bluuebunny/crossref_metadata_2025 huggingface dataset:
Automated detection of infectious disease outbreaks: hierarchical time series models
Authors: Heisterkamp Simon H. , Dekkers Arnold L. M. , Heijne Janneke C. M.
Published: September 2006

The purpose of infectious disease surveillance is to inform the public health policy makers on the incidence and trends of infectious diseases and to trigger appropriate actions to control infectious disease outbreaks. The enormous amount of data collected with automated laboratory‐based surveillance systems require automated algorithms for detecting unexpected aberrations that may signal infectious disease outbreaks. In this paper, we explore the potential of hierarchical time series models to detect deviations from expected incidence. As these count data are extremely noisy it can be expected that these models are suitable to detect signal from noise and accommodate for possible autocorrelation. The proposed procedure consists of three steps; (1) the model parameters are estimated by empirical Bayes on a training period of, e.g. a year; (2) the expected values are updated for small time steps (e.g. daily) as new data arrive; (3) threshold levels are updated conditionally on the past expected values and an alarm is triggered when the threshold level is exceeded. To test the potential of the models we estimated sensitivity, specificity and timeliness on simulated time series and compared the results with an alternative approach of a linear regression model adjusted for trends and season. We also used two observed series for Rubella notifications and Salmonella infections and compared our findings with the expert opinions on these series. The hierarchical time series models approach shows high sensitivity and specificity and correctly identifies outbreaks at an early stage. This, in our opinion, makes the proposed model a reliable tool for adequate automated detection of infectious disease outbreaks. Copyright © 2006 John Wiley & Sons, Ltd.
Spontaneous rupture of sacrococcygeal teratoma associated with acute fetal anemia
Authors: Yamaguchi Y. , Tsukimori K. , Hojo S. , Nakanami N. , Nozaki M. , Masumoto K. , Taguchi T. , Wake N.
Published: September 2006

Sacrococcygeal teratoma (SCT) is the most common congenital tumor, with affected fetuses having a high risk of perinatal complications and death. We report a case of a fetus with an SCT that developed acute anemia due to spontaneous rupture of the tumor in utero. The fetus was referred at 25 weeks' gestation for evaluation of a large solid and cystic mass in the sacral region. There were no signs of hydrops or placentomegaly. At 33 weeks' gestation, loss of variability in the fetal heart rate pattern was recorded. Doppler ultrasonography showed increased middle cerebral artery peak systolic velocity, suggesting fetal anemia. Markedly bloody amniotic fluid, with 82% hemoglobin F, was observed on amniocentesis, suggesting rupture of the SCT with active fetal bleeding. An emergency Cesarean section was performed. At delivery, the tumor was bleeding actively and the neonatal hemoglobin concentration was 3.1 g/dL. There were no findings of hemorrhage or necrosis within the tumor. The neonate received a blood transfusion, and surgical resection of the tumor was carried out on the first day after delivery. Postoperatively, the baby did well. We suggest that fetal SCTs run the risk of inducing acute fetal anemia due to intrauterine hemorrhage of the tumor, a finding which could lead to an earlier and more appropriate management of this condition. Copyright © 2006 ISUOG. Published by John Wiley & Sons, Ltd.
Crusted scabies (sarcoptic mange) in four cats due to Sarcoptes scabiei infestation
Authors: Malik Richard , Stewart Keith McKellar , Sousa Candace A. , Krockenberger Mark B. , Pope Sally , Ihrke Peter , Beatty Julia , Barrs Vanessa RD , Walton Shelley
Published: September 2006

Four new cases of sarcoptic mange in cats are described. Two cats resided in areas known to be frequented by foxes, another cohabited with a dog recently diagnosed with sarcoptic mange, while the final cat lived with a mixed breed dog that had been treated for sarcoptic mange 7 months previously. Three cases were diagnosed on the basis of characteristic mite size and morphology in skin scraping from representative lesions, situated on the head (two cases) or head and distal hind limbs (one case). Mites were highly mobile and abundant in all instances, and easily detected also in skin biopsy specimens procured from two cases. Eosinophilic inflammation, hyperkeratosis and parakeratosis were prominent in the tissue sections. In the remaining case, the diagnosis was presumptive, based on characteristic lesions, cohabitation with a canine scabies patient and positive response to scabicide therapy. Pruritus was not a prominent clinical feature in any patient and was considered to be absent in three of the four cases. Lesions in three cats with long-standing disease were reminiscent of crusted scabies (synonym: Norwegian scabies, parakeratotic scabies) as seen in human patients. In three cases, in-contact human carriers developed itchy cutaneous papular lesions. Two cases responded promptly to therapy with systemic avermectin drugs, while one responded to topical treatment with lime sulphur and the remaining cat received both a lime sulphur rinse and ivermectin. Sarcoptic mange should be considered in the differential diagnosis of cats with non-pruritic crusting skin diseases, especially when there is contact with foxes or dogs, and when owners have itchy papular lesions.
The impact of supply, demand and grain quality on the UK bread and feed wheat price differential in the UK
Authors: HOLLINS P. D. , KETTLEWELL P. S. , PARSONS S. T. , ATKINSON M. D.
Published: September 2006

The difference between the bread wheat and feed wheat prices in the UK (the premium) is an important influence on behaviour throughout the entire grain chain. The aim of the present study was to quantify the influence of grain quality and other factors on interannual variation in the premium calculated as a proportion of the feed price. A hypothetical model of the UK wheat economy was devised, appropriate annual national data from 1982 to 2000 were collected for each component and multiple regression was used to develop a statistical model for the premium.

