bluuebunny/crossref_metadata_2025 huggingface dataset:
Structure of low‐level jet streams ahead of mid‐latitude cold fronts
Authors: Browning K. A. , Pardoe C. W.
Published: February 2007

Several case studies are presented showing the structure of ana‐cold fronts over the British Isles. One of the cases is analysed in detail using data acquired on the Isles of Scilly to avoid any confusing effects due to topography. All of the fronts described are characterized by a narrow band of shallow but vigorous convection at the surface cold front; this convection is essentially two‐dimensional and is termed line convection. In each case the line convection is bounded on its forward side by a low‐level jet reaching 25 to 30 m s−1; behind the line convection the winds decrease abruptly. The low‐level jet is embedded within a ‘convective boundary layer’, reaching its maximum velocity at 900 to 850 mb, and it consists of a tongue of anomalously warm, moist air, which has had a trajectory over an even warmer sea.

It is shown that the line convection can be regarded as part of a mesoscale ‘right‐hand corkscrew circulation’ within the low‐level jet. The line convection constitutes one flank of the jet; it is characterized by very strong cyclonic shear and is fed by frictional convergence of air from beneath the jet core within the lowest 100 mb. Some of the air which ascends within the line convection subsequently flows forward and gently subsides within the upper part of the low‐level jet as part of the corkscrew circulation; however, most of the air which ascends within the line convection is extruded from the boundary layer and ascends in a rearward direction as slantwise convection above the inclined cold frontal zone. Precipitation grown in the slantwise convection falls into the cold air behind the surface cold front and the heat sink resulting from the partial evaporation of this precipitation probably accentuates the sharpness of the boundary of the low‐level jet at the surface cold front.
Balance of kinetic energy in the tropical circulation over the Western Pacific
Authors: Kung E. C.
Published: February 2007

The balance of kinetic energy in the large‐scale disturbances and general flow of the tropical circulation was investigated with special Marshall Islands upper‐air network data during 1958.

The cross‐isobaric generation of eddy kinetic energy has two maxima: in the lower boundary and in the upper troposphere. However, the intensity of generation is about one to two orders of magnitude smaller than that in synoptic disturbances in the middle latitudes. A major portion of the generated eddy kinetic energy is exported outside the area. The space eddies are shown to derive a significant amount of kinetic energy from the kinetic energy reservoir of the basic flow in the area. The eddy kinetic energy is mainly dissipated in the lower boundary. There is a small amount of eddy dissipation in the upper troposphere. However, as a whole the free atmosphere provides very little damping to the disturbances through eddy dissipation.

The kinetic energy balance in the general flow is determined mainly by the cross‐isobaric generation of kinetic energy and the dissipation term. The vertical distribution of the cross‐isobaric generation shows there is a large internal source of kinetic energy in the tropospheric easterlies and the kinetic energy is destroyed adiabatically in the upper‐level westerlies and easterlies. The vertical profile of the dissipation closely follows that of the generation. Examination of the dissipation term obtained as the residual term of the kinetic energy equation suggests that processes of different scales of motion are significantly involved in the kinetic energy balance of the observed scale.
Mesoscale air motions derived from wind finding dropsonde data: The warm front and rainbands of 18 January 1971
Authors: Roach W. T. , Hardman M. E.
Published: February 2007

A diagnostic dynamical study is presented of the three‐dimensional field of motion based on data from dropsondes released through the warm‐frontal rainband situation of 18 January 1971, and is complementary to an earlier radar‐synoptic study of this situation.

Principal features of interest are:

The identification of two low level jets. The first (axis below 1km) lies just ahead of and parallel to the surface warm front. The second (axis near 2km) overrides the first at an angle of about 50° and may be a continuation of the cold front jet overriding the warm front just ahead of the point of occlusion. The flow in the lower jet appears to be supergeostrophic; in the upper jet slightly subgeostrophic.

A distinct mesoscale perturbation of the synoptic scale wind field associated with the rainbands above the warm front. Large negative values of the vertical component of absolute vorticity were observed in the main rainband.

The mesoscale fields of motion produce a marked ‘peak’ in the spectrum of horizontal and vertical kinetic energy.

These and other features are discussed in relation to the results of a model of frontogenesis by B. J. Hoskins. Possible causes of the circulation associated with the rainbands and the interaction with other scales of motion are considered.
Turbulent diffusion within a wheat canopy: I. Measurement using nitrous oxide
Authors: Legg B. J.
Published: February 2007

A new method is described for measuring the vertical component of the coefficient of turbulent diffusion, K, within a wheat canopy. A uniform controlled flux of nitrous oxide was released from a network of nylon tubes at ground level, and K was calculated from the concentration gradient measured at the centre of the network.

The method was first used above the canopy when the crop was short, and the results agreed with those obtained from the wind profile and energy balance. Experiments with different sizes of distribution area showed that in most conditions a radius of only 12m was adequate to give a vertical flux that was constant within 15% to a height of 1m in a canopy 1·25m tall.

