bluuebunny/crossref_metadata_2025 huggingface dataset:
Closing the global radiocarbon budget 1945–2005
Authors: Naegler Tobias , Levin Ingeborg
Published: June 2006

The global radiocarbon cycle of the last 60 years was simulated with the Global Radiocarbon Exploration Model (GRACE). The total radiocarbon production by atmospheric nuclear bomb tests was determined using available stratospheric and tropospheric radiocarbon (14C) observations as constraints. To estimate the range of uncertainty in the explosive force of atmospheric nuclear bomb tests and their respective 14C yield factor, we applied different published bomb test compilations. Furthermore, to account for a possible small bias in the available stratospheric excess radiocarbon observations, we tested the different bomb test compilations with both uncorrected and corrected stratospheric 14C observations. For each of these scenarios of the total bomb 14C burden, the model simulated the distribution of excess radiocarbon among the stratosphere, troposphere, biosphere, and ocean carbon reservoirs. With a global bomb 14C production of 598–632 · 1026 atoms (99–105 kmol) 14C between 1945 and 1980, simulated excess radiocarbon inventories are in good agreement with all available stratospheric and tropospheric radiocarbon observations as well as with the latest estimates of the ocean excess radiocarbon inventories during the GEOSECS and WOCE surveys from Peacock (2004) and Key et al. (2004). For the very first time, our model is thus capable of closing the excess radiocarbon budget on the basis of our current knowledge of exchange rates and reservoir sizes in the global carbon system.
Inter‐ and intra‐continental transport of radioactive cesium released by boreal forest fires
Authors: Wotawa G. , De Geer L.‐E. , Becker A. , D'Amours R. , Jean M. , Servranckx R. , Ungar K.
Published: June 2006

A high‐precision radionuclide monitoring site was established in Yellowknife/Canada in 2003. Far away from nuclear activities, regular signals of 137Cs were found there during the summers of 2003 and 2004. We show that these signals can be explained by transport from fires burning in the boreal forests of North America and Asia. This finding has important implications. It demonstrates that 137Cs deposited world‐wide from past nuclear testing is re‐injected into the atmosphere by combustion to a significant extent and on a large scale, and is subsequently transported across great distances. Besides this, the analysis shows how efficiently a new receptor‐oriented atmospheric transport modeling technique can be used to check whether a 3D emission inventory is consistent with discrete point measurements.
Small slow‐strain steps and their forerunners observed in gold mine in South Africa
Authors: Naoi Makoto , Ogasawara Hiroshi , Takeuchi Junichi , Yamamoto Akihito , Shimoda Naoyuki , Morishita Ken , Ishii Hiroshi , Nakao Shigeru , van Aswegen Gerrie , Mendecki Aleksander J. , Lenegan Patrick , Ebrahim‐Trollope Rookshana , Iio Yoshihisa
Published: June 2006

The Research Group for Semi‐controlled Earthquake‐generation Experiments in South African deep gold mines (SeeSA) has continuously monitored strain changes with a resolution of 24 bit 25 Hz at the Bambanani mine near Welkom. An Ishii borehole strainmeter was installed at a depth of 2.4 km near the potential M ∼ 3 earthquake source area. Instantaneous strain steps of ∼10−4 strains associated with two M2 events were observed within a length of seismic fault. These steps were followed by significant post‐seismic creep‐like drift, but not preceded by forerunners. Analysis of the continuous 25 Hz data reveals many smaller steps with much longer durations (100 ms ∼ 100 s) than seen in normal earthquakes (−1 < M < 2) with source durations of 1 ms∼50 ms. Some of the especially slow steps were preceded by accelerations in strain, the maximum being as large as one‐third of the step.
Concept Map-Based Knowledge Modeling: Perspectives from Information and Knowledge Visualization
Authors: Coffey John W , Hoffman Robert , Cañas Alberto
Published: June 2006

This article explores the idea of knowledge modeling as defined at the Florida Institute for Human and Machine Cognition. The notion of knowledge modeling is described to illustrate a particular method by which concept maps might be employed to create a useful structure and organization of other information and knowledge resources. Knowledge model structuring and navigational schemes afforded by the approach are described and illustrated. An example of a knowledge model pertaining to weather forecasting on the Gulf coast of the United States is presented to illustrate these ideas. Examples of how information visualization techniques have been and might be applied to the knowledge modeling scheme are discussed. Ideas pertaining to how knowledge models might serve as learning resources are briefly presented throughout. The article concludes with additional discourse regarding specific ways in which the knowledge modeling approach might be employed to create, present, and organize effective electronic learning resources.
Interaction energy and surface reconstruction between sheets of layered silicates
Authors: Heinz Hendrik , Vaia R. A. , Farmer B. L.
Published: June 2006