The statistical model included livestock numbers (calculated as pig equivalents), Hagberg falling number and wheat stocks, which together explained 0·80 of the interannual variation in the premium. A high premium was associated with high livestock numbers, low Hagberg falling number and low wheat stocks. These variables were included in the hypothetical model because: livestock numbers represent demand for feed wheat; Hagberg falling number is a quality criterion for purchase of bread wheat with a low value indicating poor quality and thus a smaller supply of bread wheat; wheat stocks are one of the sources of supply of wheat. It was concluded that of the 16 supply, demand or price variables in the hypothetical model the main variables associated with the premium from 1982 to 2000 were demand for feed wheat, quality of the wheat harvest and carry-over of wheat from the previous harvest.
Proceedings of the Second Meeting of the EURO Working group on Operational Research (OR) in Agriculture and Forest Management
Authors: PLÀ L. M.
Published: September 2006

This working group, which is concerned with operational research methods and applications to agricultural science in its broad meaning (i.e. including Forest Management and Fisheries), was formed in 2003 within the European Association of Operational Research Societies (EURO). The first meeting of the group was held at the former Silsoe Research Institute two years ago. The next meeting will be held in 2007 within the XXII EURO Conference in Prague. The group intends to start regular meetings at approximately yearly intervals in association with the EURO Conferences. The second meeting of the working group, chaired by Dr. L. M. Plà of the University of Lleida and organized as a stream within the XXI EURO Conference, was held at the University of Iceland in Reykjavík from 3rd–5th July 2006 where the following papers were read.
Expression of Suaeda salsa glutathione S-transferase in transgenic rice resulted in a different level of abiotic stress resistance
Authors: ZHAO F. , ZHANG H.
Published: September 2006

Glutathione S-transferases (EC 2.5.1.18, GSTs) are a family of multifunctional enzymes that play important roles in oxidative stress resistance. In the present study, it was investigated whether expressing Suaeda salsa GST in transgenic rice (Oryza sativa L. cv Zhonghua No.11) could confer resistance to abiotic stress. Several types of stress, including salt, paraquat and chilling were applied. It was shown that following paraquat applications, the activity of GST, catalase (CAT, EC 1.11.1.6) and superoxide dismutase (SOD, EC 1.15.1.1) increased significantly in the GST transgenic plants compared with non-transgenics. Following NaCl and chilling stresses, only SOD and CAT activities increased markedly in the transgenics and there were no significant differences in GST expression between transgenics and non-transgenics. Moreover, in stressed plants, the generation of H2O2 and Malon dialdehyde decreased more in the transgenics than in non-transgenics. These results imply that expression of the Suaeda salsa GST in transgenic rice could enhance abiotic stress tolerance and the antioxidant enzymes of the active oxygen-scavenging system might play integral roles in the protection of plants from oxidative stress.
PARENTAL PREFERENCE FOR SONS AND DAUGHTERS IN A WESTERN INDUSTRIAL SETTING: EVIDENCE AND IMPLICATIONS
Authors: KIPPEN REBECCA , EVANS ANN , GRAY EDITH
Published: September 2006

This paper considers whether sex composition of existing children in Australian families is an important factor in parity progression. Using census data from 1981, 1986, 1991, 1996 and 2001, women are linked with their co-resident children, allowing investigation of family sex composition and its changing impact over time on the propensity to have another child. The study finds that parents are much more likely to have a third and fourth birth if existing children are all of the same sex, indicating a strong preference for children of both sexes. This increased propensity has added around three per cent to the fertility of recent cohorts. The paper concludes with a discussion of the potential impact of sex-selection technologies on fertility. The authors argue that future widespread use of reliable sex-selection technologies might act to increase fertility in the short term, but would lead to a long-term reduction in fertility.
WHEN ANCIENT MEETS MODERN: THE RELATIONSHIP BETWEEN POSTPARTUM NON-SUSCEPTIBILITY AND CONTRACEPTION IN SUB-SAHARAN AFRICA
Authors: BROWN MARK
Published: September 2006

Extended durations of postpartum non-susceptibility (PPNS) comprising lactational amenorrhoea and associated taboos on sex have been a central component of traditional reproductive regimes in sub-Saharan Africa. In situations of rising contraceptive prevalence this paper draws on data from the Demographic Health Surveys to consider the neglected interface between ancient and modern methods of regulation. The analysis reports striking contrasts between countries. At one extreme a woman’s natural susceptibility status appears to have little bearing on the decision to use contraception in Zimbabwe, with widespread ‘double-protection’. By contrast, contraceptive use in Kenya and Ghana builds directly onto underlying patterns of PPNS. Possible explanations for the differences and the implications for theory and policy are discussed.
Stomatogenesis of the marine ciliate Paranophrys magna (Protozoa: Ciliophora: Scuticociliatida) from Qingdao, China
Authors: Ma Hongwei , Song Weibo , Hu Xiaozhong
Published: September 2006

