolisa
Published: November 2008

We describe a 37-year-old patient with placenta previa, placenta accreta, and a history of four previous cesarean sections who experienced massive hemorrhage after mid-trimester abortion by dilation and evacuation.
Ultrasound in Screening for Neonatal Adrenal Hemorrhage
Authors: Felc Zlata
Published: November 2008

Neonatal adrenal hemorrhage is common. Relatively large size and extensive vascularity of the gland results in its vulnerability to trauma and traumatic asphyxial injuries. The reported incidence from necropsies is 1.7 per 1000 births. Ultrasound scans were performed on each of 8374 consecutive newborns delivered throughout 48 months ending December 31,1993, in the Department of Obstetrics and Gynaecology. During our screening, 16 cases of adrenal hemorrhage (10 males and 6 females) were noted at an incidence of 1.9 per 1000. All of the cases of adrenal hemorrhages remained intracapsular with spontaneous resolution. Thirteen cases were right sided, two cases were left sided, and one case was bilateral. None required surgical exploration. Neonatal treatment included further phototherapy in 12 cases, blood transfusions in five cases, and antibiotics in three cases. Signs of transient adrenocortical insufficiency were observed in one child.
Cysticercosis as a Cause of Seizure Disorder in Pregnancy: Case Report and Review of Literature
Authors: Kurl Rita , Montella Karen Rosene
Published: November 2008

We describe a case of neurocysticercosis presenting as a seizure disorder during early pregnancy, including a discussion of diagnostic evaluation, differential diagnosis, review of the literature, and management during pregnancy.
Neonatal Tricuspid Insufficiency with Abnormal Tricuspid Valve Treated with Extracorporeal Membrane Oxygenation (ECMO): Possible Extension of ECMO Use
Authors: Marsh T. David , Shelton Leslie W.
Published: November 2008

Extracorporeal membrane oxygenation is now an accepted method of treatment for neonatal hypoxemia due to a number of causes. We extend the indications of ECMO to hypoxemia secondary to dysplastic tricuspid valve. We report the case of a neonate with congenital dysplastic tricuspid valve who responded to ECMO.
Outcome and Management of Babies with Prenatal Ultrasonographic Renal Abnormalities
Authors: Lam Barbara C.C. , Wong Sik-Nin , Yeung Chap-Yung , Tang Mary H.Y. , Ghosh A.
Published: November 2008

Between January 1987 and December 1990, 60 fetuses were found to have renal abnormalities on antenatal ultrasonography. Six fetuses were aborted because of major renal abnormalities with or without associated chromosomal aberrations. Twelve babies with major renal abnormalities died in the immediate neonatal period. Forty-two babies were studied after birth and followed up. Babies who were found to have mild dilation of the renal pelvis of 6 to 10 mm during fetal life revealed either normal renal findings in the postnatal period or complete resolution of the abnormalities within the first year. Significant pelvic dilation of more than 10 mm occurred in 32 babies. A significant proportion (34%) had transitional hydronephrosis that resolved spontaneously during the follow-up period (mean, 2œ years; range, Iœ to 4œ years). Extrarenal pelvis, another benign condition, accounted for 15.6%. Most babies with pelviureteral junction obstruction (15%) and vesicoureteral junction obstruction (6.2%) required early neonatal surgery. The technetium-99m diethylenetriamine renal scan with the diuretic renogram half-time was found to be a very useful tool to distinguish between obstructive and nonobstructive hydronephrosis. With early diagnosis and intervention, the prognosis for many of these renal abnormalities is much more favorable and such information is invaluable for antenatal counseling.
Prenatal Diagnosis of a Neurenteric Cyst by Magnetic Resonance Imaging
Authors: Gulrajani Meenakshi , David Karen , Sy Wilfredo , Braithwaite Angelica
Published: November 2008

We report a case of neuroenteric cysts in which the diagnosis was made prenatally by magnetic resonance imaging. These neuroenteric cysts are developmental anomalies of the alimentary tract in connection with midline neural structures that are usually diagnosed in the first decade of life. Magnetic resonance imaging not only helped to make the diagnosis early, but enabled appropriate counseling of the mother and follow-up of the infant so that planning of surgery was optimal.
Disorder effect on the density of states in Landau quantized graphene
Authors: Dóra B.
Published: November 2008

