bluuebunny/crossref_metadata_2025 huggingface dataset:
Development of a new indicator of pollutant loads and its application to the Chesapeake Bay watershed
Authors: Keller Troy A. , Shenk Gary W. , Williams Michael R. , Batiuk Richard A.
Published: January 2010

Pollutant load reductions are often required to restore aquatic ecosystems experiencing eutrophication. Loads can be estimated using watershed models or data from monitoring stations, however data availability can limit the timeliness or comprehensiveness of the load estimates. We developed an approach to address this challenge that used watershed model results to estimate the proportion of annual nonpoint source nitrogen (N), phosphorus (P) and sediment (Sed) loads derived from unmonitored catchments. This proportion was multiplied by the nonpoint portion of United States Geological Survey (USGS) estimated annual river loads to account for annual variation in hydrologic conditions. Total loads were calculated as the sum of measured river loads, reported point sources from unmonitored areas and the estimated nonpoint source loads from unmonitored catchments. We applied this approach to the Chesapeake Bay because of its socio‐economic and ecological importance. Median watershed loads for N, P and Sed were 140, 6.4 and 3030 Mg year−1, respectively (1990–2004). Nonpoint source loads from the monitored areas constituted the greatest source of N, P and Sed (55, 47 and 74% respectively) to the Bay. The high N, P and Sed yield rates (7.3, 0.38 and 99 kg ha−1 year−1, respectively) from nonpoint loads originating from unmonitored areas near the Bay resulted in 25, 32 and 26% (N, P and Sed, respectively) of the Bay's total loads (excluding direct atmospheric deposition, shoreline erosion and oceanic inputs). Disproportionately high loads of P and Seds were associated with years that experienced elevated discharge whereas N loads were directly related to discharge. Error estimates indicated that our methods were most reliable for N (±6%) but reasonable for P (±22%) and provide an effective technique for the timely estimation of pollutant loads from watersheds with unmonitored catchments. Management strategies that decrease N deposition and reduce runoff to control P and Sed transport will effectively reduce pollutant loads. Published in 2010 by John Wiley & Sons, Ltd.
Testing one premise of scientific inquiry in science classrooms: Examining students' scientific explanations and student learning
Authors: Ruiz‐Primo Maria Araceli , Li Min , Tsai Shin‐Ping , Schneider Julie
Published: January 2010

In this study, we analyzed the quality of students' written scientific explanations found in notebooks and explored the link between the quality of the explanations and students' learning. We propose an approach to systematically analyzing and scoring the quality of students' explanations based on three components: claim, evidence to support it, and a reasoning that justifies the link between the claim and the evidence. We collected students' science notebooks from eight science inquiry‐based middle‐school classrooms in five states. All classrooms implemented the same scientific‐inquiry based curriculum. The study focuses on one of the implemented investigations and the students' explanations that resulted from it. Nine students' notebooks were selected within each classroom. Therefore, a total of 72 students' notebooks were analyzed and scored using the proposed approach. Quality of students' explanations was linked with students' performance in different types of assessments administered as the end‐of‐unit test: multiple‐choice test, predict‐observe‐explain, performance assessment, and a short open‐ended question. Results indicated that: (a) Students' written explanations can be reliably scored with the proposed approach. (b) Constructing explanations were not widely implemented in the classrooms studied despite its significance in the context of inquiry‐based science instruction. (c) Overall, a low percentage of students (18%) provided explanations with the three expected components. The majority of the sample (40%) provided only claims without any supporting data or reasoning. And (d) the magnitude of the correlations between students' quality of explanations and their performance, were all positive but varied in magnitude according to the type of assessment. We concluded that engaging students in the construction of high quality explanations may be related to higher levels of student performance. The opportunities to construct explanations in science‐inquiry based classrooms, however, seem to be limited. © 2010 Wiley Periodicals, Inc. J Res Sci Teach 47: 583–608, 2010
A link layer protocol and link‐state routing protocol suite for multi‐channelad hocnetworks
Authors: Yoon Wonyong , Vaidya N. H.
Published: January 2010

We propose a link layer protocol and link‐state routing protocol suite for multi‐channelad hocnetworks. The proposed protocol suite addresses several practical issues that arise when nodes equipped with two radio interfaces want to utilize available channels. The routing layer makes a hybrid channel assignment where one interface is fixed and the other is switchable. Based on that, the routing layer runs a shortest path routing algorithm augmented with channel diversity. The link layer implements a slotted structure to minimize broadcast overhead inherent to multi‐channel networks. By using flow‐ and packet‐level simulators, we make some important observations. First, a hybrid channel assignment is good for connectivity and amenable to shortest‐path routing. Second, seeking a shortest‐path can be a better routing strategy in terms of global system throughput than complex channel‐diverse routing. Third, channel switching delay is not a throttling factor in terms of global system throughput. Copyright © 2010 John Wiley & Sons, Ltd.
Cleft Lip and Palate as a Cost‐effective Health Care Treatment in the Developing World
Authors: Magee William P. , Vander Burg Richard , Hatcher Kristin Ward
Published: January 2010

Background

The considerable number of surgical procedures performed each year, as well as the significant burden of surgical disease globally, have brought surgery into the arena of public health concerns. Several articles have shown the cost‐effectiveness of surgical interventions in the developing world. The authors suggest that surgery has an important role in global public health, specifically through international volunteer surgical missions as a vehicle for delivery.