The morphology and stomatogenesis of the marine scuticociliate Paranophrys magna, collected from a crab-culturing pond in Qingdao, China, were studied. It possessed typical characteristics of the genus Paranophrys. The stomatogenesis of this species corresponds basically with the results provided in previous studies for this genus, the main sequence develops can be generalized as follows according to the Qingdao population: (i) in the proter: the remnant of the parental paroral membrane generates the new paroral membrane and the scutica; and (ii) in the opisthe: both the paroral membrane and scutica originate from the proliferation of the anterior part of the secondary primordial field, membranelles 1&2 derive from the posterior part of the secondary primordial field, while membranelle 3 from the proliferation of the parental scutica which form the primary primordial field.  Some differences between our results and previous descriptions are compared and discussed.
Deep-sea polychaetes from north-west Africa, including a description of a new species of Neopolynoe (Polynoidae)
Authors: Kirkegaard J.B.
Published: September 2006

Polychaete worms obtained by RRS ‘Discovery’ from 200 to 4850 m north-west of Africa in 1979 contained 24 species of which five: Macellicephala violacea, Bathyeliosona abyssicola, Laetmonice filicornis, Maldanella harai and Potamilla torelli were present in the abyssal zone (>2000 m). Macellicephala violacea is widely distributed in the Arctic and the present record is the southern-most record of this species. Fifteen species were recorded from the bathyal zone, many of which have a wide distribution in the oceans. A Neopolynoe species from the bathyal zone is new to science.
Evidence for morphological and genetic divergence in Perinereis cultrifera (Polychaeta: Nereididae) from two habitat types at Elba Island
Authors: Maltagliati Ferruccio , Camilli Laura , Lardicci Claudio , Castelli Alberto
Published: September 2006

Differentiation between two samples of the polychaete Perinereis cultrifera collected in a brackish-water habitat and in an adjacent marine site at Elba Island (Italy) was assessed by morphological (number of paragnaths on the zones of the pharynx) and genetic (allozymes) approaches. Mean number of paragnaths differed significantly in zones IIl, IIr, III and V by t-test (P<0·05). Multidimensional scaling performed on Manhattan distances separated the individuals in two groups with a narrow zone of juxtaposition. Electrophoretic analyses of 22 allozyme loci revealed high levels of both within- and between-sample genetic heterogeneity, with a large number of private alleles. A general deficit of heterozygotes accounted for deviations from the Hardy–Weinberg equilibrium. Nei's genetic distance (D=0·185±0·018) and the mean value of the coancestry coefficient (Θ=0·381± 0·123, P<0·001 by permutation test) indicated considerable genetic divergence between the two samples. We concluded that the two groups can be assigned to sibling species. The observed divergence between the two samples may results from absence of gene flow and subsequent microallopatric differentiation through genetic drift, or, assuming migration between populations of the two sites, the model of divergence with gene flow may be compatible with this system.
A new species of Branchiomaldane (Polychaeta: Arenicolidae) from the State of São Paulo, south-eastern Brazil
Authors: de Matos Nogueira João Miguel , Rizzo Alexandra Elaine
Published: September 2006

A new species of Branchiomaldane was identified in a collection of polychaetes living in colonies of a stony coral. Branchiomaldane maryae sp. nov. differs from all other species of the genus by the presence of lensed eyes and 1–3 branchial filaments per parapodium. Comparisons between B. maryae sp. nov. and the other species of the genus are provided, together with some phylogenetic considerations on the position of the genus.
Morphometric study of the nereidid Laeonereis acuta (Annelida: Polychaeta)
Authors: Omena Elianne P. , Amaral Antonia Cecília Z.
Published: September 2006

In order to find the most suitable parameter for measuring the nereidid Laonereis acuta, correlations between total length or weight and eight morphological measurements: width of prostomium and 2nd, 6th, 13th and 19th setigers, length of the prostomium, length through segment 6th and length through segment 13th, were established. The width measurements showed the highest values of r, and were the most reliable indicators of size. Comparisons between weight and morphological measurements showed a similar pattern as well as negative allometric growth.
Elysia subornata (Mollusca) a potential control agent of the alga Caulerpa taxifolia (Chlorophyta) in the Mediterranean Sea
Authors: Thibaut Thierry , Meinesz Alexandre , Amade Philippe , Charrier Stéphane , De Angelis Kate , Ierardi Santina , Mangialajo Luisa , Melnick Jennifer , Vidal Valérie
Published: September 2006

The biological characteristics of Elysia subornata (Mollusca: Opisthobranchia) were studied in an aquarium to assess its risks and chance of success as a potential biological control agent against the invasive alga Caulerpa taxifolia (Chlorophyta) in the Mediterranean Sea. This species feeds only on Caulerpa and has benthic larval development. Dietary switching is possible on some Mediterranean Caulerpales but feeding on other algae and sea grass is unlikely. The main limiting factor for the success of studied Caribbean strain of E. subornata are the Mediterranean winter temperatures which are lethal for that species. For the five months of the year which are favourable for feeding, growth and reproduction, the tested strain of E. subornata cannot reach a population density capable of controlling C. taxifolia.
Shape and surface variations of syphon openings during complete tidal cycles in Mya arenaria in the intertidal zone
Authors: Thorin S. , Robinet T. , Laffaille P. , Vincent B.
Published: September 2006