The possible error in K was estimated to be 10 to 15% in the lower half of the canopy increasing to 30 to 40% above 1·0m. This is a useful complement to the energy and momentum balance methods that are very inaccurate in the lower half of the canopy.
Momentum transport by the thermal tide in the stratosphere of Venus
Authors: Plumb R. A.
Published: February 2007

The response of a stratified Boussinesq fluid subjected to a moving periodic thermal forcing is analysed and the role of thermal stratification in the generation of a mean ‘zonal’ motion discussed. In the parameter range where the phase speed of this forcing is much less than the speed of the gravest gravity wave mode, the problem may be treated as one of momentum transport by damped internal gravity waves, though the analysis does not require that the damping be small. Results from a simple model show that mean flow speeds much larger than the speed of heat source motion can be generated by this mechanism. Whilst, in the parameter range appropriate (to the best of our present knowledge) to the stratosphere of Venus, some assumptions of the analysis are violated, it is argued that mean winds of the order of 100m s−1 may be generated, thus supporting the suggestion of Schubert and Whitehead that this mechanism is responsible for the observed four‐day rotation of that planet's equatorial stratosphere. It is shown that the ratio of mean wind velocity to the speed of the subsolar point is independent of the length of the solar day, and that it is largely determined by the distribution of radiative heating and cooling in the planetary atmosphere.
Hemispheric coupling ‐ evidence of a cross‐equatorial planetary wave‐guide in the stratosphere
Authors: Barnett J. J.
Published: February 2007

Temperature measurements at stratopause levels made by the Selective Chopper Radiometer on the Nimbus 5 satellite have been used to study the wavenumber‐one component of the near‐stationary eddy field. Sixteen months of data are presented. Tropical amplitudes underwent a 6–month oscillation, being small (<0·2 K) near the solstices and large (∼0·6 K) near the equinoxes when the large eddies associated with winter were simultaneously present in both hemispheres. The direction of meridional phase tilt and the continuity of phase across the equator suggest that at these times a wave was able to propagate from the more active to the quieter hemisphere, reaching 30° latitude or more. These results fit with the simple theory that stationary planetary waves propagate only when the wind is westerly, since wind at these levels is westerly over the whole globe only near the equinoxes.
The interpretation of the crystalline and air bubble structures of hailstones
Authors: Macklin W. C. , Carras J. N. , Rye P. J.
Published: February 2007

The factors which determine the crystalline and air bubble structures of accreted ice have recently been elucidated. It is now possible to ascertain the growth histories of hailstones of approximately spherical symmetry from studies of their internal structure. In principle this analysis can be extended to oblate hailstones once their aerodynamic behaviour is known. Six large hailstones 4 to 6.5cm maximum dimension, two from each of three severe storms, have been analysed. The orientation distributions and sizes of the crystals in the hailstone layers indicate that most of the growth of the hailstones took place at ambient temperatures between about −20 and −25°C, i.e. between 2.7 and 3.7km above the freezing level. The air bubble concentrations and size distributions show that all the hailstones grew with surface temperatures ranging from −1°C for the clear layers to about −11°C for opaque layers comprised of very small crystals. Heat balance considerations indicate that the effective liquid water concentrations in which the hailstones consequently grew were between 3 and 1g m−3. On the assumption that the median volume radius of the cloud droplet distribution was 10μm, the growth of most of the hailstones took place in liquid water concentrations of about the adiabatic values. However, fluctuations in the liquid water concentration of up to some 30% are required to explain the observed air bubble and crystal structures. The fact that the hailstones grew largely between the −20 and −25°C levels indicates that they were balanced in the updraught for most of their history. Since the hailstone fallspeed increases with radius, this meant that the updraught experienced by the hailstone increased steadily with time. There are two possible explanations for this: the strength of the updraught could have increased with time; alternatively, the hailstones could have moved around the main core of the updraught to encounter increasing updraught speeds, as suggested in the Browning and Foote (1975) three‐dimensional model of severe storms.
Extremizing downwind concentration of pollutants from plane area sources
Authors: Ailam G. , Neumann J.
Published: February 2007

Given is a horizontal plot of land P, a fraction of the area of which is assigned to an activity that produces air pollution. The latter area will be denoted S (source). Although the fraction of P allocated to S is fixed, we are otherwise free to determine the location and shape of S within the confines of P. Also given is either a second piece of land or a finite set of points in the same horizontal plane as P. That second piece of land, or set of points, will be denoted R (receptor). We assume that: the source strength density is steady and uniform across S; the wind and the turbulence are likewise steady and uniform along horizontal planes. We now wish to determine the shape of S and its location within P so as to minimize, or to maximize, the average pollution concentration in air at R due to S. By providing a duality principle and applying it to the present case, we show that the bounding curve of S is fixed by a concentration isopleth ‘associated’ with a hypothetical area source represented by R and the given boundary of P. The isopleth of concern is the one that encloses the prescribed area of S within the limits of P. Further, it is pointed out that the case of maximization is ordinarily simpler than that of minimization. In some cases S is not ‘connected’.