Interactions between two layered silicate sheets, as found in various nanoscale materials, are investigated as a function of sheet separation using molecular dynamics simulation. The model systems are periodic in the xy plane, open in the z direction, and subjected to stepwise separation of the two silicate sheets starting at equilibrium. Computed cleavage energies are 383mJ∕m2 for K-mica, 133mJ∕m2 for K-montmorillonite (cation exchange capacity=91), 45mJ∕m2 for octadecylammonium (C18)-mica, and 40mJ∕m2 for C18-montmorillonite. These values are in quantitative agreement with experimental data and aid in the molecular-level interpretation. When alkali ions are present at the interface between the silicate sheets, partitioning of the cations between the surfaces is observed at 0.25nm separation (mica) and 0.30nm separation (montmorillonite). Originally strong electrostatic attraction between the two silicate sheets is then reduced to 5% (mica) and 15% (montmorillonite). Weaker van der Waals interactions decay within 1.0nm separation. The total interaction energy between sheets of alkali clay is less than 1mJ∕m2 after 1.5nm separation. When C18 surfactants are present on the surfaces, the organic layer (>0.8nm) acts as a spacer between the silicate sheets so that positively charged ammonium head groups remain essentially in the same position on the surfaces of the two sheets at any separation. As a result, electrostatic interactions are efficiently shielded and dispersive interactions account for the interfacial energy. The flexibility of the hydrocarbon chains leads to stretching, disorder, and occasional rearrangements of ammonium head groups to neighbor cavities on the silicate surface at medium separation (1.0–2.0nm). The total interaction energy amounts to less than 1mJ∕m2 after 3nm separation.
New formulation and implementation for volume polarization in dielectric continuum theory
Authors: Chipman Daniel M.
Published: June 2006

In the use of dielectric continuum theory to model bulk solvation effects on the electronic structure and properties of a solute, volume polarization contributions due to quantum mechanical penetration of the solute charge density outside the cavity nominally enclosing it are known to be significant. This work provides a new formulation and implementation of methods for solution of the requisite Poisson equation. In previous formulations the determination of the surface polarization contribution required evaluation of the difficult to calculate electric field generated by the volume polarization. It is shown that this problematic quantity can be eliminated in favor of other more easily evaluated quantities. That formal advance also opens the way for a more efficient apparatus to be implemented for calculation of the direct contribution of volume polarization to the solvation energy. The new formulation and its practical implementation are described, and illustrative numerical results are given for several neutral and ionic solutes to study the convergence and precision in practice.
Scanning tunneling spectroscopy of methyl- and ethyl-terminated Si(111) surfaces
Authors: Yu Hongbin , Webb Lauren J. , Heath James R. , Lewis Nathan S.
Published: June 2006

Methyl- and ethyl-terminated Si(111) surfaces prepared by a two-step chlorination/alkylation method were characterized by low temperature scanning tunneling spectroscopy (STS). The STS data showed remarkably low levels of midgap states on the CH3- and C2H5-terminated Si surfaces. A large conductance gap relative to the Si band gap was observed for both surfaces as well as for the hydrogen-terminated Si(111) surface. This large gap is ascribed to scanning tunneling microscope tip-induced band bending resulting from a low density of midgap states which avoid pinning of the Fermi levels on these passivated surfaces.
Analysis of multiconfigurational wave functions in terms of hole-particle distributions
Authors: Luzanov A. V. , Prezhdo O. V.
Published: June 2006

A detailed study of hole-particle distributions in many-electron molecular systems is presented, based on a representation of the high-order density matrices obtained by an operator technique reminiscent of Bogolyubov’s quantum statistical operator theory. A rigorous definition of density matrices of arbitrary order is given for a composite system of holes and particles. Particular attention is focused on the description of mixed hole-particle distributions. The main results are given as the functionals of excitation operators (generators) that are used in the conventional configuration interaction (CI) and coupled cluster (CC) theories. Local atomic occupation numbers for holes and particles are introduced to provide a measure of the participation of specific atoms in the electron correlation processes. The corresponding total occupations—as well as the hole-hole, particle-particle, and hole-particle mean distances—provide a useful and physically intuitive description of electron correlation. Suitable computational schemes for numerical evaluation of the above characteristics within full CI and typical CC approaches are presented. The insights one can gain with the developed approach into the peculiarities and nuances of the hole-particle picture in typical electronic processes such as excitation and molecular dissociation are illustrated with specific computations on small molecules and closed-shell atoms.
Spectral geometry of κ-Minkowski space
Authors: D’Andrea Francesco
Published: June 2006

After recalling Snyder’s idea [Phys. Rev. 71, 38 (1947)] of using vector fields over a smooth manifold as “coordinates on a noncommutative space,” we discuss a two-dimensional toy-model whose “dual” noncommutative coordinates form a Lie algebra: this is the well-known κ-Minkowski space [Phys. Lett. B 334, 348 (1994)]. We show how to improve Snyder’s idea using the tools of quantum groups and noncommutative geometry. We find a natural representation of the coordinate algebra of κ-Minkowski as linear operators on an Hilbert space (a major problem in the construction of a physical theory), study its “spectral properties,” and discuss how to obtain a Dirac operator for this space. We describe two Dirac operators. The first is associated with a spectral triple. We prove that the cyclic integral of Dimitrijevic et al. [Eur. Phys. J. C 31, 129 (2003)] can be obtained as Dixmier trace associated to this triple. The second Dirac operator is equivariant for the action of the quantum Euclidean group, but it has unbounded commutators with the algebra.
Isotopic effects for the ground 1S1(L=) states in the light two-electron ions
Authors: Frolov Alexei M.
Published: June 2006

The total energies and various bound state properties are determined to very high accuracy for the ground 1S1(L=0) states in some light two-electron ions, including the Li+, Be2+, B3+, and C4+ ions. The corrections due to the finite nuclear masses and lowest order QED corrections (∼α3) are considered/computed for each of these ions. In particular, the specific mass shift is determined for each of the Li+, Be2+, B3+, and C4+ ions. We also discuss the field shift related to the extended nuclear charge distribution.
Application of photonic crystals in submicron damage detection and quantification
Authors: El-Kady I. , Reda Taha M. M. , Su M. F.
Published: June 2006