Since the degree of syphonal opening can be an index of the pumping activity, the shape and the surface of syphon openings in Mya arenaria were filmed with an underwater camera at two stations in the middle of the intertidal zone. The individuals were perpendicularly oriented to the main current direction or parallel with the inhalant syphon upstream during flood tide, causing refiltration risks during ebb tide. The surface of the inhalant opening (SI) was strongly reduced with increasing current speeds. Its shape (XI) varied with the individual's orientation and had a tendency to become more circular with time. The surface of the exhalant opening (SE) decreased and its shape (XE) flattened with increasing current velocity and with time. However, variations of XI and XE were weak. Current direction had no significant effect on SI, SE, and XE, but did cause a strong decrease of the SE/SI ratio during ebb in individuals exposed to important refiltration risks during ebb tide. Significant negative correlations between stomach content in phaeopigments and SI and SE suggest that a syphonal constriction could contribute to more efficient feeding. For parallel oriented individuals, the decreases of SE, SE/SI, and XE during ebb can then be interpreted as an attempt to deviate or increase the excurrent velocity relative to the incurrent so as to limit refiltration. We suggest that decreases in opening surface and shape may serve, above all, to increase syphon current jet velocity in syphonate bivalves.
PCR from the CPR offers a historical perspective on marine population ecology
Authors: Kirby R.R. , Reid P.C.
Published: September 2006

The Continuous Plankton Recorder (CPR) survey has collected plankton samples from regular tracks across the world's oceans for almost 70 y. Over 299,000 spatially extensive CPR samples are archived and stored in buffered formalin. This CPR archive offers huge potential to study changes in marine communities using molecular data from a period when marine pollution, exploitation and global anthropogenic impact were much less pronounced. However, to harness the amount of data available within the CPR archive fully, it is necessary to improve techniques of larval identification, to genus and species preferably, and to obtain genetic information for historical studies of population ecology. To increase the potential of the CPR database this paper describes the first extraction, amplification by the polymerase chain reaction and utilization of a DNA sequence (mitochondrial 16S rDNA) from a CPR sample, a formalin fixed larval sandeel.
Predicting post-traumatic stress disorder: validation of the Trauma Screening Questionnaire in victims of assault
Authors: WALTERS JAMES T. R. , BISSON JONATHAN I. , SHEPHERD JONATHAN P.
Published: September 2006

Background. No accurate means of determining which individuals will develop post-traumatic stress disorder (PTSD) following a traumatic event has yet been identified. This study aimed to determine the validity of the Trauma Screening Questionnaire (TSQ) in predicting the development of PTSD following assault.

Method. Five hundred and sixty-two individuals who presented to an emergency unit following assault completed the TSQ between 1 and 3 weeks later. The Davidson Trauma Scale (DTS) was completed by the same individuals at 1 month and 6 months following assault to determine the presence of PTSD. The predictive power of the TSQ was determined by statistical tests.

Results. The TSQ was an effective means of predicting future PTSD, with a sensitivity of 0·85, specificity 0·89, negative predictive value (NPV) 0·98 and efficiency 0·90. The positive predictive value (PPV) was lower (0·48), probably as a result of the relatively low prevalence of PTSD at 1 month (11%) and 6 months (8%) following the assault.

Conclusions. This study suggests that the TSQ can be used between 1 and 3 weeks after assault to help identify individuals who will develop PTSD.
Epidemic influenza and vitamin D
Authors: CANNELL J. J. , VIETH R. , UMHAU J. C. , HOLICK M. F. , GRANT W. B. , MADRONICH S. , GARLAND C. F. , GIOVANNUCCI E.
Published: September 2006

In 1981, R. Edgar Hope-Simpson proposed that a ‘seasonal stimulus’ intimately associated with solar radiation explained the remarkable seasonality of epidemic influenza. Solar radiation triggers robust seasonal vitamin D production in the skin; vitamin D deficiency is common in the winter, and activated vitamin D, 1,25(OH)2D, a steroid hormone, has profound effects on human immunity. 1,25(OH)2D acts as an immune system modulator, preventing excessive expression of inflammatory cytokines and increasing the ‘oxidative burst’ potential of macrophages. Perhaps most importantly, it dramatically stimulates the expression of potent anti-microbial peptides, which exist in neutrophils, monocytes, natural killer cells, and in epithelial cells lining the respiratory tract where they play a major role in protecting the lung from infection. Volunteers inoculated with live attenuated influenza virus are more likely to develop fever and serological evidence of an immune response in the winter. Vitamin D deficiency predisposes children to respiratory infections. Ultraviolet radiation (either from artificial sources or from sunlight) reduces the incidence of viral respiratory infections, as does cod liver oil (which contains vitamin D). An interventional study showed that vitamin D reduces the incidence of respiratory infections in children. We conclude that vitamin D, or lack of it, may be Hope-Simpson's ‘seasonal stimulus’.
Burden of paediatric invasive pneumococcal disease in Europe, 2005
Authors: McINTOSH E. D. G. , FRITZELL B. , FLETCHER M. A.
Published: September 2006

