bluuebunny/crossref_metadata_2025 huggingface dataset:
Associated risk factors in children who had late presentation of developmental dysplasia of the hip
Authors: Abu Hassan Freih Odeh , Shannak Akram
Published: September 2007

Purpose

The purpose of this study was to assess the role of clinical examination, associated risk factors and plain radiograph of the pelvis in children who had late presentation of DDH.

Methods

We report on a 7-year prospective study, in children who had late presentation of developmental dysplasia of the hip (DDH). For this purpose, 740 hips in 370 referred children, age range 3–7 months (mean 3.44 months) were clinically and radiologically assessed, and the associated risk factors recorded.

Results

Female sex, first born, positive family history and breech presentation were confirmed as risk factors for DDH. Significant findings were an increased risk for vaginal delivery over caesarean section for breech presentation ( P = 0.002). There was an increased risk for caesarean section in the absence of breech presentation. Multiple births and preterm births had a reduced risk. For breech presentation, the risk of DDH was estimated to be at least 1.6% for girls and 3.4% for boys; a combination of factors increased the risk. Limitation of abduction (43.2%) and asymmetry of the groin skin folds (72.7%) were found to be the two most common clinical findings associated with DDH. Bilateral acetabular dysplasia is more common than unilateral dysplasia. Foot deformities were rarely encountered in children with acetabular dysplasia.

Conclusions

The percentage of first-born babies who had DDH is lower than reported in the literature (34%), but still shows significant risk. We did find that bilateral acetabular dysplasia is more common than unilateral dysplasia. Torticollis and foot deformities are rarely found to be associated with DDH. All these findings needs further evaluation in children who had surgical treatment for DDH, to see if they are different from dysplastic groups. Limitation of abduction is an important clinical finding, but is not always associated with DDH. Asymmetry of the skin folds in the groin were found to be an important clinical finding associated with DDH for all age groups. As clinical examination depends on many factors, and most DDH cases are of the dysplastic type, it is mandatory to depend on further diagnostic tools for confirmation of DDH.
Promoter polymorphism of the matrix metalloproteinase 3 gene is associated with regurgitation and left ventricular remodelling in mitral valve prolapse patients
Authors: Oceandy Delvac , Yusoff Rahal , Baudoin Florence M. , Neyses Ludwig , Ray Simon G.
Published: September 2007

Background and aims:

Mitral valve prolapse (MVP) is common and highly variable in its severity, but the factors underlying this variability are unclear. In this study, we tested the hypothesis that polymorphic variations in Matrix Metalloproteinase (MMP) genes might be predictors of left ventricular (LV) remodelling and severity of regurgitation in MVP.

Methods and results:

70 MVP patients and 75 normal subjects were studied. We performed comprehensive echocardiography and analyzed promoter polymorphisms in the MMP‐1 and MMP‐3 genes. The MMP‐3 ‐1612 5A/6A polymorphism showed strong associations with indices of mitral regurgitation and LV remodelling: Patients with 5A/5A allele had more pronounced remodelling and more severe mitral regurgitation than patients with the 6A/6A or 5A/6A alleles. We then cloned and sequenced 2 kb fragments of MMP‐3 promoter from patients with 5A/5A and 6A/6A genotypes and found 4 different sets of promoter haplotypes. Promoter analysis showed that higher promoter activity was related to a more severe phenotype and that the haplotype variants had a more dominant role in determining the activity.

Conclusions:

Our data identifies the MMP‐3 promoter haplotype as a novel marker of an adverse disease course in MVP, suggesting the presence of genetic determinants for the severity of MVP.
Cellular signaling is potentially regulated by cell density in receptor trafficking networks
Authors: Zi Zhike , Klipp Edda
Published: September 2007

Previous work has shown that receptor trafficking is a potential site for the control of signaling pathways. In most biological experiments, the ligand concentration and cell density vary within a wide range among different systems. However, there is less attention to systematically analyze how much cellular signal response is affected by cell densities. Here, we use a quantitative mathematical model to investigate signal responses in different receptor trafficking networks by simultaneous variations of ligand concentration and cell density. Computational analysis of the model revealed that receptor trafficking networks have potential sigmoid responses to ratio between ligand and surface receptor number per cell, which is a key factor to control the signaling responses in receptor trafficking networks. Furthermore, cell density also affects the robustness of dose–response curve upon the variation of binding affinity.
Computational analysis of microRNA‐mediated antiviral defense in humans
Authors: Watanabe Yuka , Kishi Atsuko , Yachie Nozomu , Kanai Akio , Tomita Masaru
Published: September 2007

Recent studies have proposed the interesting perspective that viral gene expression is downregulated by host microRNAs (miRNAs), small non‐coding RNAs well known as post‐transcriptional gene regulators. We computationally predicted human miRNA target sites within 228 human‐infecting and 348 invertebrate‐infecting virus genomes, and we observed that human‐infecting viruses were more likely than invertebrate‐infecting ones to be targeted by human miRNAs. We listed 62 possible human miRNA‐targeted viruses from 6 families, most of which consisted of single‐stranded RNA viruses. These results suggest that miRNAs extensively mediate antiviral defenses in humans.
The von Hippel–Lindau tumour suppressor interacts with microtubules through kinesin‐2
Authors: Lolkema Martijn P. , Mans Dorus A. , Snijckers Cristel M. , van Noort Mascha , van Beest Moniek , Voest Emile E. , Giles Rachel H.
Published: September 2007