We study the effect of Gaussian potential (on-site) and unidirectional bond disorder on the density of states (DOS) of Landau quantized graphene. The broadening of the Landau levels depends weakly on energy and the symmetry of the disorder except at the Dirac point. There, the peak in the DOS is enhanced significantly by bond disorder. For stronger disorder, Landau quantization becomes irrelevant, the discrete structures from Landau levels disappear, and we recover the zero field DOS.
Tight-binding study of nonmagnetic-defect-induced magnetism in graphene
Authors: Kumazaki H. , Hirashima D. S.
Published: November 2008

This review describes a study of nonmagnetic-defect-induced magnetism of graphene on the basis of a tight-binding model. A vacancy induces around itself a quasilocalized impurity state at the chemical potential and leads to formation of local magnetic moments. The connection between a quasilocalized state around a vacancy and the edge localized states near a zigzag edge is studied in detail. Magnetism associated with many vacancies and edge structures is also reviewed. Some new results of magnetism associated with many vacancies are presented.
Effect of next-nearest-neighbor hopping on the electronic properties of graphene
Authors: Suprunenko Y. F. , Gorbar E. V. , Loktev V. M. , Sharapov S. G.
Published: November 2008

In the tight-binding approximation, we take into account the next-nearest-neighbor hopping in graphene that leads to nonrelativistic-like corrections in its low energy spectrum. The electronic density of states in a magnetic field is found and the fan diagram is plotted, which interpolates between those for the relativistic and nonrelativistic limiting cases. It is shown that the Berry phase for the system under consideration coincides exactly with its value for the relativistic system.
Local heating method for growth of aligned carbon nanotubes at low ambient temperature
Authors: Dittmer S. , Mudgal S. , Nerushev O. A. , Campbell E. E. B.
Published: November 2008

We use a highly localized resistive heating technique to grow vertically aligned multiwalled nanotube films and aligned single-walled nanotubes on substrates with an average temperature of less than 100°C. The temperature at the catalyst can easily be as high as 1000°C but an extremely high temperature gradient ensures that the surrounding chip is held at much lower temperatures, even as close as 1μm away from the local heater. We demonstrate the influence of temperature on the height of multiwalled nanotube films, illustrate the feasibility of sequential growth of single-walled nanotubes by switching between local heaters and also show that nanotubes can be grown over temperature-sensitive materials such as resist polymer.
Semiclassical approach to the description of the basic properties of nanoobjects
Authors: Kornyushin Y.
Published: November 2008

A review of results obtained in the framework of the semiclassical approach in nanophysics is presented. A semiclassical description based on electrostatics and the Thomas-Fermi model is used to calculate the dimensions of the electronic shell of a fullerene molecule and a carbon nanotube. This simplified approach yields surprisingly accurate results in some cases. The semiclassical approach provides a rather good description of the dimensions of the electronic shell of a fullerene molecule. Two types of dipole oscillations in a fullerene molecule are considered and their frequencies calculated. Similar calculations are performed for a carbon nanotube also. These results look rather reasonable. Three types of dipole oscillations in a carbon nanotube are considered and their frequencies calculated. The frequencies of the longitudinal collective oscillations of delocalized electrons in a carbon peapod are calculated as well. A metallic cluster is modeled as a spherical ball. It is shown that the metallic cluster is stable; its bulk modulus and the frequency of the dipole oscillation of the electronic shell relative to the ions are calculated.
Computer simulation study of a single polymer chain in an attractive solvent
Authors: Antypov Dmytro , Elliott James A.
Published: November 2008

The behavior of a linear polymer chain is studied in a solvent with high affinity for the polymer. The coil dimensions and specific heat are calculated as a function of chain length, solvent concentration, and polymer-solvent attraction strength εps. All other interactions are limited to excluded volume repulsion, which implies that the Flory–Huggins χ parameter is negative. Using both on-lattice and off-lattice models of a polymer chain in explicit solvent, we study a transition from weak to strong association regimes. In all cases studied, the system’s heat capacity is a nonmonotonic function of ερs with a maximum at attraction strengths of the order of several kBT. This peak originates from restriction of local conformational degrees of freedom due to the associated solvent rather than from a partial chain collapse which onsets as attractive solvent content is decreased.
Multimode quantum dynamics using Gaussian wavepackets: The Gaussian-based multiconfiguration time-dependent Hartree (G-MCTDH) method applied to the absorption spectrum of pyrazine
Authors: Burghardt I. , Giri K. , Worth G. A.
Published: November 2008

