bluuebunny/crossref_metadata_2025_split huggingface dataset:
Generalized periodicity and primitivity for words
Authors: Ito Masami , Lischke Gerhard 
Published: January 2007

AbstractStarting from six kinds of periodicity of words we define six sets of words which are primitive in different senses and we investigate their relationships. We show that only three of the sets are external Marcus contextual languages with choice but none of them is an external contextual language without choice or an internal contextual language. For the time complexity of deciding any of our sets by one‐tape Turing machines, n 2 is a lower bound and this is optimal in two cases. The notions of roots and degrees of words and languages, which are strongly connected to periodicity and primitivity, are also considered, and we show that there can be an arbitrarily large gap between the complexity of a language and that of its roots. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Mass transport properties of auxetic (negative Poisson's ratio) foams
Authors: Alderson A. , Rasburn J. , Evans K. E. 
Published: January 2007

AbstractAn auxetic foam structure is described which has the property of widening when stretched (negative Poisson's ratio behaviour), in contrast to the situation with most materials which narrow when stretched. The fabrication of this material involves a combination of heat and compressive treatments of a conventional commercial air‐filtration foam. The resulting microstructure is examined by scanning electron microscopy (SEM). The pertinent mechanical properties are described in terms of the changes in specimen dimensions and associated strains. From these quantities, Poisson's ratios are determined for the large strain regime involved. The property of being able to open pores by stretching the material is a useful feature in various types of filtration application. In particular, where the long‐term efficiency of the process is hindered by ingress of particles into the system which block the active pore structure, the marriage of permeability and mechanical deformation via a negative Poisson's ratio offers an alternative to other methods of clearance. This notion is illustrated by the use of some very simple tests in which the foam is challenged by glass beads of uniform diameter. Simple air pressure‐drop tests are also performed on auxetic and conventional foams to demonstrate that the change in permeability due to mechanical deformation enables a means of varying the pressure‐drop acting across an auxetic foam to a far greater degree than is possible for the conventional foams. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Atomistic characterization of structural and elastic properties of auxetic crystalline SiO2
Authors: Kimizuka Hajime , Ogata Shigenobu , Shibutani Yoji 
Published: January 2007

AbstractThe structural and elastic changes with volume expansion in α ‐quartz and α ‐cristobalite, the typical polymorphs of silicon dioxide (SiO2), have been studied through first‐principles calculations using the projector‐augmented‐wave (PAW) method, with particular emphasis on their negative Poisson's ratio behavior under negative pressure. The dominant mechanism of expansion is the increase of the Si–O–Si angles within their crystalline structures, whereas the SiO4 tetrahedron undergoes only a slight distortion. We provide theoretical ab initio results for a complete set of independent elastic constants of quartz and cristobalite with volume expansion. The present simulations confirm that the negative Poisson's ratio behavior is enhanced in the expansive phases of both polymorphs under negative pressures, with retaining strong elastic anisotropy. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On a nonclassical thermoviscomechanical stress in the vortex field in the type‐II superconductor
Authors: Maruszewski B. T. 
Published: January 2007

AbstractMagnetic flux can penetrate a type‐II superconductor in the form of Abrikosov vortices (also called flux lines, flux tubes, or fluxons), each carrying a quantum of magnetic flux. These tiny vortices of supercurrent tend to arrange themselves in a triangular and/or quadratic flux‐line lattice, which is more or less perturbed by material inhomogeneities that pin the flux lines. Pinning is caused by imperfections of the crystal lattice, such as dislocations, point defects, grain boundaries, etc. Hence, a honeycomb‐like pattern of the vortex array presents some mechanical properties. If the Lorentz force of interactions between the vortices is much bigger than the pinning force, the vortex lattice behaves elastically. So we assume that the pinning force is negligible in the sequel and we deal with soft vortices. The vortex motion in the vortex lattice and/or creep of the vortices in the vortex fluid is accompanied by energy dissipation. Hence, except for the elastic properties, the vortex field is also of a viscous character. The main aim of the paper is a formulation of a thermoviscoelastic stress‐strain constitutive law consisted of coexistence of the ordered and disordered states of the vortex field. Its form describes an auxetic‐like thermomechanical (anomalous) property of the vortex field. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The calibration of the intramolecular nitrogen isotope distribution in nitrous oxide measured by isotope ratio mass spectrometry
Authors: Westley Marian B. , Popp Brian N. , Rust Terri M. 
Published: January 2007