Examples are given for the application of the theoretical results.
Response of the atmosphere to a tropical Atlantic ocean temperature anomaly
Authors: Rowntree P. R.
Published: February 2007

Observed tropical Atlantic temperature anomalies for January 1963 have been used in a hemispheric model in an attempt to assess the extratropical effects of a tropical ocean temperature anomaly and to compare them with the results of previously reported experiments on tropical forcing. Falls of surface pressure were obtained over the warmed tropical water and extended north at least to 60°N over the east Atlantic, the northward limit of the falls varying considerably between three 80‐day experiment pairs as was to be expected from the tropical forcing experiments. The maximum amplitude of the mid‐latitude response (up to 7mb) was also consistent with that expected. One of the three experiment pairs produced an Atlantic pressure anomaly pattern similar to the average for the winter (1962–1963) in which the ocean anomaly was observed. The model is shown to give results which compared well with observations in winters with anomalous tropical Atlantic temperatures.
Cloud top heights from temperature sounding instruments
Authors: McCleese D. J. , Wilson L. S.
Published: February 2007

A method for deriving cloud top heights using satellite remote temperature sounding instruments is described. The weighting functions of a 15μm CO2 tropospheric temperature sounder are modified by the presence of cloud in the sounding column. The relative effect of cloud on two or more such weighting functions in successive soundings along an orbital or scanning track is shown to be a simple function of cloud height. The method permits cloud heights to be found without the need to derive cloud amount. Results from the Nimbus 5 Selective Chopper Radiometer are presented.
Profiles and evaporation
Authors: Penman H. L. , Long I. F.
Published: February 2007

It is suggested that in all conditions of stability either of two slightly different profile equations can be used, both carrying in‐built stability weighting factors for use in transport equations. Setting Λ = In(z—d)/z0 the more convenient equation for field use is u = S0 Λe−nΛ/2, where n is dependent on stability (+ in lapse, — in inversion): the important assumptions in physics are that d and z0 are surface constants, and that S0 = u*/k for all values of n, as it is for n = 0. For other values of n, the standard plot of vn̈. In(z—d) has a slope, S ( = du/dΛ), at some average values ū, λ, and backward extrapolation to Λ = 0 gives an intercept ui such that ui/ū = nλ/2 = y. The weighting factor for the shear, f = S0/S, thus becomes ey/(1—y). To find y, u/ū is plotted against U, where U is the velocity measured in a neutral period. No knowledge of temperature gradient is needed – other than ability to recognize when it was near enough to zero to be able to pick out U, z profiles. Because λ appears in y, the roughness length, z0, does not vanish: in effect, it replaces the extra ‘length’ that is put into other stability weighting factors – not needed here.

Profiles of wind, temperature and humidity above and within two large plots of kale (one irrigated) are studied in detail for short periods of strong lapse and strong inversion, first to show the high quality in anemometry needed to exploit the profile equation (barely achieved on the north plot, and not on the other); second, to demonstrate a way of correcting for zero errors in the thermometry: and, third, to show that above the crop the profiles of wind and water vapour pressure have the same shape, and the Bowen ratio is invariant with height. Within the crop, in both lapse and inversion, the top of the crop is the source or sink for sensible heat transfer. In a humidity inversion, the top is also the sink for latent heat transfer, but in a lapse the source is at, or close to, the virtual sink for momentum at z = d+z0.

Evaporation from the north (unirrigated) plot was calculated for 44 days (27 June to 8 August 1971), each day's total being the sum of six estimates for 4‐hour periods. Two weighting factors were used: first, a factor ϕ, based on Richardson number; second, the factor f2. The 44‐day totals were 128mm (using ϕ; identical with calculated potential evaporation), and 137mm (using f2). More detailed study of 13 days in the period (using f2) showed that in the diurnal cycle, evaporation, on average, is zero in the eight hours of darkness, very small from 04 to 08h, large from 08 to 16h, and moderate from 16 to 20h. The energy balance is satisfactory. Comparison of Bowen ratios over the two plots indicated that E(irrigated)/E(unirrigated) was about 1.06. A direct comparison (neutron moisture meter) gave a ratio near 1.10. (The absolute values are suspect.)
Inland penetration of sea‐breeze fronts
Authors: Simpson J. E. , Mansfield D. A. , Milford J. R.
Published: February 2007

The advance inland of the sea‐breeze past Lasham, 45 km from the south coast of England, has been measured over a period of twelve years. In this time 76 sea‐breeze fronts passed Lasham, 36 passed Reading and 12 reached Harwell, 85km from the coast. the rate of advance from Lasham to Harwell in calm or light offshore winds was close to 3 ms−1, and the latter station was passed after sunset at a mean time of 2105 GMT. With onshore winds fronts only appear 30 or 40 km inland, and some fronts may be modified by effects due to the east coast. In some cases detailed measurements were made using pilot balloons, an instrumented motor‐glider and radar. the fronts were shown to have raised heads about twice the depth of the following flow and within the heads dry patches occur. Variable secondary flows are inferred and comparison with water‐tank models shows that several dynamical features in the tank and in the atmosphere are similar. Measurements support the picture of the development of the front during the day as a gravity current, and theoretical rates of advance are deduced. the observed acceleration of the front in the late afternoon is explained in terms of the increased temperature contrast at the front due to the decrease in solar heating of the sea‐air. Shortly before sunset, a sea‐breeze vortex may be detached from the rest of the flow. In a case study, it is shown that friction at the upper surface is at least five times that at the ground, and heat and humidity budgets are given for the detached vortex.
Experimental comparison between visible and near infrared attenuation of solar radiation in hazes and fogs
Authors: Tomasi Claudio , Guzzi Rodolfo
Published: February 2007

