bluuebunny/crossref_metadata_2025 huggingface dataset:
Indestructibility and level by level equivalence and inequivalence
Authors: Apter Arthur W.
Published: January 2007

If κ < λ are such that κ is indestructibly supercompact and λ is 2λ supercompact, it is known from [4] that

δ is a measurable cardinal which is not a limit of measurable cardinals and δ violates level by level equivalence between strong compactness and supercompactness}

must be unbounded in κ. On the other hand, using a variant of the argument used to establish this fact, it is possible to prove that if κ < λ are such that κ is indestructibly supercompact and λ is measurable, then

δ is a measurable cardinal which is not a limit of measurable cardinals and δ satisfies level by level equivalence between strong compactness and supercompactness}

must be unbounded in κ. The two aforementioned phenomena, however, need not occur in a universe with an indestructibly supercompact cardinal and sufficiently few large cardinals. In particular, we show how to construct a model with an indestructibly supercompact cardinal κ in which if δ < κ is a measurable cardinal which is not a limit of measurable cardinals, then δ must satisfy level by level equivalence between strong compactness and supercompactness. We also, however, show how to construct a model with an indestructibly supercompact cardinal κ in which if δ < κ is a measurable cardinal which is not a limit of measurable cardinals, then δ must violate level by level equivalence between strong compactness and supercompactness. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Generalized periodicity and primitivity for words
Authors: Ito Masami , Lischke Gerhard
Published: January 2007

Starting 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

An 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

The 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

Magnetic 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

Two 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

A 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

We 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

In 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

Objective

To examine the prevalence and risk factors of vitamin deficiencies among older Thai adults.

Methods

The 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.

Results

The 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.

Conclusion

The 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

Objective

The 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.

Design

This study is a cross-sectional evaluation of parent interviews and adolescent surveys from Project EAT (Eating Among Teens).

Subjects

Subjects 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.

Results

Results 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.

Conclusions

Fast-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

Objectives

To 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.

Design

A 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 subjects

A representative sample of 550 mothers in north-east Burkina Faso.

Results

The 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.

Conclusion

The 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

Objectives

To 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.

Setting

Mallickbari Union, Bhaluka, a rural area located about 100 km north of Dhaka, Bangladesh.

Participants

Five hundred and twenty-six infants followed for 6 to 12 months.

Results

Of 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.

Conclusions

This 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

Objective

Infants 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.

Design

Comparison of the prevalence of stunting, wasting and underweight in U5 and U3 with or without inclusion of the age group 0–5 months.

Setting

Demographic and Health Surveys and Multiple Indicator Cluster Surveys from 76 developing countries and countries in transition.

Subjects

Children under 3 or under 5 years of age included in the surveys.

Results

Excluding 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.

Conclusion

All 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

Objective

Paternal 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.

Design

Data 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).

Setting

In total, 175 583 households from urban slum areas in Indonesia.

Subjects

Children 0–59 months of age.

Results

The 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.

Conclusions

Among poor families in urban slum areas of Indonesia, paternal smoking diverts household money from food to tobacco and exacerbates child malnutrition.
Photolithographic Patterning of C2C12 Myotubes using Vitronectin as Growth Substrate in Serum‐Free Medium
Authors: Molnar Peter , Wang Weishi , Natarajan Anupama , Rumsey John W. , Hickman James J.
Published: January 2007

The C2C12 cell line is frequently used as a model of skeletal muscle differentiation. In our serum‐free defined culture system, differentiation of C2C12 cells into myotubes required surface‐bound signals such as substrate‐adsorbed vitronectin or laminin. On the basis of this substrate requirement of myotube formation, we developed a photolithography‐based method to pattern C2C12 myotubes, where myotubes formed exclusively on vitronectin surface patterns. We have determined that the optimal line width to form single myotubes is approximately 30 μm. To illustrate a possible application of this method, we patterned myotubes on the top of commercial substrate‐embedded microelectrodes. In contrast to previous experiments where cell patterning was achieved by selective attachment of the cells to patterned surfaces in a medium that contained all of the factors necessary for differentiation, this study illustrates that surface patterning of a signaling molecule, which is essential for skeletal muscle differentiation in a defined system, can result in the formation of aligned myotubes on the patterns. This technique is being developed for applications in cell biology, tissue engineering, and robotics.
Chemical and dynamical processes in the mesospheric emissive layer: First results of stereoscopic observations
Authors: Faivre M. , Moreels G. , Pautet D. , Clairemidi J. , Dumont F. , Lorin O. , Colas F.
Published: January 2007