Synthesis and maintenance of primary cilia are regulated by the von Hippel–Lindau (VHL) tumour suppressor protein. Recent studies indicate that this regulation is linked to microtubule‐dependent functions of pVHL such as orienting microtubule growth and increasing plus‐end microtubule stability, however little is known how this occurs. We have identified the kinesin‐2 motor complex, known to regulate cilia, as a novel and endogenous pVHL binding partner. The interaction with kinesin‐2 facilitates pVHL binding to microtubules. These data suggest that microtubule‐dependent functions of pVHL are influenced by kinesin‐2.
Sphingosine 1‐phosphate (S1P) inhibits monocyte–endothelial cell interaction by regulating of RhoA activity
Authors: Tani Mariko , Kawakami Akio , Nagai Miyuzu , Shimokado Kentaro , Kondo Kazuo , Yoshida Masayuki
Published: September 2007

Recent studies suggest that sphingosine 1‐phosphate (S1P) protects against atherosclerosis. We assessed the effects of S1P on monocyte–endothelial interaction in the presence of inflammatory mediators. Pretreatment of THP‐1 cells with S1P abolished Phorbol 12 myristate 13‐acetate (PMA)‐induced THP‐1 cell adhesion to human umbilical vein endothelial cells (HUVECs). S1P inhibited PMA‐induced activation of RhoA, but not PKCs. S1P activated p190Rho GTPase activation protein (GAP) only in the presence of PMA, suggesting an inhibitory effect of S1P and PMA to suppress RhoA. In conclusion, S1P inhibited monocyte–endothelial interactions by inhibiting RhoA activity which may explain its anti‐atherogenic effects.
Ethical issues in vesico‐vaginal fistula care and research
Authors: Wall L.L.
Published: September 2007

The plight of women in poor nonindustrialized countries who have incurred catastrophic childbirth injuries, such as vesico‐vaginal and recto‐vaginal fistulas, from prolonged obstructed labor is receiving increased attention from the world medical community. While the good intentions that have prompted this greater concern are not in doubt, intentions by themselves are insufficient guarantees of ethical conduct in programs developed to repair these injuries. Clinical proposals put forward to deal with the problem of fistula must undergo critical analysis to insure that basic ethical requirements are met. This article emphasizes the vulnerability to exploitation of women with obstetric fistulas and reviews the basic principles of medical ethics relevant to fistula care.
Evaluation of Undifferentiated Carcinoma of Nasopharyngeal Type with Thallium‐201 and Technetium‐99m MIBI SPECT
Authors: Sobic‐Saranovic Dragana P. , Pendjer Ivica P. , Kozarevic Nebojsa Dj. , Artiko Vera M. , Mikic Anton A. , Obradovic Vladimir B.
Published: August 2007

OBJECTIVE

To determine the value of 201‐thallium (201‐Tl) and technetium‐99m sestamibi (Tc‐99m MIBI) single photon emission computed tomography (SPECT) for detecting primary undifferentiated carcinoma of nasopharyngeal type (UCNT), residual/recurrent tissue, and lymph node involvement.

STUDY DESIGN AND SETTING

SPECT of head and neck was prospectively performed in 46 patients with a history of UCNT (201‐Tl in 24 patients, Tc‐99m MIBI in 22). CT/MRI findings, clinical follow‐up, and pathohistological verification served as a gold standard for calculating sensitivity, specificity, and accuracy of each scintigraphic technique. Tumor‐to‐background index (T/Bg) was derived when SPECT findings were positive.

RESULTS

Sensitivity of 201‐Tl SPECT was 87 percent, with 78 percent specificity, 83 percent accuracy, and T/Bg of 4.05 ± 1.50. Tc‐99m MIBI SPECT had 85 percent sensitivity, 78 percent specificity, 82 percent accuracy, and T/Bg of 4.45 ± 1.27.

CONCLUSION AND SIGNIFICANCE

201‐Tl SPECT and Tc‐99m MIBI SPECT are useful for detecting primary UCNT, residual/recurrent disease, and lymph node involvement. This use is particularly valuable after chemoradiotherapy when CT/MRI may be ambiguous.
Hearing Loss in Behçet Syndrome
Authors: Mahdi Bakhshaee , Mehdi Ghasemi Mohammad , Reza Hatef Mohammad , Mahdieh Talebmehr , Taghi Shakeri Mohammad
Published: August 2007

OBJECTIVE

To determine the prevalence and characteristics of hearing loss in Behçet syndrome.

STUDY DESIGN AND SETTING

This study included 27 patients with Behçet syndrome and 35 sex‐and age‐matched controls. A complete audiological evaluation was performed.

RESULTS

The average pure‐tone audiograms from both groups showed a statistically significant hearing loss in the Behçet group. Sixteen patients (59.26%) showed some degrees of senso‐rineural hearing loss (SNHL), with the high‐frequency type (4, 8, 10, and 12 kHz) being the most common pattern (93.75%). Hearing loss was the fourth most common manifestation. Although the patient's age, sex, and the duration of the disease were not related to hearing loss, there was a significant correlation between a negative pathergy test and hearing loss in patients with Behçet syndrome.

CONCLUSION

We should consider audiovestibular involvement in Behçet syndrome as a common finding.
Comparison of Approaches for Oral Cavity Cancer Resection: Lip‐Split versus Visor Flap
Authors: Cilento Benjamin W. , Izzard Mark , Weymuller Ernest A. , Futran Neal
Published: August 2007

OBJECTIVE

To compare lip‐split and visor flap approaches to the oral cavity in terms of morbidity, margins, and locoregional recurrence.