Measurements of extinction of solar radiation in spectral intervals centred at 0.50, 1.03 and 3.70 μm are presented for different types of attenuating atmosphere. It appears that the ratios between the total optical thickness in the visible and in the near infrared can give information about the evolution of the water droplet size distribution during the growth of hazes and fogs.
Qualitative and quantitative analysis of toosendanin in Melia toosendan Sieb. Et Zucc (Meliaceae) with liquid chromatography/tandem mass spectrometry
Authors: Ong Eng Shi , Ong Choon Nam
Published: February 2007

Toosendanin (TSN) is a triterpenoid derivative found in Melia toosendan Sieb. Et Zucc (Meliaceae) or chinaberry. TSN present in the medicinal plants was first isolated and established by spectroscopic methods. In this report, high‐performance liquid chromatography (HPLC) separation using columns of smaller particle size with tandem mass spectrometry (MSn) was used for the rapid determination of TSN in botanical extracts. A comparison of different fragmentation patterns shows that the results from positive and negative ion electrospray ionization (ESI)‐MSn are complementary. The two modes can yield structurally significant information for the characterization and rapid identification of TSN in botanical extracts. The data obtained showed that MS3 generated more characteristic ions that are useful for the identification of TSN in unknown samples. The separation of TSN was achieved with a water/acetonitrile gradient system using a short C18 reversed‐phase column with small particle size (50 × 2.0 mm, 3.5 µm). With LC/MS, the quantitative analysis of TSN in the botanical extracts was done using external standard calibration and the method precision was found to vary from 4.3 to 7.6% (RSD, n = 5) on different days. Copyright © 2007 John Wiley & Sons, Ltd.
Developing a new teaching approach for the chemical bonding concept aligned with current scientific and pedagogical knowledge
Authors: Nahum Tami Levy , Mamlok‐Naaman Rachel , Hofstein Avi , Krajcik Joseph
Published: February 2007

The traditional pedagogical approach for teaching chemical bonding is often overly simplistic and not aligned with the most up‐to‐date scientific models. As a result, high‐school students around the world lack fundamental understanding of chemical bonding. In order to improve students' understanding of this concept, it was essential to propose a systemic treatment, namely, revising the scientific content, the pedagogical approach, and the assessment methods regarding this concept. Therefore, the main goal of this study was to build a conceptual framework that provides an advanced scientific and pedagogical foundation regarding the chemical bonding concept—one that will guide chemistry curriculum developers as well. A conceptual framework for a new teaching approach was constructed with lead‐chemistry teachers, science (chemistry) educators, and research chemists. We suggest that chemical bonding should be taught based on elemental principles and by using the idea of a continuum of bond strengths. Our process includes the formulation of learning goals aligned with current scientific knowledge. Moreover, we suggest that constructing assessment tasks on carefully specified learning goals, which are described in terms of learning performances, may enable educators to foster and examine much deeper levels of students' understanding. © 2007 Wiley Periodicals, Inc. Sci Ed 91:579–603, 2007
Lipopolysaccharide regulates toll‐like receptor 4 expression in human aortic smooth muscle cells
Authors: Li Hongli , He Ying , Zhang Jianjun , Sun Shuhan , Sun Baogui
Published: February 2007

Lipopolysaccharide (LPS) is a potent activator of cells of the immune and inflammatory systems, including macrophages, monocytes, and endothelial cells (EC). Toll‐like receptor 4 (TLR4) has been identified as the primary receptor for LPS. Vascular smooth muscle cells (VSMCs) likely contribute significantly to the inflammation induced by low‐level LPS in patients who are at risk for atherosclerosis. Previous study indicated that functional TLR4 was present in VSMCs. However, it remains unclear whether low levels of commercial LPS preparations can affect TLR4 expression in early stage. Here Real‐time quantitative PCR analysis was used to detect TLR4 mRNA expression; Immunofluorescence, Western blot analysis and flow cytometery were used to examine TLR4 protein expression. It was shown that TLR4 was present in Human Aortic Smooth Muscle Cells (HASMCs). LPS can up‐regulate TLR4 mRNA and protein expression in HASMCs in dose‐ and time‐dependant manner. These data indicate that LPS regulate TLR4 expression in HASMCs.
Role of melatonin in the eye and ocular dysfunctions
Authors: LUNDMARK PER O. , PANDI-PERUMAL SEITHIKURIPPU R. , SRINIVASAN VENKATARAMANUJAN , CARDINALI DANIEL P.
Published: February 2007

Melatonin is a ubiquitous molecule and widely distributed in nature, with functional activity occurring in unicellular organisms, plants, fungi, and animals. Several studies have indicated that melatonin synthesis occurs in the retina of most vertebrates, including mammals. The retinal biosynthesis of melatonin and the mechanisms involved in the regulation of this process have been extensively studied. Circadian clocks located in the photoreceptors and retinal neurons regulate melatonin synthesis in the eye. Photoreceptors, dopaminergic amacrine neurons, and horizontal cells of the retina, corneal epithelium, stroma endothelium, and the sclera all have melatonin receptors, indicating a widespread ocular function for melatonin. In addition, melatonin is an effective antioxidant which scavenges free radicals and up-regulates several antioxidant enzymes. It also has a strong antiapoptotic signaling function, an effect that it exerts even during ischemia. Melatonin cytoprotective properties may have practical implications in the treatment of ocular diseases, like glaucoma and age-related macular degeneration.
The Clergy Discipline Measure 2003: A Canter Through its Provisions and Procedures
Authors: Iles Adrian
Published: February 2007

