bluuebunny/crossref_metadata_2025 huggingface dataset:
Surface-enhanced Raman scattering from ordered Ag nanocluster arrays
Authors: Schmidt Jason P. , Cross Sarah E. , Buratto Steven K.
Published: November 2004

We have examined the effect of ordered silver nanocluster substrates on the surface-enhanced Raman spectrum of rhodamine 6G (R6G). Triangular shaped silver nanocluster arrays with order on the ∼100 μm range were prepared using nanosphere lithography. Direct comparisons of R6G surface-enhanced Raman spectroscopy (SERS) signals between ordered nanocluster regions and amorphous Ag regions prepared under identical deposition conditions provide strong evidence of an electromagnetic field enhancement attributed to the unique nanocluster morphology. We have obtained order of magnitude enhancement factors for both 200 and 90 nm Ag nanocluster SERS substrates relative to Ag films.
Joint experimental and theoretical study of vibrationally inelastic electron scattering on propane
Authors: Popović Duška B. , David Donald E. , Michl Josef , Čurı́k Roman , Čársky Petr
Published: November 2004

Vibrational electron energy loss spectra were measured for propane at incident energies of 3, 6, 10, 15, 20, and 25 eV at scattering angles of 40°, 55°, 70°, 85°, and 100°. The spectra are compared with the results of ab initio calculations using a recently developed two-channel discrete momentum representation method. Good agreement between theory and experiment was found for large scattering angles and energies above the resonant region.
Molecular exchange dynamics in partially filled microscale and nanoscale pores of silica glasses studied by field-cycling nuclear magnetic resonance relaxometry
Authors: Mattea C. , Kimmich R. , Ardelean I. , Wonorahardjo S. , Farrher G.
Published: November 2004

Nuclear magnetic spin-lattice relaxation experiments have been performed in partially filled porous glasses with wetting and nonwetting fluids. The frequency dependence of the spin-lattice relaxation rate in Vycor (4 nm pores) and VitraPOR #5 (1 μm pores) silica glasses was studied as a function of the filling degree with the aid of field-cycling NMR relaxometry. The species of primary interest were water (“polar”) and cyclohexane (“nonpolar”). Spin-lattice relaxation was examined in the frequency range from 1 kHz to 400 MHz with the aid of a field-cycling NMR relaxometer and an ordinary 400 MHz NMR spectrometer. Three different mobility states of the fluid molecules are distinguished: The adsorbed state at the pore walls, the bulklike liquid phase, and the vapor phase. The adsorbate spin-lattice relaxation rate is dominated by the “reorientation mediated by translational displacements” (RMTD) mechanism taking place at the adsorbate/matrix interface at frequencies low enough to neglect rotational diffusion of the molecules. The experimental data are analyzed in terms of molecular exchange between the different mobility states. Judged from the dependence of the spin-lattice relaxation rates on the filling degree, limits for slow and fast exchange (relative to the RMTD time scale) can be distinguished and identified. It is concluded that water always shows the features of slow exchange irrespective of the investigated pore sizes and filling degrees. This is in contrast to cyclohexane which is subject to slow exchange in micrometer pores, whereas fast exchange occurs in nanoscopic pores. The latter case implies that the vapor phase contributes to molecular dynamics in this case at low filling degrees while it is negligible otherwise.
Electron kinetics in a cooling plasma
Authors: Helander P. , Smith H. , Fülöp T. , Eriksson L.-G.
Published: November 2004

The distribution function of suprathermal electrons in a slowly cooling plasma is calculated by an asymptotic expansion in the cooling rate divided by the collision frequency. Since the collision frequency decreases with increasing velocity, a high-energy tail forms in the electron distribution function as the bulk population cools down. Under certain simplifying assumptions (slow cooling, constant density, Born approximation of cross sections), the distribution function evolves to a self-similar state where the tail is inversely proportional to the cube of the velocity. Its practical consequences are discussed briefly.
Low voltage lead titanate/Si one-transistor ferroelectric memory with good device characteristics
Authors: Sun C. L. , Chen S. Y. , Liao C. C. , Chin Albert
Published: November 2004

We have developed one-transistor ferroelectric memory using lead titanate (PTO) as a gate dielectric directly formed on Si without any buffer layer. The PTO/Si metal–oxide–semiconductor field-effect transistor memory has shown a large threshold voltage shift of 1.6 V at only ±4V program/erase voltages. The corresponding good interface was achieved by lowering the anneal temperature to 450 °C. Besides the sharp capacitance change of 0.17μF∕Vcm2, it was also evidenced by the high mobility of 169cm2∕Vs close to high-κ HfO2. In addition, long retention >1000s and endurance >1011 stress cycles in the device suggested good memory characteristics.
Film and interface layer properties of ultraviolet-ozone oxidized hafnia and zirconia gate dielectrics on silicon substrates
Authors: Chi David , McIntyre Paul C.
Published: November 2004