Methods

Eight Operation Smile medical missions from 2008 are analyzed using the disability‐adjusted life year (DALY) framework and disability weights from the life tables of the first Disease Control Priorities Project (DCP1). The DCP1 life tables suggest that the entire burden of disease from a cleft lip and palate is incurred within the first 4 years of life. The same group of missions is analyzed using life tables modified by the authors to reflect the disability associated with cleft lip and palate that goes beyond the first 5 years of life.

Results

Using the DCP1 life tables, the cost per patient during the eight Operation Smile missions analyzed was $278 and $1827 with an average of $796. Using the life tables modified by the authors, the cost per patient was between $7.36 and $96.04 (average $33.94).

Conclusions

The absence of disability weights for untreated cleft lip and palate after the fifth year of life does not fit with the reality of living with an unrepaired cleft lip or palate. The authors conclude that secondary interventions alleviate disability and should enable an individual to approach a zero residual disability weight.
Factors Predicting Outcome of Total Thyroidectomy in Young Patients with Multiple Endocrine Neoplasia Type 2: A Nationwide Long‐Term Follow‐up Study
Authors: Schreinemakers Jennifer M. J. , Vriens Menno R. , Valk Gerlof D. , de Groot Jan‐Willem B. , Plukker John T. , Bax Klaas (N.) M. A. , Hamming Jaap F. , van der Luijt Rob B. , Aronson Daniel C. , Borel Rinkes Inne H. M.
Published: January 2010

Background

Multiple endocrine neoplasia type 2 (MEN 2) is caused by a RET mutation in chromosome 10. All MEN 2 patients develop medullary thyroid carcinoma (MTC). The age‐related risk of MTC is associated with the type of RET mutation. Our aim was to identify prognostic factors associated with recurrent MTC in MEN 2 patients.

Methods

In a nationwide case–control study, all patients who underwent total thyroidectomy in the Netherlands under the age of 20 years were classified into standard (1), high (2), or very high risk (3) for MTC based on RET‐mutation type. Disease‐free patients were compared with those with recurrent disease.

Results

A total of 93 patients were included in the study. Sixty‐six percent had MTC on histology, the youngest being 1 year old. Codon 634 was most affected. Sixteen (18%) patients had persistent or recurrent disease, one of whom died. Significantly associated determinants of outcome in univariate analysis were higher age at surgery, no age‐appropriate prophylactic surgery according to risk level, elevated preoperative calcitonin levels, affected codon, and the presence of lymph node metastases at surgery. On multivariate analysis only age of surgery was the single independent factor associated with persistent disease.

Conclusions

Prophylactic thyroidectomy beyond the recommended age is associated with persistent/recurrent disease. In addition, codon 634 mutation is associated with a high risk of recurrence requiring early surgery for all these patients.
Tetrahydrobiopterin responsiveness after extended loading test of 12 Danish PKU patients with the Y414C mutation
Authors: Nielsen Jytte Bieber , Nielsen Karin E. , Güttler Flemming
Published: January 2010

Phenylketonuria (PKU) is an inherited metabolic disease characterized by phenylalanine (Phe) accumulation due to defects in the enzyme phenylalanine hydroxylase (PAH). Phe accumulation can lead to cognitive impairment. Some individuals with PKU respond to tetrahydrobiopterin (BH4) treatment, the natural cofactor of PAH, by a reduction in blood Phe concentrations. We tested 12 patients with PKU, 8–29 years of age, all carrying the common Y414C mutation in the PAH gene. Three were homozygous and nine were compound heterozygous, with the second mutation being a putative null mutation. During the study period, genuine protein was increased to approximately 1 g/kg. The patients were treated with 20, 10, and 5 mg BH4/kg/day for 1 week on each dose, starting with 20 mg/kg. A positive response was defined as a decline in blood Phe > 30%. Blood Phe was measured four times a week. Nonresponding children were excluded from the study. Eleven of 12 patients had a positive response with 20 mg/kg, 5/10 responded on 10 mg/kg, and 1/9 on 5 mg/kg. Two were late responders, with a response on 20 mg/kg after >48 h. We could confirm the previously reported inconsistent responsiveness of Y414C in the nine heterozygous patients, whereas the three homozygous patients had early median Phe declines of 73%, 51%, and 27%, respectively, on the three different doses. The varying responses despite uniform trial conditions and genotypes may be due to individual differences in BH4 absorption or metabolism. No side effects were observed.
Nonlinear diffusion with a bounded stationary level surface
Authors: Magnanini Rolando , Sakaguchi Shigeru
Published: January 2010

We consider nonlinear diffusion of some substance in a container (not necessarily bounded) with bounded boundary of class

C^{2}

. Suppose that, initially, the container is empty and, at all times, the substance at its boundary is kept at density 1. We show that, if the container contains a proper

C^{2}

-subdomain on whose boundary the substance has constant density at each given time, then the boundary of the container must be a sphere. We also consider nonlinear diffusion in the whole

\mathbb{R}^{N}

of some substance whose density is initially a characteristic function of the complement of a domain with bounded

C^{2}

boundary, and obtain similar results. These results are also extended to the heat flow in the sphere

\mathbb{S}^{N}

and the hyperbolic space

\mathbb{H}^{N}

.