The Gaussian-based multiconfiguration time-dependent Hartree (G-MCTDH) method is applied to calculate the S2(ππ∗) absorption spectrum of the pyrazine molecule, whose diffuse structure results from the ultrafast nonadiabatic dynamics at the S2-S1 conical intersection. The 24-mode second-order vibronic-coupling model of Raab et al. [J. Chem. Phys. 110, 936 (1999)] is employed, along with 4-mode and 10-mode reduced-dimensional variants of this model. G-MCTDH can be used either as an all-Gaussian approach or else as a hybrid method using a partitioning into primary modes, treated by conventional MCTDH basis functions, and secondary modes described by Gaussian particles. Comparison with standard MCTDH calculations shows that the method converges to the exact result. The variational, nonclassical evolution of the moving Gaussian basis is a key element in obtaining convergence. For high-dimensional systems, convergence is significantly accelerated if the method is employed as a hybrid scheme.
Lasers and photodetectors for mid-infrared 2–3 μm applications
Authors: Lei Wen , Jagadish Chennupati
Published: November 2008

This paper presents an overview of the recent developments in III–V semiconductor lasers and detectors operating in the 2–3 μm wavelength range, which are highly desirable for various important applications, such as military, communications, molecular spectroscopy, biomedical surgery, and environmental protection. The lasers and detectors with different structure designs are discussed and compared. Advantages and disadvantages of each design are also discussed. Promising materials and structures to obtain high performance lasers and detectors operating in the 2–3 μm region are also suggested.
Electronic transitions in cis- and trans-dichloroethylenes and tetrachloroethylene
Authors: Arulmozhiraja Sundaram , Ehara Masahiro , Nakatsuji Hiroshi
Published: November 2008

Electronic structures of trans- and cis-dichloroethylenes and tetrachloroethylene were studied using symmetry-adapted cluster configuration interaction theory. Basis sets up to the aug-cc-pVTZ of Dunning, Jr., augmented with appropriate Rydberg functions were used for the calculations. The results derived in the present study show good agreement with the available experimental values. In all cases, the main bright excitation was the π→π∗ transition. The other vertical excitations, π→σ∗, n→σ∗, and n→π∗, which have not been studied before, were also investigated. First Rydberg series involving transitions from the π orbitals to one 3s, three 3p, and five 3d orbitals were identified clearly. Several new assignments and reassignments of features in the experimental spectra were suggested. Contrary to earlier prediction, two n-σ∗ states, along with a π-σ∗ state in the dichloroethylenes, were calculated to be located above the main π-π∗ state. Accordingly, crossing between both the n-σ∗ states with the bright π-π∗ state is highly likely, unlike conclusions made in the earlier studies. This indicates that the photodissociation mechanism proposed by the earlier calculations warrants revision. Several low-lying triplet excited states were also studied. Electronic spectra of trans-1-chloro-2-fluoroethylene and cis-1-chloro-2-fluoroethylene were also calculated. The π→π∗ transitions of these haloethylenes are compared and interpreted in terms of the inductive and resonance effects.
Size-dependent oxidation in ZnO nanoparticles embedded in ion-implanted silica
Authors: Tagliente M. A. , Massaro M. , Mattei G. , Mazzoldi P. , Bello V. , Pellegrini G.
Published: November 2008

ZnO – SiO 2 nanocomposites were synthesized by ion implanting a Zn+ beam in a silica slide and by annealing in oxidizing atmosphere at 800 °C. A detailed structural and optical characterization was performed by using glancing incidence x-ray diffraction, transmission electron microscopy combined with selected area electron diffraction and energy dispersive spectrometry, optical absorption, and photoluminescence spectroscopies. Samples obtained with three different Zn+ fluences in the range 1–2×1017 ions/cm2 have been investigated. According to the results, Zn crystalline nanoparticles were found in the as-implanted Zn–SiO2 samples. The size of the Zn nanoparticles was proportional to the implantation fluence. The annealing in oxidizing atmosphere promotes the total oxidation of the Zn nanoparticles with a preferential migration of the nanoparticles toward the surface of the sample along with an opposite and less pronounced diffusion toward the bulk of the matrix. A relatively strong excitonic peak from the ZnO nanoparticles was observed both in the optical absorption and photoluminescence spectra. We found that the oxidation of the Zn nanoparticles is size-dependent because the time necessary for the total oxidation of the nanoparticles increases with the decreasing in the size of the nanoparticles. This size-oxidation correlation has been explained in terms of arguments related to the stress of the Zn nanoparticles.
Reynolds stress closure for nonequilibrium effects in turbulent flows
Authors: Hamlington Peter E. , Dahm Werner J. A.
Published: November 2008