Within the European Union (EU), documenting the burden of invasive pneumococcal disease (IPD) in infants and children is important for coordinating effective pneumococcal immunization policies. Our objective was to document the burden of IPD in countries of the EU plus Switzerland and Norway. European affiliates of Wyeth Vaccines made available recent epidemiological data on IPD from local disease surveillance programmes, including unpublished sources. Recent literature and websites were also searched to provide as wide a representation as possible. This included OVID and abstracts from a number of international meetings, dating from the year 2000. The reported rates of paediatric IPD per 100 000 (age) ranged from a low of 1·7 (<2 years) to 4·2 (2–15 years) in Sweden to a high of 93·5 to 174 (<2 years) to 56·2 (<5 years) in Spain. The percentage of circulating serotypes causing IPD that are covered by 7-valent pneumococcal conjugate vaccine (PCV) IPD serotype coverage ranged from 60% to 80% for European children aged <2 years. Under reporting, differences in reporting methods, antibiotic prescribing and disparities in blood-culturing practices may explain the differences in reported disease incidence. Because of the excellent clinical efficacy of the PCV against IPD, national pneumococcal vaccination programmes in Europe have the potential to prevent much morbidity and mortality.
Calculating the probability of detecting radio signals from alien civilizations
Authors: Horvat Marko
Published: September 2006

Although it might not be self-evident, it is in fact entirely possible to calculate the probability of detecting alien radio signals by understanding what types of extraterrestrial radio emissions can be expected and what properties these emissions can have. Using the Drake equation as the obvious starting point, and logically identifying and enumerating constraints of interstellar radio communications, may yield the possibility of detecting a genuine alien radio signal.
Rheologic inferences from the levees of lava flows on Mars
Authors: Glaze Lori S. , Baloga Stephen M.
Published: September 2006

A new methodology is presented for estimating the rate of levee growth for channelized lava flows on the basis of spatial changes in the dimensions of the channels and levees. The rate of levee growth can then be used to describe the decrease in flow rate as a function of distance along the flow and, subsequently, to constrain rheologic behavior along the flow length. One terrestrial (Mauna Loa 1984 1A) and two Martian (one on the plains north of Pavonis Mons, one near the summit of Ascraeus Mons) examples are shown. A linear “levee building rate function” adequately describes levee growth for all three examples, with the overall magnitude of the rate function inversely correlated with the total volume of material in the levees. Theoretical levee widths based on these linear functions are consistent with those measured in the field or from planetary images. Assuming Newtonian rheologies, the viscosity increases for the Mauna Loa and Pavonis Mons lava flows are about an order of magnitude greater than when the levee building process is ignored. Application to the Mauna Loa 1984 1A flow shows that the model provides results more consistent with independent petrologic studies as well as field observations of the levee formation process. Viscosity changes at Ascraeus Mons are similar to those estimated previously (Zimbelman, 1985) because of the constant thickness of the flow.
SPCZ migration and ENSO events during the 20th century as revealed by climate proxies from a Fiji coral
Authors: Juillet‐Leclerc A. , Thiria S. , Naveau P. , Delcroix T. , Le Bec N. , Blamart D. , Corrège T.
Published: September 2006

Instrumental sea surface temperature (SST) and sea surface salinity (SSS) records since 1975 have indicated that migrations of the South Pacific Convergence Zone (SPCZ) are strongly related to El Niño‐Southern Oscillation (ENSO) events. To reconstruct independent SSS and SST time series for the past century and document this SPCZ and ENSO relationship prior to 1975, we apply a neural network analysis to seven climate proxies derived from a coral skeleton collected in Fiji. These reconstructions suggest that five SPCZ migrations linked to ENSO occurred between 1908 and 1970 while as many migrations occurred during the last three decades, highlighting the recent enhanced frequency of ENSO occurrence.
Evaluation of environmental conditions for the formation of severe local storms across the Indian subcontinent
Authors: Yamane Y. , Hayashi T.
Published: September 2006

The spatial and temporal distributions of thermal instability and vertical wind shear in the Indian subcontinent are evaluated as the important factors for occurrence and development of severe local storms and compared with the climatology of severe local storms across the Indian subcontinent. High thermal instability and vertical wind shear occur in Bangladesh and northeastern India during the pre‐monsoon season (from March to May), peaking in April. There is great potential for severe local storms during the pre‐monsoon season in Bangladesh and northeastern India.
Relaxation of central Arctic Ocean hydrography to pre‐1990s climatology
Authors: Morison J. , Steele M. , Kikuchi T. , Falkner K. , Smethie W.
Published: September 2006

Upper ocean hydrography in the central Arctic Ocean has relaxed since 2000 to near‐climatological conditions that pertained before the dramatic changes of the 1990s. The behavior of the anomalies of temperature and salinity in the central Arctic Ocean follow a first‐order linear response to the AO with time constant of 5 years and a delay of 3 years.
On the relationship between the strength of the Brewer‐Dobson circulation and the age of stratospheric air
Authors: Austin John , Li Feng
Published: September 2006

The strength of the Brewer‐Dobson circulation is computed for multi‐decadal simulations of a coupled chemistry‐climate model covering the period 1960 to 2100. The circulation strength, as computed from the tropical mass upwelling, generally increases throughout the simulations. The model also includes an age of air tracer which generally decreases during the simulations. The two different transport concepts of mass upwelling and reciprocal of the age of air are investigated empirically from the model simulations. The results indicate that the variables are linearly related in the model but with a change of gradient some time near 2005. Possible reasons for the change of gradient are discussed.
Spatial relation between the 1908 Messina Straits earthquake slip and recent earthquake distribution
Authors: Amoruso A. , Crescentini L. , Neri G. , Orecchio B. , Scarpa R.
Published: September 2006