The mesospheric emissive layer is an efficient tracer of the dynamical processes propagating in the atmosphere at that level. CCD images in the near infrared taken from the ground at slant angles often reveal the existence of wavy fields. A series of such images has been transformed, using matrix operations, producing a downward satellite‐type view that covers a circular area of radius ∼1000 km at the altitude of the layer. The Fourier characteristics of the wave system are measured using a Morlet‐type wavelet generator function with horizontal wavelengths of mostly ∼20–40 km and 100–150 km and temporal periods of ∼15–30 min. An oxygen‐hydrogen model is used to evaluate the response of the emissive layer to a progressive density wave. The altitude of the layer is modulated with an amplitude of ∼0.8–1.8 km when a density wave propagates vertically. The layer thickness is slightly modulated and is equal to ∼7 km. Stereoscopic pairs of photographs taken simultaneously on 8–9 September 2000 at the Château‐Renard and Pic du Midi observatories are used to obtain surface maps of the emission layer barycenter altitude. A stereocorrelation method suitable for low contrast objects without discrete contours is employed. Preliminary results for areas ∼50 × 50 km2 are presented. The surface maps of the layer barycenter altitude depict the existence of waves. They show the same wavy structure and compare favorably with the maps showing the emission intensity.
On some biases of estimating the global distribution of air‐sea CO2 flux by bulk parameterizations
Authors: Zhang Xin , Cai Wei‐Jun
Published: January 2007

It is important to examine the parameterizations used in calculating air‐sea exchange fluxes as they are essential in developing global carbon models and in carbon budget calculations. We quantify the potential biases involved in the parameterizations. Adopting a non‐zero gas transfer velocity for low wind areas results in a significant increase in the CO2 flux in equatorial regions with a net increase of +0.2 Pg C yr−1 in the total sea‐air global flux. The ocean “cool skin temperature” effect on CO2 flux estimation is found to be an order of magnitude smaller than early estimations. The previously unknown salty‐skin effect has an opposite contribution that cancels the cool‐skin effect. Comparing different wind speeds derived from satellite data and Global Circulation Models (GCM), the most significant divergence is found at the low wind equatorial regions regarding the CO2 flux estimation.
Planetary boundary layer energetics simulated from a regional climate model over Europe for present climate and climate change conditions
Authors: Sánchez E. , Yagüe C. , Gaertner M. A.
Published: January 2007

This paper presents a description of the planetary boundary layer (PBL) for current (1960–1990) and future (2070–2100) climate periods as obtained from a regional climate model (RCM) centered on the Mediterranean basin. Vertically integrated turbulent kinetic energy (TKEZ) and boundary layer height (zi) are used to describe PBL energetics. Present climate shows a TKEZ annual cycle with a clear summer maximum for southern regions, while northern regions of Europe exhibit a smoother or even a lack of cycle. Future climate conditions exhibit a similar behaviour, with an increase in the summer maximum peaks. A detailed analysis of summer surface climate change energetics over land shows an increased Bowen ratio and decreases in the evaporative fraction. The enhanced sensible heat flux responsible for these results causes an energy surplus inside the PBL, resulting in increased convective activity and corresponding TKEZ. These results are consistent with temperature increases obtained by several other model simulations, and also indicate that changes in the turbulent transport from the PBL to the free troposphere can affect atmospheric circulations.
Caribbean and Pacific moisture sources on the Isthmus of Panama revealed from stalagmite and surface water δ18O gradients
Authors: Lachniet Matthew S. , Patterson William P. , Burns Steve , Asmerom Yemane , Polyak Victor
Published: January 2007