DESIGN AND SETTING

Retrospective case series at the University of Washington, Seattle.

METHODS

Seventy patients undergoing resection of advanced (T4) anterior oral cavity squamous cell carcinoma requiring fibula reconstruction were grouped according to surgical access procedure performed (lip‐split [LS] or visor flap [VF]). Data on surgical morbidity, margin status, and outcomes were compared.

RESULTS

Recurrence rates and positive margins were similar for both groups. Rates of postoperative fistulae were 6.8% (LS) vs 0% (VF) and for oral incompetence 14.6% (LS) vs 6.9% (VF). Most of the fistulas (37.5%) were in irradiated patients. Neither group had any malunions.

CONCLUSIONS

There is no significant difference in pathological margins or rates of local recurrence when using either the lip‐split or the visor approach. The lip‐split approach has a higher rate of postoperative fistula formation than the visor flap approach; fistula formation may be associated with previous irradiation.
Comparison of LigaSure Vessel Sealing System, Harmonic Scalpel, and Cold Knife Tonsillectomy
Authors: Lachanas Vassilios A. , Hajiioannou John K. , Karatzias George T. , Filios Dimitrios , Koutsias Stylianos , Mourgelas Charalambos
Published: August 2007

OBJECTIVE

We sought to compare LigaSure Vessel Sealing System tonsillectomy (LT), Harmonic Scalpel tonsillectomy (HST), and cold knife tonsillectomy (CKT).

STUDY DESIGN

We conducted a prospective study on 161 adult patients undergoing tonsillectomy. Subjects were randomized to LT, HST, or CKT groups, and intraoperative bleeding, operative time, postoperative pain, and complication rates were assessed.

RESULTS

The LT, HST, and CKT groups consisted of 50, 43, and 37 individuals, respectively. Intraoperative bleeding was significantly lower in the LT group, whereas bleeding in the HST group was significantly lower than that in the CKT group. Operative time and postoperative pain were significantly lower in the LT and HST groups. One primary hemorrhage occurred in the HST group, and one occurred in he CKT group. Secondary hemorrhage occurred in one, two, and one patients in the LT, HST, and CKT groups, respectively.

CONCLUSION

LT and HST have shown comparable results regarding intraoperative blood loss, postoperative hemorrhage, and pain. Compared with CKT, both were associated with less intra‐operative blood loss and pain.
The nature of the growth pattern and of the metabolic response to fasting in the rat are dependent upon the dietary protein and folic acid intakes of their pregnant dams and post-weaning fat consumption
Authors: Burdge Graham C. , Lillycrop Karen A. , Jackson Alan A. , Gluckman Peter D. , Hanson Mark A.
Published: August 2007

The nutritional cues which induce different phenotypes from a single genotype in developing offspring are poorly understood. How well prenatal nutrient availability before birth predicts that after birth may also determine the offspring's response to later metabolic challenge. We investigated the effect of feeding pregnant rats diets containing protein at 180 g/kg (Control) or 90 g/kg (protein-restricted, PR) and either 1 or 5 mg folic acid/kg on growth and metabolic response to fasting in their offspring, and also the effect of diets with different fat contents (40 g/kg (Fat4) or 100 g/kg (Fat10)) after weaning. Offspring of dams fed the PR diet with 5 mg/kg folic acid were significantly lighter than other offspring. The PR offspring fed the Fat4diet had lower plasma TAG than the Control offspring, but this relationship was reversed when offspring were fed Fat10. Increasing the folic acid content of the Control or PR maternal diets induced opposing effects on plasma TAG, NEFA, β-hydroxybutyrate and glucose concentrations in offspring fed Fat4. The effect was accentuated in offspring fed the Fat10diet such that these metabolites were increased in the Control offspring, but reduced in the PR offspring. These data show for the first time that maternal dietary folic acid intake alters offspring phenotype depending upon dietary protein intake, and that this effect is modified by fat intake after weaning. Prevention by increased folic acid intake of an altered metabolic phenotype by maternal protein-restriction may be at the expense of somatic growth.
Shear-weakening of the transitional regime for granular flow
Authors: LU KEVIN , BRODSKY E. E. , KAVEHPOUR H. P.
Published: August 2007

This paper experimentally investigates the rheology of dense granular flow through itssolid-like to fluid-like transition. Between the well-established flow regimes – quasi-static and grain-inertial – the physical description of the transition remains elusive. Our experiment uses a top-rotating torsional shear cell capable of ± 1 μm accuracy in height and 5 decades (10−3 − 100 rad s−1) in rotation rate. The data on beach sand shows that shear and normal stresses exhibit an inverse rate-dependence under a controlledvolume environment in the transitional regime, while in the limiting regimes the results are in agreement with previous work. Theshear-weakening stresses illustrate a previouslyunknown ‘dip’ with increasingshear rate. Under a controlled-pressure environment, however, the shear-compacting volume-fraction ‘peaks’ with increasing shear-rate. We combine these results from both configurations to infer a constitutive law based on a rate-invariant granular fluid compressibility. The formulation provides an equation-of-state for dynamic granular systems, with state variables of pressure, strain rate and free-volume-fraction. Fitting parameters from independent constant-volume and constant-pressure data shows good agreement in validating our model. Moreover, the degree of grain jaggedness is essential to the rate-dependence within the transitional regime. The results on the solid–fluid transitionmay elucidate the evolution of granular flow anisotropies.
Dynamics of a sessile drop in forced vibration
Authors: VUKASINOVIC BOJAN , SMITH MARC K. , GLEZER ARI
Published: August 2007

