bluuebunny/crossref_metadata_2025 huggingface dataset:
Swallowing Function after Chemoradiation for Advanced Stage Oropharyngeal Cancer
Authors: Shiley Samuel G. , Hargunani Christopher A. , Skoner Judith M. , Holland John M. , Wax Mark K.
Published: February 2006

OBJECTIVE

Advanced‐stage oropharyngeal cancer may be treated either surgically or nonsurgically. We reported previously functional outcomes after surgical resection with free‐tissue transfer. In the present study, we evaluated swallowing function after combined chemoradiation for oropharyngeal cancer.

STUDY DESIGN AND SETTING

Retrospective review of 30 patients treated at a tertiary academic center for Stage III/IV oropharyngeal cancer with sequential or concurrent chemoradiation from 1994 to 2003.

RESULTS

Inclusion criteria were met by 27 of 30 (90%) patients. Most patients had base of tongue lesions (67%) and Stage IV disease (93%). Gastrostomy was carried out in 22 (82%) patients either before or during treatment. Three months after chemoradiation, 33% (9/27) were consuming all nutrition orally, 22% (6 of 27) were NPO, and 45% (12 of 27) had some oral intake but still required tube feeds. One year after treatment, 53% (10 of 19) had an exclusively oral diet whereas 47% still required tube feeds including 1 patient (5%) who was NPO. In patients without recurrence and follow‐up length >1 year, 69% (9 of 13) were consuming all nutrition orally whereas 31% still required gastrostomy tube (G‐tube) support. A higher rate of G‐tube dependence was observed in patients treated for base of tongue lesions vs tonsil lesions (67% vs 25%, P = 0.049, χ2 analysis).

CONCLUSIONS

At this institution, the short‐term (3‐4 months) rate of G‐tube dependence was similar after surgical and non‐surgical treatment of oropharyngeal cancer. One year after chemoradiation, 31% of patients without recurrence still required tube feeds.

SIGNIFICANCE

These results suggest that organ‐preservation protocols do not reduce the prevalence of chronic dysphagia and G‐tube dependence after management of oropharyngeal cancer.

EBM rating: C‐4

© 2006 American Academy of Otolaryngology–Head and Neck Surgery Foundation, Inc. All rights reserved.
Tracheotomy in the First Year of Life: Outcomes in Term Infants, the Vanderbilt Experience
Authors: Wootten Christopher T. , French Lesley C. , Thomas Robert G. , Neblett Wallace W. , Werkhaven Jay A. , Cofer Shelagh A.
Published: February 2006

OBJECTIVE

In an era emphasizing critical care of preterm infants, we characterize the indications and outcomes of tracheotomies performed in the first year of life in term infants compared to preterm infants.

METHODS

Retrospective study of 127 tracheotomies performed in the first year of life at a tertiary‐care children's hospital between 1988‐2004.

RESULTS

Mean gestational ages of the term and preterm groups were 38.97 and 29.71 weeks, respectively (P < 0.001). Indications for tracheotomy were upper airway abnormalities in 53% for the term group. The number of subsequent airway procedures required was 1.39 in the term group, achieving decannulation in 36.3%, with a 20.5% mortality rate.

CONCLUSION

Compared to preterm infants, the term decannulation rate was favorable, as chronic lung disease was uncommon. However, non‐tracheotomy‐related mortalities remained high.

SIGNIFICANCE

Tracheotomies are often performed for relief of upper airway obstruction, and congenital and acquired comorbidities not related to tracheotomy are associated with adverse outcomes in term infants.

EBM rating: C‐4

©2006 American Academy of Otolaryngology–Head and Neck Surgery Foundation, Inc. All rights reserved.
An Otolaryngology, Neurology, Allergy, and Primary Care Consensus on Diagnosis and Treatment of Sinus Headache
Authors: Levine Howard L. , Setzen Michael , Cady Roger K. , Dodick David W. , Schreiber Curtis P. , Eross Eric J. , Blumenthal Harvey J. , Lumry William R. , Berman Gary D. , Durham Paul L.
Published: February 2006

While “sinus” headache is a widely accepted clinical diagnosis, many medical specialists consider it to be an uncommon cause of recurrent headaches. Unnecessary diagnostic studies, surgical interventions, and medical treatments are often the result of the inappropriate diagnosis of sinus headache. Both the International Headache Society and the American Academy of Otolaryngology–Head and Neck Surgery have attempted to characterize conditions leading to headaches of rhinogenic origin. However, they have done so from different perspectives and in isolation from the other specialty groups. An interdisciplinary ad hoc committee recently convened to discuss the role of sinus disease and the nose in the etiology of headache and to review recent epidemiologic studies suggesting that sinus headache (headache of rhinogenic origin) and migraine are frequently confused with one another. Clinical trial data are presented which clearly indicate that the majority of sinus headaches can actually be classified as migraines. This committee reviewed scientific evidence available from multiple disciplines and concludes that considerable research and clinical study are needed to further understand and explain the role of nasal pathology and autonomic activation in migraine and headaches of rhinogenic origin. However, there was a consensus from this group that greater diagnostic and therapeutic attention needs to be given to patients complaining of sinus headache that may indeed be due to the nose.
A Comparison of Nasendoscopy and Multiview Videofluoroscopy in Assessing Velopharyngeal Insufficiency
Authors: Lam Derek J. , Starr Jacqueline R. , Perkins Jonathan A. , Lewis Charlotte W. , Eblen Linda E. , Dunlap Julie , Sie Kathleen C.Y.
Published: February 2006

OBJECTIVES

1) To compare nasendoscopy (NE) and multiview fluoroscopy (MVF) in assessing velopharyngeal gap size; and 2) to determine the relationship between these assessments and velopharyngeal insufficiency (VPI) severity.