The Clergy Discipline Measure 2003 came into force on 1 January 2006. It provides a new structure for dealing with formal complaints of misconduct against members of the clergy, except in relation to matters involving doctrine, ritual or ceremonial, which continue to be governed by the Ecclesiastical Jurisdiction Measure 1963. This paper concentrates on the new disciplinary procedures in respect of priests and deacons, rather than those for bishops and archbishops.
Law, Religion and Gender Equality
Authors: Rivers Julian
Published: February 2007

This article traces the recent development of gender equality law, understood broadly to embrace sex, transsexual and sexual orientation discrimination. Against this background it considers the ‘problem’ of religion from two perspectives. First, religion is seen as representing a problematic obstacle to the pursuit of a modern gender equality programme, and this results in judicial tendencies to criticise religion and constrain its significance. Second, religions and religious bodies themselves have difficulties with the new ethic underlying recent legal changes. The tension between religious ethics and the new law has resulted in a series of exceptions for religious bodies. However, these are rather narrow, and can be viewed as the minimum necessary to satisfy international and European human rights standards. The article then considers the enigma of equality and the question-begging nature of much of the law made in its name. It concludes that modern problems are better seen not as a clash between religious liberty and gender equality, but as a shift in conceptions of equality. At the same time, this shift has been accompanied by a significant juridification of what for a long time have been social spaces virtually immune from secular legal regulation. Ironically, a new establishment is being created which barely tolerates dissenters.
The Legal Protection of Believers and Beliefs in the United Kingdom
Authors: Oliva Javier García
Published: February 2007

The enactment of the Racial and Religious Hatred Act 2006 is the most recent legal mechanism developed to protect believers, beliefs and religious feelings in the United Kingdom. Despite the recognition of a certain degree of overlap between the different categories, this article proposes a broad distinction between legal devices which protect believers and those which safeguard beliefs and religious feelings. The common law offence of blasphemy is analysed, taking into consideration the response of both the UK courts and the European Court of Human Rights. The endorsement of the English law of blasphemy by Strasbourg is particularly relevant. Furthermore, this paper focuses on different instruments that, throughout the last few decades, have been articulated to protect the faithful, such as the crimes of religiously aggravated offences and the offence of incitement to religious hatred.
Leadership in Medieval English Nunneries
Authors: Chapman Alice
Published: February 2007

VALERIE G SPEAR Boydell and Brewer, Woodbridge, 2005, xix +244 pp incl bibliography and
index (hardback £45.00) ISSN: 1-84383-150-3
Religious Freedom in the Liberal State
Authors: Munro Colin
Published: February 2007

REX AHDAR AND IAN LEIGH Oxford University Press, Oxford, 2005, xxxvi + 410 pp (hardback £60.00) ISBN 0-19-925362-5
Once in a Lifetime: the Date of the Wayland's Smithy Long Barrow
Authors: Whittle Alasdair , Bayliss Alex , Wysocki Michael
Published: February 2007

Twenty-three radiocarbon results are now available from the Wayland's Smithy long barrow, and are presented within an interpretive Bayesian statistical framework. Four alternative archaeological interpretations of the sequence are considered, each with a separate Bayesian model, though only two are presented in detail. The differences are based on different readings of the sequence of Wayland's Smithy II. In our preferred interpretation of the sequence, the primary mortuary structure was some kind of lidded wooden box, accessible for deposition over a period of time, and then closed by the mound of Wayland's Smithy I; Wayland's Smithy II was a unitary construction, with transepted chambers, secondary kerb and secondary ditches all constructed together. In the Bayesian model for this interpretation, deposition began in the earlier thirty-sixth century cal. bc, and probably lasted for a generation. A gap of probably 40–100 years ensued, before the first small mound was constructed in 3520–3470 cal. bc. After another gap, probably of only 1–35 years, the second phase of the monument was probably constructed in the middle to later part of the thirty-fifth century cal. bc (3460–3400 cal. bc), and its use probably extended to the middle decades of the thirty-fourth century cal. bc. Results are discussed in relation to the local setting, the nature of mortuary rites and the creation of tradition.
Infant feeding practices in Xinjiang Uygur Autonomous Region, People's Republic of China
Authors: Xu Fenglian , Binns Colin , Wu Jing , Yihan Re , Zhao Yun , Lee Andy
Published: February 2007

Aims

To document infant feeding methods in the first six months of life in Xinjiang Uygur Autonomous Region, People's Republic of China, 2003–2004. Some problems with breast-feeding in the area are explained.

Methods

A longitudinal study of infant feeding practices was undertaken. A total of 1219 mothers who delivered babies during 2003 and 2004 were interviewed in five hospitals or institutes, and after discharge were contacted in person or by telephone at approximately monthly intervals to obtain details of infant feeding practices. Multivariate logistic regression analysis was used to explore factors associated with breast-feeding initiation.