Nous considérons la diffusion non linéaire d'une substance dans un récipient (pas nécessairement borné) avec frontière bornée de classe

C^{2}

. Supposons qu'initialement, le récipient soit vide et, à sa frontière, la densité de la substance soit gardée à tout moment égale à 1. Nous montrons que, si le récipient contient un sous-domaine

C^{2}

propre à la frontière duquel la substance est gardée à tout moment à densité constante, alors la frontière du récipient doit être une sphère. Nous considérons aussi la diffusion non linéaire dans tout

\mathbb{R}^{N}

d'une substance dont la densité est initialement une fonction caractéristique du complémentaire d'un domaine ayant la frontière bornée et

C^{2}

, et nous obtenons des résultats semblables. Ces résultats sont aussi généralisés au cas du flux de chaleur dans la sphère

\mathbb{S}^{N}

et l'espace hyperbolique

\mathbb{H}^{N}

.
White matter integrity and cortical metabolic associations in aging and dementia
Authors: Kuczynski Beth , Targan Elizabeth , Madison Cindee , Weiner Michael , Zhang Yu , Reed Bruce , Chui Helena C. , Jagust William
Published: January 2010

Background

Studies show that white matter hyperintensities, regardless of location, primarily affect frontal lobe metabolism and function. This report investigated how regional white matter integrity (measured as fractional anisotropy [FA]) relates to brain metabolism, to unravel the complex relationship between white matter changes and brain metabolism.

Objective

To elucidate the relationship between white matter integrity and gray matter metabolism using diffusion tensor imaging and fluorodeoxyglucose‐positron emission tomography in a cohort of 16 subjects ranging from normal to demented (age, >55 years).

Methods

Mean FA values from white matter regions underlying the medial prefrontal, inferior‐lateral prefrontal, parietal association, and posterior temporal areas and the corpus callosum were regressed with glucose metabolism (by positron emission tomography), using statistical parametric mapping (P < 0.005; voxel cluster, >100). Regional cerebral glucose metabolism was the primary outcome measure. According to our hypothesis, those hypometabolic cortical regions affected by Alzheimer's disease would correlate with a lower FA of associated tracks.

Results

Our data show inter‐regional positive correlations between FA and gray matter metabolism for the prefrontal cortex, temporal, and parietal regions. Our results suggest that left prefrontal FA is associated with left temporal and parietal metabolism. Further, left posterior temporal FA correlated with left prefrontal metabolism. Finally, bilateral parietal FA correlated with bilateral temporal metabolism.

Conclusions

These regions are associated with cognitive processes affected in Alzheimer's disease and cerebrovascular disease, suggesting a link with white matter degeneration and gray matter hypometabolism. Therefore, cortical function and white matter degeneration are related in aging and dementia.
Subtypes of depression among patients with Alzheimer's disease and other dementias
Authors: Castilla-Puentes Ruby C. , Habeych Miguel E.
Published: January 2010

Objectives

We compared the prevalence of subtypes of depression in patients with Alzheimer's disease (AD), vascular dementia (VaD), and unspecified dementia (UD).

Methods

Using the Integrated Healthcare Information Services database, we conducted an analysis of subtypes of depression (major depressive disorder, depressive disorder not otherwise specified, dysthymic disorder; depressive psychosis, and adjustment disorder depressive) among patients with AD, VaD, and UD. Six thousand four hundred and forty patients aged 60 years or older with dementia (2947 with AD, 725 with VaD, and 2768 with UD) were identified from January 1 to December 31, 2001. Both subtypes of depression and dementia subgroups were diagnosed using criteria from the International Classification of Diseases, 9th version.

Results

The overall prevalence of depressive disorders was 27.41%. The prevalence of depressive disorders was significantly higher in VaD (44.14%) and UD (32.48%) patients compared with AD (18.53%, P < .0001) patients. The AD patients had the lowest prevalence of all subtypes of depression. The VaD patients, compared with both AD and UD (P < .005), had a significantly higher prevalence of: 1) depressive disorder not otherwise specified, 2) major depressive disorder, and 3) dysthymic disorder. Adjustment disorder with depressive symptoms was more common in the UD subgroup, whereas the rate of depressive psychosis was similar in all dementia subgroups

Conclusions

This study supports the view that depressive disorders are more prevalent in VaD compared with UD and AD, and provides indicators to the clinician for further evaluation of depression in dementia subgroups
Toward an Alzheimer's disease diagnosis via high‐resolution blood gene expression
Authors: Fehlbaum-Beurdeley Pascale , Jarrige-Le Prado Anne Charlotte , Pallares Diego , Carrière Jennifer , Guihal Caroline , Soucaille Cyril , Rouet Fabien , Drouin Dominique , Sol Olivier , Jordan Heather , Wu Darong , Lei Ling , Einstein Richard , Schweighoffer Fabien , Bracco Laurent
Published: January 2010

Background

There is a significant need for reliable molecular biomarkers to aid in Alzheimer's disease (AD) clinical diagnosis.

Methods

We performed a genome‐wide investigation of the human transcriptome, taking into account the discriminatory power of splice variations from the blood of 80 AD patients and 70 nondemented control (NDC) individuals.

