bluuebunny/crossref_metadata_2025 huggingface dataset:
The effect of plant population and distribution on the yield and quality of swedes
Authors: Lang R. W. , Holmes J. C.
Published: March 2009

1. An investigation into the effects of plant population level and irregularity of plant spacing on the yield and quality of swedes is reported.

2. There was no significant evidence that irregular plant spacing, such as might be produced by mechanical singling, gave a lower yield than regular spacing.

3. Total yield of roots was similar for all plant populations tested (range 15,000–50,000) but at low populations both the number and weight of diseased roots was greater than at higher populations.

4. As the population was increased, the drymatter percentage in the roots increased due to the higher proportion of skin on small roots compared with large roots.
The effect of changes in concentrations of dry matter, and of fat and protein in milk substitute diets for veal calves
Authors: Stobo I. J. F. , Roy J. H. B. , Ganderton P.
Published: March 2009

The effect of a gradual increase in dry-matter concentration from 140 g/kg (LD diets) to a maximum of 215 g/kg (HD diets), and the effect of an increase in fat concentration from 225 g/kg D.M. and reduction in protein concentration from 298 g/kg D.M. (LF diets) to 254g fat and 211g protein/kg D.M. respectively (HF diets) was examined with 32 Friesian bull calves in a 2 × 2 factorial experiment. Milk substitutes were offered ad libitum in two feeds daily from 2 days of age. The dietary changes were first introduced at 7 weeks of age and differences became progressively greater as further changes were made at 9, 11 and 13 weeks. The calves were slaughtered at 16 weeks of age.

Dry-matter intake for calves given the HD diets increased faster with age after 7 weeks than that for calves given the LD diets. For the period 7–16 weeks, calves given the HD diets consumed 17% more D.M. than those given the LD diets and had a 13% greater rate of live-weight gain (1·57 v. 1·39 kg/day), although most of the increase in weight gain occurred between 9 and 13 weeks of age.

There was no significant effect on D.M. intake or on live-weight gain of altering the fat and protein concentrations in the milk substitute, although feed conversion ratio (kg D.M. intake/kg weight gain) was higher for the HF than for the LF diets. Apparent digestibility of D.M., crude protein and fat were reduced with the HF diets, but the efficiency of retention of the digested nitrogen was improved. During the second and third weeks of life, D.M. intake reached a peak at approximately 67 g/kg0·75 and subsequently declined to stabilize at about 56 g/kg0·75. However, a gradual increase in concentration of the milk substitute from 140 to 215 g D.M./kg increased intake to about 62 g D.M./kg0·75. The results clearly indicate that, at a dietary concentration of 140 g D.M./kg, maximum D.M. intake cannot be achieved because the volume of fluid that needs to be ingested exceeds the capacity of the digestive system. In contrast, at reconstitution rates increasing from 140 to 215 g D.M./kg, distension of the stomach becomes less important and physiological and metabolic factors seem to assume a greater role in the control of feed intake.
Enhancement of iron availability by some organic materials
Authors: Parsa A. A. , Wallace A. , Martin J. P.
Published: March 2009

In a preliminary laboratory experiment in Iran, not reported here, 5 out of 30 plant materials incorporated into a highly calcareous soil had a positive effect on increasing the DTPA- (diethylenetriaminepentaacetic acid)-extractable Fe and all except one significantly increased the vegetative growth of sorghum. The plant materials included Lawsonia inermis L., Malva silvestris L., Zyzyphus nummularia Wak. and Lavandula carnopifolia L. A glasshouse study was repeated with two California soils pretreated with 0·5% Fe2O3 to determine if these organic materials have practical value in making Fe available to plants. A calcareous, Fe-deficient Hacienda (fine-loamy, mixed, thermic aquic natrargid) and a non-calcareous Yolo (fine-silty, mixed, non-acid, thermic typic xerothents). The previously mentioned organic materials and Laminaria saccharina L. (Lamour) were incorporated into the soils at two rates, 15000 and 20000μg/g, as air dry and in ash form. An adequate supply of major and micronutrients other than Fe was ensured. Other treatments included 5 μg Fe/g as FeSO4, Fe-138 chelate and control. All of the plant materials with the exception of L. carnopifolia significantly increased dry-matter yield and Fe, Zn, Cu and Mn uptake by sorghum in the Hacienda soil. In the Yolo soil the above were not significant. Thin-layer chromatography of the extracts of the plant materials revealed the presence of significant quantities of phenolic substances.
Birthcoat fibre type arrays of lambs and some adult fleece traits
Authors: Guirgis R. A.
Published: March 2009

In a study of two coarse-wool breeds (Awassi and Hamdani) the birthcoat and adult fleece were sampled from six body positions. Mean fibre diameter, mean fibre length, mean staple length and the percentages of fibre types were studied in relation to the birthcoat fibre type arrays.

The birthcoat of the two coarse wool breeds showed only plateau and saddle fibre type arrays. In Awassi lambs, plateau arrays were all P3 type whereas in Hamdani 28·6% of the plateau arrays were Po and the rest were P3 indicating a stronger base in the latter. S/P ratios, calculated from fibre types, were 2·22 and 2·27, at birth, and 3·56 and 2·93 at 4–8 weeks of age, in Awassi and Hamdani respectively. Awassi birthcoats showed more precipice within the CT group than those of Hamdani and plateau arrays were more endowed with the precipice than were saddle arrays.