STUDY DESIGN AND SETTING

Retrospective review of consecutive patients with VPI at a tertiary care children's hospital, assessed with NE and MVF between 1996 and 2003.

RESULTS

177 subjects. NE and MVF gap areas were correlated (R = 0.34, 95% CI 0.26‐0.41). In adjusted analysis, VPI severity was associated with: 1) NE gap area (OR = 2.78, 95% CI 1.96‐3.95), 2) MVF gap area (OR 1.64, 95% CI 1.37‐1.95), 3) age <5 years (OR 3.30, 95% CI 1.47‐7.38), and 4) previously repaired cleft palate (OR 0.48, 95% CI 0.25‐0.94).

CONCLUSIONS AND SIGNIFICANCE

NE and MVF assessments provide complementary information and are correlated. Both are associated with VPI severity. However, the “bird's‐eye view” provided by NE has a stronger correlation with VPI severity than MVF.
Endoscopic Resection of Sinonasal Inverted Papilloma: A Meta‐analysis
Authors: Busquets Jose M. , Hwang Peter H.
Published: February 2006

OBJECTIVES

Endoscopic resection has become an increasingly popular method of treating sinonasal inverted papillomas. The literature on endoscopic approaches to inverted papilloma consists primarily of relatively small case series (grade C evidence). This study aims to systematically review and integrate the available literature to objectively compare success rates of endoscopic versus nonendoscopic tumor resection techniques.

STUDY DESIGN

A systematic review of the literature on resection of inverted papillomas.

METHODS

Comprehensive review of the English‐language literature on resection of inverted papillomas was performed. The reports were subdivided into endoscopic approaches versus nonendoscopic approaches, applying strict inclusion and exclusion criteria. Our institution's experience with endoscopic treatment of inverted papilloma was also included. Studies from the era of endoscopic sinus surgery (1992‐2004) formed a “contemporary” cohort and were compared with a “historical” cohort developed from the literature between 1970 and 1995.

RESULTS

Thirty‐two studies were included in the contemporary cohort, comprising 714 patients treated endoscopically and 346 patients treated nonendoscopically. Thirteen studies in the historical cohort yielded 692 patients treated nonendoscopically. There was a significantly lower recurrence rate in the contemporary cohort compared with the historical cohort (15% v 20%, P = 0.02). Within the contemporary cohort, endoscopically treated patients had significantly lower recurrences than nonendoscopically treated patients (12% v 20%, P < 0.01). Notably, the recurrence rate for nonendoscopically treated patients in the contemporary cohort was equivalent to that of the nonendoscopic patients in the historical cohort (20% v 19%, P = 0.78).

CONCLUSIONS

A systematic review of the literature supports endoscopic resection as a favorable treatment option for most cases of sinonasal inverted papilloma.
Antibiotics to Improve Recovery Following Tonsillectomy: A Systematic Review
Authors: Dhiwakar Muthuswamy , Eng Chee Y. , Selvaraj Sivasubramaniam , McKerrow William S.
Published: February 2006

OBJECTIVE

To determine if antibiotics improve recovery following tonsillectomy.

STUDY DESIGN

Data sources: Electronic databases Medline, Embase, and Cochrane Controlled Trials Register were searched using relevant search terms. Additional trials, if any, were retrieved by searching the references from all identified trials, reviews, correspondences, editorials, and conference proceedings. No language restriction was applied. Study selection: Systematic review of trials in which antibiotic was administered as a study medication intraoperatively and/or postoperatively, in children or adults undergoing tonsillectomy or adenotonsillectomy. Only randomized, placebo‐controlled, double‐blind trials attaining preset quality scores were included. Outcomes analyzed: 1) pain, need for analgesia, fever, halitosis, and return to normal diet and activities; 2) secondary hemorrhage using 2 parameters—significant hemorrhage (ie, warranting readmission, blood transfusion, or return to theatre for hemostasis) and total hemorrhage; and 3) adverse events.

RESULTS

Five trials met the eligibility criteria. Antibiotics significantly reduced the number of subjects manifesting fever (relative risk [RR]: 0.62, 95% confidence interval [CI]: 0.45, 0.85) and duration of halitosis (− 1.94 [−3.57, −0.30] days), and marginally reduced the time taken to resume normal activity (−0.63 [− 1.12, −0.14] days), but had no significant effect in reducing pain scores (−0.01 [−0.60, 0.57]) or need for analgesia. Similarly, there was no significant difference in the time taken to resume normal diet or incidence of significant and total hemorrhage, although data was underpowered to detect differences for these outcomes. In the antibiotic group 4 patients developed an adverse reaction (3 cases of rash and 1 case of oropharyngeal candidiasis), while in the control group 1 patient had an adverse reaction (rash). The RR of antibiotic‐related adverse events was 2.45 (0.45, 13.31).