The interfacial dynamics of a sessile water drop was investigated experimentally. The low-viscosity drop was forced by an underlying diaphragm driven vertically by a piezoelectric actuator. This high-frequency forcing produced very low diaphragm displacements, even at high acceleration amplitudes. As the driving amplitude was increased from zero, the drop exhibited several transitions to states of increasing spatio-temporal complexity. The first state of the forced drop consisted of harmonic axisymmetric standing waves that were present for even the smallest diaphragm motion. Wave modes up to 14 were observed an compared to theoretical results. As the forcing amplitude increased above a critical value, a parametrically driven instability occurred that resulted in the appearance of subharmonic azimuthal waves along the contact line. The critical accelerations and the resulting wavenumbers of the azimuthal waves were documented. For larger values of the forcing amplitude, the subharmonic azimuthal waves coupled with the harmonic axisymmetric waves to produce a striking new lattice-like wave pattern. With a further increase in the forcing amplitude, the lattice mode disappeared and the interface evolved into a highly disordered state, dominated by subharmonic wave motion. The characteristics of the lattice and pre-ejection modes were documented with phase-locked measurements and spectral analysis. Finally, as the forcing amplitude increased above another critical value, the interface broke up via droplet ejection from individual wave crests.
Turbulent flow on a planar moving belt and a rotating disk: modelling and comparisons
Authors: McDARBY JOHN M. , SMITH FRANK T.
Published: August 2007

Modelling of the fully turbulent flow produced on a moving belt and of that induced ona rotating disk is described, for each of which a more analytical approach is adopted than previously seen. The analysis for the two-dimensional moving belt indicates novel structures and these are found to carry over directly to the rotating disk flow which, ignoring the transitional regime, is three-componential but two-dimensional due to axisymmetry. This is based on addressing the Reynolds-averaged Navier–Stokes equations together with an eddy viscosity model, with the flow structure being analysed for high Reynolds numbers. A classical (von Kármán) constant within the model plays an important and surprising role, indicating that each of the belt and the disk flows has quite a massive thickness. Comparisons made with previous work show varying degrees of agreement. The approach, including the new prediction of massive thicknesses independent of the Reynoldsnumber, is expected to extend to flows induced by rotary blades, by related rotary devices and by other configurations of industrial interest.
Singularity-theoretic methods in robot kinematics
Authors: Donelan P. S.
Published: August 2007

The significance of singularities in the design and control of robot manipulators is well known, and there is an extensive literature on the determination and analysis of singularities for a wide variety of serial and parallel manipulators—indeed such an analysis is an essential part of manipulator design. Singularity theory provides methodologies for a deeper analysis with the aim of classifying singularities, providing local models and local and global invariants. This paper surveys applications of singularity-theoretic methods in robot kinematics and presents some new results.
Numerical simulation of vortex dynamics in Ginzburg-Landau-Schrödinger equation
Authors: ZHANG YANZHI , BAO WEIZHU , DU QIANG
Published: September 2007

The rich dynamics of quantized vortices governed by the Ginzburg-Landau-Schrödinger equation (GLSE) is an interesting problem studied in many application fields. Although recent mathematical analysis and numerical simulations have led to a much better understanding of such dynamics, many important questions remain open. In this article, we consider numerical simulations of the GLSE in two dimensions with non-zero far-field conditions. Using two-dimensional polar coordinates, transversely highly oscillating far-field conditions can be efficiently resolved in the phase space, thus giving rise to an unconditionally stable, efficient and accurate time-splitting method for the problem under consideration. This method is also time reversible for the case of the non-linear Schrödinger equation. By applying this numerical method to the GLSE, we obtain some conclusive experimental findings on issues such as the stability of quantized vortex, interaction of two vortices, dynamics of the quantized vortex lattice and the motion of vortex with an inhomogeneous external potential. Discussions on these simulation results and the recent theoretical studies are made to provide further understanding of the vortex stability and vortex dynamics described by the GLSE.
Climatology of aerosol composition (organic versus inorganic) at nonurban sites on a west‐east transect across Europe
Authors: Pio C. A. , Legrand M. , Oliveira T. , Afonso J. , Santos C. , Caseiro A. , Fialho P. , Barata F. , Puxbaum H. , Sanchez‐Ochoa A. , Kasper‐Giebl A. , Gelencsér A. , Preunkert S. , Schock M.
Published: August 2007