We report on the use of ultraviolet-ozone (UVO) oxidation of thin film hafnium and zirconium to fabricate high-dielectric constant (high-k) gate oxides with chemically modified silicon dioxide-based interface layers on silicon (100) substrates. Using x-ray photoelectron spectroscopy and high-resolution transmission electron microscopy, the oxidation state and thickness of the interfacial layer are characterized before and after UVO exposure. Reduction of the chemical oxide followed by reoxidation is observed. The reoxidized silicon is found to be substoichiometric. Thickness series fabricated by repeating the UVO process multiple times for the same substrate indicate a constant interface layer thickness. Inverse capacitance density versus physical thickness plots were used to determine that the dielectric constants for the UVO HfO2 and UVO ZrO2 are 17.3 and 24.8, respectively.
High-resolution transmission electron microscopy analysis of the interface between a Tl-1223 (001) superconducting film and an untextured Ag substrate
Authors: Kim Bong-Jun , Matsui Yoshio , Horiuchi Shigeo , Jeong Dae-Yeong , Deinhofer Christian , Gritzner Gerhard
Published: November 2004

The interface between a screen-printed (Tl0.5Pb0.5)(Sr0.85Ba0.15)2Ca2Cu3Oy (Tl-1223) superconducting film and an untextured Ag substrate is analyzed by transmission electron microscopy (TEM). Preferential orientation between the Tl-1223 grains and the Ag substrate is found. The (001) plane of Tl-1223 grains is parallel to and the {113} plane of Ag is almost parallel to the interface. High-resolution TEM images show that CuO2 planes contact the faceted {113} planes of Ag substrate at the interface. A mechanism for the preferential growth of the Tl-1223 (001) film on untextured Ag substrate is proposed.
Tunable field imbalance and spin precession in magnetic double layers
Authors: Au Y. , Sooryakumar R. , Bussmann K.
Published: November 2004

We report on the manipulation of spin-wave mode profiles by a field imbalance in magnetic double layers produced by the combination of an external field (Hext) and an in-plane spacer layer current-induced Amperian field (Hcur). The magnetizations between layers are tuned from antiparallel to parallel alignment and the associated oscillation amplitudes monitored by Brillouin light scattering. While the results are well accounted for by Maxwell and Landau–Lifshitz equations, a mechanical coupled pendulum analog in a variable unbalanced gravitational acceleration (Δg) provides insight into the underlying physics. It is pointed out that the application of magnetic field pulses of specific strength and duration will lead to direct cross-communication between spin-wave normal modes, a feature unique to the tunable local imbalanced field.
Microscopic study on the behavior of the {311} facet in the selective epitaxial growth of Si(100)
Authors: Lee Gun-Do , Lim Seung-Hyun , Yoon Euijoon
Published: November 2004

The behavior of the {311} facet, which is observed in the selective epitaxial growth of Si(100), is investigated by ab initio calculations and by tight-binding calculations using the environment-dependent tight-binding Si potential. The most stable structure of the {311} facet in the long range order is found to be 3×2 interstitial structure based on the calculation of the surface energy. By comparing the maximum binding energies of adatoms on various structures of Si(311), it is found that the phase transition observed at ∼700°C is the transition from the 3×2 interstitial to the 3×1 interstitial structure and the phase transition is responsible for the behavior of the {311} facet. By tight-binding molecular dynamics simulation, it is also confirmed that the transition from the 3×2 interstitial to the 3×1 interstitial structure is induced by an adatom at high temperature and it corresponds to the transition from the 3×2 to the 3×1 phase of the Si(311) surface observed in experiment.
Environment effects on the Raman spectra of individual single-wall carbon nanotubes: Suspended and grown on polycrystalline silicon
Authors: Son Hyungbin , Hori Yuki , Chou S. G. , Nezich D. , Samsonidze Ge. G. , Dresselhaus G. , Dresselhaus M. S. , Barros Eduardo B.
Published: November 2004

An enhanced Raman signal is observed from individual suspended single-wall carbon nanotubes (SWNTs) and from isolated SWNTs grown on an n-doped polycrystalline silicon film used in standard silicon processing. The radial breathing modes of the Raman spectra taken from suspended SWNTs exhibit narrow linewidths, which indicate a relatively unperturbed environment for suspended SWNTs. Clear Raman signals from intermediate frequency modes in the frequency range from 520to1200cm−1 are presented, which might allow a detailed study of the phonon band structure of individual SWNTs.
Cryogenic variable temperature ultrahigh vacuum scanning tunneling microscope for single molecule studies on silicon surfaces
Authors: Foley E. T. , Yoder N. L. , Guisinger N. P. , Hersam M. C.
Published: November 2004

The design and performance of a variable temperature ultrahigh vacuum (UHV) scanning tunneling microscope (STM) is presented. This STM operates from 8.2 to 300 K in a UHV environment with a base pressure of less than 6×10−11 Torr. Cooling is achieved from 300 to 80 K within 3.5 h and from 80 to 8.2 K within 4.5 h. The base temperature of 8.2 K is maintained at a liquid helium consumption rate of 0.9 l/h. This design allows for direct optical access to the tip-sample interface and direct line-of-sight dosing while the sample is mounted in the STM. The STM tip may be coarse translated laterally in two dimensions through a 6-mm-diam area at all temperatures. With the feedback loop off, the drift in the tip-sample spacing is approximately 0.008 Å/min at 8.2 K. Atomic resolution feedback controlled lithography is performed on hydrogen passivated Si(100) and differential tunneling conductance maps are gathered for isolated cyclopentene molecules on unpassivated Si(100), thus demonstrating that this system is well suited for studying single molecules on silicon surfaces from 8.2 to 300 K.
Thermal effects on the magnetic-field dependence of spin-transfer-induced magnetization reversal
Authors: Lacour D. , Katine J. A. , Smith N. , Carey M. J. , Childress J. R.
Published: November 2004