We re‐analyze coseismic surface displacement data of the 1908 Messina earthquake, taking into account both correlated and uncorrelated uncertainties, to re‐determine the slip distribution on the fault plane. Using a data set of earthquakes occurred at crustal depth in the Messina Straits between July 1988 and December 2004, we evidence a peculiar recent seismicity distribution inside the fault volume of the 1908 Messina Straits earthquake with respect to other regions in the area. An unusually large number of earthquakes is found in regions smoothly ringing slipped areas. Our results seem consistent with static Coulomb stress variations inside the fault volume and regional strain rate from GPS data, but could also suggest that in the last 15–20 years the 1908 earthquake source has been releasing strain accumulated in portions of it which did not rupture during the 1908 event.
When Katrina hit California
Authors: Gerstoft Peter , Fehler Michael C. , Sabra Karim G.
Published: September 2006

Beamforming of seismic noise recorded on 150 Southern California stations was used to identify body and surface waves generated by Katrina. Surface wave microseisms are commonly associated with oceanic storms; there are no previous comprehensive body wave observations. The temporal evolution of the surface and body waves was different, indicating a different source mechanism for the two wave types. The body‐waves originated in shallow water east of New Orleans and propagated deep inside the Earth. The surface waves have source location that varies with frequency with the lowest frequency surface waves originating west of the hurricane track and the higher frequency ones to the east. The seismic observations are consistent with ocean wave hindcasts and provide clear association of microseism noise with storm activity.
The Fragment Constant Method for Predicting Octanol–Air Partition Coefficients of Persistent Organic Pollutants at Different Temperatures
Authors: Li Xuehua , Chen Jingwen , Zhang Li , Qiao Xianliang , Huang Liping
Published: September 2006

The octanol–air partition coefficient (KOA) is a key physicochemical parameter for describing the partition of organic pollutants between air and environmental organic phases. Experimental determination of KOA is costly and time consuming, and sometimes restricted by lack of sufficiently pure chemicals. There is a need to develop a simple but accurate method to estimate KOA. In the present study, a fragment constant model based on five fragment constants and one structural correction factor, was developed for predicting logKOA at temperatures ranging from 10 to 40°C. The model was validated as successful by statistical analysis and external experimental logKOA data. Compared to other quantitative structure–property relationship methods, the present model has the advantage that it is much easier to implement. As aromatic compounds that contain C, H, O, Cl, and Br atoms, were included in the training set used to develop the model, the current fragment model applies to a wide range of chlorinated and brominated aromatic pollutants, such as chlorobenzenes, polychlorinated naphthalenes, polychlorinated biphenyls, polychlorinated dibenzo-p-dioxins and dibenzofurans, polycyclic aromatic hydrocarbons, and polybrominated diphenyl ethers, all of which are typical persistent organic pollutants. Further study is necessary to expand the utility of the method to all halogenated aliphatic and aromatic compounds.
A Reference Multiparameter Viscosity Equation for Propane with an Optimized Functional Form
Authors: Scalabrin G. , Marchi P. , Span R.
Published: September 2006

A multiparameter viscosity equation for propane, valid in wide temperature and pressure ranges, was developed through an optimization technique for the functional form. The obtained results are very satisfactory, showing an average absolute deviation of 0.28% for the currently available 1024 primary data points. This is a significant improvement with respect to the reference equation available in the literature. As usual, both the development and the evaluation of the viscosity equation requires a highly accurate equation of state in order to convert the independent variables used for the experimental data, in most applications, (T,P), into the independent variables of the viscosity equation, (T,ρ). The heuristic technique used to develop the equation allows to select consistent data sets and thus it is a powerful tool for screening the available experimental data. The present limit for the accuracy achievable in the representation of the viscosity surface of a pure fluid is set by the uncertainty level of the experimental data rather than by the effectiveness of the proposed modeling method.
Shear dynamics of hydration layers
Authors: Leng Yongsheng , Cummings Peter T.
Published: September 2006

Molecular dynamics (MD) simulations have been performed to investigate the shear dynamics of hydration layers of the thickness of D=0.61–2.44nm confined between two mica surfaces. Emphases are placed on the external shear response and internal relaxation properties of aqueous films. For D=0.92–2.44nm liquid phase, the shear responses are fluidic and similar to those observed in surface force balance experiments [U. Raviv and J. Klein, Science 297, 1540 (2002)]. However, for the bilayer ice (D=0.61nm) [Y. S. Leng and P. T. Cummings, J. Chem. Phys. 124, 74711 (2006)] significant shear enhancement and shear thinning over a wide range of shear rates in MD regime are observed. The rotational relaxation time of water molecules in this bilayer ice is found to be as high as 0.017ms (10−5s). Extrapolating the shear rate to the inverse of this longest relaxation time, we obtain a very high shear viscosity for the bilayer ice, which is also observed quite recently for D⩽0.6±0.3nm hydration layers [H. Sakuma et al., Phys. Rev. Lett. 96, 46104 (2006)]. We further investigate the boundary slip of water molecules and hydrated K+ ions and concluded that no-slip boundary condition should hold for aqueous salt solution under extreme confinement between hydrophilic mica surfaces, provided that the confined film is of Newtonian fluid.
Motion of a branched polymer chain in confinement: A Monte Carlo study
Authors: Romiszowski Piotr , Sikorski Andrzej
Published: September 2006