We propose the use of photonic crystals (PC) for submicron damage detection and quantification. The idea is based on the inherent tie between PC topology and its corresponding spectral frequency response. We demonstrate using a simulation model that a PC sensor attached to a polymer substrate will experience significant changes in its band gap profile when microdamage is induced in the substrate. A damage metric, developed using principles of fuzzy pattern recognition, is used to quantify the change in the spectral response in relation to the level of induced damage. Finally, different damage scenarios demonstrating coincidence with results are examined and reported.
Compliant tin-based buffers for the growth of defect-free strained heterostructures on silicon
Authors: Tolle John , Roucka Radek , Chizmeshya Andrew V. G. , Kouvetakis John , D’Costa Vijay R. , Menéndez José
Published: June 2006

We describe the compliant behavior of Ge1−ySny buffer layers grown strain-free on Si(100). Deposition of lattice-mismatched epilayers on these buffers introduces significant strains in both systems. Ge1−x−y′SixSny′ and Ge1−xSix alloys are deposited on these buffers via reactions of designer hydrides to quantify these strains in detail. X-ray analysis reveals that Ge1−x−y′SixSny′∕Ge1−ySny and Ge1−xSix∕Ge1−ySny bilayers adopt strain states which minimize their combined elastic energy, as if the films were decoupled from the substrate. Compliant Ge1−ySny buffers thereby enable growth of highly mismatched Ge-rich semiconductors on Si and thus facilitate the long-sought on-chip integration of micro- and optoelectronic functions.
Single silicon vacancy-oxygen complex defect and variable retention time phenomenon in dynamic random access memories
Authors: Umeda T. , Okonogi K. , Ohyu K. , Tsukada S. , Hamada K. , Fujieda S. , Mochizuki Y.
Published: June 2006

The variable retention time phenomenon has recently been highlighted as an important issue in dynamic random access memory (DRAM) technology. Based on electrically detected magnetic resonance and simulation studies, we suggest that a single Si vacancy-oxygen complex defect is responsible for this phenomenon, when the defect is embedded in the near surface drain-gate boundary of a DRAM cell.
Biaxial stress dependence of the electrostimulated near-band-gap spectrum of GaN epitaxial film grown on (0001) sapphire substrate
Authors: Wan Keshu , Porporati Alessandro Alan , Feng Gan , Yang Hui , Pezzotti Giuseppe
Published: June 2006

The biaxial piezospectroscopic coefficient (i.e., the rate of spectral shift with stress) of the electrostimulated near-band-gap luminescence of gallium nitride (GaN) was determined as Π=−25.8±0.2meV∕GPa. A controlled biaxial stress field was applied on a hexagonal GaN film, epitaxially grown on (0001) sapphire using a ball-on-ring biaxial bending jig, and the spectral shift of the electrostimulated near-band-gap was measured in situ in the scanning electron microscope. This calibration method can be useful to overcome the lack of a bulk crystal of relatively large size for more conventional uniaxial bending calibrations, which has so far hampered the precise determination of the piezospectroscopic coefficient of GaN. The main source of error involved with the present calibration method is represented by the selection of appropriate values for the elastic stiffness constants of both film and substrate. The ball-on-ring calibration method can be generally applied to directly determine the biaxial-stress dependence of selected cathodoluminescence bands of epilayer/substrate materials without requiring separation of the film from the substrate.
Guided-mode resonance Brewster filters with multiple channels
Authors: Wang Zhanshan , Sang Tian , Wang Li , Zhu Jingtao , Wu Yonggang , Chen Lingyan
Published: June 2006

In this letter, a type of guided-mode resonance (GMR) reflection filter incorporating multimode resonance and the Brewster effect is presented. Long-range, low sidebands, and multiple channels are found to be obtainable for a single-layer GMR reflection filter with a TM-polarized plane wave incident at the Brewster angle. Detailed characteristics are calculated using rigorous coupled-wave analysis. In our calculation, for TM-polarized incident wave, we find it sufficiently accurate to calculate the effect index by using the zero-order permittivity ε0,TM of the effective media theory, and narrowband multichannel reflectance can be achieved at the Brewster angle by tuning the grating depth.
Ultrathin HfO2 (equivalent oxide thickness=1.1nm) metal-oxide-semiconductor capacitors on n-GaAs substrate with germanium passivation
Authors: Kim Hyoung-Sub , Ok Injo , Zhang Manhong , Choi Changhwan , Lee Tackhwi , Zhu Feng , Thareja Gaurav , Yu Lu , Lee Jack C.
Published: June 2006

We present the capacitance-voltage characteristics of TaN∕HfO2∕n-GaAs metaloxide-semiconductor capacitors, with an equivalent oxide thickness (EOT) of 10.9Å, low frequency dispersion, and a low leakage current density (Jg) of ∼10−6A∕cm2 at ∣VG−VFB∣=1V. Physical vapor deposited high-k dielectric film (HfO2) and a thin germanium (Ge) interfacial control layer (ICL) were used to achieve the low EOTs. As postdeposition annealing (PDA) time increases beyond a critical point, EOT and Jg also abnormally increase due to the degradation of the interface between Ge and GaAs surface, which was well indicated in electron energy loss spectroscopy, energy dispersive x-ray spectroscopy, and transmission electron microscopy analyses. Results indicate that a thin Ge ICL, optimized conditions for PDA, as well as high-k material (HfO2) play important roles in allowing further EOT scale down and in providing a high-quality interface.
Magnetoconductivity in the presence of Bychkov-Rashba spin-orbit interaction
Authors: Punnoose Alexander
Published: June 2006