We have developed a self-aligned, high-yield process to fabricate current-perpendicular-to-plane giant magnetoresistance (GMR) spin-valve sensors of sub-100-nm dimensions. A pinned synthetic antiferromagnet is used as the reference layer which minimizes dipole coupling to the free layer and field-induced rotation of the reference layer. We find that the critical currents for spin-transfer-induced magnetization reversal of the free layer vary dramatically with relatively small changes in the in-plane magnetic field, in contrast to theoretical predictions based on stability analysis of the Gilbert equations of magnetization dynamics, including Slonczewski-type spin-torque terms. The discrepancy is believed due to thermal fluctuations over the time scale of the measurements. Once thermal fluctuations are taken into account, we find good quantitative agreement between our experimental results and numerical simulations.
Evidence for alkali metal formation at a cathode interface of organic electroluminescent devices by thermal decomposition of alkali metal carboxylates during their vapor deposition
Authors: Ganzorig Chimed , Fujihira Masamichi
Published: November 2004

This study examines the possibility of thermal decomposition of Na salts of acetate, benzoate, and fluoride during vacuum vapor deposition using a quartz crystal microbalance to measure negative frequency shift (Δf) caused by increasing mass deposited from the same amount of source materials. Cs acetate is also examined. We compare the negative frequency shift-source current (Δf–I) curves of the Na salts with those of organic materials such as tris(8-hydroxyquinoline)aluminum and N,N′-diphenyl-N,N′-bis(3-methylphenyl)-1,1′-biphenyl-4,4′-diamine. CH3COONa and C6H5COONa exhibit much lower Δf than the organic materials. CH3COOCs gives much larger Δf than CH3COONa due to the higher atomic weight of Cs. These exhibit clear evidence for alkali metal formation by thermal decomposition during vapor deposition of alkali metal carboxylates.
Microwave-induced plasma reactor based on a domestic microwave oven for bulk solid state chemistry
Authors: Brooks David J. , Douthwaite Richard E.
Published: November 2004

A microwave-induced plasma (MIP) reactor has been constructed from a domestic microwave oven (DMO) and applied to the bulk synthesis of solid state compounds. Low pressure MIP can be initiated and maintained using a range of gases including Ar, N2, NH3, O2, Cl2, and H2S. In order to obtain reproducible synthesis conditions the apparatus is designed to allow control of gas flow rate, gas composition, and pressure. The use of the reactor is demonstrated by the synthesis of three binary metal nitrides formed in a NH3 MIP. The reactions are rapid and the products show good crystallinity and phase purity as judged by powder x-ray diffraction.
Microwave characterization of (Pb,La)TiO3 thin films integrated on ZrO2∕SiO2∕Si wafers by sol-gel techniques
Authors: Song Z. T. , Wang Y. , Chan H. L. W. , Choy C. L. , Feng S. L.
Published: November 2004

Polycrystalline perovskite lead lanthanum titanate (PLT) thin films were prepared by a sol-gel method on ZrO2∕SiO2∕Si substrates. The structure of the films was studied by x-ray diffraction and scanning electron microscopy, and the microwave dielectric properties characterized on a network analyzer. A strong dependence of the dielectric constant of PLT films and, correspondingly, the resonance frequency of PLT-based interdigital capacitor on the sample preparation conditions were observed. They resulted from the structural transformation of PLT from a layered structure to a uniform film as the annealing temperature was raised from 550to700°C, suggesting a possible way to modify the device performance by controlling the layered structure of the ferroelectric film.
Femtosecond real-time pump–probe imaging spectroscopy
Authors: Furukawa Naoki , Mair Chad E. , Kleiman Valeria D. , Takeda Jun
Published: November 2004

Real-time pump–probe imaging spectroscopy with femtosecond time resolution is demonstrated. This method allows real-time mapping of frequency- and time-resolved transient absorption of materials at once. We can clearly measure the image of the transient absorption spectra of β-carotene with wide temporal and spectral ranges in a short accumulation time. Since the typical accumulation time is about two orders of magnitude shorter than that by the conventional pump–probe technique, this method becomes a powerful spectroscopic tool to study ultrafast relaxation and dynamics on organic/biochemical materials, which easily undergo photofatigue after many repetitions of the pump–probe sequence.
Silicon doping dependence of highly conductive n-type Al0.7Ga0.3N
Authors: Zhu K. , Nakarmi M. L. , Kim K. H. , Lin J. Y. , Jiang H. X.
Published: November 2004