A composite sample from the back and mid-side, in Awassi, and from the back and britch, in Hamdani, was found to be most representative of the birthcoat fibre types.

In the adult fleece of the Awassi breed, the mean fibre length following plateau arrays exceeded those following saddle arrays.

In Hamdani, the saddle arrays developed into coarser fibres in average diameter than those of plateau arrays whereas in Awassi no difference occurred. Awassi plateau arrays were followed by higher within-staple variability in distribution of fibre length than were saddle arrays, whereas in the distribution of fibre diameter there was no difference. In Hamdani, however, saddle arrays were followed by slightly higher within-stable variability in both length and diameter than were plateau arrays.

Birthcoat samples that had a transition in the CT group or had saddle array developed into adult fleeces with greater frequency of normal distribution in both fibre length and diameter, within staple. Adult fleeces that showed frequent bimodal distribution of both diameter and length, within staple, were those with birthcoats that had a precipice in length, or in coarseness and length, within their CT group or those with birthcoats that had plateau arrays.
Results from experiments comparing aqueous and anhydrous ammonia with ‘nitro-chalk’ for grass cut for silage
Authors: Widdowson F. V. , Penny A. , Flint R. C.
Published: March 2009

In five experiments made at Rothamsted from 1966 to 1970 ‘Nitro-Chalk’ (ammonium nitrate–calcium carbonate mixture, 21% N) was broadcast for grass cut for silage, either in a single dose in spring or divided equally for three cuts. The ‘Nitro-Chalk’ was used to evaluate anhydrous ammonia (82% N) in 1966, anhydrous ammonia and aqueous ammonia (approximately 26% N) in 1967, 1968 and 1969, and anhydrous ammonia, aqueous ammonia and aqueous urea (18% N) in 1970. All these fertilizers were applied to give 125, 250, 375 and 500 kg N/ha, except in 1968 when 250, 375, 500 and 625 kg N/ha were given.

Anhydrous ammonia gave smaller yields (of dry matter) than the other N fertilizers except in 1968, a wet year, when it was at least as good as ‘Nitro-Chalk’, but slightly less good than aqueous ammonia. Yields were larger with autumn- than with springinjected aqueous ammonia and larger with either, than with equivalent single doses of ‘Nitro-Chalk’. Yields with aqueous ammonia were also larger than with ‘Nitro-Chalk’ divided equally for three cuts when more than 375 kg N/ha was tested, but smaller with less. Aqueous urea was as good as a single dose of ‘Nitro-Chalk’ but less good than divided ‘Nitro-Chalk’ in 1970, the only year it was tested. ‘Nitro-Chalk’ divided equally for three cuts gave larger yields than when a single dose of up to 375 kg N/ha was given, but with more N than this a single dose was better.

Apparent recovery of N was least from anhydrous ammonia and differed little between autumn and spring injection in 1968, the only year when a valid comparison was possible. Apparent recoveries of N from autumn and from spring-injected aqueous ammonia and from ‘Nitro-Chalk’ broadcast in a single dose differed little, nor did the proportion of the N recovered at each cut. Recovery from ‘Nitro-Chalk’ broadcast in three equal amounts was more uniform, but little larger.

Judged by yield, no more than 375 kg N/ha was justified; grass given this amount of N either as aqueous ammonia or as ‘Nitro-Chalk’ removed approximately 29 kg of N, 3 kg of P (7 kg P2O6), 26 kg of K (31 kg K2O) and 2 kg of Mg (3 kg MgO) per tonne of dry matter produced.
Sources of magnesium for sugar beet, potatoes and wheat grown on an acid sandy soil at Woburn, Beds.
Authors: Bolton J.
Published: March 2009

Magnesium deficiencies have occurred on most crops grown on sandy soil of the Cottenham Series at Woburn (Bolton & Penny, 1968). This paper gives the results of an experiment on this soil comparing the relative effects of dolomite (MgCO3. CaCO3), Epsom salt (MgSO4. 7H2O) with and without limestone (CaCO8), and calcined magnesite (MgO) on the yields and composition of sugar beet, potatoes and spring wheat grown in successive years. Effects on soil composition are also given.
Effect of suckling on reproductive activities of Bunaji cows during the postpartum period
Authors: Eduvie L. O. , Dawuda P. M.
Published: March 2009

Forty-one cows were used to determine calving intervals, intervals from calving to conception and pregnancy rates at 60–90 days postpartum for suckled and nonsuckled Bunaji cows. Twelve of the cows (six suckled and six non-suckled) were used to study the serum progesterone concentrations during the postpartum period. The mean intervals from calving to conception were 232·5 and 72·6 with calving intervals of 512·5 and 352·6 days for suckled and non-suckled cows, respectively. Pregnancy rates at 60–90 days postpartum were 21·1 and 72·7% for suckled and non-suckled animals, respectively. The overall mean calving interval and interval from calving to conception for all cows were 426·7 and 146·7 days, respectively, with a conception rate of 48·8%.