A closed-form analytic formula for the magnetoconductivity in the diffusive regime is derived in the presence of Bychkov-Rashba spin-orbit interaction in two dimensions. It is shown that at low fields B⪡BSO, where BSO is the characteristic field associated with spin precession, D’yakonov-Perel’ mechanism leads to spin relaxation, while for B⪢BSO spin relaxation is suppressed and the resulting spin precession contributes a Berry phaselike spin phase to the magnetoconductivity. The relative simplicity of the formula greatly facilitates data fitting, allowing for the strength of the spin-orbit coupling to be easily extracted.
Oxygen induced molecular reorientation on aluminum
Authors: Winter B. , Berkebile S. , Ivanco J. , Koller G. , Netzer F. P. , Ramsey M. G.
Published: June 2006

Para-sexiphenyl films grow on Al(111) at room temperature such that the molecules are oriented with their molecular axes parallel to the Al surface. Here we demonstrate that the presence of oxygen on the Al substrate prior to deposition leads to a reorientation of the molecules in which their axes are nearly perpendicular to the Al surface. This reorientation also leads to a difference in the electronic structure and an improvement in the band alignment of 1.0eV. The contribution of substrate order to molecular orientation in organic films is discussed.
In situ symbiotic seed germination and propagation of terrestrial orchid seedlings for establishment at field sites
Authors: Batty A. L. , Brundrett M. C. , Dixon K. W. , Sivasithamparam K.
Published: June 2006

The establishment of five species of temperate terrestrial orchids (Caladenia arenicola Hopper & A.P.Brown, Diuris magnifica D.L.Jones, D. micrantha D.L.Jones, Pterostylis sanginea D.LJones & M.A.Clem. and Thelymitra manginiorum ms) in natural habitat through in situ seed sowing, or by planting of seedlings and dormant tubers, was evaluated. Seed of the Western Australian temperate terrestrial taxa, Caladenia arenicola and Pterostylis sanguinea germinated best when sown into soil inoculated with mycorrhizal fungi at field sites but failed to develop the tubers necessary for surviving summer dormancy. However, seedling survival improved when actively growing symbiotic seedlings were transferred to natural habitat during the growing season. Caladenia arenicola and P. sanguinea seedlings survived the initial transfer to field sites but only P. sanguinea survived into the second growing season. Highest survival was obtained by translocating dormant tubers of C. arenicola and Diuris magnifica, with D. magnifica persisting at the site 5 years after translocation. However, outplanted C. arenicola survived for only 2 years. In another trial, where seedlings and dormant tubers of a rare orchid Thelymitra manginiorum were translocated into eucalypt woodland, 18% persisted after 5 years. The rare orchid D. micrantha exhibited the highest survival rates, with greater than 80% of tubers surviving 5 years after transfer of mature dormant tubers to field sites. This study highlights the benefit of using optimised methods for seedling production by symbiotic germination and nursery growth to produce advanced seedlings or dormant tubers to maximise the survival of translocated plants. It also demonstrates the need to consider different strategies when dealing with individual species.
Early pregnancy factor in marsupials
Authors: Cruz Y. P. , Morton H. , Cavanagh A. C. , Selwood L. , Wilson S. D. , Sasaki M.
Published: June 2006

Maternal recognition of pregnancy in marsupials occurs in more subtle ways than it does in eutherians. For instance, unlike in eutherians, the plasma progesterone profiles of pregnant and non-pregnant animals are similar during the luteal phase. It is typically during the brief luteal phase that both gestation and parturition occur in marsupials. Yet histological and physiological changes have been documented between gravid and non-gravid uteri in certain monovular marsupials and between pregnant and non-pregnant animals in polyovular marsupials. Early pregnancy factor (EPF), a 10.8-kDa serum protein known to be homologous to chaperonin 10, is associated with maternal immunosuppression, embryonic development and pregnancy in eutherian mammals. It has been reported in two Australian marsupials: the dasyurid Sminthopsis macroura and the phalangerid Trichosurus vulpecula. This paper documents its occurrence in the New World didelphid Monodelphis domestica. EPF is detectable by rosette inhibition assay in the peripheral circulation of pregnant but not of non-pregnant or pseudopregnant animals. Our work focuses on the embryo–maternal signalling role of EPF during pregnancy. Because progesterone-driven changes are similar in pregnant and non-pregnant marsupials, these animals are an excellent laboratory model in which to investigate the role of EPF in orchestrating the physiological changes necessary to sustain pregnancy.
Status and applications of genomic resources for the gray, short-tailed opossum, Monodelphis domestica, an American marsupial model for comparative biology
Authors: Samollow Paul B.
Published: June 2006