CONCLUSION

Antibiotics appear to be effective in reducing some, but not all, morbid outcomes following tonsillectomy, and may increase the risk of adverse events. Further trials are needed to better define the role of antibiotics in facilitating post‐tonsillectomy recovery.
Tracking recorded fires using charcoal morphology from the sedimentary sequence of Prosser Lake, British Columbia (Canada)
Authors: Enache Mihaela D. , Cumming Brian F.
Published: February 2006

Quantitative analyses of variations in morphological features of charcoal were undertaken in a 210Pb-dated sediment core from Prosser Lake (British Columbia, Canada). Seven morphological types of charcoal were defined by particle shape, major–minor axis ratio, apparent porosity and progradation to unburned material. The distribution of morphotypes and total charcoal abundances were assessed as a proxy for fire events recorded between 1919 and 2000 and to subsequent mechanisms of transportation–sedimentation to lake sediments. Charcoal morphotypes showed distinct relationships to recorded area burned by fires. Fragile charcoal fragments with highly irregular porosity (termed Type M) displayed the strongest correlation to burned area (r2 = 0.51; P = 0.0001) and did not produce any false-positive signal for fires recorded within a radius of 20 km around the lake. We infer that high porosity and low density Type M fragments are aerially transported and directly deposited on the lake, and that the fragility of Type M charcoal prevents significant quantities from being secondarily transported and incorporated into the sedimentary record. We propose that charcoal morphology is an important but underutilized technique that can yield important insights into fire type, proximity and transportation–sedimentation processes.
Patterns of intra-word phonological variability during the second year of life
Authors: SOSA ANNA VOGEL , STOEL-GAMMON CAROL
Published: February 2006

Phonological representation for adult speakers is generally assumed to include sub-lexical information at the level of the phoneme. Some have suggested, however, that young children operate with more holistic lexical representations. If young children use whole-word representation and adults employ phonemic representation, then a component of phonological development includes a transition from holistic to segmental storage of phonological information. The present study addresses the nature of this transition by investigating the prevalence and patterns of intra-word production variability during the first year of lexical acquisition (1;0–2;0). Longitudinal data from four typically developing children were analysed to determine variability at each age. Patterns of variability are discussed in relation to chronological age and productive vocabulary size. Results show high overall rates of variability, as well as a peak in variability corresponding to the onset of combinatorial speech, suggesting that phonological reorganization may commence somewhat later than previously thought.
Language in boys with fragile X syndrome
Authors: LEVY YONATA , GOTTESMAN RIKI , BOROCHOWITZ ZVI , FRYDMAN MOSHE , SAGI MICHAL
Published: February 2006

The current paper reports of language production in 15 Hebrew-speaking boys, aged 9;0–13;0, with fully methylated, non-mosaic fragile X syndrome and no concomitant diagnosis of autism. Contrary to expectations, seven children were non-verbal. Language production in the verbal children was studied in free conversations and in context-bound speech. Despite extra caution in calculating MLU, participants' language level was not predicted by mean utterance length. Context bound speech resulted in grammatically more advanced performance than free conversation, and performance in both contexts differed in important ways from performance of typically developing MLU-matched controls. The relevance of MLU as a predictor of productive grammar in disordered populations is briefly discussed.
The use of nouns and verbs by Japanese children and their caregivers in book-reading and toy-playing contexts
Authors: OGURA TAMIKO , DALE PHILIP S. , YAMASHITA YUKIE , MURASE TOSHIKI , MAHIEU AKI
Published: February 2006

Japanese provides a valuable contrast for crosslinguistic studies of noun and verb dominance in early child language, and the effect of input on the early lexicon. In this study, 31 Japanese children between 1;0 and 2;0 and their caregivers were recorded in two contexts: joint bookreading and play with toys. Context had the largest effect, as nouns were much more frequent in the book context. Noun dominance was constant across development in the book context, but in the toy context there was a shift away as children developed from single words through the presyntactic stage to the syntactic stage. Caregiver language was verb dominant in a number of respects across development in the toy context, and thus was not closely related to child lexical balance. We conclude that in early lexical development, all children have a conceptual disposition to learn nouns. With vocabulary growth and the emergence of grammar, the proportion of verbs increases substantially, and at this stage properties of the input language may influence development.
Prelinguistic pitch patterns expressing ‘communication’ and ‘apprehension’
Authors: PAPAELIOU CHRISTINA F. , TREVARTHEN COLWYN
Published: February 2006

This study examined whether pitch patterns of prelinguistic vocalizations could discriminate between social vocalizations, uttered apparently with the intention to communicate, and ‘private’ speech, related to solitary activities as an expression of ‘thinking’. Four healthy ten month old English-speaking infants (2 boys and 2 girls) were simultaneously video- and audiorecorded in their homes under two conditions: (A) when the infant was playing with mother, and (B) when the infant was alone. One hundred and fifty-six vocalizations were classified as ‘communicative’, if accompanied by non-vocal communicative behaviour, or as ‘investigative’, if accompanied by explorative activities. For the acoustic analysis, an automatic PITCH PATTERN RECOGNITION (PPR) software system was developed. The PPR-system could distinguish ‘communicative’ from ‘investigative’ vocalizations with an overall accuracy of 91·67%. These findings confirm that prelinguistic vocalizations might serve both as means of purposeful communication and as a tool of thought. These are the functions later assumed by language.
‘To define means to say what you know about things’: the development of definitional skills as metalinguistic acquisition
Authors: BENELLI BEATRICE , BELACCHI CARMEN , GINI GIANLUCA , LUCANGELI DANIELA
Published: February 2006