AbstractTwo alternative approaches for the calibration of the intramolecular nitrogen isotope distribution in nitrous oxide using isotope ratio mass spectrometry have yielded a difference in the 15N site preference (defined as the difference between the δ15N of the central and end position nitrogen in NNO) of tropospheric N2O of almost 30‰. One approach is based on adding small amounts of labeled 15N2O to the N2O reference gas and tracking the subsequent changes in m/z 30, 31, 44, 45 and 46, and this yields a 15N site preference of 46.3 ± 1.4‰ for tropospheric N2O. The other involves the synthesis of N2O by thermal decomposition of isotopically characterized ammonium nitrate and yields a 15N site preference of 18.7 ± 2.2‰ for tropospheric N2O. Both approaches neglect to fully account for isotope effects associated with the formation of NO+ fragment ions from the different isotopic species of N2O in the ion source of a mass spectrometer. These effects vary with conditions in the ion source and make it impossible to reproduce a calibration based on the addition of isotopically enriched N2O on mass spectrometers with different ion source configurations. These effects have a much smaller impact on the comparison of a laboratory reference gas with N2O synthesized from isotopically characterized ammonium nitrate. This second approach was successfully replicated and leads us to advocate the acceptance of the site preference value 18.7 ± 2.2‰ for tropospheric N2O as the provisional community standard until further independent calibrations are developed and validated. We present a technique for evaluating the isotope effects associated with fragment ion formation and revised equations for converting ion signal ratios into isotopomer ratios. Copyright © 2007 John Wiley & Sons, Ltd.
A combined nuclear magnetic resonance and computational study of monohydroxyflavones applied to product ion mass spectra
Authors: Burns Darcy C. , Ellis David A. , Li Hongxia , Lewars Errol G. , March Raymond E. 
Published: January 2007

AbstractA method is presented for the estimation of 13C‐chemical shifts for carbon atoms in protonated and deprotonated molecules; in principle, this method can be applied to ions in general. Experimental 13C‐chemical shifts were found to vary linearly with computed atomic charges using the PM3 method. Pseudo‐13C‐chemical shifts for atoms in protonated and deprotonated molecules can be estimated from computed atomic charges for such atoms using the above linear relationship. The pseudo‐13C‐chemical shifts obtained were applied to the rationalization of product ion mass spectra of protonated and deprotonated molecules of flavone and 3‐, 5‐, 6‐, 7‐, 2′‐, 3′‐, and 4′‐hydroxyflavones, where product ion formation is due to either cross‐ring cleavage of the C‐ring (retro‐Diels‐Alder reaction) or to cleavage of a C‐ring bond followed by loss of either a small neutral molecule or a radical. The total product ion abundance ratio of C‐ring cross cleavage to C‐ring bond cleavage, γ, varied by a factor of 660 for deprotonated monohydroxyflavones, i.e., from 0.014:1 to 9.27:1. The magnitude of γ, which is dependent on the relative bond orders within the C‐ring of the protonated and deprotonated molecules of monohydroxyflavones, can be rationalized on the basis of the magnitudes of the 13C‐ and 1H‐chemical shifts as determined by nuclear magnetic resonance spectroscopy. Copyright © 2007 John Wiley & Sons, Ltd.
Prevalence‐dependent diagnostic accuracy measures
Authors: Li Jialiang , Fine Jason P. , Safdar Nasia 
Published: January 2007