Highly conductive Si-doped n-type Al0.7Ga0.3N alloys were grown by metalorganic chemical vapor deposition on sapphire substrates. Variable temperature Hall-effect measurements have been employed to study the electrical properties for samples with nominal Si dopant concentration (NSi) from 2.6 to 6.8×1019cm−3. For the sample with NSi=6.0×1019cm−3, we have achieved n-type resistivity of 0.0075Ωcm with an electron concentration of 3.3×1019cm−3 and mobility of 25cm2∕Vs at room temperature. For the same sample, the effective donor (Si) activation energy E0 was determined to be as low as 10meV. E0 increases to 25meV as NSi is reduced to 2.6×1019cm−3, which can be explained by the bandgap renormalization effect. This implies that heavy doping is necessary in high-Al-content AlGaN alloys to bring down the donor activation energy, therefore a higher conductivity.
Giant magnetoresistance monitoring of magnetic picodroplets in an integrated microfluidic system
Authors: Pekas Nikola , Porter Marc D. , Tondra Mark , Popple Anthony , Jander Albrecht
Published: November 2004

This letter describes the integration of giant magnetoresistance (GMR) sensors with a microfluidic system for the velocity and size monitoring, and enumeration of flowing magnetic entities. We have fabricated a microdevice that enables: (1) controlled formation of picoliter-sized droplets of a ferrofluid separated by a nonmagnetic oil; and (2) continuous-flow sensing of these ferrofluid droplets. It is shown that the flow velocity, droplet size, and droplet-formation frequency can readily be determined from the GMR response. These results are validated by comparisons to fluorescence microscopy data.
The chemical activity of metal compound nanoparticles: Importance of electronic and steric effects in M8C12 (M=Ti, V, Mo) metcars
Authors: Liu Ping , Rodriguez José A. , Muckerman James T.
Published: November 2004

Density functional theory was employed to investigate the chemical activity of metal carbide nanoparticles. The present calculations indicate that M8C12 (M=Ti, V, Mo) nanoparticles exhibit a unique behavior compared to metal [M(001)] and metal carbide surfaces [M2C(001) and MC(001)]. It is found that the nanoparticles behave very reactive in spite of the high carbon concentration in some reactions, while surprisingly inert in other cases. Our study reveals that the unexpected activity is the result of the interplay of shifts in the metal d-bands and distortions in the geometry of the metal carbide nanoparticles.
Photorefractive polymer composite operating at the optical communication wavelength of 1550 nm
Authors: Tay Savaş , Thomas Jayan , Eralp Muhsin , Li Guoqiang , Kippelen Bernard , Marder Seth R. , Meredith Gerald , Schülzgen Axel , Peyghambarian N.
Published: November 2004

A photorefractive polymer composite sensitized at 1550 nm through direct two-photon absorption has been developed. We show an external diffraction efficiency of 3% in four-wave-mixing experiments and perform holographic reconstruction of distorted images utilizing thin-film devices made of this polymer composite. Amongst other potential applications, the demonstration of accurate, dynamic aberration correction through holography in this all-organic photorefractive device presents an alternative to complex adaptive optics systems currently employed in through-air optical communication links.
Solid state protein monolayers: Morphological, conformational, and functional properties
Authors: Pompa P. P. , Biasco A. , Frascerra V. , Calabi F. , Cingolani R. , Rinaldi R. , Verbeet M. Ph. , de Waal E. , Canters G. W.
Published: November 2004

We have studied the morphological, conformational, and electron-transfer (ET) function of the metalloprotein azurin in the solid state, by a combination of physical investigation methods, namely atomic force microscopy, intrinsic fluorescence spectroscopy, and scanning tunneling microscopy. We demonstrate that a “solid state protein film” maintains its nativelike conformation and ET function, even after removal of the aqueous solvent.
Some effects of leaf-roll virus on the development and growth of the potato plant
Authors: Bald JG , Hutton EM
Published: November 2004

A detailed field trial and other experiments were made to explore the effects of leaf roll on the growth of different varieties of potato. The shoots of a tolerant variety, Up to Date, were little changed in size by infection at emergence, but during the early vegetative stage of development the growth rate of the haulm was reduced. The shoots of an intolerant variety, Bismark, were probably smaller in size at emergence, and for a period during the vegetative stage of development the tops of the plants grew at the same reduced rate as those of Up to Date and three other varieties. These other three varieties, which were intermediate in tolerance, were intermediate in growth reaction between Up to Date and Bismark. The tolerant variety, Up to Date, during the first stages of tuberation, reacted to infection without serious changes in length of stolons or time of initiation of tubers. The intolerant variety, Bismark, reacted with a shortening of stolons and a hastening of tuber initiation. The reduction in size of various parts of the plant was greater for intolerant than for tolerant varieties. The numbers of leaves developing on the main axes of both tolerant and intolerant varieties were reduced by infection. The reduction in the proportion of leaf area contributed by axillary shoots to the total leaf area of infected plants, was similar in the tolerant and intolerant variety, in spite of the difference in the size of the plants. In the intolerant variety, Bismark, there was a change in type of axillary growth above ground as well as a change in vigour. The course of development of the foliar parts of the plant during maturity and senescence demonstrated the serious alteration in growth characteristics of the infected plants of the intolerant variety Bismark. There was relatively little alteration in the tolerant variety, Up to Date. Incomplete data suggest that losses in yield due to infection are not due to a reduction in efficiency per unit of leaf area in the production of tubers by infected plants. The reduction can be accounted for on the basis of reduced growth rate, loss in size of haulm. The repercussions of these findings on the problem of breeding for resistance against leaf roll are mentioned.
Seedling blight. I. Seed colour and soil in relation to pre-emergence blight of William Massey peas
Authors: Angell HR
Published: November 2004