Some authors have suggested that definitional skills include metalinguistic components (Watson, 1985; Snow, 1990; McGhee-Bidlack, 1991). The present study therefore empirically investigated relations between the ability to define words and level of metalinguistic awareness in 280 Italian children (with ages ranging from 5 to 11 years) and in two groups of 40 adults each (with low and high educational levels, respectively). We used a definitional task presenting 24 terms (nouns, verbs, and adjectives, which were either concrete or abstract) and a task examining 6 different aspects of metalinguistic awareness. Our aim was to demonstrate that metalinguistic skills can positively predict the formal quality of definitions and to identify various aspects of metalinguistic skills that might be directly related to definitional skills. Results showed better performance on both tasks as a function of age and educational level; they also confirmed the important roles of metalinguistic ability and educational level in producing well-structured formal definitions.
Investigating the aetiology of and evaluating the impact of the Men C vaccination programme on probable meningococcal disease in England and Wales
Authors: GRANEROD J. , DAVISON K. L. , RAMSAY M. E. , CROWCROFT N. S.
Published: February 2006

The aims were to (1) investigate the aetiology of probable meningococcal disease, where a clinical diagnosis is made in the absence of laboratory data, and (2) evaluate the impact of the Men C vaccination programme in England and Wales. Multiple linear regression analyses were carried out using data reported to Enhanced Surveillance of Meningococcal Disease (ESMD) and laboratory reports of isolates of organisms causing symptoms that mimic meningococcal disease. Confirmed meningococcal disease appeared to be a significant predictor of probable disease. Thus, an additional reduction in meningococcal disease attributable to the serogroup C vaccination campaign was evident in probable disease over and above that observed in confirmed cases alone. Enteroviruses were a significant contributor to cases of probable meningitis and influenza appeared to be a significant contributor to probable cases of septicaemia. This analysis confirms the success seen following the Men C vaccination campaign and gives an indication of the aetiologies of other causes of probable meningitis and septicaemia reported to ESMD.
Diabetes in later life
Authors: Aspray Terence J.
Published: February 2006

Type 2 diabetes is a chronic progressive condition with a prevalence which rises with age. Its origins are believed to be multifactorial, and include genetic effects and environmental interactions, which may start in the uterus (with an association with low birth weight) and early developmental plasticity, resulting in compensatory growth through childhood and a tendency to abnormal glucose tolerance in adult life. The consequences are multi-systemic, with a combination of microvascular and macrovascular disease affecting multiple organs of the body. There is a high level of morbidity and mortality, typically accruing through adult life and into older age.
Flood warning and the use of weather radar in Scotland: a study of flood events in the Ruchill Water catchment
Authors: Cranston Michael D. , Black Andrew R.
Published: February 2006

This paper reports on work that demonstrates that weather radar can yield remarkably accurate rainfall measurements in Scotland. Analysis of data during 1999 and 2000 shows Nimrod radar data to have no consistent error bias and a 24% mean error in storm rainfall totals. For rivers such as the Ruchill Water in the Perthshire Highlands this highlights the fact that the observations and quality control corrections utilised by the Met Office Nimrod system may offer particular benefits in certain flood warning applications. Assessment of wind data indicates that smaller errors occur in Nimrod radar observations during lower wind speeds (less than 15 knots) and with an easterly airflow. However, errors may also be attributed to occasions when the Numerical Weather Prediction model fails to represent the wind conditions correctly at ground level. Copyright © 2006 Royal Meteorological Society.
Tropical storm impact in Central America
Authors: Palmieri Sabino , Teodonio Lorenzo , Anna Maria Siani  , Casale Giuseppe Rocco
Published: February 2006

In this study of tropical storm impacts in Central America, the relationship between physical variables (available in ‘real time’) and damage is explored, and a simple tool for early approximate evaluation of the impact is developed. Land track and energy dissipation appear as the most interesting parameters that modulate the hurricane impact. Because of the difficulty of attaching a monetary estimate to the damage caused in a large number of cases (as is required in a statistical approach), an ‘Impact Index’ based on the logarithm of casualties is introduced. Thereafter, within a subset of events in which damage in monetary terms is known, a rough link between damage and the Impact Index is derived.

Shortly after a new event, as soon as land track and energy dissipation are known, either by means of an empirical equation or using a contour graph, the Impact Index may be determined. Another empirical equation allows a rough estimate of damage in monetary units, but because this estimate is based on a limited number of cases, it must be treated with caution. The methodology is tested for a small set of independent cases.