Owing to its small size, favourable reproductive characteristics, and simple husbandry, the gray, short-tailed opossum, Monodelphis domestica, has become the most widely distributed and intensively utilised laboratory-bred research marsupial in the world today. This article provides an overview of the current state and future projections of genomic resources for this species and discusses the potential impact of this growing resource base on active research areas that use M. domestica as a model system. The resources discussed include: fully arrayed, bacterial artificial chromosome (BAC) libraries; an expanding linkage map; developing full-genome BAC-contig and chromosomal fluorescence in situ hybridisation maps; public websites providing access to the M. domestica whole-genome-shotgun sequence trace database and the whole-genome sequence assembly; and a new project underway to create an expressed-sequence database and microchip expression arrays for functional genomics applications. Major research areas discussed span a variety of genetic, evolutionary, physiologic, reproductive, developmental, and behavioural topics, including: comparative immunogenetics; genomic imprinting; reproductive biology; neurobiology; photobiology and carcinogenesis; genetics of lipoprotein metabolism; developmental and behavioural endocrinology; sexual differentiation and development; embryonic and fetal development; meiotic recombination; genome evolution; molecular evolution and phylogenetics; and more.
Parturition and perfect prematurity: birth in marsupials
Authors: Shaw Geoff , Renfree Marilyn B.
Published: June 2006

Marsupials are distinguished from eutherian mammals in their mode of reproduction. They give birth to a highly altricial young, which completes its development whilst attached to a teat, usually within a pouch. The marsupial neonate has relatively well-developed digestive, respiratory and circulatory systems but retains its fetal excretory system with a fully functional mesonephric kidney and undifferentiated gonads and genitalia. We have investigated birth in the tammar wallaby (Macropus eugenii) and shown that the tiny (400 mg) fetus determines the time of its own delivery. Although plasma progesterone falls, and oestradiol associated with the postpartum oestrus typically rises, around the time of parturition, neither hormone is essential for the timing of birth. However relaxin may loosen the connective tissue of the cervix and vaginae for birth. Labour starts suddenly and is completed within minutes. Both prostaglandins and mesotocin are essential for the contractions that deliver the young. Prostaglandins from the reproductive tract act via the brain to control parturient behaviour. In the last 2 days of gestation fetal adrenal glucocorticoid production increases, promoting lung maturation and surfactant production and ultimately triggering labour. The accessibility of the altricial neonatal marsupial provides a unique opportunity for experimental manipulation of organ development and maturation.
Targeted gene disruption of methionine aminopeptidase 2 results in an embryonic gastrulation defect and endothelial cell growth arrest
Authors: Yeh Jing-Ruey J. , Ju Rong , Brdlik Cathleen M. , Zhang Wenjun , Zhang Yi , Matyskiela Mary E. , Shotwell Joseph D. , Crews Craig M.
Published: June 2006

The antiangiogenic agent fumagillin (Fg) and its analog TNP-470 bind to intracellular metalloprotease methionine aminopeptidase-2 (MetAP-2) and inhibit endothelial cell growth in a p53-dependent manner. To confirm the role of MetAP-2 in endothelial cell proliferation and to validate it as a physiological target for the Fg class of antiangiogenic agents, we have generated a conditional MetAP-2 knockout mouse. Ubiquitous deletion of the MetAP-2 gene (
MAP2
) resulted in an early gastrulation defect, which is bypassed in double MetAP-2/p53 knockout embryos. Targeted deletion of
MAP2
specifically in the hemangioblast lineage resulted in abnormal vascular development, and these embryos die at the midsomite stage. In addition, knockdown of MetAP-2 using small interfering RNA or homologous recombination specifically suppresses the proliferation of cultured endothelial cells. Together, these results demonstrate an essential role for MetAP-2 in angiogenesis and indicate that MetAP-2 is responsible for the endothelial cell growth arrest induced by Fg and its derivatives.
Posttranslational regulation of the mammalian circadian clock by cryptochrome and protein phosphatase 5
Authors: Partch Carrie L. , Shields Katherine F. , Thompson Carol L. , Selby Christopher P. , Sancar Aziz
Published: June 2006

The molecular oscillator that drives circadian rhythmicity in mammals obtains its near 24-h periodicity from posttranslational regulation of clock proteins. Activity of the major clock kinase casein kinase I (CKI) ε is regulated by inhibitory autophosphorylation. Here we show that protein phosphatase (PP) 5 regulates the kinase activity of CKIε. We demonstrate that cryptochrome regulates clock protein phosphorylation by modulating the effect of PP5 on CKIε. Like CKIε, PP5 is expressed both in the master circadian clock in the suprachiasmatic nuclei and in peripheral tissues independent of the clock. Expression of a dominant-negative PP5 mutant reduces PER phosphorylation by CKIε
in vivo
, and down-regulation of PP5 significantly reduces the amplitude of circadian cycling in cultured human fibroblasts. Collectively, these findings indicate that PP5, CKIε, and cryptochrome dynamically regulate the mammalian circadian clock.
Risk factors for iron-deficiency anaemia among pregnant women living in rural Vietnam
Authors: Aikawa Ritsuko , Khan Ngyen C , Sasaki Satoshi , Binns Colin W
Published: June 2006

Objective

To assess the prevalence of anaemia in rural Vietnam and to determine its risk factors.

Design

A cross-sectional survey.

Setting

Vietnam, Nghe An Province.

Study population

The total number of participants was 439. Of these participants, one was excluded from the study due to a mental disorder. Forty-seven did not participate in the test for parasites and 68 did not complete at least one of the questions.