Based on serum content of progesterone and rectal palpation of ovaries, one of six suckled cows resumed ovarian activities within the first 90 days of calving with peak progesterone of 0·7 ng/ml. Four of six non-suckled cows resumed cyclic activities and conceived within the same period. Two of the four cows conceived at the first postpartum cycle and the remaining two conceived at the second cycle. The serum progesterone concentrations of the cows ranged from 0·1 to 6·9 ng/ml during the nonfertile cycle and 0·1 to 15 ng/ml at pregnancy. It is concluded that suckling interfered with ovarian activities and thus conception during the postpartum period, resulting in a prolonged calving interval.
Effects of physiological age of seed tubers on seed yield and regrowth of progeny tubers in potatoes
Authors: O'Brien P. J. , Jones J. L. , Allen E. J. , Raouf G. S. M.
Published: March 2009

Four experiments are reported in which the effects of a range of physiological ages of seed tubers on growth and yield in seed crops and regrowth of the progeny seed were studied. Increasing the age of seed in Home Guard, Arran Comet, Pentland Javelin and Désirée advanced emergence, tuber initiation and early growth but restricted leaf area index and reduced the number of tubers and seed tuber yield. In these varieties increasing the physiological age of seed shortened the dormancy of the progeny seed and slightly increased sprout lengths at replanting but in Home Guard had no effects on field growth and tuber yield.

In a further series of experiments at Tenby seed of five varieties (Home Guard, Red Craigs Royal, Désirée, Maris Piper and Stormont Enterprise) was multiplied over 2 years using husbandry methods designed to produce seed of contrasting ages. Once-grown seed from Tenby which had been planted and harvested early in the season was stored at either 4 or 12 °C and grown again at Tenby before being stored again at either 4 or 12 °C. The seed resulting from this multiplication over 2 years was compared with seed imported from seed-growing areas stored at the two temperatures. The seasons for the two multiplications at Tenby (1975 and 1976) were hot and were followed by an especially cold and late spring yet few differences between seed from Tenby and other areas could be detected. Where seed from different areas entered sprouting temperatures at different times and therefore produced different ages of seed at replanting large effects on yield were found. Storage temperature had large effects on regrowth of tubers in Home Guard, Red Craigs Royal and Stormont Enterprise for storage at 12 °C produced ‘little potato disorder’ in the majority of plants in one storage phase while storage at lower temperature produced full plant stands and yields. The results provided no support for the suggestion that repeated multiplication in warm lowland areas may lead to cumulative deterioration in the performance of seed.
Modification of yield components and stem length in spring barley by the application of growth retardants prior to main shoot stem elongation
Authors: Waddington S. R. , Cartwright Phyllis
Published: March 2009

The ability of mepiquat chloride and chlormequat growth retardants to modify grain yield components and stem length in two contrasting spring barley cultivars was evaluated in 2 years of small scale field experiments in central southern England. Interactions with plant population density and sowing date were studied.

The mid-tall cv. Koru was more responsive than the shorter high tillering ‘erectoides’ cv. Goldmarker. Early treatments of mepiquat chloride (applied before the start of main shoot stem elongation) on Koru raised grain yield/plant in both years. Early treatments with chlormequat and later applications (during main shoot stem elongation) of either retardant were largely ineffective. Yield increases were achieved by raising the number of spikes/plant along with the number of grains/spike and the above-ground biomass in certain later-formed, lower ranking shoots.

A medium plant population density (250 plants/m2) allowed the best response to early treatment with mepiquat chloride, as did a normally-timed sowing in contrast to a late one. Retardant-induced improvements in yield components in Koru were positively correlated with plant height, the result of over-compensation in the length of upper internodes.

It appears that effective treatments reduced the dominance of the main shoot during tillering, allowing greater initiation and survival of florets (grain sites) in smaller shoots.
Effect of dose and time of atrazine application on weed infestation and yield of fodder sorghum
Authors: Harika A. S. , Tomer P. S. , Ganguly T. K.
Published: March 2009

A field experiment comprising four rates of application of atrazine (0·25, 0·50, 0·75 and 1·0 kg/ha), three times of application (pre-emergence, 10 days after emergence and 20 days after emergence) and two additional treatments of unweeded and weedfree-crop was conducted at the National Dairy Research Institute, Karnal during the rainy seasons of 1979 and 1981. Application of atrazine at 0·25 and 0·5 kg/ha preemergence and 10 days after emergence gave effective control of weeds and resulted in green and dry fodder yields of sorghum similar to weed-free conditions. It was noted that pre-emergence application of the atrazine at 1·0 kg/ha showed a phytotoxic effect on sorghum and resulted in significant reduction in green and dry fodder yields compared with 0·5 kg atrazine/ha.
Effects of summer drought and spring defoliation on carbohydrate reserves, persistence and recovery of two populations of cocksfoot (Dactylis glomerata) in a Mediterranean environment
Authors: Volaire F.
Published: March 2009

The ability to survive severe summer water stress determines the persistence, and therefore autumn yield, of temperate grasses in the Mediterranean environment. In the island of Corsica, sward survival and changes in carbohydrate content were investigated over 2 years, in two contrasting populations of cocksfoot (Dactylis glomerataL.): KM2, an early-flowering population of Mediterranean origin and Lutetia, a late-flowering cultivar bred in North West France.

In Expt 1 (1987/88) three spring defoliation intensities were imposed. In Expt 2 (1989/90) three levels of water deficit were imposed under a rain shelter.