Results

We characterized a blood RNA signature composed of 170 oligonucleotide probe sets associated with 133 genes that can correctly distinguish AD patients from NDC with a sensitivity of 100% and specificity of 96%. Functionally, this signature highlights genes involved in pathways that were associated with macrophages and lymphocytes within AD patients: Transforming growth factor (TGF‐β) signaling, oxidative stress, innate immunity and inflammation, cholesterol homeostasis, and lipid‐raft perturbation, whereas other genes may also provide new insights in the biology of AD.

Conclusions

This study provides proof‐of‐concept that whole‐blood profiling can generate an AD‐associated classification signature via the specific relative expression of biologically relevant RNAs. Such a signature will need to be validated with extended patient cohorts, and evaluated to learn whether it can differentiate AD from others types of dementia.
Efficacy of a medical food in mild Alzheimer's disease: A randomized, controlled trial
Authors: Scheltens Philip , Kamphuis Patrick J.G.H. , Verhey Frans R.J. , Olde Rikkert Marcel G.M. , Wurtman Richard J. , Wilkinson David , Twisk Jos W.R. , Kurz Alexander
Published: January 2010

Objective

To investigate the effect of a medical food on cognitive function in people with mild Alzheimer's disease (AD).

Methods

A total of 225 drug‐naïve AD patients participated in this randomized, double‐blind controlled trial. Patients were randomized to active product, Souvenaid, or a control drink, taken once‐daily for 12 weeks. Primary outcome measures were the delayed verbal recall task of the Wechsler Memory Scale–revised, and the 13‐item modified Alzheimer's Disease Assessment Scale–cognitive subscale at week 12.

Results

At 12 weeks, significant improvement in the delayed verbal recall task was noted in the active group compared with control (P = .021). Modified Alzheimer's Disease Assessment Scale–cognitive subscale and other outcome scores (e.g., Clinician Interview Based Impression of Change plus Caregiver Input, 12‐item Neuropsychiatric Inventory, Alzheimer's disease Co‐operative Study–Activities of Daily Living, Quality of Life in Alzheimer's Disease) were unchanged. The control group neither deteriorated nor improved. Compliance was excellent (95%) and the product was well tolerated.

Conclusions

Supplementation with a medical food including phosphatide precursors and cofactors for 12 weeks improved memory (delayed verbal recall) in mild AD patients. This proof‐of‐concept study justifies further clinical trials.
Nasal septal abscess and facial cellulitis caused by community-acquired methicillin-resistant Staphylococcus aureus
Authors: Cheng L-H , Kang B-H
Published: January 2010

Objective:

Community-acquired methicillin-resistant Staphylococcus aureus is emerging as an important pathogen. However, methicillin-resistant Staphylococcus aureus rarely causes nasal septal abscess.

Case report:

We present a case of severe, community-acquired, methicillin-resistant Staphylococcus aureus infection causing rapidly progressing sinusitis, nasal septal abscess and facial cellulitis.

Conclusion:

This report serves to remind the clinician of the expanding spectrum of severe infections caused by methicillin-resistant Staphylococcus aureus, all requiring prompt diagnosis and appropriate medical and/or surgical management.
Effective charge of photons and plasmons
Authors: MENDONÇA J. T. , SERBETO A. , ALI S.
Published: January 2010

We review the concept of photon effective charge in a plasma, and extend it to the case of longitudinal photons or plasmons. A simple electrostatic fluid model is considered in a non-magnetized and non-relativistic plasma. The contribution of the ions to the plasmon charge is also considered.
Rogue waves in the atmosphere
Authors: STENFLO LENNART , MARKLUND MATTIAS
Published: January 2010

The appearance of rogue waves is well known in oceanographics, optics, and cold matter systems. Here we show a possibility for the existence of atmospheric rogue waves.
On quantum plasma kinetic equations with a Bohmian force
Authors: HAAS FERNANDO
Published: January 2010

The dispersion relation arising from a Vlasov–Poisson system with a Bohmian force term is examined and compared to the more fundamental Bohm and Pines dispersion relation for quantum plasmas. Discrepancies are found already when considering the leading order thermal effects. The time-averaged energy densities for longitudinal modes are also shown to be noticeably different.
The role of stressful events in the development of behavioural and emotional problems from early childhood to late adolescence
Authors: Timmermans M. , van Lier P. A. C. , Koot H. M.
Published: January 2010

Background

There is growing evidence on the importance of experiences of stressful events in the development of psychopathology. This study aimed to investigate the role of stressful events in the continuity of internalizing and externalizing problems, as well as the cross-influence of these problems from early childhood to late adolescence.

Method

Data came from a general population sample of 396 children followed from the ages of 3 to 18 years. Parent-ratings of internalizing and externalizing problems at ages 3, 5, 10 and 18 years were used. Parents also reported on the presence of stressful events between the ages of 3 and 5 years, and 5 and 10 years. Adolescent reports on stressful events over the ages of 10–18 years were used. Structural equation models were used to disentangle/analyse the role of stressful events in the development of internalizing and externalizing problems.

Results

From the age of 3 years onwards externalizing symptoms predicted experiences of stressful events. In turn, these experiences predicted later externalizing problems. Stressful events also explained part of the continuity of internalizing problems from the age of 10 years onwards, but not during childhood. From childhood onwards, cross-influences from externalizing problems to subsequent internalizing problems were found to run through stressful events. Only in adolescence cross-influences from internalizing problems to externalizing problems were found, again via stressful events.