The aim of the study was a theoretical investigation of the polymer molecules located between two parallel and impenetrable surfaces which were also attractive for polymer segments. The chains were constructed of identical segments and were restricted to knots of a simple cubic lattice. Since the chains were at good solvent conditions the only interactions between the segments of the chain were the excluded volume. The properties of the model chains were determined by means of Monte Carlo simulations with a sampling algorithm based on the chain’s local changes of conformation. The differences and similarities in the structure for different adsorption regimes and the size of the slit were shown and discussed. It was observed that at certain conditions the polymer chain was adsorbed at one of the confining surfaces, and then after a certain period of time it detached from this surface and approached the opposite wall; this switch was repeated many times. The influence of the strength of the adsorption, the size of the slit, and the chain’s length on the frequency of these jumps were determined. The mechanism of the chain’s motion during the switch was also shown.
Response to “Comment on ‘Quasirelativistic theory equivalent to fully relativistic theory’ ” [J. Chem. Phys. 123, 241102 (2005)]
Authors: Kutzelnigg Werner , Liu Wenjian
Published: September 2006

A recent Communication by the present authors and an older paper by Dyall both deal with the transformation of the matrix representation of the Dirac operator in a kinetically balanced basis to a quasirelativistic Hamiltonian matrix. The main body of our Communication concerns the iterative construction of this transformation, and the numerical comparison of various iterative schemes, which has not been a topic of Dyall’s paper. Our formalism is strictly energy independent (state universal), while Dyall has studied both energy-dependent matrices (valid for a single state) and energy-independent ones. The possibility of an iterative construction of an energy-independent quasirelativistic Hamiltonian matrix has shortly been addressed by Dyall, but has not been considered seriously as basis for a working algorithm. The iteration scheme explicitly worked out by us and that implicit in Dyall’s paper are significantly different, although they have a common starting point.
Clebsch-type coordinates for nonlinear gyrokinetics in generic toroidal configurations
Authors: Xanthopoulos P. , Jenko F.
Published: September 2006

The nonlinear gyrokinetic equations are frequently used as a basis for simulations of small-scale turbulence in magnetized toroidal plasmas. In this context, field-aligned coordinates are usually employed in order to minimize the number of necessary grid points. The present work proposes a system of Clebsch-type coordinates which does not depend on the existence of flux surfaces. The construction and use of these coordinates is explained, and the corresponding formulation of the nonlinear gyrokinetic equations is accomplished. This setup paves the way toward the investigation of nonaxisymmetric toroidal geometries, also in the region of magnetic islands as well as inside the ergodic layer where flux surfaces cease to exist. For testing purposes, in the axisymmetric, large aspect ratio case, the well-known ŝ-α expressions are recovered for closed flux surfaces. Moreover, geometric data for a specific stellarator configuration are computed and discussed.
ZnSe nanowires grown on the crystal surface by femtosecond laser ablation in air
Authors: Jia T. Q. , Chen H. X. , Huang M. , Wu X. J. , Zhao F. L. , Baba M. , Suzuki M. , Kuroda H. , Qiu J. R. , Li R. X. , Xu Z. Z.
Published: September 2006

Uniform ZnSe nanowires are observed on the ablation crater on ZnSe crystal surface irradiated by femtosecond lasers in air, while other parts of the sample surface are not polluted. The nanowire growth rate is about 5μm∕s, it is higher than that fabricated by chemical vapor deposition method by a factor of 104. The nanowire length and diameter can be controlled by varying laser pulse energy and pulse number. The formation mechanism is studied and found to be self-catalyzed vapor-liquid-solid process.
Photoluminescence and phonon satellites of single InGaN∕GaN quantum wells with varying GaN cap thickness
Authors: Tan L. T. , Martin R. W. , O’Donnell K. P. , Watson I. M.
Published: September 2006

Variations in thickness of the GaN caps above single InGaN quantum wells have been studied using photoluminescence spectroscopy. Data are presented from two series of samples designed to promote energy transfer to luminescent species on the surface. Improvements in the optical properties as the GaN cap thickness increases from 2.5to15nm are accompanied by clear changes in the intensity of the LO-phonon satellites. Analysis of the strength of successive phonon satellites and the associated Huang-Rhys factors indicates that the amount of localization of the excitons is increased for the thinner cap samples. Surface depletion fields are also considered.
Magnetically controlled high damping in ferromagnetic Ni52Mn24Ga24 single crystal
Authors: Wang W. H. , Liu G. D. , Wu G. H.
Published: September 2006

An unusually high damping peak of 20% has been observed in Ni52Mn24Ga24 single crystals accompanying with martensitic transformation. The high damping capacity can be retained in the low-temperature martensite phase when a bias field of 0.4T was applied along the measurement direction. The magnetically controlled high damping and adjustable martensitic-austenitic transformation temperature indicate a great potential of using Ni–Mn–Ga alloys as high damping or energy absorbing materials in a wide temperature range.
Determination of junction temperature in AlGaInP∕GaAs light emitting diodes by self-excited photoluminescence signal
Authors: Chen N. C. , Wang Y. N. , Tseng C. Y. , Yang Y. K.
Published: September 2006