In spring, dry matter (DM) yields and water-soluble carbohydrate (WSC) concentrations in leaf bases were similar (20–35% of DM) for both populations. From June to September, WSC reserves tended to decline in Lutetia, whereas accumulation of WSC was maintained until August (45% of DM) in KM2. Fructans formed the major component, and therefore followed the same seasonal pattern, as total WSC. Contents of trisaccharide and sucrose increased in late summer as drought progressed. Contents of glucose and fructose were lower but increased in August or in September according to treatment.

In both field experiments during summer, KM2 had 50% more live tillers/m2than Lutetia, possibly because it remained in positive carbon balance for a longer period. WSC levels in summer and regrowth in autumn were reduced both by intense defoliation in spring and by severe water stress in summer. On average, autumn yields of KM2 were five times greater than those of Lutetia and the recovery yields were closely correlated with fructan contents of leaf bases in summer (r =0·80;P< 0·001).

The role of fructans and low DP-sugars as solutes in osmotic adjustment and as substrates for regrowth are discussed, and the differences between populations are analysed.
Genetic factors controlling outcrossing in faba bean (Vicia faba): effects of pollen donor and receptor genotypes and estimates of inter-receptor crossfertilization
Authors: Metz P. L. J. , Buiel A. A. M. , Van Norel A. , Helsper J. P. F. G.
Published: March 2009

For the production of hybrid and synthetic varieties, high rates of cross-fertilization are needed. Two aspects of cross-fertilization in Vicia faba L. were studied at Wageningen in 1989 and 1990. The occurrence of cross-fertilization between pollen receptor lines in large-scale assays for crossfertilization was determined. Furthermore, the contribution of the genotype of the donor, of the receptor, and of their specific interactions in terms of cross-fertilization rate were studied.

Inter-receptor cross-fertilization may represent from 2 to 70% of the total cross-fertilization. Interreceptor cross-fertilization increases when donors and receptors do not match for flowering height.

The genotype of the receptor appeared to be of importance for the cross-fertilization rate. No differences in cross-fertilization rate due to genetic differences between pollen donors were noticed. Also no significant specific donor x receptor interaction effect on cross-fertilization rate could be observed.
Cotton spacing experiments in Uganda
Authors: Hearn A. B.
Published: March 2009

Recently developed mathematical models have been used to study the effects of plant population density and arrangement on the yield of cotton in central Uganda. Optimum density did not vary with variety, but was less with bollworm infestation, infertile soils and drought. A reasonable compromise between a population density suitable for adverse conditions and one suitable for good conditions is 7·4 plants m−2. This population is best achieved with 0·45 × 0·25 m spacing but if such rows are too close to manage then 0·2 m in rows 0·7–0·9 m apart is recommended. The mathematical models used in the study are discussed and appraised.
The growth of maize. II. Dry-matter partition in three maize hybrids
Authors: Adelana B. O. , Milbourn G. M.
Published: March 2009

Work that has been reported from some African countries indicates a dependence of grain yield in maize on the duration of leaf area after flowering. This paper studies maize yield in south-east England and confirms work at a similar northern latitude in Canada which has shown that considerable remobilization of photosynthate from the stem to the ear takes place during the main ear fill period.

A similar grain yield was obtained from two contrasting hybrids. In a short early hybrid, Kelvedon 75A, there was a low peak leaf area index (5·3) but the net assimilation rate was high due possibly to efficient light interception by leaves that maintained an erect posture. Stem dry matter was also low and hence in this hybrid the high reproductive/vegetative ratio shows that there has been economy in the production of leaves and stem, especially as a 48% stem loss occurred during the period of ear fill.

In contrast, in a later hybrid, Anjou 210, the final shoot dry matter was 20% higher as the peak leaf-area index of 7·7 gave slightly higher crop growth rates than K 75A. Although the remobilization of stem dry matter was similar in both hybrids it was notable that a different partition of dry matter in the ears of Anjou 210 gave a higher grain/rachis ratio.
Mixture diallel experiments with unequal proportions of genotypes
Authors: Gleeson A. C. , McGilchrist C. A.
Published: March 2009

An analysis is suggested for an experiment investigating plant competition between different genotypes grown in pure culture and in binary mixtures with unequal proportions of genotypes. Worked examples are presented.
A radiological investigation of the effects of cannulation on intestinal motility and digesta flow in sheep
Authors: Wenham G. , Wyburn R. S.
Published: March 2009

Radiological examinations were carried out on ten sheep to see what changes in intestinal motility and flow of digesta were caused by intestinal cannulation. Barium sulphate was injected or infused into the abomasum via an implanted catheter; its passage through the intestine and associated muscular contractions were observed using X-ray image intensification. Once the normal pattern had been established for each individual, single or re-entrant cannulae were inserted into one of four positions in the small intestine.

All the cannulations caused some disruption of the normal flow of digesta, causing retention of digesta and distension of the intestine around and proximal to the intraluminal flanges of the cannulae. The duodenum was affected the most, particularly by one type of re-entrant cannula which reduced the degree of jejunal filling; peristaltic contractions often failed to propagate beyond these cannulae and also caused some retrograde movement of digesta between the cannulation site and the duodenal bulb during the irregular contraction phase (ICP) of the migrating myoelectric complex (MMC). These re-entrant cannulae also impaired the clearing effect of regular contraction phase (RCP).
An assessment of barley straw and oat hulls as energy sources for yearling cattle
Authors: Smith T. , Broster W. H. , Siviter J. W.
Published: March 2009

Three experiments, each consisting of a feeding trial plus a digestibility and nitrogen retention study, compared long barley straw with rolled barley as basal diets and oat hulls with maize starch as energy supplements for yearling dairy cattle. The protein ontent of the diets was varied by the addition of flshmeal.