Results

The prevalence of anaemia (haemoglobin (Hb) < 11.0 g dl−1) was 43.2% and of severe anaemia (Hb < 8.0 g dl−1) was 0.5%. Taking iron tablets, the consumption of eggs and the preference for Western medicine significantly and positively correlated with Hb concentration in the pregnant women in a multiple regression analysis. Pregnancy duration and hookworm infestation significantly and negatively correlated with Hb concentration in the pregnant women.

Conclusion

The prevalence of anaemia in rural Vietnam has remained as high as that found in the national anaemia survey in 2000. The results of the present study could aid in the development of an iron-deficiency anaemia programme among pregnant women in rural Vietnam that emphasises iron supplementation, parasite control and improved diet, including the consumption of eggs. The programme's focus should be on women who prefer traditional medicine to Western medicine.
Dietary intake of folate equivalents and risk of myocardial infarction in the European Prospective Investigation into Cancer and Nutrition (EPIC)–Potsdam study
Authors: Drogan Dagmar , Klipstein-Grobusch Kerstin , Dierkes Jutta , Weikert Cornelia , Boeing Heiner
Published: June 2006

Objective

To assess the relationship between intake of dietary folate equivalents and risk of myocardial infarction in a German cohort.

Design

Intake of dietary folate equivalents was assessed by a validated food-frequency questionnaire. Cox proportional hazard models were used to evaluate the association between intake of dietary folate equivalents and risk of myocardial infarction.

Setting

The European Prospective Investigation into Cancer and Nutrition (EPIC)–Potsdam cohort, Germany.

Subjects

Subjects were 22 245 apparently healthy non-users of vitamin supplements aged 35–64 years.

Results

During 4.6 years of follow-up, 129 incident cases of myocardial infarction were identified. Compared with intake below the median (103 μg), higher intake of dietary folate equivalents was associated with a multivariate-adjusted hazard ratio (HR) of 0.57 (95% confidence interval (CI) 0.36–0.91). The inverse association of folate intake and myocardial infarction risk was stronger in participants with an ethanol intake equal to or above the sex-specific median (HR = 0.37, 95% CI 0.18–0.79) and attenuated in those with a low ethanol intake (HR = 0.67, 95% CI 0.37–1.22).

Conclusion

An increased intake of dietary folate equivalents was observed to be associated with decreased risk of myocardial infarction in a German study population, pointing towards the importance of folate intake with respect to primary prevention of myocardial infarction.
Women's input into household decisions and their nutritional status in three resource-constrained settings
Authors: Hindin Michelle J
Published: June 2006

Objective

To understand the role of women's input into household decisions as a possible factor contributing to women's undernutrition in settings where HIV/AIDS and drought have constrained household resources.

Design and setting

Three cross-sectional surveys of non-pregnant women in partnerships without a birth in the last 3 months were analysed. Factors associated with chronic energy deficiency (CED), defined as body mass index of < 18.5 kg m−2, were assessed among 1920 women in Zimbabwe, 2870 women in Zambia and 6219 women in Malawi.

Results

Prevalence of CED was 4.2% in Zimbabwe, 13.5% in Zambia and 6.7% in Malawi. In Malawi, women with less input into decisions were more likely to have CED. After multivariable adjustment, each additional decision made by the partner increased the odds of CED in Malawi by 1.08 (95% confidence interval (CI) 1.02–1.15); each additional decision made by the woman decreased the odds of CED by 0.90 (95% CI 0.88–0.97). Malawian women with all the final say or with partners with no final say had significantly more CED than expected (odds ratio (OR) = 2.88, 95% CI 1.42–5.83 and OR = 1.64, 95% CI 1.06–2.52, respectively), and removing these points increased the magnitude and significance of the linear trends. In Zambia, the relationship was found for urban women only and no associations were found in Zimbabwe.

Conclusions

Input into household decisions may be a key factor in the cycle of drought and CED. Women with both low input and CED may lose productive capacity, putting them at greater risk of food insecurity and potentially HIV/AIDS in high prevalence settings.
Breakfast eating and overweight in a pre-school population: is there a link?
Authors: Dubois Lise , Girard Manon , Kent Monique Potvin
Published: June 2006

Objectives

To analyse the socio-economic factors related to breakfast eating, the association between breakfast eating and overweight, and to gain a more thorough understanding of the relationship between these two elements in a population-based cohort of 4.5-year-old children. We hypothesised that a relationship could be observed between breakfast skipping and overweight independently of socio-economic factors such as ethnicity, maternal education, single parenting and family income.

Design

A population-based study whereby standardised nutritional interviews were conducted with each child's parent. The children's height and weight were taken by a trained nutritionist and parents were asked about their child's breakfast eating.

Setting

The analyses were performed using data from the Québec Longitudinal Study of Child Development (1998–2002), conducted by Santé Québec (Canada).

Subjects

Subjects were 1549 children between the ages of 44 and 56 months, with a mean age of 49 months.

Results

Almost a tenth (9.8%) of the children did not eat breakfast every day. A greater proportion of children with immigrant mothers (19.4% vs. 8.3% from non-immigrant mothers), with mothers with no high school diploma (17.5% vs. <10% for higher educated mothers) and from low-income families (15% for income of $39 999 or less vs. 5–10% for better income) did not eat breakfast every day. Not eating breakfast every day nearly doubled the odds (odds ratio = 1.9, 95% confidence interval 1.2–3.2) of being overweight at 4.5 years when mother's immigrant status, household income and number of overweight/obese parents were part of the analysis.