AbstractWe study prevalence‐dependent diagnostic accuracy measures, specifically, positive and negative predictive values. These measures permit an assessment of the clinical utility of diagnostic tests across populations with different disease prevalences. In many cases, prevalence may not be known with certainty and the evaluation of the diagnostic tests must account for this uncertainty. A sensitivity analysis may be desired across a prevalence continuum defining low to high‐risk populations. For this scenario, simultaneous inference about the predictive values across a range of prevalences is proposed. For situations where a non‐point prior distribution on prevalence is specified, we suggest inferences based on averaging the accuracy measures with respect to the prior, leading to simple numerical summaries. The methods are illustrated in a meta‐analysis of diagnostic tests for intravascular device‐related bloodstream infection, where the prevalence may vary widely both within and across populations. Copyright © 2007 John Wiley & Sons, Ltd.
Multivariate scan statistics for disease surveillance
Authors: Kulldorff Martin , Mostashari Farzad , Duczmal Luiz , Katherine Yih W. , Kleinman Ken , Platt Richard 
Published: January 2007

AbstractIn disease surveillance, there are often many different data sets or data groupings for which we wish to do surveillance. If each data set is analysed separately rather than combined, the statistical power to detect an outbreak that is present in all data sets may suffer due to low numbers in each. On the other hand, if the data sets are added by taking the sum of the counts, then a signal that is primarily present in one data set may be hidden due to random noise in the other data sets.In this paper, we present an extension of the spatial and space–time scan statistic that simultaneously incorporates multiple data sets into a single likelihood function, so that a signal is generated whether it occurs in only one or in multiple data sets. This is done by defining the combined log likelihood as the sum of the individual log likelihoods for those data sets for which the observed case count is more than the expected. We also present another extension, where the concept of combining likelihoods from different data sets is used to adjust for covariates.Using data from the National Bioterrorism Syndromic Surveillance Demonstration Project, we illustrate the new method using physician telephone calls, regular physician visits and urgent care visits by Harvard Pilgrim Health Care members cared for by Harvard Vanguard Medical Associates, a large multi‐specialty group practice in Massachusetts. For upper and lower gastrointestinal (GI) illness, there were on average 20 telephone calls, nine urgent care visits and 22 regular physician visits per day. The strongest signal was generated by a single data set and due to a familial outbreak of pinworm disease. The second and third strongest signals were generated by the combined strength of two of the three data sets. Copyright © 2007 John Wiley & Sons, Ltd.
Epidemiological survey of vitamin deficiencies in older Thai adults: implications for national policy planning
Authors: Assantachai Prasert , Lekhakula Somsong 
Published: January 2007

AbstractObjectiveTo examine the prevalence and risk factors of vitamin deficiencies among older Thai adults.MethodsThe cross-sectional study was conducted in four rural communities, one from each of the four main regions of Thailand. In total, 2336 subjects aged 60 years and over were recruited. Anthropometric variables, demographic data, blood glucose and lipid profile, albumin, globulin and blood levels of vitamin A, β-carotene, folic acid, vitamin B12, vitamin C, vitamin E and vitamin B1 were all measured.ResultsThe prevalence of vitamin deficiencies was 0.6% for vitamin B12, 6.1% for vitamin A, 9.9% for vitamin C, 30.1% for vitamin B1, 38.8% for erythrocyte folate, 55.5% for vitamin E and 83.0% for β-carotene. Male gender was a common risk factor for at least three vitamin deficiencies, i.e. β-carotene, folate and vitamin E. Being a manual worker was a common risk factor of β-carotene and vitamin B1 deficiency. Poor income was found as a risk factor only in erythrocyte folate deficiency while increasing age was a significant factor only in vitamin C deficiency.ConclusionThe prevalence of vitamin deficiencies among older Thai people was quite different from that found in Western countries, reflecting different socio-economic backgrounds. Vitamin deficiency was not only from poor food intake but also from the dietary habit of monotonous food consumption in older people. Some common associated factors of atherosclerosis were also significantly related to folate and vitamin E deficiencies.
Fast food for family meals: relationships with parent and adolescent food intake, home food availability and weight status
Authors: Boutelle Kerri N , Fulkerson Jayne A , Neumark-Sztainer Dianne , Story Mary , French Simone A 
Published: January 2007