Growth rates were reduced by the dietary combination of high fibre and low protein, so that diets rich in straw, or containing a supplement of oat hulls, gave a large response to a supplement of fishmeal compared with low straw or maize starch supplemented diets. The data suggest a crude protein concentration of 115 g/kg dry matter as a requirement for high fibre diets supplemented with fishmeal, when fed to yearling cattle. Retention of nitrogen reflected the pattern of live-weight gain. Molar proportions of VFA were affected by changes in the roughage: concentrates ratio, except where energy and protein intakes were both low.

Barley straw was of a higher nutritive value than oat hulls.
Bragg resonance of waves in a two-layer fluid propagating over bottom ripples. Part II. Numerical simulation
Authors: ALAM MOHAMMAD-REZA , LIU YUMING , YUE DICK K. P.
Published: March 2009

We develop a direct numerical method to study the general problem of nonlinear interactions of surface/interfacial waves with variable bottom topography in a two-layer density stratified fluid. We extend a powerful high-order spectral (HOS) method for nonlinear gravity wave dynamics in a homogeneous fluid to the case of a two-layer fluid over non-uniform bottom. The method is capable of capturing the nonlinear interactions among large number of surface/interfacial wave mode and bottom ripple components up to an arbitrary high order. The method preserves exponential convergence with respect to the number of modes of the original HOS and the (approximately) linear effort with respect to mode number and interaction order. The method is validated through systematic convergence tests and comparison to a semi-analytic solution we obtain for an exact nonlinear Stokes waves on a two-layer fluid (in uniform depth). We apply the numerical method to the three classes of generalized Bragg resonances studied in Alam, Liu & Yue (J. Fluid Mech., vol. 624, 2009, p. 225), and compare the perturbation predictions obtained there with the direct simulation results. An important finding is possibly the important effect of even higher-order nonlinear interactions not accounted for in the leading-order perturbation analyses. To illustrate the efficacy of the numerical method to the general problem, we consider a somewhat more complicated case involving two incident waves and three bottom ripple components with wavenumbers that lead to the possibility of multiple Bragg resonances. It is shown that the ensuing multiple (near) resonant interactions result in the generation of multiple new transmitted/reflected waves that fill a broad wavenumber band eventually leading to the loss of order and chaotic motion.
Neogene uplift of the Tian Shan Mountains observed in the magnetic record of the Jingou River section (northwest China)
Authors: Charreau Julien , Chen Yan , Gilder Stuart , Barrier Laurie , Dominguez Stéphane , Augier Romain , Sen Sevket , Avouac Jean‐Philippe , Gallaud Audrey , Graveleau Fabien , Wang Qingchen
Published: March 2009

The Tian Shan Mountains constitute central Asia's longest and highest mountain range. Understanding their Cenozoic uplift history thus bears on mountain building processes in general, and on how deformation has occurred under the influence of the India‐Asia collision in particular. In order to help decipher the uplift history of the Tian Shan, we collected 970 samples for magnetostratigraphic analysis along a 4571‐m‐thick section at the Jingou River (Xinjiang Province, China). Stepwise alternating field and thermal demagnetization isolate a linear magnetization component that is interpreted as primary. From this component, a magnetostratigraphic column composed of 67 polarity chrons are correlated with the reference geomagnetic polarity timescale between ∼1 Ma and ∼23.6 Ma, with some uncertainty below ∼21 Ma. This correlation places precise temporal control on the Neogene stratigraphy of the southern Junggar Basin and provides evidence for two significant stepwise increases in sediment accumulation rate at ∼16–15 Ma and ∼11–10 Ma. Rock magnetic parameters also undergo important changes at ∼16–15 Ma and ∼11–10 Ma that correlate with changes in sedimentary depositional environments. Together with previous work, we conclude that growth history of the modern Tian Shan Mountains includes two pulses of uplift and erosion at ∼16–15 Ma and ∼11–10 Ma. Middle to upper Tertiary rocks around the Tian Shan record very young (<∼5 Ma) counterclockwise paleomagnetic rotations, on the order of 15° to 20°, which are interpreted as because of strain partitioning with a component of sinistral shear that localized rotations in the piedmont.
Dynamics of plate bending at the trench and slab‐plate coupling
Authors: Capitanio F. A. , Morra G. , Goes S.
Published: March 2009