Using a local soil the emergence of samples of William Massey peas supplied by nineteen growers varied from less than 50 to more than 80 per cent. In tests of ten samples, those with cotyledons more uniformly green in colour germiwated best. The percentage emergence of green peas from a local soil was significantly higher than that of yellow peas from the same sample, that of yellow-green peas being intermediate. Low percentage emergence of the yellow peas was due partly to a fraction of seed of low vitality common to all colours and partly to a low degree of resistance to fungal infection. Emergence of a sample of peas sown in three different soils was 39, 60, and 83 per cent. Differences in the percentages were due mainly to the influence of the soil environment on the susceptibility of the yellow pea fraction to pre-emergence blight. Percentage emergence of yellow peas and green peas also appears to be inversely correlated with reputed soil fertility. The percentage emergence of a sample of peas can be varied significantly, by varying the soil in which the seed is sown during the first three days of germination. The fungus associated with pre-emergence blight in all soils that have been sufficiently tested is commonly referred to as Pythium ultimum Trow. In addition to the usual dusting methods, control of pre-emergence blight of peas may be improved by the use of resistant seed and where possible the selection of suitable soils for sowing such seed. Appendix I contains a note on the name Pythium ultimum (Trow).
Observations on the control of the cattle tick with preparations of DDT and Benzene Hexachloride (BHC) in dips
Authors: Norris KR , Roulston WJ , Snowball GJ
Published: November 2004

Two formulations of DDT and one of BHC were tested against the cattle tick (Boophilus microplus Canest.). The DDT preparations, a dispersible powder and a dispersible paste, were not as toxic to the tick as the colloidal formulation reported on by Hitchcock and Mackerras (1947). The BHC preparation at a concentration of 0.05 per cent. gamma isomer killed almost all ticks but the period of protection against reinfestation was shorter than that afforded by this colloidal DDT preparation. The results of analyses are presented to illustrate the concentrations maintained during dippings and the rates of dispersion and settling.
Observations on the bionomics of Linognathus pedalis
Authors: Scott MT
Published: November 2004

Studies on the life cycle and on populations of Linognathus pedalis are described. The incubation period of the egg is 17 days, followed by three nymphal instars, each of approximately 7 days, and a preoviposition period of 5 days. The period from egg to egg is, therefore, approximately 43 days. The female deposits approximately one egg per day. There is a pronounced seasonal fluctuation in populations, which reach a maximum from July to October and a minimum from December to March. Lambs are most susceptible to L. pedalis and may become infested within a few hours after birth. Infestations may be acquired either by direct contact with infested sheep or from an infested environment. Under suitable conditions of temperature and humidity, L. pedalis can survive far up to 18 days away from the sheep, and it has been shown experimentally that lambs can become infested from pastures at least three clays after removal of infested sheep.
Studies in the variation of soil reaction. III. Variations at the Waite Agricultural Institute
Authors: Raupach M
Published: November 2004

Variations in reaction and total soluble salts of a red-brown earth from South Australia have been assessed. Seasonal changes are discernible for reaction but are largely masked by spatial variations even over small areas. The amplitude of the seasonal changes is of the order of 0.15 of a pH unit, the soil returning to the same pH value during the succeeding season. Spatial variations have been found for organic carbon, nitrogen, clay, and exchangeable cations over small areas. Data have been presented to show that while the mean soil reaction does not vary widely, there is a variation in the variance of the reaction values about the mean with season. The change of the reaction status of the soil with time over a small area does not consist of a uniform increase and decrease of 911 the reaction values in the area but rather of a reorganization of all hydrogen ion contributing factors to give difference in dispersion about the mean value.
Identification of the volatile fatty acid in the peripheral blood and rumen of cattle and the blood of other species
Authors: McClymont GL
Published: November 2004

Volatile fatty acid isolated from nine samples of peripheral blood from four cows contained, on a molecular basis, from 90.0 to 97.0 per cent. of acetic acid (mean 93.3 per cent.). The remainder comprised, as mean values, propionic acid, 2.39 per cent.; butyric acid, 2.61 per cent.; and a group of at least three acids between butyric and octanoic, 1.84 per cent. The significance of the high proportion of acetic acid in the volatile fatty acid of bovine peripheral blood is discussed. Only traces of esterified acids lower than octanoic could be found in bovine blood lipides. Volatile fatty acids were found also in the blood of the rabbit, guinea pig, horse, and pig and in human plasma. Here again a high proportion of acetic acid was recorded. Volatile fatty acid isolated from nine samples of ruminal contents from two cows contained on a molecular basis from 52.3 to 69.0 per cent. of acetic acid (mean 60.0 per cent.). The remainder comprised, as mean values, propionic acid, 21.8 per cent.; butyric acid, 14.4 per cent.; and acids higher than butyric (apparently largely valeric and hesanoic), 3.8 per cent. This limited number of analyses indicated no gross effect of type of feed on the proportion of the acids in the rumen.
Further experiments in the control of Aphodius howitti Hope by DDT
Authors: Carne PB
Published: November 2004