AbstractObjectiveThe purpose of the present study was to examine the prevalence of fast-food purchases for family meals and the associations with sociodemographic variables, dietary intake, home food environment, and weight status in adolescents and their parents.DesignThis study is a cross-sectional evaluation of parent interviews and adolescent surveys from Project EAT (Eating Among Teens).SubjectsSubjects included 902 middle-school and high-school adolescents (53% female, 47% male) and their parents (89% female, 11% male). The adolescent population was ethnically diverse: 29% white, 24% black, 21% Asian American, 14% Hispanic and 12% other.ResultsResults showed that parents who reported purchasing fast food for family meals at least 3 times per week were significantly more likely than parents who reported purchasing fewer fast-food family meals to report the availability of soda pop and chips in the home. Adolescents in homes with fewer than 3 fast-food family meals per week were significantly more likely than adolescents in homes with more fast-food family meals to report having vegetables and milk served with meals at home. Fast-food purchases for family meals were positively associated with the intake of fast foods and salty snack foods for both parents and adolescents; and weight status among parents. Fast-food purchases for family meals were negatively associated with parental vegetable intake.ConclusionsFast-food purchases may be helpful for busy families, but families need to be educated on the effects of fast food for family meals and how to choose healthier, convenient family meals.
Measuring dietary diversity in rural Burkina Faso: comparison of a 1-day and a 3-day dietary recall
Authors: Savy M , Martin-Prével Y , Traissac P , Delpeuch F 
Published: January 2007

AbstractObjectivesTo compare dietary diversity scores measured over a 1-day and a 3-day period, and to assess their relationships with socio-economic characteristics and the nutritional status of rural African women.DesignA qualitative dietary recall allowed calculation of a dietary diversity score (DDS; number of food groups consumed out of a total of nine). Body mass index (BMI) and body fat percentage (BFP) were used to assess the nutritional status of women.Setting and subjectsA representative sample of 550 mothers in north-east Burkina Faso.ResultsThe DDS increased from 3.5 to 4.4 when calculated from a 1-day or a 3-day recall (P < 0.0001), although for the latter the DDS was affected by memory bias. The DDS calculated from a 1-day recall was higher when a market day occurred during the recall period. Both scores were linked to the sociodemographic and economic characteristics of the women. Women in the lowest DDS tertile calculated from the 1-day recall had a mean BMI of 20.5 kg m− 2and 17.7% of them were underweight, versus 21.6 kg m− 2and 3.5% for those in the highest tertile (P = 0.0003 and 0.0007, respectively). The DDS calculated from the 1-day recall was also linked to mean BFP; all these links remained significant after adjustment for confounders. For the 3-day period, no such relationships were found to be significant after adjustment.ConclusionThe DDS calculated from a 1-day dietary recall was sufficient to predict the women's nutritional status. In such a context attention should be paid to market days.
The impact of food supplementation on infant weight gain in rural Bangladesh; an assessment of the Bangladesh Integrated Nutritional Program (BINP)
Authors: Begum Housne Ara , Mascie-Taylor CGN , Nahar Shamsun 
Published: January 2007

AbstractObjectivesTo examine the efficiency of the Bangladesh Integrated Nutritional Program (BINP) in identifying which infants should be supplemented, whether full supplementation was given for the stipulated period of time, and whether the correct exit criteria from the supplementation programme were used. To test whether targeted food supplementation of infants between 6–12 months of age resulted in enhanced weight gain.SettingMallickbari Union, Bhaluka, a rural area located about 100 km north of Dhaka, Bangladesh.ParticipantsFive hundred and twenty-six infants followed for 6 to 12 months.ResultsOf the 526 infants studied, 368 should have received supplementation based on BINP criteria but only 111 infants (30%) did so, while a further 13% were incorrectly given supplementation. So in total over half (52.8%) of the sample was incorrectly identified for supplementation. In addition, less than a quarter of the infants received the full 90 days of supplementation and close to half of the infants exited the programme without the requisite weight gain. Infants were assigned to one of four groups: correctly supplemented, correctly non-supplemented, incorrectly supplemented or incorrectly non-supplemented. This classification provided natural controls; the correctly supplemented infants versus the incorrectly non-supplemented infants, and the correctly non-supplemented infants versus the incorrectly supplemented infants. There were no significant differences in weight gain between the correctly supplemented group and the incorrectly non-supplemented group or between the correctly non-supplemented and the incorrectly supplemented groups, nor was there any evidence of growth faltering in the incorrectly non-supplemented group.ConclusionsThis study found serious programmatic deficiencies – inability to identify growth faltering in infants, failure to supplement for the full time period and incorrect exit procedures. There was no evidence that food supplementation had any impact on improving infant weight gain.
Excluding infants under 6 months of age from surveys: impact on prevalence of pre-school undernutrition
Authors: Lopriore C , Dop M-C , Solal-Céligny A , Lagnado G 
Published: January 2007