We test the hypothesis that the Pacific Ocean contributes moisture to the Intertropical Convergence Zone (ITCZ) over southern Central America, by spatial analysis of surface water δ18O values from Panama and Costa Rica. The δ18O values decrease with distance from the Caribbean Sea to the isthmian divide then gradually increase from the divide toward the Pacific slope, which suggests a contribution of both Caribbean and Pacific sourced moisture to the isthmus. We estimated the Pacific moisture contribution for Pacific slope regions of 22% to 64%. The δ18O values from stalagmites from five cave systems demonstrate decreasing δ18O values with distance from the Caribbean, implicating the Atlantic Basin as a dominant moisture source. Constraining modern moisture sources is important for the interpretation of stable isotopic proxy records of past rainfall, because of the combined influence of Pacific and Atlantic ocean‐atmosphere phenomena on ITCZ rainfall over the Isthmus of Panama.
A two‐dimensional particle code simulation of inertial Alfvén waves and auroral electron acceleration
Authors: Swift Daniel W.
Published: January 2007

A two‐dimensional particle code used to simulate the propagation of inertial Alfvén waves down auroral field lines. The simulation domain is 20,000 km parallel to the magnetic field and some tens of kilometers perpendicular to the field. Electrons are tied to the magnetic field. Effects of a variable magnetic field and magnetic mirror force are included. A spatially narrow Alfvén pulse is launched by application of a variable potential with peak amplitude of 100 V at the top of the simulation domain. If the thickness of the pulse is less than the electron inertial length, the pulse tends to broaden as it propagates down the field line. The result is a parallel electric field considerably smaller than might be expected, assuming a wave whose perpendicular wavelength maps along magnetic field lines. In this model the strongest interaction between the electrons and the Alfvén wave occurs in the 3000 to 7000 km altitude range with an energy gain of the order 100 eV. The downward acceleration was strongest when the applied excitation consisted of a moving positive pulse followed by a negative pulse. Strongest upward acceleration was seen when the polarity was reversed. When the magnitude of the driving potential was doubled, there appeared to be some acceleration in the 9000 to 18,000 km altitude range and acceleration of some particles to 1.5 keV.
Ischemic Preconditioning Reveals that GLT1/EAAT2 Glutamate Transporter is a Novel PPARγ Target Gene Involved in Neuroprotection
Authors: Romera Cristina , Hurtado Olivia , Mallolas Judith , Pereira Marta P , Morales Jesús R , Romera Alejandro , Serena Joaquín , Vivancos José , Nombela Florentino , Lorenzo Pedro , Lizasoain Ignacio , Moro Maria A
Published: January 2007

Excessive levels of extracellular glutamate in the nervous system are excitotoxic and lead to neuronal death. Glutamate transport, mainly by glutamate transporter GLT1/EAAT2, is the only mechanism for maintaining extracellular glutamate concentrations below excitotoxic levels in the central nervous system. We recently showed that neuroprotection after experimental ischemic preconditioning (IPC) involves, at least partly, the upregulation of the GLT1/EAAT2 glutamate transporter in astrocytes, but the mechanisms were unknown. Thus, we decided to explore whether activation of the nuclear receptor peroxisome proliferator-activated receptor (PPAR)γ, known for its antidiabetic and antiinflammatory properties, is involved in glutamate transport. First, we found that the PPARγ antagonist T0070907 inhibits both IPC-induced tolerance and reduction of glutamate release after lethal oxygen-glucose deprivation (OGD) (70.1% ± 3.4% versus 97.7% ± 5.2% of OGD-induced lactate dehydrogenase (LDH) release and 61.8% ± 5.9% versus 85.9% ± 7.9% of OGD-induced glutamate release in IPC and IPC + T0070907 1 μmol/L, respectively, n = 6 to 12, P < 0.05), as well as IPC-induced astrocytic GLT-1 overexpression. IPC also caused an increase in nuclear PPARγ transcriptional activity in neurons and astrocytes (122.1% ± 8.1% and 158.6% ± 22.6% of control PPARγ transcriptional activity, n = 6, P < 0.05). Second, the PPARγ agonist rosiglitazone increased both GLT-1/EAAT2 mRNA and protein expression and [3H]glutamate uptake, and reduced OGD-induced cell death and glutamate release (76.3% ± 7.9% and 65.5% ± 15.1% of OGD-induced LDH and glutamate release in rosiglitazone 1 μmol/l, respectively, n = 6 to 12, P < 0.05). Finally, we have identified six putative PPAR response elements (PPREs) in the GLT1/EAAT2 promoter and, consistently, rosiglitazone increased fourfold GLT1/EAAT2 promoter activity. All these data show that the GLT1/EAAT2 glutamate transporter is a target gene of PPARγ leading to neuroprotection by increasing glutamate uptake.
( 00 l ) epitaxial Ag(Ta0.5Nb0.5)O3 thin films on (001)SrRuO3∕(001)LaAlO3 substrates by chemical solution deposition
Authors: Telli M. B. , Bharadwaja S. S. N. , Biegalski M. D. , Cheng J. G. , Trolier-McKinstry S.
Published: January 2007