Conclusion

Although our results require replication before public policy changes can be advocated, encouraging breakfast consumption among pre-school children is probably warranted and targeting families of low socio-economic status could potentially help in the prevention of childhood obesity.
Association of carotenoids, tocopherols and vitamin C in plasma with allergic rhinitis and allergic sensitisation in adults
Authors: Kompauer Iris , Heinrich Joachim , Wolfram Guenther , Linseisen Jakob
Published: June 2006

Objectives

Antioxidant nutrients like carotenoids, tocopherols and vitamin C have been suggested to protect against allergic rhinitis and allergic sensitisation but scientific evidence is scarce. The aims of the study were to measure the plasma concentration of six carotenoids, α- and γ-tocopherol and vitamin C as biomarkers of the intake, absorption and subsequent metabolism of these nutrients, and to assess their association with allergic rhinitis and sensitisation.

Method

Data from a cross-sectional study on representative dietary and lifestyle habits of the population of Bavaria, Germany, were analysed. The plasma levels of six carotenoids (α-carotene, β-carotene, lycopene, lutein/zeaxanthin, canthaxanthin and cryptoxanthin) as well as of α-tocopherol, γ-tocopherol and vitamin C were measured in 547 adults aged between 19 and 81 years. Participants with specific serum immunoglobulin E ≥700 U l−1 were categorised as sensitised. The association of plasma antioxidant levels, allergic rhinitis and allergic sensitisation was assessed by means of unconditional logistic regression models.

Results

We observed a negative association between plasma total carotenoids and the prevalence of allergic rhinitis, with odds ratio (95% confidence interval) of 1.13 (0.54–2.39) for the second, 0.72 (0.33–1.58) for the third and 0.44 (0.19–1.03) for the fourth quartile of total carotenoids concentration (P for trend = 0.0332); results for lycopene failed to reach statistical significance (P = 0.0608). Other single carotenoids, tocopherols and vitamin C were unrelated to allergic rhinitis. Allergic sensitisation was negatively associated with plasma γ-tocopherol, with odds ratio (95% confidence interval) of 0.92 (0.51–1.65) for the second, 1.00 (0.56–1.80) for the third and 0.45 (0.23–0.88) for the fourth quartile of plasma γ-tocopherol concentration (P for trend = 0.0410). No other antioxidant was significantly related to allergic sensitisation.

Conclusions

High plasma carotenoid concentrations reflecting a diet high in various fruits and vegetables might have a protective effect on allergic rhinitis in adulthood.
Dietary iron intake and risk of non-fatal acute myocardial infarction
Authors: Tavani Alessandra , Gallus Silvano , Bosetti Cristina , Parpinel Maria , Negri Eva , La Vecchia Carlo
Published: June 2006

Objective

The relation between several measures of body iron and atherosclerotic disease, particularly acute myocardial infarction (AMI), is debated. This is of specific interest since iron is frequently included in supplementation and fortification of foods. We assessed the relation between dietary iron intake and the risk of non-fatal AMI.

Design

Case–control study. The information was collected by interviewers using a food-frequency questionnaire tested for validity and reproducibility. Adjusted odds ratios (OR) and 95% confidence intervals (CI) were obtained by multiple unconditional logistic regression models, including terms for energy and alcohol intakea, as well as for sociodemographic factors, tobacco and other major recognised risk factors for AMI.

Setting

Milan, Italy, between 1995 and 1999.

Subjects

Cases were 507 patients, below age 79 years, with a first episode of non-fatal AMI, and controls were 478 patients admitted to hospital for a wide spectrum of acute conditions unrelated to known or potential AMI risk factors.

Results

Compared with patients in the lowest tertile of total iron intake, the OR was 0.48 (95% CI 0.29–0.82) for those in the highest tertile. The corresponding value for haem iron was 0.71 (95% CI 0.48–1.06), for non-haem, non-alcohol iron was 0.80 (95% CI 0.51–1.24) and for iron derived from alcoholic beverages was 0.60 (95% CI 0.40–0.90). Sex-specific OR for total iron intake were not heterogeneous.

Conclusions

In this Italian population dietary iron intake was inversely related to AMI risk. This inverse association may depend on other nutrients present in the major sources of iron in the Italian diet.
Saturated fat in the diet of Spanish children: relationship with anthropometric, alimentary, nutritional and lipid profiles
Authors: Royo-Bordonada MA , Garcés C , Gorgojo L , Martín-Moreno JM , Lasunción MA , Rodríguez-Artalejo F , Fernández O , de Oya M
Published: June 2006

Objective

To compare the anthropometric, alimentary, nutritional and lipid profiles and global diet quality of Spanish children according to saturated fat intake.

Design

This was a cross-sectional study. Food data were collected using a food-frequency questionnaire.

Subjects and methods

The sample included 1112 children of both sexes, aged between 6 and 7 years, selected by means of random cluster sampling in schools. The plasma lipid profile included measurements of low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), triglycerides, apolipoprotein A1 (apoA1) and apolipoprotein B (apoB). Global diet quality was evaluated by the Dietary Variety Index (DVI) and the Healthy Eating Index (HEI).