Continued observations on Aphodius populations in a pasture treated with DDT in 1946 (Carne 1948) indicate that a single such treatment results in a marked depression of the larval population for at least three seasons. It has been shown that dosages of DDT as low as 10 ounces† per acre result in an effective control of first-instar larvae. The use of DDT-impregnated superphosphate is a simple and effective means of preventing the occurrence of Aphodius infestations in susceptible pastures.
Plant responses to nitrogen and sulphur on a heavy clay soil from the Darling Downs, south-east Queensland
Authors: Andrew CS , Kipps EH , Barford H
Published: November 2004

Pot experiments in connection with investigations into poor establishment of certain pasture species on several heavy clay soils on the Darling Downs have shown nitrogen and sulphur to be the principal elements limiting plant growth. Addition of these nutrients in combination to the soil has resulted in a substantial increase in plant growth associated with an even greater increase in protein production. These increases greatly exceed those obtained with either nutrient singly. Zinc availability in the soil is also discussed.
Seedling blight. 6. The effect of mixtures of unsterilized soils, and of reinfesting steamed soils, on seedling blight of poppies and peas
Authors: Angell HR
Published: November 2004

Soils of different seedling blight potential were used in various combinations in pot experiments to ascertain the effect of the mixtures on the incidence of seedling blight. The species of Pythium associated with seedling blight of peas and poppies were widely and well distributed throughout the soils, three of which had never before been sown to these or related crops. Four grams of each of three soils were added in turn as inoculum to 2.5 kg. of each of the other two soils. Stands of peas and poppies were generally unaffected by such small additions, but in one instance the stand of peas was reduced. Similar experiments were made with four unsteamed soils as inoculum, each added to the same four soils which had previously been steamed. The soil inoculum which caused seedling blight of peas on an unsteamed soil caused much greater reduction in stands of peas on all four steamed soils. Percentage stands of poppies were reduced in two soils. In another series of experiments, unsteamed soils of contrasting seedling blight potential each mixed in three proportions. The transition from good to poor stands of poppies was gradual, and tended to be directly proportional to the percentage of one of the component soils, whereas with peas the transition was abrupt, a high percentage of seedling blight being obtained by incorporating in the mixture the soil which had a high disease potential to peas. It appears that the stand of peas in the soil which was common to both mixtures was influenced principally by the pathogens, whereas the stand of poppies was influenced almost wholly by the conditioning factor, which was the general character of the soil itself.
Soil-structure changes in a long-term citrus experiment.
Authors: Greacen EL , Perkman O
Published: November 2004

Data are given on the changes induced in the physical properties of the soil in a factorial experiment in which cultural, irrigation, and nitrogen treatments are being tested on citrus. Apart from an increase in the non-capillary porosity of the surface layer to the depth of cultivation, there is no difference to be noted in porosity between the cultivated plots with the addition of organic matter and the uncultivated bare-surface plots where no organic matter is added. Under permanent sod the total non-capillary porosity is reduced but larger pores are present, 44 per cent. being in the form of insect burrows 2 mm. and more in diameter. The initial infiltration rates of the cultivated plots reflect the high porosity of the surface layer, but there is no difference in the final infiltration rates for these and the bare-surface plots. The infiltration rate of the sod plots is four times as high as in the other treatments, and is attributable to the effective hydraulic area of the faunal burrows. Cultivation has reduced aggregate stability as compared with uncultivated bare-surface and sod treatments, and the sod plots are considerably better in this respect than the bare-surface plots. This is not reflected in the soil organic carbon contents. Aggregate stability increases with increasing ammonium sulphate applications regardless of the cultural treatments. This is associated with increasing soil acidity, which, incidentally, may influence structure through its effect on microflora and exchangeable cations.
Studies in soil fertility with special reference to organic manures. III. Residual effects of the organic matter.
Authors: Williams RF , Spencer K
Published: November 2004

The results of two field experiments and a pot-culture experiment to assess the residual effects of organic manures of the plant-residue type are reported. In the first field experiment, to which superphosphate was added at seeding, no residual effects of the organic manures were observed. In the second field experiment, with cabbage as the test crop, rice-hull pretreatment gave a highly significant yield increase of seven tons per acre. This is attributed to increased phosphorus supply, and the interpretation is supported by analytical data for the cabbage heads. A parallel pot-culture experiment with tomatoes confirmed the findings of the field experiment and indicated that the nitrogen status of the soil had also been slightly improved by rice-hull pretreatment. It is shown that at the beginning of the cabbage and pot-culture experiments, rice-hull pretreatment had increased the inorganic but not the organic soil-phosphorus fractions. The development of the interaction of current phosphorus treatment with rice-hull pretreatment is illustrated by seedling-harvest data for the cabbage experiment, and weekly leaf-area measurements are used in a detailed study of treatment interactions in the pot-culture experiment.
Rhizosphere relationships of subterranean clover. I. Interactions between strains of Rhizobium trifolii.
Authors: Harris JR
Published: November 2004