AbstractObjectiveInfants aged 0–5 months are not systematically included in assessments of child nutritional status and are generally excluded from surveys conducted in emergencies. We estimated the impact of excluding 0–5-month-old infants on the prevalence of stunting, wasting and underweight among children under 5 years (U5) and under 3 years (U3) of age.DesignComparison of the prevalence of stunting, wasting and underweight in U5 and U3 with or without inclusion of the age group 0–5 months.SettingDemographic and Health Surveys and Multiple Indicator Cluster Surveys from 76 developing countries and countries in transition.SubjectsChildren under 3 or under 5 years of age included in the surveys.ResultsExcluding 0–5-month-old infants resulted in an overestimation of the prevalence of stunting, wasting and underweight in U5 of 3.0, 0.3 and 2.6 percentage points, respectively, and of 4.8, 1.0 and 5.2 percentage points, respectively, in U3. The overestimation for wasting was negligible. The regions showing the highest overestimations for stunting and underweight were Asia and sub-Saharan Africa. Overall, countries with high prevalences of stunting and underweight showed especially large overestimations. The prevalence of underweight in infants aged 0–5 months was correlated with the prevalence of low maternal body mass index.ConclusionAll surveys, even in situations of nutrition emergency, should include 0–5-month-old infants. Strictly comparable age ranges are essential in nutrition surveys for monitoring trends and evaluating programme impact. Greater awareness of prenatal and early child undernutrition is needed among policy-makers.
Paternal smoking is associated with increased risk of child malnutrition among poor urban families in Indonesia
Authors: Semba Richard D , Kalm Leah M , Pee Saskia de , Ricks Michelle O , Sari Mayang , Bloem Martin W 
Published: January 2007

AbstractObjectivePaternal smoking is highly prevalent in Asia, and tobacco may account for a large proportion of household expenditures among poor families. We sought to characterise the relationship between paternal smoking, child malnutrition and food expenditures.DesignData on smoking, household expenditures and child malnutrition were examined in a stratified multistage cluster sample of households in the Indonesia nutrition surveillance system. Main outcome measures were child wasting (weight-for-height Z-score < − 2), underweight (weight-for-age Z-score < − 2) and stunting (height-for-age Z-score < − 2), and severe wasting, underweight and stunting (defined by respective Z-scores < − 3).SettingIn total, 175 583 households from urban slum areas in Indonesia.SubjectsChildren 0–59 months of age.ResultsThe prevalence of paternal smoking was 73.8%. After adjusting for child gender and age, maternal age and education, and weekly per capita household expenditures, paternal smoking was associated with child stunting (odds ratio (OR) = 1.11, 95% confidence interval (CI) 1.08–1.14, P < 0.0001), severe wasting (OR = 1.17, 95% CI 1.03–1.33, P = 0.018) and severe stunting (OR = 1.09, 95% CI 1.04–1.15, P < 0.001). In households where the father was a smoker, tobacco accounted for 22% of weekly per capita household expenditures, with less money spent on food compared with households in which the father was a non-smoker.ConclusionsAmong poor families in urban slum areas of Indonesia, paternal smoking diverts household money from food to tobacco and exacerbates child malnutrition.