Results

‘Any breast-feeding’ rates at discharge and at 0.5, 1.5, 2.5, 3.5, 4.5 and 6 months were 92.2, 91.3, 89.9, 88.8, 87.7, 86.0 and 73.0%, respectively. ‘Exclusive breast-feeding’ rates at discharge and at 0.5, 1.5, 2.5, 3.5, 4.5 and 6 months were 66.2, 47.6, 30.1, 25.8, 22.1, 13.0 and 6.2%, respectively. The main problem of breast-feeding in Xinjiang was the early introduction of formula or water. The average duration of ‘exclusive breast-feeding’ was 1.8 months (95% confidence interval (CI) 1.7–2.0), of ‘full breast-feeding’ 2.8 months (95% CI 2.7–2.9) and of ‘any breast-feeding’ 5.3 months (95% CI 5.2–5.4).

Conclusions

Infant feeding methods in Xinjiang were documented in this study and the main problems with infant feeding in Xinjiang are discussed. Further studies are needed to identify factors associated with ‘exclusive breast-feeding’ and duration.
Electron paramagnetic resonance in transition metal-doped ZnO nanowires
Authors: Ankiewicz A. O. , Carmo M. C. , Sobolev N. A. , Gehlhoff W. , Kaidashev E. M. , Rahm A. , Lorenz M. , Grundmann M.
Published: February 2007

The wide-band-gap zinc oxide-based diluted magnetic semiconductors currently attract considerable attention due to their possible use in spintronic devices. In this work, we studied ZnO nanowire samples synthesized on 10×10 mm2 a-plane sapphire substrates by high-pressure pulsed laser deposition. The samples were characterized by scanning electron microscopy (SEM) and electron paramagnetic resonance (EPR) in the X-band (≃9.3 GHz) from T=4 to 300 K. According to the SEM pictures, the nanowires exhibit a length of about 1 μm and are aligned perpendicular to the substrate surface. The structures have a hexagonal cross section and their diameter ranges from 60 nm up to 150 nm. For the lowest nominal concentrations of xMn=3 at. % and xCo=5 at. %, we detect the anisotropic EPR spectra of isolated Mn2+ (3d5, S6) and Co2+ (3d7, F4), respectively, on Zn sites. The detection of the well-resolved anisotropic spectra proves a coherent crystallographic orientation of the nanowires. The linewidth was larger than the best values reported in the literature. Nevertheless, it was possible to identify two different components, A and B, of the reported spectra. From the temperature dependence of the EPR intensity, we found that both components exhibit paramagnetic behavior and are present in a concentration ratio of NB∕NA=1.4. In the case of the Mn-doped ZnO wires, the linewidth increases with increasing Mn concentration due to the dipole-dipole interaction of the paramagnetic ions. At the highest used nominal concentration, xMn=10 at. %, an additional broad single line is observed.
Giant dielectric constant and resistance-pressure sensitivity in carbon nanotubes/rubber nanocomposites with low percolation threshold
Authors: Jiang Mei-Juan , Dang Zhi-Min , Xu Hai-Ping
Published: February 2007

Nanocomposites consisting of methylvinyl silicone rubber (VMQ) with excellent elasticity as polymer matrix and multiwall carbon nanotube (MWNT) with large slenderness ratio and high conductivity as filler were fabricated by a solution method and subsequently hot pressing technology. Studies on dielectric property and resistance-pressure sensitivity of the MWNT/VMQ composites showed that there was a giant dielectric constant and significant resistance-pressure sensitivity as the concentration of MWNT was near a low percolation threshold, fc≈0.012. After the composite applied an enough pressure for long time, the resistance-pressure sensitivity still shows an excellent reproducibility due to the good dispersion and low loading of MWNT.
Tomographic reconstruction of picosecond acoustic strain propagation
Authors: Tomoda Motonobu , Matsuda Osamu , Wright Oliver B. , Li Voti Roberto
Published: February 2007

By means of an ultrafast optical technique, picosecond acoustic strain pulses in a transparent medium are tomographically visualized. The authors reconstruct strain pulses in Au-coated glass from time-domain reflectivity changes as a function of the optical angle of incidence, with ∼1ps temporal and ∼100nm spatial resolutions.
Room temperature ferromagnetism in Mn+-implanted Si nanowires
Authors: Wu H. W. , Tsai C. J. , Chen L. J.
Published: February 2007

Room temperature ferromagnetism of Mn+-implanted Si nanowires (NWs) has been discovered. The saturation magnetization was found to increase with the Mn concentration. Healing the damages in crystallinity at 600°C led to an increase in magnetization, while the ferromagnetism disappeared upon annealing at 800°C as Mn atoms segregated to the surface of NWs. The results indicate that Mn+-implanted Si NWs are potentially useful for nanoscale spintronics applications.
Enhanced interface mixing of Fe∕Si bilayers on preamorphized silicon substrates
Authors: Bibić N. , Milinović V. , Lieb K. P. , Milosavljević M. , Schrempel F.
Published: February 2007