A study was made of a number of effective and ineffective strains of Rhizobium trifolii in association with subterranean clover (Trifolium subterraneum L.), variety Bacchus Marsh. Where these were inoculated singly into sterilized soils in pot experiments conducted in the greenhouse, typical effective, ineffective, or intermediate plant reactions were obtained. Where more than one strain was inoculated, competition between strains took place and was reflected in nodule pattern and plant reaction. Some strains consistently failed to produce appreciable nodules in the presence of other rhizobia, some showed modification to varying degrees, and some were unaffected. Such behaviour was found to be closely linked with the ability of the strain to proliferate in the rhizosphere of the host plant, and placement of inoculum was shown to influence plant reaction. The concept of "incursion" as a property of a rhizobial strain is suggested. An incursive strain is one able to migrate from the initial site of inoculation and establish an adequate population in the root zone of the susceptible host despite the presence of active elements of the indigenous microflora and microfauna, including antagonistic and predatory forms. The property of incursion is independent of considerations of efficiency of nitrogen fixation or virulence for the host plant. Strains of rhizobia which are poorly incursive may fail to infect the host upon which they have been inoculated if subject to competition from indigenous rhizobia already established in the soil. The necessity of assessing properties of virulence and incursion as well as efficiency of nitrogen fixation in selecting rhizobia for purposes of commercial inoculation is stressed, and the methods of making such tests are discussed.
Selection for economic characters in Australian Merino sheep.
Authors: Morley FHW
Published: November 2004

The effect of inbreeding and parent-offspring regressions for some economic characters of Merino sheep were estimated by a least-squares procedure. The model was: Yi = a + b1X1i + b2X2i + ei ,where Yi and X1i represent the phenotype and coefficient of inbreeding of the ith sheep, X2i the phenotype of the dam of that sheep, and ei the random deviation of Y, from its expected value. Increased coefficients of inbreeding were accompanied by highly significant decreases in greasy and clean fleece weights, body weight, and fold score. No significant association was observed between inbreeding and yield, staple length, crimps per inch, or birthcoat grading. Increased inbreeding was associated with decreased survival. Significant correlations between X1 and X2 were demonstrated for fleece weights, staple length, body weight, and crimps per inch. The implications of these correlations are discussed. The parent-offspring regressions were all highly significant. Estimates of heritability were high for all characters studied. The importance of these findings on the effectiveness of selection for flock improvement is considered.
Development of the fibre population in N-type sheep.
Authors: Fraser AS , Ross JM , Wright GM
Published: November 2004

Several types of follicles occur in the skin of sheep. These have been shown to differ in the types of fibres they form, when these are classified on shape of tip curl, occurrence of medulla, size of crimps, rate of growth, and frequency of shedding as kemps. Fibre type frequency distributions have been analysed. In non-N-type, halo-hairs and fibres with a sickle-shaped tip, forming the pre-curly-tip group, can only be formed in primary central follicles, which ordinarily all grow pre-curly-tip fibres, although occasionally these follicles produce curly-tip fibres. The primary lateral follicles all grow curly-tip fibres which grow also in the early secondary follicles. The late secondary follicles grow fibres with a tip of indefinite shape, histerotrichs. In N-type sheep primary centrals always form pre-curly-tip fibres, with the reservation that in Plateau arrays with few or no fibres classed as supersickle- fibres it is believed that some fibres called hairy-tip–curly-tip fibres grow in primary central follicles; primary laterals form hairy-tip–curly-tip fibres save in some N/+ lambs; and the secondaries form curly-tip and histerotrich fibres. The primary follicles are strongly affected by the N and nr genes, which have much less effect, if any, on the secondaries. Fibre growth rates and consequently size of crimps, and frequency of occurrence of brown fibres and of shedding as kemps, are all higher in primary than in secondary fibres in N-type sheep, and in N-type than in non-N-type, showing that the N and nr genes affect the primary more than the secondary follicles in these characteristics.
The effect of intensity of daylight on egg production of fowls in cages.
Authors: Skaller F , Allen TE , Sheldon BL
Published: November 2004

Fowls kept in individual laying cages may be exposed to very different intensities of daylight according to the position of the cage in relation ta the source of light. Daylight-intensity readings in two buildings housing laying-cage batteries varied from 1-8 ft. candles at 4.30 p.m. and 7-11 ft. candles at 9.30 a.m., in positions of low light, to 16-35 ft. candles at 4.30 p.m. and 65-172 ft. candles at 9.30 a.m. in positions of high light. Analysis of records from 170 pullets from selected positions showed no significant difference among egg production of birds exposed to this range of light intensities,
Competition among pasture plants. II. The influence of density on flowering and seed production in annual pasture plants.
Authors: Donald CM
Published: November 2004

Inflorescence and seed production were studied in swards of varying 5 density of two annual Mediterranean pasture plants, Trifolium subterraneum L. and Lolium rigidum Gaud., each in pure culture. While the maximum level of dry matter production, achieved at moderate densities, was maintained at all higher densities, seed production showed a peak at moderate densities and thereafter a progressive decline. The greatest number of inflorescences was produced at densities exceeding those of peak seed production. Although the most widely spaced plants had the greatest numbers of inflorescences and seeds per plant, they had smaller seeds and fewer seeds per inflorescence than did substantially denser swards, apparently owing to intense intra-plant (inter-inflorescence) competition at the widest spacings. It is suggested that the results can be explained in terms of the changing competitive relationships between and within the plants of the sward at the times of initiation of flower primordia, of floral development, and of seed production. Dense swards give most of the attributes needed in the use of these plants for grazing purposes; for seed multiplication swards of moderate densities give the highest yields of seed per unit area.
Pasture studies on the coastal lowlands of subtropical Queensland. I. Introduction and initial plant nutrient studies.
Authors: Andrew CS , Bryan WW
Published: November 2004