Results

Energy intake, DVI and HEI of children from the lower quartile of saturated fat intake (LL) were higher (P< 001) than in the remaining children (UL). However, there were no significant differences in average height or weight between groups. The UL children had lower intakes of meat, fish, vegetables, fruits and olive oil and a higher intake of dairy products (P< 0.001). The intakes of fibre, vitamins C, D, B6, E and folic acid were higher in the LL children, who had lower intakes of vitamin A and calcium. The ratios LDL-C/HDL-C and apoB/apoA1 were lower (P= 0.04) in the LL children (1.87 and 0.52, respectively) than in the UL children (2.02 and 0.54, respectively).

Conclusions

The growth rate of children does not seem to be affected by the level of saturated fat intake. Furthermore, at the levels of intake observed in this study, diets with less saturated fat are associated with better alimentary, nutritional and plasma lipid profiles.
Assessment of diet in young children with an emphasis on fruit and vegetable intake: using CADET – Child and Diet Evaluation Tool
Authors: Cade JE , Frear L , Greenwood DC
Published: June 2006

Objectives

To develop a concise, simple tool for use by non-specialists to assess diet in children aged 3–7 years attending primary schools.

Design

A 24-hour food tick list covering all aspects of the diet and with a focus on fruit and vegetable consumption was developed. This was compared against a 24-hour semi-weighed food diary obtained for the same day as the tick list.

Setting

Six primary schools with a range of socio-economic and ethnic backgrounds from a large city in the north of England (Leeds).

Participants

One hundred and eighty children returned completed packs of information; a response rate of 77% of those who were willing to take part, 48% of those approached.

Results

On average, 2.4 items of fruit including juice (2.1 items as 5-a-day count) were eaten and 1.6 items of vegetables (excluding potato). Twenty-seven per cent and 36% of boys and 23% and 24% of girls reported not eating any fruit or vegetables, respectively, on the recording day. Correlations comparing the diary and tick list were high for both foods (ranger= 0.44 to 0.89) and nutrients (ranger= 0.41 to 0.68). The level of misclassification was much less than would be expected by chance. Parent and teacher evaluation of the tick list was very positive. Parents felt the tick list was easy and quick to complete.

Conclusion

The Child and Diet Evaluation Tool (CADET) tick list has been used successfully for rapid collection of food and nutrient information from children aged 3–7 years from diverse social and ethnic backgrounds. The tool has performed better than many food-frequency questionnaires in comparison to a food diary.
Using epidemiological models to estimate the health effects of diet behaviour change: the example of tailored fruit and vegetable promotion
Authors: Veerman J Lennert , Barendregt Jan J , Mackenbach Johan P , Brug Johannes
Published: June 2006

Objective

To explore the use of epidemiological modelling for the estimation of health effects of behaviour change interventions, using the example of computer-tailored nutrition education aimed at fruit and vegetable consumption in The Netherlands.

Design

The effects of the intervention on changes in consumption were obtained from an earlier evaluation study. The effect on health outcomes was estimated using an epidemiological multi-state life table model. Input data for the model consisted of relative risk estimates for cardiovascular disease and cancers, data on disease occurrence and mortality, and survey data on the consumption of fruits and vegetables.

Results

If the computer-tailored nutrition education reached the entire adult population and the effects were sustained, it could result in a mortality decrease of 0.4 to 0.7% and save 72 to 115 life-years per 100 000 persons aged 25 years or older. Healthy life expectancy is estimated to increase by 32.7 days for men and 25.3 days for women. The true effect is likely to lie between this theoretical maximum and zero effect, depending mostly on durability of behaviour change and reach of the intervention.

Conclusion

Epidemiological models can be used to estimate the health impact of health promotion interventions.
Risk factors for overweight among Brazilian adolescents of low-income families: a case–control study
Authors: Silveira Daniela , De Aguiar Carrazedo Taddei José Augusto , Escrivão Maria Arlete Meil Schimith , Oliveira Fernanda Luisa Ceragioli , Ancona-Lopez Fabio
Published: June 2006

Objective

To study risk factors for overweight among Brazilian adolescents of low-income families.

Design

Case–control study of obese and non-obese adolescents.

Setting

Anthropometric survey including 1420 students (aged 14–19 years) attending a public high school in São Paulo, Brazil.

Methods

Selection of 83 overweight (body mass index (BMI) >85th percentile) and 89 non-overweight (BMI >5th percentile and <85th percentile) subjects, frequency-matched by age, gender, pubertal development and socio-economic status. Among the nutritional, familial and behavioural data available, five covariates (parents' obesity, adolescents' past obesity, to have a best friend, dietary restriction and habit of napping) were included in the fitted hierarchical conditional logistic regression models.

Measurements

Parents or guardians and adolescents were weighed, measured and answered a pre-tested questionnaire applied by trained nutritionists and paediatricians.

Results

The prevalence of overweight was 15.2%. As previous risks, obese parents and obesity during infancy presented odds ratios (OR) and 95% confidence intervals (CI) of 2.23 (1.15–4.35) and 3.60 (1.47–8.80), respectively. As concurrent factors, the habit of napping, to have a best friend and reported dietary restriction presented OR (95% CI) of 3.43 (1.32–8.92), 5.15 (1.76–15.07) and 7.26 (2.95–17.88), respectively. Dietary patterns, frequency of obesogenic foods and other physical activity indicators presented no statistical significance.

Conclusion

In case–control studies, OR may overestimate the true risks. Parents' obesity and previous childhood obesity were identified as risk factors; therefore these factors should be the target for preventive programmes and policies in order to prevent the burden of obesity in the near future.