In the framework of the European CARBOSOL project (Present and Retrospective State of Organic versus Inorganic Aerosol over Europe: Implications for Climate), atmospheric aerosol was continuously sampled for 2 years at six sites along a west‐east transect extending from Azores, in the mid‐Atlantic Ocean, to K‐Puszta (Hungary), in central Europe. Aerosols were analyzed for 210Pb, inorganic ions, elemental (EC) and organic (OC) carbon, water soluble organic carbon (WSOC), macromolecular type (humic‐like) organic substances (HULIS), C2–C5 diacids, cellulose, and levoglucosan. Pooled aerosol filters were also used for the identification of different families of organic compounds by gas chromatography/mass spectrometry, GC/MS, as well as 14C determinations. The data resulted in a climatological overview of the aerosol composition over Europe in the various seasons, from west to east, and from the boundary layer to the free troposphere. The paper first summarizes the characteristics of the sites and collected samples and then focuses on the aerosol mass partitioning (mass closure, inorganic versus organic, EC versus OC, water soluble versus insoluble OC), giving an insight on the sources of carbonaceous aerosol present in rural and natural background areas in Europe. It also introduces the main role of other companion papers dealing with CARBOSOL aerosol data that are also presented in this issue.
Seasonal trends and possible sources of brown carbon based on 2‐year aerosol measurements at six sites in Europe
Authors: Lukács Hajnalka , Gelencsér András , Hammer Samuel , Puxbaum Hans , Pio Casimiro , Legrand Michel , Kasper‐Giebl Anne , Handler Markus , Limbeck Andreas , Simpson David , Preunkert Suzanne
Published: August 2007

Brown carbon is a ubiquitous and unidentified component of organic aerosol which has recently come into the forefront of atmospheric research. This component is strongly linked to the class of humic‐like substances (HULIS) in aerosol whose ultimate origin is still being debated. Using a simplified spectroscopic method the concentrations of brown carbon have been determined in aqueous extracts of fine aerosol collected during the CARBOSOL project. On the basis of the results of 2‐year measurements of several aerosol constituents at six European sites, possible sources of brown carbon are inferred. Biomass burning (possibly domestic wood burning) is shown to be a major source of brown carbon in winter. At elevated sites in spring, smoke from agricultural fires may be an additional source. Direct comparison of measured brown carbon concentrations with HULIS determined by an independent method reveals that the two quantities correlate well at low‐elevation sites throughout the year. At high‐elevation sites the correlation is still high for winter but becomes markedly lower in summer, implying different sources and/or atmospheric sinks of brown carbon and HULIS. The results shed some light on the relationships between atmospheric brown carbon and HULIS, two ill‐defined and overlapping components of organic aerosol.
Seasonal and regional air quality and atmospheric deposition in the eastern United States
Authors: Sickles Joseph E. , Shadwick Douglas S.
Published: September 2007

The atmospheric concentration, wet deposition, and inferred dry deposition of selected air pollutants reported over two 5‐year periods in the 1990s at or near 34 rural Clean Air Status and Trends Network (CASTNET) sites located in the eastern United States (U.S.) are adjusted for known biases, composed into seasonal values, and examined. Several terms are defined for the current study, where OxN is the measured oxidized nitrogen (i.e., airborne OxN is the sum of airborne HNO3 and NO3−, expressed as nitrogen), NH4 is the measured reduced nitrogen (i.e., airborne NH4 is the aerosol NH4+, expressed as nitrogen), N is the sum of measured oxidized and reduced forms of nitrogen, expressed as nitrogen, and S is the measured oxidized sulfur (i.e., airborne S is the sum of airborne SO2 and SO42−, expressed as sulfur). The atmospheric NH3 concentration is not monitored in the current study. Similar patterns of seasonal and regional behavior are found consistently in both periods. In the east, atmospheric concentration, estimated deposition velocity, precipitation rate, inferred dry deposition, wet deposition, and total (dry plus wet) deposition estimates of each of the monitored chemical constituents display regular seasonal cycles of behavior. High and low seasonal values occur in summer and winter, respectively, for atmospheric concentration and dry deposition of SO42−, NH4+, O3, HNO3, and N; for dry OxN deposition; for wet S and H+ deposition; and for total OxN and N deposition. In contrast, high seasonal values of SO2 concentration and dry deposition, and atmospheric NO3− concentration occur in winter. In the east, SO2 composes a major portion (≈70%) of the atmospheric S concentration and is the dominant (>85%) contributor to dry S deposition. Although aerosol NH4+ represents a major portion of the measured atmospheric N concentration (≈67%), HNO3 dominates estimates of both dry OxN (>90%) and N (>75%) deposition. Dry deposition contributes ≈15%, 38%, and 43% to total deposition of NH4, OxN, and S, and these appear to be conservative estimates. Wet deposition is a major contributor to total deposition, generally peaking in summer or spring. Total S, OxN, and N deposition peak in summer. Although mean O3 concentration is ≈70% larger in summer than winter, dry O3 deposition estimates in the east are >5 times higher in summer. Within the uncertainty of current conservative estimates, dry deposition of SO42−, HNO3, OxN, N, and O3 appears to be highest at the high‐elevation subset of sites. This underscores the potential importance of dry deposition as a stressor to high‐elevation ecosystems in the eastern U.S.
Precipitation, soil moisture, and climate database, Little River Experimental Watershed, Georgia, United States
Authors: Bosch D. D. , Sheridan J. M. , Marshall L. K.
Published: September 2007

The U.S. Department of Agriculture Agricultural Research Service Southeast Watershed Research Laboratory (SEWRL) initiated a watershed research program at the Little River Experimental Watershed in 1967. Continuous rainfall measurement across the watershed began at that time. Forty‐six precipitation gauges and three climate stations are currently in operation. Soil moisture measurements were added to 29 of the rainfall sites from 2001 to 2006. The research quantifies critical information related to long‐term and seasonal climatic relationships, hydrologic budgets for the region, water quality studies, and natural resource planning. Rainfall data from the network have been used to evaluate storm characteristics, climatic patterns, and long‐term averages for the region. Soil moisture data have been used to examine large‐scale patterns across the region and for comparison to remotely sensed data. All data are available on the SEWRL anonymous ftp site (ftp://www.tiftonars.org/).
Do earthquake precursors really exist?
Authors: Rishbeth Henry
Published: September 2007

Pulinets [2007] discusses “ionospheric precursors” of earthquakes observed at Chung‐Li (Taiwan). If such precursors really exist and, as suggested, are caused by localized electric fields of seismic origin, those fields would be mirrored at Chung‐Li's magnetically conjugate point near 8°S, 121°E,and would cause similar localized effects there. Are these conjugate effects seen in the satellite data?