Conclusions

From childhood onwards to late adolescence, stressful events play a significant role in both the continuity and the co-occurrence of externalizing and internalizing problems. Theoretical and methodological implications of these findings are discussed.
Neuronal correlates of affective theory of mind in schizophrenia out-patients: evidence for a baseline deficit
Authors: Mier D. , Sauer C. , Lis S. , Esslinger C. , Wilhelm J. , Gallhofer B. , Kirsch P.
Published: January 2010

Background

Schizophrenia out-patients have deficits in affective theory of mind (ToM) but also on more basal levels of social cognition, such as the processing of neutral and emotional expressions. These deficits are associated with changes in brain activation in the amygdala and the superior temporal sulcus (STS). However, until now there have been no studies that examined these different levels of social cognition and their neurobiological underpinnings in patients within one design.

Method

Sixteen medicated schizophrenia out-patients and 16 matched healthy controls were studied with functional magnetic resonance imaging (fMRI) during a social cognition task that allows the investigation of affective ToM (aToM), emotion recognition and the processing of neutral facial expressions.

Results

Patients showed a deficit in emotion recognition and a more prominent deficit in aToM. The performance in aToM and in emotion recognition was correlated in the control group but not in the schizophrenia group. Region-of-interest analysis of functional brain imaging data revealed no difference between groups during aToM, but a hyperactivation in the schizophrenia group in the left amygdala and right STS during emotion recognition and the processing of neutral facial expressions.

Conclusions

The results indicate that schizophrenia out-patients have deficits at several levels of social cognition and provide the first evidence that deficits on higher-order social cognitive processes in schizophrenia may be traced back to an aberrant processing of faces per se.
Uncovering History: Private Sector Care Homes for Older People in England
Authors: JOHNSON JULIA , ROLPH SHEENA , SMITH RANDALL
Published: January 2010

In conducting his research for The Last Refuge (1962), Peter Townsend visited 173 public, voluntary and private residential care homes for older people in England and Wales. Drawing on his data, now archived at the University of Essex, we traced the subsequent history of these homes and revisited a sample that were still functioning as care homes in 2006. In this article, we focus on the 42 private homes he visited, some of which remain open and were revisited by us in 2005–06. The pre-1980 history of private sector residential care provision for older people is an elusive and poorly charted topic. Drawing on the two data sets for then and now, this article contributes new insights into this area of UK policy and practice.
Flagship Ahoy
Authors: Mäkelä Marjukka
Published: January 2010

Welcome to the 26th volume of the International Journal of Technology Assessment in Health Care (IJTAHC). The editorial office has moved from the Institute of Health Economics in Alberta, Canada, to the National Institute for Health and Welfare (THL) in Finland and its Finnish Office for Health Technology Assessment (FINOHTA). It is exciting and challenging to take the helm of this journal. Knowing its history and cherishing its strengths, I wish to keep the HTA community engaged in making and using the journal as its scientific sounding board and its flagship.
Companion animals: a reservoir for methicillin-resistantStaphylococcus aureusin the community?
Authors: LOEFFLER A. , LLOYD D. H.
Published: January 2010

This article reviews the literature on the epidemiology of methicillin-resistantStaphylococcus aureus(MRSA) in dogs, cats and horses. Over the past 10 years, MRSA has emerged as an important pathogen in veterinary medicine, especially in countries with a high MRSA burden in human hospitals. During the same period, community-associated MRSA (CA-MRSA) infections in humans without apparent links to healthcare facilities have increased dramatically. Although animal infections occur outside human hospitals, significant epidemiological, clinical and genetic differences exist between CA-MRSA in humans and the majority of MRSA infections in the different animal species. The recognition of MRSA in animals has raised concern over their role as potential reservoirs or vectors for human MRSA infection in the community. However, available data on MRSA transmission between humans and companion animals are limited and the public health impact of such transmission needs to be the subject of more detailed epidemiological studies.
Trends for influenza and pneumonia hospitalization in the older population: age, period, and cohort effects
Authors: COHEN S. A. , KLASSEN A. C. , AHMED S. , AGREE E. M. , LOUIS T. A. , NAUMOVA E. N.
Published: January 2010

Birth cohort has been shown to be related to morbidity and mortality from other diseases and conditions, yet little is known about the potential for birth cohort in its relation to pneumonia and influenza (P&I) outcomes. This issue is particularly important in older adults, who experience the highest disease burden and most severe complications from these largely preventable diseases. The objective of this analysis is to assess P&I patterns in US seniors with respect to age, time, and birth cohort. All Medicare hospitalizations due to P&I (ICD-9CM codes 480-487) were abstracted and categorized by single-year of age and influenza year. These counts were then divided by intercensal estimates of age-specific population levels extracted from the US Census Bureau to obtain age- and season-specific rates. Rates were log-transformed and linear models were used to assess the relationships in P&I rates and age, influenza year, and cohort. The increase in disease rates with age accounted for most of the variability by age and influenza season. Consistent relationships between disease rates and birth cohorts remained, even after controlling for age. Seasonal associations were stronger for influenza than for pneumonia. These findings suggest that there may be a set of unmeasured characteristics or events people of certain ages experienced contemporaneously that may account for the observed differences in P&I rates in birth cohorts. Further understanding of these circumstances and those resulting age and cohort groups most vulnerable to P&I may help to target health services towards those most at risk of disease.
Imaging detailed crustal structure and magmatic intrusion across the Ethiopian Rift using a dense linear broadband array
Authors: Cornwell D. G. , Maguire P. K. H. , England R. W. , Stuart G. W.
Published: January 2010