Ion-beam mixing of Fe∕Si bilayers, induced at room temperature by 100keV Ar+40, 180keV Kr+86, and 250keV Xe+132 ions, was investigated. The study focuses on the influence of the preamorphization of the Si(100) substrates by 1.0keV Ar-ion irradiation. Rutherford backscattering spectroscopy as well as scanning and transmission electron microscopies were applied for structural characterization. The mixing rate across the preamorphized Fe∕Si interface was, on average, by 76% higher than that of crystalline Si.
Pressure effects on mechanical properties of bulk metallic glass
Authors: Yu P. , Bai H. Y. , Zhao J. G. , Jin C. Q. , Wang W. H.
Published: February 2007

The effects of high pressure (up to 5GPa) on the mechanical properties of a typical Zr41Ti14Cu12.5Ni10Be22.5 bulk metallic glass (BMG) have been investigated. It is found that the high-pressure pretreatment at room temperature can significantly improve the mechanical performance of the BMG. Particularly, the compressive plasticity of the BMG can be increased as large to as 12% by 4.5GPa pressure pretreatment. The origin of the pressure effect on mechanical properties is studied.
Radiation pattern of Lamb waves generated by a circular magnetostrictive patch transducer
Authors: Lee Ju Seung , Cho Seung Hyun , Kim Yoon Young
Published: February 2007

When a circular magnetostrictive patch bonded to a plate is subjected to static biasing and dynamic actuating magnetic fields, the patch deformation generates guided waves in the plate. To fully understand the characteristics of the circular patch-based transducer, the radiation pattern of the Lamb waves for arbitrary relative orientations of the two fields was experimentally investigated. The largest Lamb wave in an aluminum plate was generated when the two field directions make some oblique angle around 70°, not when they are parallel. The experimental findings were explained by a theoretical analysis.
Complete stabilization and improvement of the characteristics of tunnel junctions by thermal annealing
Authors: Koppinen P. J. , Väistö L. M. , Maasilta I. J.
Published: February 2007

The authors have observed that submicron sized Al–AlOx–Al tunnel junctions can be stabilized completely by annealing them in vacuum at temperatures between 350 and 450°C. In addition, low temperature characterization of the samples after the annealing treatment showed a marked improvement of the tunneling characteristics due to the disappearance of unwanted resonances in the current. Charging energy, tunneling resistance, barrier thickness, and height all increase after the treatment. The superconducting gap is not affected, but supercurrent is reduced in accordance with the increase of tunneling resistance.
Irreversible modification of Ge2Sb2Te5 phase change material by nanometer-thin Ti adhesion layers in a device-compatible stack
Authors: Cabral C. , Chen K. N. , Krusin-Elbaum L. , Deline V.
Published: February 2007

The authors report on an interaction between chalcogenide phase-change material Ge2Sb2Te5 and a thin Ti adhesion layer considered for integration into a structure of a memory cell. Segregation of Te atoms in the chalcogenide film to the interface drives an interaction between Ti and Te atoms and formation of Ti–Te binary phases. This reaction has distinct signatures in the film-stack stress even for a nanometer-thin Ti layer. The irreversible Te segregation and modification of Ge2Sb2Te5 change the crystallization process, completely suppressing the final transformation into an otherwise stable hcp phase, and thus impacts the ultimate life cycle of such a phase-change based memory cell.
Comparison of deterministic growth models fitted to length-at-age data of the piked spurdog (Squalus megalops) in south-eastern Australia
Authors: Braccini J. Matías , Gillanders Bronwyn M. , Walker Terence I. , Tovar-Avila Javier
Published: February 2007

Age and growth estimates of Squalus megalops were derived from the first dorsal fin spine of 452 sharks, ranging from 274 to 622 mm total length. Age bias plots and indices of precision indicated that the ageing method was precise and unbiased. Edge analysis of the enameled surface of whole spines and similarities in the banding pattern deposited in the enameled surface of spines and in spine sections supported the hypothesis of annual band formation. Multiple versions of two growth models were fitted to length-at-age data, from which a two-phase von Bertalanffy model produced the best fit. For males, the change in growth rate corresponded with size-at-maturity, whereas for females, the change was slightly before size-at-maturity. Regardless of the growth model used, growth rate of females (0.034 to 0.098 years–1) was very low, making S. megalops highly susceptible to overexploitation by fisheries.
RETRACTED: Structural basis for nucleotide exchange on Gαisubunits and receptor coupling specificity
Authors: Johnston Christopher A. , Siderovski David P.
Published: February 2007

Heterotrimeric G proteins are molecular switches that relay information intracellularly in response to various extracellular signals. How ligand-activated G protein-coupled receptors act at a distance to exert exchange activity on the Gα nucleotide binding pocket is poorly understood. Here we describe the synergistic action of two peptides: one from the third intracellular loop of the D2 dopamine receptor (D2N), and a second, Gα·GDP-binding peptide (KB-752) that mimics the proposed role of Gβγ in receptor-promoted nucleotide exchange. The structure of both peptides in complex with Gαi1suggests that conformational changes in the β3/α2 loop and β6 strand act in concert for efficient nucleotide exchange. Two key residues in the α4 helix were found to define a receptor/Gαicoupling specificity determinant.
Embryo stability and vulnerability in an always changing world
Authors: Hamdoun Amro , Epel David
Published: February 2007