Too many papers say, in effect,“An earthquake has happened! Can we see a bump in the ionosphere a few days beforehand? Yes, we can! It's a precursor!” No surprise there. The F2 layer at 300 kilometers (the relevant ionospheric layer) frequently shows bumps. The few days of Chung‐Li ionospheric data preceding the quakes of 16 September and 21 October 1999, shown by Kamogawa [2006] and Pulinets [2007], respectively, look like typical F2 layer variations at times of geomagnetic activity, which was indeed prevalent during these periods. Significant dayto‐day variations occurred, too, as far away as Australia, the United States, and the United Kingdom. So all solar‐geophysical conditions must be taken into account before attributing F2 layer variations to forthcoming earthquakes.
Higher waves along U.S. East Coast linked to hurricanes
Authors: Komar Paul D. , Allan Jonathan C.
Published: September 2007

Ocean wave heights measured by buoys along the U.S. Atlantic coast document an increase during the summer months when hurricanes are most important to wave generation. Wave heights greater than 3 meters, which can be attributed to specific hurricanes, have increased on average by 0.7–1.8 meters in the past 30 years, with the southernmost buoy that is offshore of Charleston, S.C., experiencing the highest rate of increase. The most extreme hourly averaged wave heights generated by major hurricanes have increased from about 7 meters early in the records of the buoys to more than 10 meters during the most recent decade. This increase in wave heights can be attributed in large part to a progressive intensification of the hurricanes, which Emanuel [2005] has documented through his analyses of hurricane wind speeds.
Global network is launched to monitor isotopes in rivers
Authors: Vitvar Tomas , Aggarwal Pradeep K. , Herczeg Andrew L.
Published: September 2007

The Global Network of Isotopes in Rivers (GNIR), launched by the International Atomic Energy Agency (IAEA) in 2007, compiles water isotope data on rivers to complement the 45‐year‐old IAEA/World Meteorological Organization (WMO) global network of isotopes in precipitation (GNIP).

River runoff carries an integrated memory of hydrological processes in a basin. Recent studies [e.g., Vörösmarty and Meybeck, 2004] suggest that the impacts of storages, diversions, and redirection of streamflow for water supply, hydropower, and irrigation might surpass the impact of recent and anticipated future climate changes on river runoff. Consequences of these effects include changes in the frequency and extent of flooding, increased sediment load, altered groundwater recharge, and degradation of water quality and riparian ecosystems. These consequences often result in political disputes or upstream‐downstream inequities. GNIR aims to provide an improved understanding of stream/aquifer interactions, the impacts of climate changes on river runoff, and especially human impacts on river discharge with the use of isotope data.
Turkey makes major investment in earthquake research
Authors: Inan Sedat , Ergintav Semih , Saatçilar Ruhi , Tüzel Bekir , İravul Yildiz
Published: September 2007

Following the devastating Mw 7.4 İzmit earthquake on 17 August 1999, major state‐of‐the‐art earthquake studies were conducted in the Marmara region of northwestern Turkey. However, other faults with the potential to generate big and potentially devastating earthquakes occur in a variety of different tectonic regimes in Turkey, and these faults and regions have not received similar attention.

For example, the East Anatolian Fault (EAF) is influenced by the convergence of the Arabian and Anatolian plates along the Zagros‐Bitlis suture zone. Faults in the Aegean Extensional Province (AEP) are purely normal faults. The main faults in the Marmara region occur within both transtensional and transpressional domains (locations are shown in Figure I). All of these regions pose seismic hazards and also require focused study.
Satellite remote sensing of cloud base height for convective cloud fields: A case study
Authors: Meerkötter Ralf , Zinner Tobias
Published: September 2007

A method is proposed for estimating base heights of convective clouds from satellite data. The approach takes advantage of the fact that convective water clouds appear as geometrically and optically thin clouds near an approximately constant condensation level in their earliest stage of growth and that deriving geometrical thicknesses for such thin clouds is less error prone. Striking is the fact that the method also provides the base height for clouds with large vertical extensions and high optical thicknesses. The method has been applied to NOAA/AVHRR data of 20 selected cloud scenes. For an evaluation satellite retrieved cloud base heights have been compared to surface ceilometer measurements at the same time. First results are encouraging. The standard deviation of the differences between satellite and ceilometer measurements is ±369m with no systematic bias.
Irminger Water variability in the West Greenland Current
Authors: Myers Paul G. , Kulan Nilgun , Ribergaard Mads H.
Published: August 2007

We examine the historical variability of Irminger Water (IW) along 3 sections across the West Greenland Current over 1950–2005. Significant variability in the salinity, size and position of the IW core are seen over time. Some of the saltiest and warmest IW ever recorded have been seen since 1995 (comparable to previous maximums in the 1960s). During these periods, the volume of IW is also larger, leading to larger transports into the Labrador Sea. For the period 1984–2005 transports at Cape Farewell are 3.8 ± 0.9 Sv, 7.5 ± 2.2 × 1013 J and 8.5 ± 1.8 mSv of salt referenced to 35.0. LSW formation is also correlated to IW transport at Cape Farewell with a lag of one year (0.51).
Estimation of sonic layer depth from surface parameters
Authors: Jain Sarika , Ali M. M. , Sen P. N.
Published: September 2007