Epitaxial silver tantalate niobate, Ag(Ta0.5Nb0.5)O3 (ATN), thin films on (001)SrRuO3∕(001)LaAlO3 substrates were deposited by a chemical solution deposition route. The solution was prepared using niobium ethoxide, tantalum ethoxide, and silver nitrate precursors in a 2-methoxyethanol and pyridine solvents. Films were crystallized between 450 and 800°C in O2 ambient. X-ray diffraction data demonstrated cube-on-cube epitaxy, with a limited reaction between the ATN thin films and the SrRuO3. The dielectric constants of the epitaxial films improved from 260 to 360 at 100kHz with an increase in the crystallization temperatures from 500to800°C. It is speculated that the phase transition between the orthorhombic M2 and M3 phases (which occurs at ∼330K in ceramics) is shifted to lower temperatures (⩽99K) for the films. For a film that was crystallized at 750°C, the frequency dependence was small (⩽20.3%) within the range of 1Hz–100kHz, the capacitance change, ΔC∕C, was small (⩽12.1%) over the temperature range of −20–120°C with a corresponding temperature coefficient of capacitance of −0.11%∕°C at room temperature at 100kHz, and the dc field tunability was not hysteretic, but was limited to 4.8% with a 150kV∕cm bias.
Effect of composition on coupled electric, magnetic, and dielectric properties of two phase particulate magnetoelectric composite
Authors: Devan R. S. , Chougule B. K.
Published: January 2007

The particulate composite materials of ferrite-ferroelectric ceramics viz. nickel-cobalt-copper ferrite (i.e., Ni0.94Co0.01Cu0.05Fe2O4) and barium titanate were synthesized by the double sintering ceramic technique. The presence of constituent phases in the composites was confirmed by x-ray diffraction studies. The average grain size was calculated by using a scanning electron micrograph. The electrical properties such as dc resistivity and thermo-emf were measured as a function of temperature and volume fraction of constituent phases. The ac conductivity was calculated from dielectric data in the frequency range from 100Hzto1MHz. It is concluded that the conduction in the present composites is due to small polarons. The relative dielectric constant measured as a function of applied frequency varies with the variation in the dc resistivity and molar fraction of constituent phases. It shows dispersion in the lower frequency range. The hysteresis behavior was studied to understand the magnetic properties such as saturation magnetization (Ms) and magnetic moment (μB). The static magnetoelectric (ME) voltage coefficient was measured as a function of applied dc magnetic field. It increases first and then falls down with increasing magnetic field. The variation in ME response has been explained in terms of content of ferrite phase, resistivity of composites, and intensity of magnetic field. The maximum ME conversion factor of 637μV∕cmOe was observed for the composite with 30% Ni0.94Co0.01Cu0.05Fe2O4+70% BaTiO3. These composites may be useful as phase shifters, magnetic sensors, cables, etc.
Growth of Co precipitates in irradiated dilute Ag–Co alloys
Authors: Chee S. W. , Krasnochtchekov P. , Averback R. S.
Published: January 2007