Vulnerability to tropical cyclones depends not only on natural factors but also on sociopolitical conditions. A coupled sociological and environmental approach is believed to be the best way to improve the early impact estimate methodology. Copyright © 2006 Royal Meteorological Society.
Moist convective instability over the Arabian Sea during the Asian summer monsoon, 2002
Authors: Murthy B. S. , Sivaramakrishnan S.
Published: February 2006

The moist convective instability over the Arabian Sea during the Arabian Sea Monsoon Experiment 2002 is studied using high resolution radiosonde data over the Arabian Sea off the west coast of India and inland at Goa (15°21′N,73°51′E). The vertical structure of the lower troposphere is discussed in terms of the profiles of conserved variables and the time series of convective available potential energy (CAPE), mixed‐layer depth, lifting condensation level and level of free convection. Analysis shows that the Arabian Sea within 200 km of the west coast of India is characteristically a low‐CAPE region irrespective of whether it is a good or bad monsoon season. Little or no variability in the mean (0–500 Pa) lapse rate during July and August indicates the quasi‐equilibrium state of the tropical atmosphere during the summer monsoon with an approximate balance between the convective and large‐scale forces. Large‐scale forcing for the ascent of surface air seems to be of prime importance for triggering deep convection and rainfall over the East Arabian Sea. Case studies of precipitating convection over inland at Goa during the monsoon indicate a moistening and warming of the lower troposphere following the convection. Copyright © 2006 Royal Meteorological Society.
Using health impacts to assess atmospheric carbon monoxide models
Authors: Dirks Kim N. , Sturman Andrew P. , Johns Murray D.
Published: February 2006

Atmospheric pollution models are generally evaluated using measures of the difference between predicted and observed concentrations. These statistics can be inadequate as they tend to be sensitive to small errors in the timing of peak events that are generally of little consequence from a health point of view. This paper presents a technique for evaluating atmospheric carbon monoxide models based on the statistical properties of the uptake of carbon monoxide, rather than relying on traditional model evaluation measures. A simple semi‐empirical atmospheric carbon monoxide model is used as an example to illustrate the approach. Copyright © 2006 Royal Meteorological Society.
Nontidal oceanic contribution to length‐of‐day changes estimated from two ocean models during 1992–2001
Authors: Yan Haoming , Zhong Min , Zhu Yaozhong , Liu Lintao , Cao Xianhe
Published: February 2006

Contributions of ocean bottom pressure and currents to changes in the length of day (LOD) during 1992–2001 are evaluated at seasonal timescales by using two different ocean general circulation model products developed at the Scripps Institution of Oceanography and the University of Maryland. The annual amplitudes for the two bottom pressure terms of oceanic angular momentum (OAM) differ by approximately a factor of 3, while their annual phases are similar. Comparing the gravity‐derived nonatmosphere LOD changes with the two OAM bottom pressure terms at annual frequency, we find obvious discrepancies in phase. This result indicates that excitation of LOD changes by other sources, such as hydrology, is also important. The annual amplitudes and phases of the two OAM current terms compare well with those of the observed LOD minus gravity‐derived LOD changes and axial atmosphere angular momentum wind term but only if wind effects between 10 and 0.3 hPa levels are not included in the latter. The two OAM series have similar seasonal amplitudes and phases, but they differ substantially when examined in different latitudinal bands. The annual amplitudes of two OAM‐induced LOD changes are comparable with that of the nonatmosphere LOD changes, but the semiannual amplitudes are far smaller. Our study indicates that the oceanic effects on LOD should continue to be examined. In addition, the effects of zonal winds (10–0.3 hPa) on LOD are more significant than that of atmospheric surface pressures at semiannual frequency, while they play almost the same roles for annual term.
MHD simulation of the transpolar potential after a solar‐wind density pulse
Authors: Ober D. M. , Wilson G. R. , Maynard N. C. , Burke W. J. , Siebert K. D.
Published: February 2006

On 10 January 1997 an isolated solar wind density pulse, with other interplanetary parameters remaining steady, led to an enhanced transpolar potential (ΦTP) that is not predicted by either the Weimer or Siscoe‐Hill models. However, a magnetohydrodynamic simulation of the magnetosphere's response to a sudden increase in solar wind density does predict an ΦTP increase consistent with satellite observations during the 10 January 1997 event. The response is transient, decaying after several tens of minutes toward an equilibrium that is close to the original potential. The simulated ΦTP increase derives from erosion of the dayside magnetopause and transport of newly opened flux across the polar cap. The exponential decay of ΦTP results from inductance in the magnetosphere‐ionosphere circuit.
Channelization on plateaus composed of weakly cohesive fine sediment
Authors: Izumi N. , Fujii K.
Published: February 2006

In this paper, we present a mathematical model of the formation of gullies at the downstream end of plateaus composed of weakly cohesive fine material such as freshly deposited volcanic ash as an extension of the theory of channel inception on purely erosional slopes proposed by Izumi and Parker (2000). We perform a linear stability analysis using the momentum equations of flow, the transport equation of suspended sediment, and the Exner equation for beds subject to both erosion and deposition of bed material. We find from the analysis that deposition leads to uniform growth of perturbations at small wave numbers (or large wavelengths) and suppresses the dominant wavelength associated with the maximum growth rate. When the effect of deposition increases further, channel initiation itself tends to be inhibited. As long as the effect of deposition is not large, slopes become unstable to transverse perturbations, and the dominant wavelength appears in the range of 6–15 times the Froude critical depth of the sheet flow on slopes, divided by the bottom friction coefficient. Assuming that the bottom friction coefficient is of the order of 0.01, we find that the dominant gully spacing is of the order of 1000 times the Froude critical depth, which is similar to the result obtained in the case without deposition. We find that deposition affects channel initiation itself rather than channel spacing.
Permeability and porosity images based on P‐wave surface seismic data: Application to a south Florida aquifer
Authors: Parra Jorge O. , Hackert Chris L. , Bennett Michael W.
Published: February 2006