Sonic layer depth (SLD), an important parameter in underwater acoustics, is the near surface depth of first maxima of the sound speed in the ocean. The lack of direct observations of vertical profiles of velocimeters or temperature and salinity, from which sound speed and SLD can be calculated, hampers the investigation of SLD. In this study, we demonstrate SLD estimation using artificial neural network (ANN) from surface measurements that can be replaced with satellite observations later. Surface and subsurface measurements from a central Arabian Sea mooring are used for this purpose. The estimated SLD had a root mean square error (correlation coefficient) of 11.83 m (0.84). Approximately 76% (91%) of estimations lie within ±10 m (±20 m). SLD has also been estimated from surface parameters using multiple regression technique (MRT). ANN proved its superiority over MRT in estimating SLD from surface parameters.
Long‐term drought severity variations in Morocco
Authors: Esper Jan , Frank David , Büntgen Ulf , Verstege Anne , Luterbacher Jürg , Xoplaki Elena
Published: September 2007

Cedrus atlantica ring width data are used to reconstruct long‐term changes in the Palmer Drought Severity Index (PDSI) over the past 953 years in Morocco, NW Africa. The reconstruction captures the dry conditions since the 1980s well and places this extreme period within a millennium‐long context. PDSI values were above average for most of the 1450–1980 period, which let recent drought appear exceptional. However, our results also indicate that this pluvial episode of the past millennium was preceded by generally drier conditions back to 1049. Comparison of PDSI estimates with large‐scale pressure field reconstructions revealed steady synoptic patterns for drought conditions over the past 350 years. The long‐term changes from initially dry to pluvial to recent dry conditions are similar to PDSI trends reported from N America, and we suggest that they are related to long‐term temperature changes, potentially teleconnected with ENSO variability and forced by solar irradiance changes.
Thermal wind forcing and atmospheric angular momentum: Origin of the Earth's delayed response to ENSO
Authors: Dickey Jean O. , Marcus Steven L. , Chin Toshio M.
Published: August 2007

Interannual length‐of‐day variations and ENSO indices such as the Southern Oscillation Index (SOI) and Nino 3.4 SST are well correlated as a consequence of angular momentum conservation. During an El Nino event, the westerly winds increase, which raises the atmospheric angular momentum (AAM); as a result, the solid Earth must slow down, which increases the duration of the day (length‐of‐day: LOD). However, a lag has been observed with the SOI and Nino 3.4 SST leading the LOD and AAM series by one–two months; to date no dynamical explanation has been offered. The dominant excitation mechanism of interannual LOD is the wind term, driven largely by thermal winds arising from the poleward gradient of tropical temperature (TT). We show that the TT gradient (TTG), which peaks 1–2 months after the Nino 3.4 SST anomaly, is the source of the thermal winds that drive the LOD anomaly and account for this well‐known ENSO‐Earth rotation lag.
Phase behavior of dipolar associating fluids from the SAFT-VR+D equation of state
Authors: Zhao Honggang , Ding Yuanyuan , McCabe Clare
Published: August 2007

The statistical associating fluid theory for potentials of variable range plus dipole (SAFT-VR+D) is extended to study associating dipolar fluids. In the SAFT-VR+D approach dipolar interactions are taken into account through the use of the generalized mean spherical approximation to describe a reference fluid of dipolar square-well segments. This enables the effect of the dipolar interactions on the thermodynamics and structure of fluids to be explicitly described. Predictions for the thermodynamic properties and phase behavior of dipolar associating square-well monomers with one, two, and four association sites are considered and compared with new isothermal-isobaric and Gibbs ensemble Monte Carlo simulation data. The results show that the SAFT-VR+D equation provides a good description of the phase behavior of dipolar associating fluids. Additionally we have applied the new theoretical approach to study the vapor pressure and saturated liquid density of water.
Decoupling of the Dirac equation correct to the third order for the magnetic perturbation
Authors: Ootani Y. , Maeda H. , Fukui H.
Published: August 2007

A two-component relativistic theory accurately decoupling the positive and negative states of the Dirac Hamiltonian that includes magnetic perturbations is derived. The derived theory eliminates all of the odd terms originating from the nuclear attraction potential V and the first-order odd terms originating from the magnetic vector potential A, which connect the positive states to the negative states. The electronic energy obtained by the decoupling is correct to the third order with respect to A due to the (2n+1) rule. The decoupling is exact for the magnetic shielding calculation. However, the calculation of the diamagnetic property requires both the positive and negative states of the unperturbed (A=0) Hamiltonian. The derived theory is applied to the relativistic calculation of nuclear magnetic shielding tensors of HX (X=F,Cl,Br,I) systems at the Hartree-Fock level. The results indicate that such a substantially exact decoupling calculation well reproduces the four-component Dirac-Hartree-Fock results.
Oblique propagation of electromagnetic waves in a kappa-Maxwellian plasma
Authors: Cattaert Tom , Hellberg Manfred A. , Mace Richard L.
Published: August 2007