From consideration of turbulence anisotropy dynamics due to spatial or temporal variations in the mean strain rate, a new Reynolds stress closure for nonequilibrium effects in turbulent flows has been developed. This closure, formally derived from the Reynolds stress anisotropy transport equation, results in an effective strain rate tensor that accounts for the strain rate history to which the turbulence has been subjected. In contrast to prior nonequilibrium models that have sought to address nonequilibrium effects via changes in the eddy viscosity, the present approach accounts for nonequilibrium effects in the fundamental relation between the anisotropy tensor and the strain rate tensor. The time-local form of the nonequilibrium closure can be readily implemented in place of the classical equilibrium Boussinesq closure on which most existing computational frameworks are currently based. This new closure is applied here to four substantially different classes of nonequilibrium test problems. Results show dramatically improved agreement with experimental and computational data, without the need to vary any model parameters, when compared with the standard equilibrium closure and with various prior nonequilibrium closures.
Formation and nonvolatile memory characteristics of multilayer nickel-silicide NCs embedded in nitride layer
Authors: Chen Wei-Ren , Chang Ting-Chang , Yeh Jui-Lung , Sze S. M. , Chang Chun-Yen
Published: November 2008

The authors provided the formation and memory effects of nonvolatile multilayer nickel-silicide nanocrystal memory in this study. This proposed structure can efficiently improve the drawbacks of current floating gate and single-layer nanocrystal memories for the next-generation nonvolatile memory application. The charge trapping layer of multilayer structure was deposited by sputtering a commixed target (Ni0.3Si0.7) in the argon and nitrogen ambiance, and then used a low temperature rapid thermal annealing to form uniform nanocrystals. Transmission electron microscope images clearly show the multilayer and single-layer nanocrystal structures embedded in SiNx. X-ray photoelectron spectroscopy and x-ray diffraction also present the chemical states and crystallization of nanocrystals under different annealing temperature treatments. The capacitor with different memory structures was also studied and exhibited hysteresis characteristics after electrical operation. In addition, the multilayer nanocrystals revealed better charge storage ability and reliability than the single-layer nanocrystals.
To the mechanisms of failure wave
Authors: Kanel G. I. , Bless S. J. , Savinykh A. S. , Razorenov S. V. , Chen T. , Rajendran A.
Published: November 2008

Results of shock-wave experiments with free and prestressed samples of K8 and K14 crown glasses are presented. Controlled confinement pressure on the specimen of around 200 MPa was provided by installing a shrink-fit metal sleeve on the lateral surface of the sample disk. Results of measurements of the free surface velocity histories show that prestressing leads to earlier stopping of the failure wave. Thus, the compressive transverse stress increases the failure threshold that is in agreement with existing criteria of compressive fracture. However, sensitivity of the failure threshold to the confinement stress value is not as high as it could be expected. Measurements of the refractive indexes for the particles from the failure wave zone of recovered glass samples have shown their small increase whereas no index change for particles from the residual zone was found. It has been concluded that irreversible densification makes essential contribution to the mechanism of failure of glasses.
Luttinger liquid and polaronic effects in electron transport through a molecular transistor
Authors: Skorobagat’ko G. A. , Krive I. V.
Published: November 2008

Electron transport through a single-level quantum dot weakly coupled to Luttinger liquid leads is considered in the master equation approach. It is shown that for a weak or moderately strong interaction the differential conductance demonstrates resonant-like behavior as a function of bias and gate voltages. The inelastic channels associated with vibron-assisted electron tunneling can even dominate electron transport for a certain region of interaction strength. In the limit of strong interaction resonant behavior disappears and the differential conductance scales as a power law in temperature (linear regime) or in bias voltage (nonlinear regime).
Cross-point coronal plasma dynamics in two- and four-wire x-pinches
Authors: Madden R. E. , Bott S. C. , Haas D. , Eshaq Y. , Ueda U. , Collins G. , Beg F. N.
Published: November 2008

Studies of the late time diode gap formation in two- and four-wire tungsten x-pinches using an 80kA, 50ns current pulse are presented. Quantitative measurements of the coronal plasma density are recovered using interferometry simultaneously with laser shadowgraphy. Axial expansion of the gap occurs at ∼106cm∕s for both two- and four-wire systems and is likely to be driven by an axial J×B force resulting from radial current flow in the plasma minidiode “electrodes.” Radial density profiles suggest repinching of the low density plasma occurs after the main pinch resulting in secondary x-ray emission peak >10ns after the first, which is recorded with a pair of pin diodes.