The growth of Co precipitates in dilute AgCo alloys under 1.8MeV Kr ion irradiation was investigated by a combination of x-ray diffraction and magnetic measurements. For alloys with Co compositions ranging from 8to20at.% precipitates grow in volume approximately linearly with dose, with no indication of saturation. The variation of temperature from liquid nitrogen temperature to 300°C had little effect on the growth behavior. Precipitation kinetics in these alloys is very different from that in dilute CuCo alloys, which showed steady state precipitate sizes at temperatures below 350°C. We attribute the different behavior to the low solubility of Co in liquid Ag (in contrast to its complete solubility in liquid Cu). The quantitative results suggest that the growth of Co precipitates is derived from particle aggregation rather than Ostwald ripening.
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ZnO thin films grown by pulsed laser deposition on CeO2-buffered r-sapphire substrate
Authors: Duclère J.-R. , Doggett B. , Henry M. O. , McGlynn E. , Rajendra Kumar R. T. , Mosnier J.-P. , Perrin A. , Guilloux-Viry M.
Published: January 2007

Composite ZnO∕CeO2 thin films were grown epitaxially on r-sapphire substrates using the pulsed laser deposition technique. Their crystalline properties were established using x-ray diffraction and showed the ZnO (wurtzite structure) and CeO2 (fluorite structure) layers to be highly textured with the (20−23) and (100) orientations, respectively. ϕ-scan measurements were also carried out and the (20−23)ZnO‖(100CeO2), [1−210]ZnO‖⟨011⟩ CeO2 epitaxial relations established. The rocking curve profiles indicated that the ZnO films grew as four crystallographically equivalent domains. Series of rocking curve and χ−scan measurements at varying ϕ angles, respectively, were used to investigate the domain structure. These showed that the normal to the (20−23) plane in each domain is tilted away from the substrate normal towards one of the four equivalent CeO2 ⟨111⟩ directions by ∼1.60. Atomic force microscopy measurements showed that the ZnO∕CeO2 composite film has a granular microstructure with a rough surface (typical root mean square roughness of 7.9nm). Low temperature photoluminescence spectra showed an intense near-band-edge emission at a photon energy of 3.361eV, with a full width at half maximum of 1.8meV, testifying to the good optical quality of the ZnO material. The optical transmission of the ZnO∕CeO2 composite film was measured in the 200–1000nm spectral domain; it was completely opaque to UV radiation and became transparent with a sharp transition above 380nm. Secondary ion mass spectrometry measurements were used for depth profiling of the ZnO∕CeO2 composite structure. The corresponding data suggest that the CeO2 buffer layer acts as an efficient barrier against the diffusion of aluminum from the sapphire substrate into the ZnO layer.
Enhanced oxidation of TiAlN barriers integrated in three-dimensional ferroelectric capacitor structures
Authors: Lisoni J. G. , Johnson J. A. , Goux L. , Paraschiv V. , Maes D. , Van der Meeren H. , Willegems M. , Haspeslagh L. , Wouters D. J. , Caputa C. , Zambrano R. , Turquat Ch. , Muller Ch.
Published: January 2007

The oxidation characteristics of TiAlN films integrated in the bottom electrode (BE) stack of three-dimensional SrBi2Ta2O9-based (SBT) ferroelectric capacitors are investigated in the range of 650–800°C. The patterned TiAlN\Ir\IrO2\Pt BE is encapsulated by a thin ferroelectric SBT film deposited by metal organic chemical vapor deposition and then crystallized ex situ at temperatures higher than 650°C in oxygen. During this annealing step the TiAlN film oxidizes from the lateral side of the patterned BE mesas. Compared to the vertical oxidation in blanket TiAlN layers, the lateral oxidation rate in our capped patterned films is much larger for similar oxidation conditions. This lateral oxidation of the TiAlN is strongly correlated with the in-film SBT stress that depends upon the deposition temperature and the thickness of the SBT film: the higher the tensile stress in the SBT, the larger the TiAlN oxidation length induced. From a kinetic study, the lateral oxygen diffusion was found to be a self-limited process with activation energy of about 2.2eV and a preexponential factor D0 of 7×10−3cm2∕s. This factor, one to two orders of magnitude higher than the one obtained in blanket TiAlN layers, is indicative of interfacial diffusion. The mechanism of the increased lateral oxidation can be understood by the high tensile stress of the SBT film at the sidewall of the ferroelectric capacitors that tends to tear apart the Ir∕TiAlN interface and causes enlarged interfacial oxygen diffusion. The limiting step of the oxidation mechanism is identified as oxygen diffusion in the Al-depleted∕Ti-rich TiAlN layer that lies beyond the Al-rich film found at the very edge of the capacitors, whereas on blanket films the oxygen diffusion is limited in the Al-rich surface layer region.
In-plane order of liquid crystal molecules adsorbed on photoaligned polyimide films: Coverage dependence in submonolayer range
Authors: Usami Kiyoaki , Sakamoto Kenji , Uehara Yoichi , Ushioda Sukekatsu
Published: January 2007