Space plasmas are often observed to contain more particles in the high-energy tail than the usual Maxwellian distributions, and are well modeled by kappa distributions. The hybrid kappa-Maxwellian distribution and associated generalized plasma dispersion function ZκM were recently introduced to model magnetized space plasmas. The susceptibility tensor for a kappa-Maxwellian plasma component is derived, making use of ZκM. This enables one to make general studies of obliquely propagating electromagnetic waves in a magnetoplasma. The susceptibility and dielectric tensors reduce to the Maxwellian expressions in the limit κ→∞. As an illustration, the formalism is applied to the lower branch of the R mode and its off-parallel variant. For low κ values, low-wavenumber, low-frequency parallel whistler waves are shown to be stable, unlike the Maxwellian case, which is unstable if the perpendicular temperature exceeds the parallel temperature. A numerical study is made of the effects of the value of kappa, the propagation angle, and the temperature anisotropy ratio on dispersion and damping. The kappa-Maxwellian distribution with very low κ is found to be unstable in an overdense plasma near the electron-cyclotron frequency even when the parallel and perpendicular temperatures are equal, because of the anisotropy of the contours in velocity space.
A combined experimental and analytical investigation of the vortex stability over sharp-edged slender bodies
Authors: Cai J. S. , Cui Y. D. , Tsai H. M.
Published: August 2007

A combined experimental and analytical investigation is conducted to assess the stability of the symmetric vortex pair over three different sharp-edged slender bodies at high angles of attack. The analysis is based on a previously developed eigenvalue stability method. Corresponding experimental studies involving flow visualization in the water tunnel, force and pressure measurement in the wind tunnel are carried out. The angles of attack tested range from 15° to 40°. Overall, the experiments confirm the stability behaviors as determined from the analysis. The analytical solutions indicate that an absolute type of instability is the mechanism for the breakdown of symmetry of the vortex flow over slender conical bodies at high angles of attack. Both the experiments and the analysis reveal that a sharp-edged slender body with a smaller volume on the leeward side and a bigger volume on the windward side increases the overall stability of the symmetric vortex pair. A shape with extended sharp edges in the outboard direction on its sides further enhances the stability of the vortex pair. The analytical method can be a useful tool for exploring shapes that favor stability or instability.
Variational calculation of static and dynamic vibrational nonlinear optical properties
Authors: Luis Josep M. , Torrent-Sucarrat Miquel , Christiansen Ove , Kirtman Bernard
Published: August 2007

The vibrational configuration interaction method used to obtain static vibrational (hyper)polarizabilities is extended to dynamic nonlinear optical properties in the infinite optical frequency approximation. Illustrative calculations are carried out on H2O and NH3. The former molecule is weakly anharmonic while the latter contains a strongly anharmonic umbrella mode. The effect on vibrational (hyper)polarizabilities due to various truncations of the potential energy and property surfaces involved in the calculation are examined.
Negative differential resistance and switching behavior of redox-mediated tunnel contact
Authors: Kuznetsov Alexander M.
Published: August 2007

Theoretical description of various properties of redox-mediated tunnel contacts is presented. The dependences of the current on the overpotential and bias voltage under the sweeping voltammetry conditions are addressed. The effect of switching between two redox states on the shape of current/voltage characteristics is discussed. The shot noise and telegraph noise of the bridged contacts involving redox group are considered. Functional properties of the contact as a means for the information processing are discussed.
Electrical switching and in situ Raman scattering studies on the set-reset processes in Ge–Te–Si glass
Authors: Anbarasu M. , Asokan S. , Prusty Sudakshina , Sood A. K.
Published: August 2007

Bulk Ge15Te83Si2 glass has been found to exhibit memory-type switching for 1mA current with a threshold electric field of 7.3kV∕cm. The electrical set and reset processes have been achieved with triangular and rectangular pulses, respectively, of 1mA amplitude. In situ Raman scattering studies indicate that the degree of disorder in Ge15Te83Si2 glass is reduced from off to set state. The local structure of the sample under reset condition is similar to that in the off state. The Raman results are consistent with the switching results which indicate that the Ge15Te83Si2 glass can be set and reset easily.
Ion accumulation in an electron plasma confined on magnetic surfaces
Authors: Berkery John W. , Marksteiner Quinn R. , Pedersen Thomas Sunn , Kremer Jason P.
Published: August 2007

Accumulation of ions can alter and may destabilize the equilibrium of an electron plasma confined on magnetic surfaces. An analysis of ion sources and ion content in the Columbia Non-neutral Torus (CNT) [T.S. Pedersen, J.P. Kremer, R.G. Lefrancois, Q. Marksteiner, N. Pomphrey, W. Reiersen, F. Dahlgreen, and X. Sarasola, Fusion Sci. Technol. 50, 372 (2006)] is presented. In CNT ions are created preferentially at locations of high electron temperature, near the outer magnetic surfaces. A volumetric integral of neνiz gives an ion creation rate of 2.8×1011ions∕s. This rate of accumulation would cause neutralization of a plasma with 1011 electrons in about half a second. This is not observed experimentally, however, because currently in CNT ions are lost through recombination on insulated rods. From a steady-state balance between the calculated ion creation and loss rates, the equilibrium ion density in a 2×10−8Torr neutral pressure, 7.5×1011m−3 electron density plasma in CNT is calculated to be ni=6.2×109m−3, or 0.8%. The ion density is experimentally measured through the measurement of the ion saturation current on a large area probe to be about 6.0×109m−3 for these plasmas, which is in good agreement with the predicted value.