The bending strength of subducting lithosphere plays a critical role in the Earth's plate tectonics and mantle convection, modulating the amount of slab pull transmitted to the surface and setting the boundary conditions under which plates move and deform. However, it is the subject of a lively debate how much of the potential energy of the downgoing plate is consumed in bending the plate and how the lithospheric strength is defined during this process. We model the subduction of a viscoelastic lithosphere, driven solely by the downgoing plate's buoyancy, freely sinking in a passive mantle, represented by drag forces. To investigate the dynamics of bending, (1) we vary the density and the viscosity profile within the plate from isoviscous, where strength is distributed, to strongly layered, where strength is concentrated in a thin core, and (2) we map the stress, strain, and dissipation along the downgoing plate. The effective plate strength during bending is not a simple function of average plate viscosity but is affected by rheological layering and plate thinning. Earth‐like layered plates allow for the transmission of large fractions of slab pull (∼75–80%) through the bend and yield a net slab pull of FSPnet = 1 to 6 × 1012 N m−1, which varies with the buoyancy of plates. In all models, only a minor portion of the energy is dissipated in the bending. Surprisingly, bending dissipation hardly varies with lithospheric viscosity because in our dynamic system, the plates minimize overall dissipation rate by adjusting their bending curvature. As a result, bending dissipation, ΦB, is mainly controlled by the bending moment work rate exerted by slab pull. We propose a new analytical formulation that includes a viscosity‐dependent bending radius, which allows for assessment of the relative bending dissipation in the Earth's subduction zones using parameters from a recent global compilation. This yields estimates of ΦB/ΦTOT < 20%. These results suggest that plates on Earth weakly resist bending, yet are able to propagate a large amount of slab pull.
Has the climate recently shifted?
Authors: Swanson Kyle L. , Tsonis Anastasios A.
Published: March 2009

This paper provides an update to an earlier work that showed specific changes in the aggregate time evolution of major Northern Hemispheric atmospheric and oceanic modes of variability serve as a harbinger of climate shifts. Specifically, when the major modes of Northern Hemisphere climate variability are synchronized, or resonate, and the coupling between those modes simultaneously increases, the climate system appears to be thrown into a new state, marked by a break in the global mean temperature trend and in the character of El Niño/Southern Oscillation variability. Here, a new and improved means to quantify the coupling between climate modes confirms that another synchronization of these modes, followed by an increase in coupling occurred in 2001/02. This suggests that a break in the global mean temperature trend from the consistent warming over the 1976/77–2001/02 period may have occurred.
Fish effects on ocean current observations in the Cariaco Basin
Authors: Virmani Jyotika I. , Weisberg Robert H.
Published: March 2009

Multiple years of moored current meter observations from the Cariaco Basin show low‐frequency variations along with near‐inertial waves and further imply the persistent diurnal movement of fish species known to populate the basin. In agreement with short‐term observations from 1979, the more recent observations with acoustic Doppler current profilers provide evidence of the multidecadal presence and behavior of these species. An unwanted corollary, however, is a bias in both the vertical and horizontal components of velocity due to the fish movements. Removal of this fish bias results in large data loss (approximately 72%); however, an interpolated, non‐biased data set is developed with depth‐averaged horizontal velocities comparable to the observations, demonstrating successful elimination of the bias. Further comparisons show that the interpolated data result in minimal variance density loss at low frequencies and a reduction of variance density at high frequencies such that the interpolated data in the internal wave range more closely fit the Garrett‐Munk spectrum. The net result is a data set appropriate for further analysis. A mean downward velocity of 0.18 cm s−1 is a reflection of a biogenic particle flux and some residual fish contamination. The mean settling speed of particles in the Cariaco Basin is calculated, via Stokes law, to be smaller than 0.04 cm s−1. Velocity observations from acoustic current meters at depths greater than 400 m are impacted by the water clarity; therefore alternate methods should be used to make velocity measurements at depth.
On the representation of droplet coalescence and autoconversion: Evaluation using ambient cloud droplet size distributions
Authors: Hsieh W. C. , Jonsson H. , Wang L.‐P. , Buzorius G. , Flagan R. C. , Seinfeld J. H. , Nenes A.
Published: March 2009

In this study, we evaluate eight autoconversion parameterizations against integration of the Kinetic Collection Equation (KCE) for cloud size distributions measured during the NASA CRYSTAL‐FACE and CSTRIPE campaigns. KCE calculations are done using both the observed data and fits of these data to a gamma distribution function; it is found that the fitted distributions provide a good approximation for calculations of total coalescence but not for autoconversion because of fitting errors near the drop‐drizzle separation size. Parameterizations that explicitly compute autoconversion tend to be in better agreement with KCE but are subject to substantial uncertainty, about an order of magnitude in autoconversion rate. Including turbulence effects on droplet collection increases autoconversion by a factor of 1.82 and 1.24 for CRYSTAL‐FACE and CSTRIPE clouds, respectively; this enhancement never exceeds a factor of 3, even under the most aggressive collection conditions. Shifting the droplet‐drizzle separation radius from 20 to 25 μm results in about a twofold uncertainty in autoconversion rate. The polynomial approximation to the gravitation collection kernel used to develop parameterizations provides computation of autoconversion that agree to within 30%. Collectively, these uncertainties have an important impact on autoconversion but are all within the factor of 10 uncertainty of autoconversion parameterizations. Incorporating KCE calculations in GCM simulations of aerosol‐cloud interactions studies is computationally feasible by using precalculated collection kernel tables and can quantify the autoconversion uncertainty associated with application of parameterizations.
Thorium abundances on the Aristarchus plateau: Insights into the composition of the Aristarchus pyroclastic glass deposits
Authors: Hagerty J. J. , Lawrence D. J. , Hawke B. R. , Gaddis L. R.
Published: March 2009