We have examined the in-plane orientation of liquid crystal (LC) molecules adsorbed on polyimide films as a function of coverage over a submonolayer range. In this study we used 12-nm-thick photoaligned films of polyimide containing azobenzene in the backbone structure (Azo-PI). The in-plane molecular order of the LC layer and the Azo-PI film was determined from the polarization angle dependence of infrared absorption. Even at ∼0.2 ML (monolayer) the orientational distribution of the LC molecules was anisotropic with an in-plane order parameter almost equal to that of the Azo-PI backbone structure in the underlying film. The in-plane order parameter of the LC molecules was constant up to 1 ML. This result indicates that the orientation of the LC molecules directly adsorbed on the polyimide film is determined by the interaction between the polyimide and LC molecules. The interaction among the LC molecules in the first monolayer was found to be negligibly weak compared with that between the polyimide and LC molecules.
On Weyl channels being covariant with respect to the maximum commutative group of unitaries
Authors: Amosov Grigori G.
Published: January 2007

We investigate the Weyl channels being covariant with respect to the maximum commutative group of unitary operators. This class includes the quantum depolarizing channel and the “two-Pauli” channel as well. Then, we show that our estimation of the output entropy for a tensor product of the phase damping channel and the identity channel based upon the decreasing property of the relative entropy allows to prove the additivity conjecture for the minimal output entropy for the quantum depolarizing channel in any prime dimension and for the two-Pauli channel in the qubit case.
Reply to “Comment on `Ab initio studies of (H2O)14− clusters: Existence of surface- and interior-bound extra electrons'” [J. Chem. Phys. 125, 024307 (2006)]
Authors: Khan Arshad
Published: January 2007

In the foregoing Comment [Sommerfeld[J. Chem. Phys.125, 024307 (2006)] suggests that the computational results presented in the above referenced paper does not support the conclusion of the paper regarding the prevalence of both surface- and interior-bound electron states for (H2O)14− clusters in experiments. Herein, the author presents the method used in the selection of clusters and provide experimental results that are consistent with the findings of the paper.
Bipolar pulse generator for intense pulsed ion beam accelerator
Authors: Ito H. , Igawa K. , Kitamura I. , Masugata K.
Published: January 2007

A new type of pulsed ion beam accelerator named “bipolar pulse accelerator” (BPA) has been proposed in order to improve the purity of intense pulsed ion beams. To confirm the principle of the BPA, we developed a bipolar pulse generator for the bipolar pulse experiment, which consists of a Marx generator and a pulse forming line (PFL) with a rail gap switch on its end. In this article, we report the first experimental result of the bipolar pulse and evaluate the electrical characteristics of the bipolar pulse generator. When the bipolar pulse generator was operated at 70% of the full charge condition of the PFL, the bipolar pulse with the first (−138kV, 72ns) and the second pulse (+130kV, 70ns) was successfully obtained. The evaluation of the electrical characteristics indicates that the developed generator can produce the bipolar pulse with fast rise time and sharp reversing time.
Rolling and sliding dynamics in centrifugal spreading
Authors: Rioual F. , Piron E. , Tijskens E.
Published: January 2007

Centrifugal forcing is a usual method to spread a granular material. The dynamics of a particle in this system appears to change spectacularly according to the shape of the particle. The authors present a dynamical transition between rolling and sliding regime and a purely sliding regime as a function of the friction coefficient and the elongation of the particle. This rolling/sliding motion is indeed observed, in situ, for real particles. This simple effect of shape gives a physical interpretation able to explain the difference in the spreading velocity between round grains and elongated grains.