P‐wave surface seismic reflection data, acquired from a carbonate aquifer in southeastern Florida, are used to delineate flow units in a proposed aquifer storage and recovery (ASR) horizon. The impedance image determined by inversion from P‐wave reflection data captures most of the boundaries between hydraulic facies. The hydraulic facies properties are based on integration of the well logs and the lithology, which consists of vuggy carbonate units and sandstones. Within the proposed ASR horizon, located in the upper Floridan aquifer, low‐permeability zones consist of sandstones and highly permeable zones are carbonates with interconnected vuggy porosity. High‐resolution porosity, permeability, and impedance images based on cross‐well reflection and well logs help us evaluate the P‐wave seismic reflection results. We use well logs and cross‐well seismic data to support whether two‐dimensional seismic reflection measurements detect important flow units delineated by cross‐well high‐resolution seismic data. The data analysis demonstrates that major flow units are resolved and imaged with two‐dimensional seismic reflection techniques, although not as clearly as in the high‐resolution cross‐well data. The results suggest that the surface seismic reflection method, integrated with well logs and geology, provides the tools to assess water resources in this south Florida carbonate aquifer. However, we recommend conducting a cross‐well survey in areas where an understanding of the petrophysics is imperative to relating the seismic attributes to rock and fluid properties. This can be a critical step for planning purposes when considering a large surface‐oriented seismic survey.
Water flow processes in weathered granitic bedrock and their effects on runoff generation in a small headwater catchment
Authors: Kosugi Ken'ichirou , Katsura Shin'ya , Katsuyama Masanori , Mizuyama Takahisa
Published: February 2006

Recent studies have suggested that bedrock groundwater can exert considerable influence on runoff generation, water chemistry, and the occurrence of landslides in headwater catchments. To clarify water infiltration and redistribution processes between soil and shallow bedrock and their effect on storm and base flow discharge processes in a small headwater catchment underlain by weathered granite, we conducted hydrometric observations using soil and bedrock tensiometers combined with hydrochemical measurements and water budget analyses at three different spatial scales. Results showed that in an unchanneled 0.024‐ha headwater catchment, saturated and unsaturated infiltration from soil to bedrock is a dominant hydrological process at the soil‐bedrock interface. Annual bedrock infiltration ranged from 35 to 55% of annual precipitation and increased as precipitation increased, suggesting a high level of potential bedrock infiltration, partly explained by the high buffering capacity of the soil layer overlying the bedrock. This physical property of the soil layer was an important factor in controlling the generation of bedrock infiltration and saturated lateral flow over the bedrock. In a 0.086‐ha watershed including the unchanneled headwater catchment, exfiltration from the bedrock toward the soil layer composed more than half the annual discharge.
Mobile Phone Affects Cerebral Blood Flow in Humans
Authors: Aalto Sargo , Haarala Christian , Brück Anna , Sipilä Hannu , Hämäläinen Heikki , Rinne Juha O
Published: February 2006

Mobile phones create a radio-frequency electromagnetic field (EMF) around them when in use, the effects of which on brain physiology in humans are not well known. We studied the effects of a commercial mobile phone on regional cerebral blood flow (rCBF) in healthy humans using positron emission tomography (PET) imaging. Positron emission tomography data was acquired using a double-blind, counterbalanced study design with 12 male subjects performing a computer-controlled verbal working memory task (letter 1-back). Explorative and objective voxel-based statistical analysis revealed that a mobile phone in operation induces a local decrease in rCBF beneath the antenna in the inferior temporal cortex and an increase more distantly in the prefrontal cortex. Our results provide the first evidence, suggesting that the EMF emitted by a commercial mobile phone affects rCBF in humans. These results are consistent with the postulation that EMF induces changes in neuronal activity.
Molecular-dynamics simulations of the transport properties of a single polymer chain in two dimensions
Authors: Desai Tapan G. , Keblinski Pawel , Kumar Sanat K. , Granick Steve
Published: February 2006

Molecular-dynamics simulations are conducted to elucidate the critical factors affecting the transport properties of isolated polymer chains in strictly two dimensions. The relevance of surface inhomogeneity is critically examined. We unequivocally find that surface inhomogeneity is critical in obtaining transport behavior consistent with the recent measurements of surface diffusion for polymers adsorbed at the solid-liquid interface. For a systematic investigation of this point, heterogeneity was introduced by decorating the surface with impenetrable elements and we find that chain diffusivity crossed over from Rouse-type behavior to reptationlike with increasing surface coverage of obstacles. This transition in behavior occurred when the mean distance between obstacles is approximately equal to the end-to-end distance, Re, of the two-dimensional chain. Our results underscore the importance of surface disorder (not only literal obstacles but by reasonable extension also to other types of disorder) in determining the transport behavior of chains adsorbed to solids.
Classification of metal-oxide bonded interactions based on local potential- and kinetic-energy densities
Authors: Gibbs G. V. , Cox D. F. , Crawford T. D. , Rosso K. M. , Ross N. L. , Downs R. T.
Published: February 2006