Thorium (Th) data from the Lunar Prospector gamma ray spectrometer (LP‐GRS) are used to constrain the composition of lunar pyroclastic glass deposits on top of the Aristarchus plateau. Our goal is to use forward modeling of LP‐GRS Th data to measure the Th abundances on the plateau and then to determine if the elevated Th abundances on the plateau are associated with the pyroclastic deposits or with thorium‐rich ejecta from Aristarchus crater. We use a variety of remote sensing data to show that there is a large, homogenous portion of the pyroclastics on the plateau that has seen little or no contamination from the Th‐rich ejecta of Aristarchus crater. Our results show that the uncontaminated pyroclastic glasses on Aristarchus plateau have an average Th content of 6.7 ppm and ∼7 wt % TiO2. These Th and Ti values are consistent with Th‐rich, intermediate‐Ti yellow glasses from the lunar sample suite. On the basis of this information, we use petrologic equations and interelement correlations for the Moon to estimate the composition of the source region from which the Aristarchus glasses were derived. We find that the source region for the Aristarchus glasses contained high abundances of heat‐producing elements, which most likely served as a thermal driver for the prolonged volcanic activity in this region of the Moon.
Theoretical development on the effects of changing flow hydraulics on incipient bed load motion
Authors: Recking A.
Published: March 2009

Several decades of flume and field measurements have indicated that in rough turbulent flows the critical Shields stress increases with increasing slope and associated decreasing relative depth. This result contradicts the usual consideration of a decreased critical Shields value on very steep slopes because of increased gravitational effects. However, recent studies have demonstrated that these experimental results could be reproduced with a force balance model if the classical logarithmic velocity profile was replaced with a velocity profile that was more compatible with available velocity measurements over gravel beds. These measurements indicate the existence of a roughness layer that is a zone of almost constant velocity close to the bed, whose properties (mean velocity and turbulence) depended on the flow's relative depth. Unfortunately, velocity profile measurements for low relative depth associated with steep slopes are scarce, and it is still difficult to include such flow properties in a force balance model. Flow resistance data (on the basis of depth average velocity measurements) are very common and cover a wide range of slopes and relative depths. In this paper these data are used to fit a velocity profile including a roughness layer. When used in a force balance model for incipient motion, it adequately reproduced a data set composed of 270 critical Shields values measured in a flume with near‐uniform sediments. The relevance of this research to field problems is discussed using a data set composed of 92 critical Shields stresses obtained from field measurements. Finally, a model is proposed for field applications taking into account the slope effect.
A U.S. Carbon Cycle Science Plan: First Meeting of the Carbon Cycle Science Working Group; Washington, D. C., 17–18 November 2008
Authors: Michalak Anna M. , Jackson Rob , Marland Gregg , Sabine Christopher
Published: March 2009

The report “A U.S. carbon cycle science plan” (J. L. Sarmiento and S. C. Wofsy, U.S. Global Change Res. Program, Washington, D.C., 1999) outlined research priorities and promoted coordinated carbon cycle research across federal agencies for nearly a decade. Building on this framework and subsequent reports (available at http://www.carboncyclescience.gov/docs.php), the Carbon Cycle Science Working Group (CCSWG) was formed in 2008 to develop an updated strategy for the next decade. The recommendations of the CCSWG will go to agency managers who have collective responsibility for setting national carbon cycle science priorities and for sponsoring much of the carbon cycle research in the United States.

The first meeting of the CCSWG took place in November, with the overall goals of achieving consensus on the extent to which the 1999 plan should be updated, developing a list of overarching scientific questions to be addressed by the new plan, and identifying mechanisms for maximizing community input.
Construction and experimental application of a highly efficient temperature‐selection T‐vector
Authors: Ma Yue , Li Anxing , Wang Yongcai , Xie Mingquan , Li Jing , Zhang Sen , Wang Qiuju
Published: March 2009

T‐A cloning is the most commonly used molecular cloning technique in which T‐vector is the core tool. T‐vectors commonly used now are blue–white positive‐selection vectors based on mechanism of α‐complement of β‐galactose of Escherichia coli. Disadvantages of these traditional T‐vectors in application include insufficient positive rate and the existence of false‐positive clones, which, especially the latter, makes screening of transformant clones via colony PCR necessary. In the present study, a novel T‐vector, based on the strategy of inhibiting the growth of negative transformants by means of a lethal gene and innovative design of insertion site, was developed. The innovative design of the insertion site for PCR fragments not only guarantees complete blocking of the expression of the lethal gene when PCR fragments are inserted, but also eliminates the formation of false‐positive clones. All (100%) of 20 randomly chosen grown colonies were shown to be positive via colony PCR in four separate experimental T‐A clonings of PCR fragments with lengths between 219 and 2100 bp. The novel T‐vector developed in the present study makes colony PCR screening unnecessary, because of its extremely high efficiency of negative transformant inhibition and the mechanism for elimination of false‐positive clones. Temperature (42 °C)‐dependent positive selection greatly simplifies the procedure and lowers the cost of T‐A cloning. Furthermore, it is an ideal T‐vector for constructing libraries of PCR‐amplified DNA fragments such as SSH (suppressive subtraction hybridization) libraries because of its zero negative background performance.
The Effects of a Sound-Field Amplification System on Managerial Time in Middle School Physical Education Settings
Authors: Ryan Stu
Published: March 2009

Purpose

The focus of this research effort was to examine the effect of a sound-field amplification system on managerial time in the beginning of class in a physical education setting.

Method

A multiple baseline design across participants was used to measure change in the managerial time of 2 middle school female physical education teachers using a portable sound-field amplification system. Managerial time is defined as the cumulative amount of time that students spend on organizational, transitional, and nonsubject matter tasks in a lesson.