Continental rifting is constrained by the architecture and heterogeneous composition of lithosphere within which rifting occurs. Recent studies in Ethiopia show that the Cenozoic northern Main Ethiopian Rift (NMER) has developed in a Neoproterozoic lithospheric framework modified by a Tertiary plume, magma injection having replaced mechanical failure as the main strain accommodation mechanism. A 400 km long profile of 91 broadband seismic stations striking southeast across the NMER from the uplifted Ethiopian plateau to beyond the southern margin of the rift has provided a high‐resolution P receiver function section, here interpreted in terms of crustal architecture and composition in light of independent geophysical observations. Synrift deposits are identified over a ∼110 km wide region beneath which strain was accommodated during the early stages of rifting. Major variations in crustal thickness and seismic properties along the profile divide the crust into four distinct regions. Beneath the northwestern rift flank (average crustal thickness 37.5 km and Vp/Vs 1.82) mafic middle and lower crustal rocks are overlain by a felsic upper crust. Here a high P wave velocity lowest crustal layer (northwestern lower crustal layer) is proposed to consist of frozen gabbroic sills and possibly some partial melt. We suggest partial melting of lower crustal rocks and/or fractional crystallization may have contributed to the bimodal prerift and synrift magmatism. Also, the presence of this layer through its effect on crustal and lithospheric strength and rift‐related diking may have controlled the location and development of the NMER in the vicinity of the profile. Beneath the rift (average crustal thickness 34.5 km and Vp/Vs 1.87) the crust is subdivided into a northwestern sector, with a thinned crust and strong likelihood of partially molten rocks, and a southeastern sector, where high velocity and density anomalies and the presence of a Moho “hole” in the receiver function profile constrain the limits of a well‐developed crustal magma system. To the southeast, a 35 km wide zone marks the transition from intruded and thinned (by ∼5 km) crust beneath the rift to the amagmatic, thick crust of the southeastern rift flank (average crustal thickness 39 km and Vp/Vs 1.77) suggested to be of felsic to intermediate composition.
Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) south polar mapping: First Mars year of observations
Authors: Brown Adrian J. , Calvin Wendy M. , McGuire Patrick C. , Murchie Scott L.
Published: January 2010

We report on mapping of the south polar region of Mars using data from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) instrument. Our observations have led to the following discoveries: (1) Water ice is present in the form of pole‐circling clouds originating from the circum‐Hellas region, beginning prior to Ls = 162 and diminishing markedly at Ls = 200–204. (2) It has previously been inferred by thermal infrared observations by Titus et al. (2003) and CO2‐H2O mixture spectral models by Langevin et al. (2007) that surface water ice was present in the cryptic region in the final stages of sublimation. The high resolution of CRISM has revealed regions where only water ice is present (not a CO2‐H2O ice mixture). This water ice disappears completely by Ls = 252 and may be the source of water vapor observed by CRISM in southern latitudes between Ls = 240–260 by M. Smith et al. (2009). (3) We have estimated surface CO2 ice grain size distributions for the South Pole Residual Cap (SPRC) and the seasonal CO2 ice cap that covers it throughout summer spring and summer. Our analysis suggests that grain sizes peak at Ls = 191–199 with an apparent grain size of ∼7 ± 1 cm. By the end of the summer period our analysis demonstrates minimum apparent grain sizes of ∼5 ± 1 mm predominate in the SPRC. (4) Fine‐grained CO2 ice condenses from Ls = 0–40 and extends symmetrically away from the geographic pole, extending beyond 80°S by Ls = 4–10. No evidence for unusual CO2 depositional processes in the cryptic region is observed up to Ls = 16.
Effects of nanoparticle charging on streamer development in transformer oil-based nanofluids
Authors: Hwang J. George , Zahn Markus , O’Sullivan Francis M. , Pettersson Leif A. A. , Hjortstam Olof , Liu Rongsheng
Published: January 2010

Transformer oil-based nanofluids with conductive nanoparticle suspensions defy conventional wisdom as past experimental work showed that such nanofluids have substantially higher positive voltage breakdown levels with slower positive streamer velocities than that of pure transformer oil. This paradoxical superior electrical breakdown performance compared to that of pure oil is due to the electron charging of the nanoparticles to convert fast electrons from field ionization to slow negatively charged nanoparticle charge carriers with effective mobility reduction by a factor of about 1×105. The charging dynamics of a nanoparticle in transformer oil with both infinite and finite conductivities shows that this electron trapping is the cause of the decrease in positive streamer velocity, resulting in higher electrical breakdown strength. Analysis derives the electric field in the vicinity of the nanoparticles, electron trajectories on electric field lines that charge nanoparticles, and expressions for the charging characteristics of the nanoparticles as a function of time and dielectric permittivity and conductivity of nanoparticles and the surrounding transformer oil. This charged nanoparticle model is used with a comprehensive electrodynamic analysis for the charge generation, recombination, and transport of positive and negative ions, electrons, and charged nanoparticles between a positive high voltage sharp needle electrode and a large spherical ground electrode. Case studies show that transformer oil molecular ionization without nanoparticles cause an electric field and space charge wave to propagate between electrodes, generating heat that can cause transformer oil to vaporize, creating the positive streamer. With nanoparticles as electron scavengers, the speed of the streamer is reduced, offering improved high voltage equipment performance and reliability.
In islands and their conversion to InAs quantum dots on GaAs (100): Structural and optical properties
Authors: Urbańczyk A. , Hamhuis G. J. , Nötzel R.
Published: January 2010