A general description of the underdeveloped coastal lowlands of southern Queensland is given. Location, soils, vegetation, climate, present use, and problenls confronting investigators are dealt with. Plant nutrient studies on a low humic gley at Beerwah and a humic gley soil at Glasshouse Mountains are reported. For both soils the plant responses are qualitatively similar but they differ in degree. The limiting nutrients for plant growth are phosphorus, nitrogen, calcium, potassium, copper, zinc, molybdenum, and boron in descending order of importance. For an efficiently nodulated legume, added nitrogen is not required. Soil chemical analyses and plant analyses show that the nutrients to which responses are obtained are in extremely low supply in the soils. The effect of over-liming on these soils is discussed in relation to change of soil pH, and availability of copper and zinc. Deficiency symptoms of calcium, potassium, and copper for certain species are discussed and observations made on their intensification through the addition of other major nutrients to the soil. Maximum plant growth on these soils can only be obtained if all limiting nutrients are supplied. This may explain in part the failure of earlier attempts to establish agriculture on these soils.
The use of Penicillium chrysogenum mycelium as a fertilizer.
Authors: Thrower LB
Published: November 2004

Waste mycelium from penicillin production is useful as a fertilizer, but its effect is largely that of other organic materials. Penicillium chrysogenum Thom. does not establish itself in the soil and its beneficial influence on soil structure is due to its utilization as a substrate by rapidly growing Mucorales. Residual, crude penicillin contained in the mycelium may have an effect on the soil bacteria, but was not effective as a systemic fungicide in water culture experiments. Any influence due to residual penicillin would be of short duration because the antibiotic is unstable at normal temperatures; autolysis of the mycelium is evident after about 24 hr. Mycelial extract had an adverse effect on the germination and growth of tomato seeds, indicating that it contained a plant growth substance such as indoleacetic acid.
A survey of moisture content in some greasy wool from New South Wales.
Authors: Young SSY
Published: November 2004

A study of fleece moisture content showed that it was not evenly distributed over the body of the sheep. The lower mid side of the fleece showed the highest average moisture content, while positions such as mid shoulder, lower shoulder, flank, and belly showed moisture contents above the mean value. The mid side and mid hindquarter positions showed means approximately equal to the average for the entire fleece. Positions more exposed to the air, such as upper shoulder, upper side, and upper hindquarter, showed lower amounts of moisture. Change in relative humidity during shearing affects slightly the initial moisture content of the wool. High-yielding wool shows a higher affinity for moisture. A strong wool strain of sheep had a significantly higher moisture content than medium and fine wool strains run together in the one environment. Wools of different origin in New South Wales on the showfloor of a wool store exhibited marked and statistically significant differences in moisture content both between and within districts. The variations within districts are greater than the variations between districts. Wool packed in bales, although stored in Sydney for a period of 6 or more weeks, had not reached equilibrium with the coastal atmosphere. Differences as large as 7 per cent. were found on the showfloor. Evidence collected in this study suggests that expert wool valuers and buyers cannot or do not take into consideration moisture content differences which are as large as 6 per cent. Although existing practice in commercial yield estimation apparently does not affect the wool merchants, individual growers selling wool grown, or shorn, or both grown and shorn in drier atmospheric conditions may be losing substantially.
An evapotranspirometer
Authors: Arthur IP
Published: November 2004

The equipment is designed to measure evapotranspiration from a growing crop. It comprises a large container filled with soil and set in the field so that the top is flush with the ground surface, and a device for measuring changes in weight of the contents. The crop in the container is therefore grown under conditions which approximate closely to those in the surrounding field.
Growth of horns in sheep
Authors: Fraser AS
Published: November 2004

N-type sheep, in addition to differing from non-N-type in many characters of the fleece, also differ in the occurrence of horns. N-type sheep have horns, all non-N-type sheep are polled. Data are given of the rates of growth of horns in various N-type sheep and in Scottish Mountain Blackface sheep.
Effects of a lowland rice crop and of gypsum on a saline alkali clay
Authors: Barley KP , Hutton JT
Published: November 2004

Lowland rice cropping for one season decreased the soluble salts, particularly the chlorides, in the top 30 in. of a saline alkali clay soil. The calcium:sodium ratio increased for soluble cations, but showed little change for exchangeable cations. The surface soil became slightly more water-stable, but below 3 in. the soil became easier to disperse. These changes had little effect on the growth of an irrigated annual pasture sown after rice cropping, except in the year of establishment. After 2 years' growth of the pasture, part of the soluble salts had returned to the top 30 in. of the soil. The application of gypsum at 2 and 8 tons/acre before growing the lowland rice crop increased the ca1cium:sodium ratio of both soluble and exchangeable cations and reduced clay dispersion. Rice seedling ,establishment and yields of stubble-sown subterranean clover were higher on the gypsum-treated plots.
Spring frost damage to vines
Authors: Angus DE
Published: November 2004

Detailed temperature measurements among grape-vines, and in the inversion layer in the air overhead, are presented for two nights on which frost damage occurred. The temperatures are related to the varying degrees of damage suffered by the vines. It is concluded that the critical vine-shoot temperature was about 28½°F a t the stage of development of the vines at the time of observation. The air temperature a t the height of the vines was about 1°F higher