Results

The findings showed that the amount of managerial time at the beginning of class clearly decreased when the teacher used sound-field amplification feedback to physical education students.

Conclusion

Findings indicate an immediate need for administrators to determine the most appropriate, cost-effective procedure to support sound-field amplification systems in existing physical education settings.
Solving the Reading Crisis—Take 2: The Case for Differentiated Assessment
Authors: Kamhi Alan G.
Published: March 2009

Purpose

The responses to my initial article (A. G. Kamhi, 2007) have raised serious questions about whether embracing the narrow view of reading is the best way to reduce the persistently high levels of reading failure experienced in today’s schools. This afterword provides another attempt to offer a solution to this problem without the distraction of the narrow view of reading.

Method

This second attempt to solve the reading crisis draws on the five responses in this clinical forum and other helpful comments from colleagues who responded to the initial article in
The
ASHA Leader
.

Conclusion

The way to eliminate high levels of reading failure is to differentiate word recognition from domain-general reading comprehension and specific subject knowledge in high-stakes assessments. This differentiation will focus attention on the true crisis in American education—knowledge deficiencies in the sciences, history, math, literature, and other subject areas that are important for success in the 21
st
century.
Synthesis and magnetic properties of multifunctional CoPtAu nanoparticles
Authors: Min Ji Hyun , Wu Jun Hua , Song Ah Young , Jeon In Tak , Ju Jae-Seon , Kim Young Keun
Published: March 2009

We present the synthesis and magnetic properties of multifunctional CoPtAu alloy nanoparticles of three compositions, Co0.33Pt0.33Au0.33, Co0.2Pt0.2Au0.6, and Co0.4Pt0.4Au0.2, by a modified polyol process. The x-ray diffraction and transmission electron microscopy analyses confirm the formation of the alloy nanostructure comprising Au-rich and Pt-rich nanophases, with a narrow distribution of particle sizes and provides the detailed structural arrangements. The magnetic study shows the composition dependence of the magnetic properties of the nanoparticles, from superparamagnetic for both Co0.33Pt0.33Au0.33 and Co0.4Pt0.4Au0.2 to soft ferromagnetic for Co0.2Pt0.2Au0.6.
Microstructures and magnetic properties of rapidly solidified Ni54Fe27−2xGa19+2x ferromagnetic Heusler alloys
Authors: Aich S. , Das S. , Al-Omari I. A. , Alagarsamy P. , Chowdhury S. G. , Chakraborty M. , Shield J. E. , Sellmyer D. J.
Published: March 2009

Rapidly solidified Ni54Fe27−2xGa19+2x (x=0, 1, 2, 3, and 4) ferromagnetic shape memory alloys were made by melt-spinning with variation of Fe and Ga contents to report on the martensitic phase transformation, microstructures, and magnetic properties. Rapid solidification produced pure L21 phase by preventing the formation of γ-phase. To study the effect of heat treatment on the phase transitions, microstructures, and the magnetic properties, the melt-spun ribbons were partly heat treated at different temperatures of 800, 900, 1000, 1100, and 1200 K with holding times of 5, 10, and 15 min followed by either water quenching or air cooling. The microstructures of the as-spun ribbons as revealed by electron microscopy studies exhibited a gradual transition from cellular to dendritic structure with increasing Ga concentration and with the presence of some internal martensitic twin bands at higher Ga content. The ribbons exhibited very low coercivity with high saturation magnetization, as high as ∼87 emu/g (decreasing with Ga concentration). The above-ambient Curie temperature (TC) and the subambient martensitic transition temperature (Tm) were observed to be ∼320 and ∼195 K, respectively. At higher heat treatment temperatures formation of ductile γ phases was observed.
Boundary-layer and interior separations in the Taylor–Couette–Poiseuille flow
Authors: Ma Tian , Wang Shouhong
Published: March 2009

In this article, we derive a rigorous characterization of the boundary-layer and interior separations in the Taylor–Couette–Poiseuille flow. The results obtained provide a rigorous characterization on how, when, and where the propagating Taylor vortices (PTVs) are generated. We consider only the narrow gap and axisymmetric case where a pressure gradient is applied along the axis where the cylinders rotate and where there are no radial motions. In this case, the governing equations are an approximation of the classical Bénard equations. In particular, contrary to what is commonly believed, in the case under consideration, we show that the PTVs do not appear after the first dynamical bifurcation, and they appear only when the Taylor number is further increased to cross another critical value so that a structural bifurcation occurs. This structural bifurcation corresponds to the boundary-layer and interior separations of the flow structure in the physical space.
Basis operator bispectral analysis
Authors: Baver D. A. , Terry P. W. , Holland C.
Published: March 2009

A new procedure for calculating model coefficients from fluctuation data for fully developed turbulence is derived. This procedure differs from previous related methods in that it is constructed in a spatial rather than spectral representation. This has a number of advantages, such as reduced data set requirements, ability to represent spatially inhomogeneous systems such as the ones with curvature or zonal flows, and ability to use data from experimental diagnostics with limited spatial resolution. In this method, the model equation is represented as a linear superposition of linear and nonlinear differential operators. The coefficients of this superposition are calculated using a least-squares method. This method has been tested on simulations of fully developed two dimensional turbulence and compared to previous methods.