We report growth of crystalline In islands on GaAs (100) by molecular beam epitaxy at low temperatures. The islands have a pyramidlike shape with well defined facets and epitaxial relation with the substrate. They are of nanoscale dimensions with high density. Above a certain substrate temperature, associated with the melting point of In, noncrystalline round shaped islands form with larger size and lower density. Upon conversion of the In islands into InAs islands under As flux, the final shape does not depend on the original crystalline state but on the annealing temperature of the InAs islands. Clear photoluminescence is observed from InAs quantum dots after conversion of the crystalline In islands.
Structured shock waves and the fourth-power law
Authors: Grady Dennis E.
Published: January 2010

A fourth-power law relating the stress jump through a steady structured shock wave and the maximum strain rate within the shock wave has received recognition as a unifying relation over a sensibly wide range of materials and shock compression amplitudes. Less widely recognized is the complementary applicability of the invariance of the product of the energy dissipated and the time over which this energy is dissipated through a structure shock wave—a property with the dimensions of action. While the latter invariance implies the fourth-power behavior for steady shock waves, this invariance also has an apparent application to unsteady structured waves under certain conditions. A brief history of the origin of the fourth-power law is provided. Some commentary is offered on the physical principles of solid viscosity in the shock wave and the underlying invariance of the energy-time product in the shock wave event. The results for steady structured waves in porous and composite solids, which do not in general exhibit fourth-power behavior, are examined. Observations of systematic behaviors with component cell size and impedance disparities suggest acoustic scattering may contribute to wave structuring in selected materials.
Fluxon modes and phase-locking at 600 GHz in superconducting tunnel junction nonuniform arrays
Authors: Salez Morvan , Boussaha Faouzi
Published: January 2010

We investigated parallel arrays of superconducting Nb/AlOx/Nb tunnel junctions nonevenly distributed in a superconducting Nb/SiO/Nb microstrip transmission line. Such devices are discretized Josephson transmission lines (DJTLs) in which, from theory, magnetic flux quanta (“fluxons”) can travel as solitonic waves when a dc current bias and a dc magnetic field are applied. We observed a reproducible series of resonant branches in each device’s I−V curve, at Josephson submillimeter-wave frequencies (from 240 to 720 GHz) matching the resonances predicted using a transmission line analysis, where the loading of the N=5 junctions is fully taken into account. The nonperiodic distribution was optimized to provide rf matching over a large bandwidth (450–650 GHz typically), implying that the plasma resonance of junctions is inductively tuned out over a similar band by the array. A confirmation of this comes from the observation, at frequencies higher than the untuned junctions plasma frequency, of several Josephson phenomena reported in this article: Fiske-like resonances, phase-locking of the n=3 resonance to an external 600 GHz microwave source, rf-induced zero crossing, and resonances at fractional harmonics of the rf signal. These experimental results are all compatible with a fluxon-based resonances interpretation, as in the extensively studied long Josephson junctions yet at higher frequencies. As reported elsewhere, we could detect ∼500 GHz microwave radiation emitted by our devices in the n=1 and n=3 modes. In light of these unique properties, we propose nonuniform DJTLs as a promising type of Josephson device for submillimeter-wave oscillators and fast fluxon-based electronics.
Note: High temperature pulsed solenoid valve
Authors: Shen Wei , Sulkes Mark
Published: January 2010

We have developed a high temperature pulsed solenoid valve with reliable long term operation to at least 400 °C. As in earlier published designs, a needle extension sealing a heated orifice is lifted via solenoid actuation; the solenoid is thermally isolated from the heated orifice region. In this new implementation, superior sealing and reliability were attained by choosing a solenoid that produces considerably larger lifting forces on the magnetically actuated plunger. It is this property that facilitates easily attainable sealing and reliability, albeit with some tradeoff in attainable gas pulse durations. The cost of the solenoid valve employed is quite low and the necessary machining quite simple. Our ultimate level of sealing was attained by making a simple modification to the polished seal at the needle tip. The same sealing tip modification could easily be applied to one of the earlier high T valve designs, which could improve the attainability and tightness of sealing for these implementations.
Optical and electrical properties of gallium-doped MgxZn1−xO
Authors: Wei Wei , Jin Chunming , Narayan Jagdish , Narayan Roger J.
Published: January 2010