A classification of the hydrogen fluoride H–F-bonded interactions comprising a large number of molecules has been proposed by Espinosa et al. [J. Chem. Phys. 117, 5529 (2002)] based on the ratio ∣V(rc)∣∕G(rc) where ∣V(rc)∣ is the magnitude of the local potential-energy density and G(rc) is the local kinetic-energy density, each evaluated at a bond critical point rc. A calculation of the ratio for the M–O bonded interactions comprising a relatively large number of oxide molecules and earth materials, together with the constraints imposed by the values of ∇2ρ(rc) and the local electronic energy density, H(rc)=G(rc)+V(rc), in the H–F study, yielded practically the same classification for the oxides. This is true despite the different trends that hold between the bond critical point and local energy density properties with the bond lengths displayed by the H–F and M–O bonded interactions. On the basis of the ratio, Li–O, Na–O, and Mg–O bonded interactions classify as closed-shell ionic bonds, Be–O, Al–O, Si–O, B–O, and P–O interactions classify as bonds of intermediate character with the covalent character increasing from Be–O to P–O. N–O interactions classify as shared covalent bonds. C–O and S–O bonded interactions classify as both intermediate and covalent bonded interactions. The C–O double- and triple-bonded interactions classify as intermediate-bonded interactions, each with a substantial component of covalent character and the C–O single-bonded interaction classifies as a covalent bond whereas their local electronic energy density values indicate that they are each covalent bonded interactions. The ratios for the Be–O, Al–O, and Si–O bonded interactions indicate that they have a substantial component of ionic character despite their classification as bonds of intermediate character. The trend between the ratio and the character of the bonded interactions is consistent with trends expected from electronegativity considerations. The ratio increases as the net charges and the coordination numbers for the atoms for several Ni-sulfides decrease. On the contrary, the ratio for the Si–O bonded interactions for the orthosilicate, forsterite, Mg2SiO4, and the high-pressure silica polymorph, stishovite, decreases as the observed net atomic charges and the coordination numbers of Si and O increase in value. The ratio for the Ni–Ni bonded interactions for the Ni-sulfides and bulk Ni metal indicate that the interactions are intermediate in character with a substantial component of ionic character.
Measurement of the electronic transition dipole moment by Autler-Townes splitting: Comparison of three- and four-level excitation schemes for the Na2AΣu+1−XΣg+1 system
Authors: Ahmed E. , Hansson A. , Qi P. , Kirova T. , Lazoudis A. , Kotochigova S. , Lyyra A. M. , Li L. , Qi J. , Magnier S.
Published: February 2006

We present a fundamentally new approach for measuring the transition dipole moment of molecular transitions, which combines the benefits of quantum interference effects, such as the Autler-Townes splitting, with the familiar R-centroid approximation. This method is superior to other experimental methods for determining the absolute value of the R-dependent electronic transition dipole moment function μe(R), since it requires only an accurate measurement of the coupling laser electric field amplitude and the determination of the Rabi frequency from an Autler-Townes split fluorescence spectral line. We illustrate this method by measuring the transition dipole moment matrix element for the Na2AΣu+1(v′=25,J′=20e)-XΣg+1(v″=38,J″=21e) rovibronic transition and compare our experimental results with our ab initio calculations. We have compared the three-level (cascade) and four-level (extended Λ) excitation schemes and found that the latter is preferable in this case for two reasons. First, this excitation scheme takes advantage of the fact that the coupling field lower level is outside the thermal population range. As a result vibrational levels with larger wave function amplitudes at the outer turning point of vibration lead to larger transition dipole moment matrix elements and Rabi frequencies than those accessible from the equilibrium internuclear distance of the thermal population distribution. Second, the coupling laser can be “tuned” to different rovibronic transitions in order to determine the internuclear distance dependence of the electronic transition dipole moment function in the region of the R-centroid of each coupling laser transition. Thus the internuclear distance dependence of the transition moment function μe(R) can be determined at several very different values of the R centroid. The measured transition dipole moment matrix element for the Na2AΣu+1(v′=25,J′=20e)-XΣg+1(v″=38,J″=21e) transition is 5.5±0.2D compared to our ab initio value of 5.9 D. By using the R-centroid approximation for this transition the corresponding experimental electronic transition dipole moment is 9.72 D at Rc=4.81Å, in good agreement with our ab initio value of 10.55 D.
Coupling nonpolar and polar solvation free energies in implicit solvent models
Authors: Dzubiella J. , Swanson J. M. J. , McCammon J. A.
Published: February 2006

Recent studies on the solvation of atomistic and nanoscale solutes indicate that a strong coupling exists between the hydrophobic, dispersion, and electrostatic contributions to the solvation free energy, a facet not considered in current implicit solvent models. We suggest a theoretical formalism which accounts for coupling by minimizing the Gibbs free energy of the solvent with respect to a solvent volume exclusion function. The resulting differential equation is similar to the Laplace-Young equation for the geometrical description of capillary interfaces but is extended to microscopic scales by explicitly considering curvature corrections as well as dispersion and electrostatic contributions. Unlike existing implicit solvent approaches, the solvent accessible surface is an output of our model. The presented formalism is illustrated on spherically or cylindrically symmetrical systems of neutral or charged solutes on different length scales. The results are in agreement with computer simulations and, most importantly, demonstrate that our method captures the strong sensitivity of solvent expulsion and dewetting to the particular form of the solvent-solute interactions.
Experimental determination of a spin-orbit interval in the C″Πui5 state of N214
Authors: Pirali O. , Tokaryk D. W.
Published: February 2006