Contrary to the view that embryos and larvae are the most fragile stages of life, development is stable under real-world conditions. Early cleavage embryos are prepared for environmental vagaries by having high levels of cellular defenses already present in the egg before fertilization. Later in development, adaptive responses to the environment either buffer stress or produce alternative developmental phenotypes. These buffers, defenses, and alternative pathways set physiological limits for development under expected conditions; teratology occurs when embryos encounter unexpected environmental changes and when stress exceeds these limits. Of concern is that rapid anthropogenic changes to the environment are beyond the range of these protective mechanisms.
Iranians' Attitudes About Possible Human Immunodeficiency Virus Transmission in Dental Settings
Authors: Askarian Mehrdad , Mirzaei Kamran , Assadian Ojan
Published: February 2007

We conducted a cross-sectional survey from October through December 2004 of 8,312 residents of Shiraz, Iran, to investigate Iranians' perceptions about undergoing dental treatment in dental offices where other patients or the dentist and/or dental assistants are infected with human immunodeficiency virus (HIV). Most survey respondents (83%) had acceptable general knowledge about the mode of transmission of HIV and about acquired immunodeficiency syndrome (AIDS); however, many misconceptions were observed. A negative association was detected between the level of concern about contracting HIV/AIDS and the intention to continue treatment in services where patients with HIV/AIDS were also treated or where the dentist and/or dental assistants had HIV/AIDS.
Spectral localization in the hierarchical Anderson model
Authors: Kritchevski Evgenij
Published: February 2007

We prove that a large class of hierarchical Anderson models with spectral dimension

d

≤
2

\textrm {d}\leq 2

has only pure point spectrum.
New pseudorandom sequences constructed by quadratic residues and Lehmer numbers
Authors: Liu Huaning
Published: February 2007

Let

p
p

be an odd prime. Define
\[
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="e Subscript n Baseline equals StartLayout Enlarged left-brace 1st Row 1st Column left-parenthesis negative 1 right-parenthesis Superscript n plus n overbar Baseline comma 2nd Column a m p semicolon if n is a quadratic residue mod p comma 2nd Row 1st Column left-parenthesis negative 1 right-parenthesis Superscript n plus n overbar plus 1 Baseline comma 2nd Column a m p semicolon if n is a quadratic nonresidue mod p comma EndLayout">

e
n

=

{

(
−
1

)

n
+

n
¯

,

a
m
p
;

if 

n

 is a quadratic residue mod 

p

,

(
−
1

)

n
+

n
¯

+
1

,

a
m
p
;

if 

n

 is a quadratic nonresidue mod 

p

,

e_n = \begin {cases} (-1)^{n+\overline {n}}, & \text {if $n$ is a quadratic residue mod $p$},\\ (-1)^{n+\overline {n}+1}, & \text {if $n$ is a quadratic nonresidue mod $p$}, \end {cases}

\]
where

n
¯

\overline {n}

is the multiplicative inverse of

n
n

modulo

p
p

such that

1
≤

n
¯

≤
p
−
1

1\leq \overline {n}\leq p-1

. This paper shows that the sequence

{

e
n

}

\{e_n\}

is a “good" pseudorandom sequence, by using the properties of exponential sums, character sums, Kloosterman sums and mean value theorems of Dirichlet

L
L

-functions.
Prenatal choline availability modulates hippocampal and cerebral cortical gene expression
Authors: Mellott Tiffany J. , Follettie Maximillian T. , Diesl Veronica , Hill Andrew A. , Lopez-Coviella Ignacio , Blusztajn Jan Krzysztof
Published: February 2007

An increased supply of the essential nutrient choline during fetal development [embryonic day (E) 11‐17] in rats causes life‐long improvements in memory performance, whereas choline deficiency during this time impairs certain aspects of memory. We analyzed mRNA expression in brains of prenatally choline‐deficient, choline‐supplemented, or control rats of various ages [postnatal days (P) 1 to 34 for hippocampus and E16 to P34 for cortex] using oligonucleotide microarrays and found alterations in gene expression levels evoked by prenatal choline intake that were, in most cases, transient occurring during the P15‐P34 period. We selected a subset of genes, encoding signaling proteins, and verified the microarray data by reverse transcriptase‐polymerase chain reaction analyses. Prenatally choline‐supplemented rats had the highest expression of calcium/calmodulin (CaM)‐dependent protein kinase (CaMK) I and insulin‐like growth factor (IGF) II (Igf2) in the cortex and of the transcription factor Zif268/EGR1 in the cortex and hippocampus. Prenatally choline deficient rats had the highest expression of CaMKIIβ, protein kinase Cβ2, and GABAB receptor 1 isoforms c and d in the hippocampus. Similar changes in the expression of the proteins encoded by these genes were observed using immunoblot analyses. These data show that the prenatal supply of choline causes multiple modifications in the developmental patterns of expression of genes known to influence learning and memory and provide molecular correlates for the cognitive changes evoked by altered availability of choline in utero.—Mellott, T. J., Follettie, M. T., Diesl, V., Hill, A. A., Lopez‐Coviella, I., and Blusztajn, J. K. Prenatal choline availability modulates hippocampal and cerebral cortical gene expression. FASEB J. 21, 1311–1323 (2007)