In this study, the optical and electrical properties of epitaxial single crystal gallium-doped MgxZn1−xO thin films grown on c-plane sapphire substrates by pulsed laser deposition were investigated. In these films, the Ga content was varied from 0.05 to 7 at. % and the Mg content was varied from 5 to 15 at. %. X-ray diffraction showed that the solid solubility limit of Ga in MgxZn1−xO is less than 3 at. %. The absorption spectra were fitted to examine Ga doping effects on bandgap and band tail characteristics. Distinctive trends in fitted bandgap and band tail characteristics were determined in films with Ga content below 3 at. % and Ga content above 3 at. %. The effects of bandgap engineering on optical transparency were evaluated using transmission spectra. Carrier concentration and Hall mobility data were obtained as functions of Ga content and Mg content. The electrical properties were significantly degraded when the Ga content exceeded 3 at. %. Correlations between conduction mechanisms and gallium doping of MgxZn1−xO thin films were described. In addition, the effect of bandgap engineering on the electrical properties of epitaxial single crystal gallium-doped MgxZn1−xO thin films was discussed.
Strain in epitaxial Si/SiGe graded buffer structures grown on Si(100), Si(110), and Si(111) optically evaluated by polarized Raman spectroscopy and imaging
Authors: Mermoux M. , Crisci A. , Baillet F. , Destefanis V. , Rouchon D. , Papon A. M. , Hartmann J. M.
Published: January 2010

We report on the characterization, thanks to Raman spectroscopy and imaging of tensely strained Si films pseudomorphically grown on (001), (110), and (111) SiGe virtual substrates. The samples studied here are those described in the work of Destefanis et al. [J. Appl. Phys 106, 043508 (2009)]. They consist in 17-nm-thick strained Si layers grown at 650 °C with SiH4 as a gaseous precursor on top of polished SiGe virtual substrates of various surface orientations. We first derived the exact component array of the strain/stress field along the different growth directions. Because the relation between strain or stress and the Raman frequencies are complex, we also derive the strain-shift coefficients for the different substrate orientations considered in this work and the polarization selection rules. Visible and near-UV Raman spectroscopies were used to extract the in-plane lattice parameter of the SiGe virtual substrates and the tensile strain in the thin Si epitaxial layers on top. We have notably investigated thanks to Raman imaging the in-plane distribution of strain in Si layer/SiGe buffer stacks grown on (110) and (111) Si substrates. Original surface arrays have been highlighted for each surface orientation. Promising results have been obtained for (110) SiGe virtual substrates in terms of strain and layer quality while the technological usefulness of the (111) ones is more questionable.
Combined electron backscatter diffraction and cathodoluminescence measurements on CuInS2/Mo/glass stacks and CuInS2 thin-film solar cells
Authors: Abou-Ras D. , Jahn U. , Nichterwitz M. , Unold T. , Klaer J. , Schock H.-W.
Published: January 2010

Electron backscatter diffraction (EBSD) and cathodoluminescence (CL) measurements in a scanning electron microscope were performed on cross sections of CuInS2 thin films and ZnO/CdS/CuInS2/Mo/glass thin-film solar cells. The CuInS2 layers analyzed for the present study were grown by a rapid thermal process. The regions of the CuInS2 layers emitting high CL intensity of band-band luminescence are situated near the top surface (or close to the interface with ZnO/CdS). This can be attributed to an enhanced crystal quality of the thin films in this region. The phenomenon may be related to the recrystallization via solid-state reactions with CuxS phases, which is assumed to run from the top to the bottom of the growing CuInS2 layer. The distribution of CL intensities is independent of the sample temperature, the acceleration voltage of the electron beam, and of whether or not the ZnO/CdS window layers are present. When comparing CL images and EBSD maps on identical sample positions, pronounced intragrain CL contrast is found for individual grains. Also, it is shown that at random grain boundaries, the decreases in CL intensities are substantially larger than at Σ3 grain boundaries.
A macromodel for squeeze-film air damping in the free-molecule regime
Authors: Hong Gang , Ye Wenjing
Published: January 2010

A three-dimensional Monte Carlo (MC) simulation approach is developed for the accurate prediction of the squeeze-film air damping on microresonators in the free-molecule gas regime. Based on the MC simulations and the analytical traveling-time distribution, a macromodel, which relates air damping directly with device dimensions and operation parameters, is constructed. This model provides an efficient tool for the design of high-performance microresonators. The accuracy of the macromodel is validated through the modeling of the quality factors of several microresonators. It has been found that the relative errors of the quality factors of two resonators, as compared with experimental data, are 3.9% and 5.7%, respectively. The agreements between the macromodel results and MC simulation results, on the other hand, are excellent in all cases considered.
Bimetallic Fe–V catalyzed magnesium films exhibiting rapid and cycleable hydrogenation at 200 °C
Authors: Zahiri Beniamin , Amirkhiz Babak Shalchi , Danaie Mohsen , Mitlin David
Published: January 2010

We examined hydrogen sorption in 1.5 μm thick Mg–Fe–V films, using the binary alloys as baselines. At 200 °C both Mg–V and Mg–Fe–V absorb in tens of seconds, and desorb in tens of minutes. The ternary alloys show minimal kinetic or capacity degradation even after 105 absorption/desorption cycles. Pressure—composition isotherms yield the well-known enthalpies of α-MgH2 formation (decomposition), agreeing with x-ray diffraction results. The x-ray spectrum also shows a broad hump centered near (011) reflection of CsCl-type Fe–V phase. Our hypothesis is that a densely distributed nanoscale Fe–V acts both as a potent hydrogen dissociation catalyst and a heterogeneous nucleation site.