We have developed an experimental setup using the combination of laser optogalvanic detection and a supersonic expansion of excited N2 to record the high resolution spectrum of the (3-1) and (4-2) Herman infrared bands (C″Πui5−A′Σg+5). We report the first experimental determination of a spin-orbit interval (about 24cm−1) in the C″Πui5 state of N2 for both the (3-1) and (4-2) vibrational bands as well as the first observation of the v′=4 vibrational level.
Recurrences in rotational dynamics and experimental measurement of superfluidity in doped helium clusters
Authors: Xu Yunjie , Blinov Nicholas , Jäger Wolfgang , Roy Pierre-Nicholas
Published: February 2006

We present the first experimental evidence of recurrences in the rotational dynamics of doped helium clusters. Using the dopant molecule as an experimental microscopic probe of superfluidity, we show that in small HeN–N2O complexes, superfluidity builds up in stages correlated with the filling and completion of a solvation shell.
Identification of peptides for the surface functionalization of perovskite ferroelectrics
Authors: Reiss B. D. , Bai G.-R. , Auciello O. , Ocola L. E. , Firestone M. A.
Published: February 2006

Combinatorial phage display methods have been used to identify a heptapeptide sequence, ISLLHST, that strongly associates with a perovskite ferroelectric, Pb(ZrxTi1−x)O3 (PZT). The selectively of peptide binding to polycrystalline metalorganic chemical vapor deposition deposited PZT thin films were determined by titering and immunofluorescence microscopy. Ferroelectric properties were determined by measurement of the P-E hysteresis loop on unmodified and phage bound PZT thin films. No change in the coercive field, Ec, or the saturation polarization, Ps was observed. The remnant polarization, PR, however, showed a minor reduction after exposure to aqueous buffer and/or phage binding, possibly due to association of compensating surface charges on the PZT.
Phonon-energy-coupling enhancement: Strengthening the chemical bonds of the SiO2∕Si system
Authors: Chen Zhi , Guo Jun , Yang Fuqian
Published: February 2006

We report a new effect for the SiO2∕Si system, phonon-energy-coupling enhancement. The vibrational modes of the Si–Si and Si–O bonds exhibit enhanced energy coupling when the rapid thermal processing (RTP) is directly applied to the SiO2∕Si system. With a combination of the RTP and deuterium (D) anneal, the strongest coupling among the Si–D, Si–Si, and Si–O bonds was observed. It is shown that not only Si–D bonds but also Si–O bonds have been strengthened dramatically when this effect is applied directly to the oxide, leading to an enhanced robustness of the oxide structure. The gate leakage current has been reduced by five orders of magnitude for thin oxides (2.2nm) and two orders of magnitude for thick oxides (>3nm). The breakdown voltage has been improved by ∼30%
Equivalent circuit model for carbon nanotube Schottky barrier: Influence of neutral polarized gas molecules
Authors: Yamada Toshishige
Published: February 2006

An equivalent circuit model is proposed for the Schottky barrier at the junction between a metallic electrode and a semiconducting carbon nanotube (NT). We have applied the model to a gold-NT junction under the presence of neutral polarized NH3 molecules, and have shown that visible Schottky barrier modulation is possible for the gas densities as low as 3×1013cm−2, which is quite feasible experimentally.
Two-photon-induced reduction of metal ions for fabricating three-dimensional electrically conductive metallic microstructure
Authors: Tanaka Takuo , Ishikawa Atsushi , Kawata Satoshi
Published: February 2006

We developed techniques for fabricating three-dimensional metallic microstructures using two-photon-induced metal-ion reduction. In this process, ions in a metal-ion aqueous solution were directly reduced by a tightly focused femtosecond pulsed laser to fabricate arbitrary three-dimensional structures. A self-standing metallic microstructure with high electrical conductivity was demonstrated.
Effect of excess plasma on photoelectron spectra of nanoporous GaP
Authors: Dixit V. K. , Kumar Shailendra , Mukherjee C. , Tripathi Shilpa , Sharma Anupam , Brajpuriya Ranjeet , Chaudhari S. M.
Published: February 2006

A comparative study of the effect of excess plasma on the photoelectron spectra (PES) of crystalline gallium phosphide (GaP) wafer and “nanoporous” GaP network samples have been carried out. Rigid shift along with large changes in the line shapes of PES of nanoporous GaP have been observed in the presence of secondary light with respect to spectra measured in its absence. In case of GaP wafer, only rigid shift of PES have been observed. The valence bands offset between “nanoporous” GaP and GaOx is found 2.30eV at 300K.
Route to create large-area ordered polymeric nanochannel arrays
Authors: Müller-Buschbaum P. , Bauer E. , Maurer E. , Schlögl K. , Roth S. V. , Gehrke R.
Published: February 2006

Depositing polymdimethylsiloxane (PDMS) from an isopropanol solution onto a glass slide surface by wiping with a fuzz-free wipe results in highly ordered structures. Dewetting of the highly diluted PDMS solution and evaporation of the solvent yields nanostructures. The structure is well characterized as polymer nanochannels, separated by a mean distance of 166nm. The mean height of the shallow channels is 3nm only. The proof of having aligned structures on very large surface areas with a well defined orientation is performed with a very high resolution grazing incidence small angle x-ray scattering setup.