The photoluminescence (PL) of the GaAs substrate excited by the electroluminescence of the active layer is adopted to determine the junction temperature in AlGaInP∕GaAs light emitting diodes. Based on the Varshni equation for GaAs, the temperature measured by this approach is consistent with that obtained by the emission peak energy shift approach. As the PL signal is generated within the substrate, no calibration dependent on the device structure is necessary to determine the junction temperature of the device.
Optofluidic third order distributed feedback dye laser
Authors: Gersborg-Hansen Morten , Kristensen Anders
Published: September 2006

This letter describes the design and operation of a polymer-based third order distributed feedback (DFB) microfluidic dye laser. The device relies on light confinement in a nanostructured polymer film where an array of nanofluidic channels is filled by capillary action with a liquid dye solution which has a refractive index lower than that of the polymer. In combination with a third order DFB grating, formed by the array of nanofluidic channels, this yields a low threshold for lasing. The laser is straightforward to integrate on lab-on-a-chip microsystems where coherent, tunable light in the visible range is desired.
Preparation and photoabsorption characterization of BiFeO3 nanowires
Authors: Gao F. , Yuan Y. , Wang K. F. , Chen X. Y. , Chen F. , Liu J.-M. , Ren Z. F.
Published: September 2006

Perovskite-type polycrystalline BiFeO3 (BFO) nanowires (∼50nm in diameter and ∼5μm in length) were synthesized using the anodized alumina template technique. An energy band gap of ∼2.5eV was determined from the UV-visible diffuse reflectance spectrum, and its photocatalytic ability to produce O2 was revealed under UV irradiation. Weak ferromagnetism at room temperature and superparamagnetism at low temperature were observed for the BFO nanowires, different from the antiferromagnetic order in bulk BFO, reflecting the significant size effects on the magnetic ordering of BFO.
Long-term-retention characteristics of small inverted dots formed on congruent single-crystal LiTaO3
Authors: Odagawa Nozomi , Cho Yasuo
Published: September 2006

To investigate the long-term retention characteristics of a ferroelectric-data-storage system, 80-nm-thick congruent LiTaO3 plates with inverted-domain dot arrays composed of 100-nm-φdots were baked at 220, 250, 280, and 300°C. After heat treatment over a range of different time intervals, the dots shrank. From the change in the dot area density, the activation energy and frequency factor, parameters of the Arrhenius equation, were determined to be Ea=0.76eV and α=2.21×105, respectively. Using these parameters, lifetime length at 80°C was estimated to be more than 16yr and is sufficiently long compared with that of general memory devices.
Continuous-wave laser oscillation in subsonic flow on the 1315nm atomic iodine transition pumped by electric discharge produced O2(aΔ1)
Authors: Verdeyen Joseph T. , Carroll David L. , King Darren M. , Laystrom Julia K. , Benavides Gabriel F. , Zimmerman Joseph W. , Woodard Brian S. , Solomon Wayne C.
Published: September 2006

Herein the authors report on the demonstration of a continuous-wave laser in subsonic flow on the 1315nm transition of atomic iodine using the energy transferred to I(P1∕22) from O2(aΔ1) produced by a radio-frequency-excited electric discharge. The electric discharge was sustained in an O2–He–NO gas mixture. Downstream of the discharge, cold gas injection was employed to raise the gas density and lower the temperature of the continuous gas flow to shift the equilibrium of atomic iodine in favor of the I(P1∕22) state. The laser output power was 540mW in a stable cavity with two 99.993% reflective mirrors.
Model to determine the self-resonant frequency of micromachined spiral inductors
Authors: Chen C. C. , Lin Cheng-De , Cheng Y. T.
Published: September 2006

This letter presents an approach to characterize electron behaviors within polygonal micromachined spiral inductors in which self-resonance occurs. Combining with the concepts of anomalous dispersion, standing wave, and field scattering, the self-resonant frequency of the microinductors can be calculated by means of an associated analytical model. According to this model the self-resonant frequency (SRF) can be derived as the “free electron” frequency of the inductor material. Simulation and measurement results validate that the model can provide a satisfactory prediction to the SRF of polygonal micromachined spiral inductors.
Low-temperature fabrication and characterization of Ge-on-insulator structures
Authors: Yu C.-Y. , Lee C.-Y. , Lin C.-H. , Liu C. W.
Published: September 2006

Ge-on-insulator structures have been fabricated by wafer bonding and layer transfer techniques. Ultralow bonding temperatures of 150–300°C are employed in order to suppress hydrogen outdiffusion and to produce a low defect density, in an attempt to produce high photocurrent and photoresponse. Thus reducing the hydrogen outdiffusion results in decreased surface roughness. A low defect density is suggested by a low inversion-current leakage of the tunnel diodes. The photoresponse of the Ge-on-insulator detector is also found to increase with decreasing bonding temperature, indicating that defects caused by hydrogen implantation are passivated more effectively.
Silica nanomachining using laser plasma soft x rays
Authors: Makimura Tetsuya , Uchida Satoshi , Murakami Kouichi , Niino Hiroyuki
Published: September 2006

In order to demonstrate silica nanomachining, the authors fabricated line-and-space contact masks with spaces of 53 and 70nm on silica glass plates, followed by irradiation with laser plasma softx rays (LPSXs) with wavelengths around 10nm. Trenches with the narrowest width of 54nm and an aspect ratio of ∼1 were fabricated by the LPSX irradiation through the contact masks. It was also clarified that silica glass can be machined by irradiation with LPSXs in the wavelength range of 6–30nm in Ar gas which was used as an x-ray bandpass filter.