Water use estimates for various rice production systems in Mississippi and Arkansas     

M. C. Smith  J. H. Massey  J. Branson  J. W. Epting  D. Pennington  P. L. Tacker  J. Thomas  E. D. Vories  C. Wilson 《Irrigation Science》2007,25(2):141-147

Rice irrigation-water use was estimated in Mississippi (MS) and Arkansas (AR) in 2003 and 2004. Irrigation inputs were compared on naturally sloping (i.e. contour-levee system) and mechanically graded fields. In MS, rice production consumed, on average, 895 mm water, but irrigation inputs were greatly affected by production system. Contour-levee systems accounted for 35% of the production area and consumed 1,034 mm irrigation. Fields mechanically graded to a consistent slope of approximately 0.1% (i.e. straight-levee systems) consumed 856 mm irrigation and accounted for 60% of the production area. Fields devoid of slope (i.e. zero-grade system) accounted for 5% of the production area and consumed 382 mm irrigation. In AR, contour-levee rice production consumed 789 mm compared to 653 mm with a straight-levee system. Using low pressure, thin wall (9–10 mil) disposable irrigation tubing to deliver water to each paddy independently reduced irrigation inputs by 28% in MS and 11% in AR when compared to a single-point (levee-gate) distribution system.  相似文献   

Pesticide extraction efficiency of two solid phase disk types after shipping     

Riley MB  Dumas JA  Gbur EE  Massey JH  Mattice JD  Mersie W  Mueller TC  Potter T  Senseman SA  Watson E 《Journal of agricultural and food chemistry》2005,53(13):5079-5083

An interlaboratory study was conducted to compare pesticide recovery from Empore C(18) and Speedisks C(18)XF solid phase extraction disks after shipping. Four pesticides were used for the comparison of the two disk extraction materials: atrazine, diazinon, metolachlor, and tebuconazole. These pesticides were chosen to provide a range of physiochemical properties. Water samples were extracted onto the disk types and shipped to a cooperating laboratory for elution and analysis. The mean recoveries from Empore disks were atrazine, 95%; diazinon, 91%; metolachlor, 92%; and tebuconazole, 83%. The recoveries from Speedisks C(18)XF were atrazine, 89%; diazinon, 87%; metolachlor, 86%; and tebuconazole, 79%. Means for each of the pesticides using the different disk types were not statistically different (alpha = 0.05), but results were more variable when using Speedisks C(18)XF as compared to Empore disks. Reasons for the increased variability are discussed, but overall results indicate that Speedisks C(18)XF could be used as an alternative to Empore disks. Speedisks C(18)XF are enclosed in a plastic housing, so they can be used more easily in remote sampling sites without the possibility of glassware breakage, no prefiltration of samples is needed, and there are realignment problems that can be associated with the Empore disks.  相似文献   

Catalytic hydrolysis of vasoactive intestinal peptide by human autoantibody   总被引：11，自引：0，他引：11  

S Paul  D J Volle  C M Beach  D R Johnson  M J Powell  R J Massey 《Science (New York, N.Y.)》1989,244(4909):1158-1162

Vasoactive intestinal peptide (VIP) labeled with 125I, [Tyr10-125I]VIP, can be hydrolyzed by immunoglobulin G (IgG) purified from a human subject, as judged by trichloroacetic acid precipitation and reversed-phase high-performance liquid chromatography (HPLC). The hydrolytic activity was precipitated by antibody to human IgG, it was bound by immobilized protein G and showed a molecular mass close to 150 kilodaltons by gel filtration chromatography, properties similar to those of authentic IgG. The Fab fragment, prepared from IgG by papain treatment, retained the VIP hydrolytic activity of the IgG. Peptide fragments produced by treatment of VIP with the antibody fraction were purified by reversed-phase HPLC and identified by fast atom bombardment-mass spectrometry and peptide sequencing. The scissile bond in VIP deduced from these experiments was Gln16-Met17. The antibody concentration (73.4 fmol per milligram of IgG) and the Kd (0.4 nM) were computed from analysis of VIP binding under conditions that did not result in peptide hydrolysis. Analysis of the antibody-mediated VIP hydrolysis at varying concentrations of substrate suggested conformity with Michaelis-Menton kinetics (Km). The values for Km (37.9 X 10(-9) M) and the turnover number kcat (15.6 min-1) suggested relatively tight VIP binding and a moderate catalytic efficiency of the antibody.  相似文献   

Science education in the United States: what the scientific community can do   总被引：4，自引：0，他引：4  

W E Massey 《Science (New York, N.Y.)》1989,245(4921):915-921

It is argued that the need to improve science education should be a national priority. Ways are suggested by which the federal government and the scientific community, working together, can address this issue. It is recommended that scientists, engineers, and educators make a significant personal and institutional commitment to participate in science education activities, and that the President of the United States provide the personal leadership to generate a national commitment to the improvement of education at all levels.  相似文献   

Mental rotation of the neuronal population vector   总被引：19，自引：0，他引：19  

A P Georgopoulos  J T Lurito  M Petrides  A B Schwartz  J T Massey 《Science (New York, N.Y.)》1989,243(4888):234-236

A rhesus monkey was trained to move its arm in a direction that was perpendicular to and counterclockwise from the direction of a target light that changed in position from trial to trial. Solution of this problem was hypothesized to involve the creation and mental rotation of an imagined movement vector from the direction of the light to the direction of the movement. This hypothesis was tested directly by recording the activity of cells in the motor cortex during performance of the task and computing the neuronal population vector in successive time intervals during the reaction time. The population vector rotated gradually counterclockwise from the direction of the light to the direction of the movement at an average rate of 732 degrees per second. These results provide direct, neural evidence for the mental rotation hypothesis and indicate that the neuronal population vector is a useful tool for "reading out" and identifying cognitive operations of neuronal ensembles.  相似文献   

Attenuation of Borrelia anserina by serial passage in liquid medium     

J F Levine  M J Dykstra  W L Nicholson  R L Walker  G Massey  H J Barnes 《Research in veterinary science》1990,48(1):64-69

Borrelia anserina (Sakharoff) was successfully grown in a liquid medium (Barbour-Stoenner-Kelly) for 39 passages. By the 12th serial passage in medium, infectivity of B anserina for chicks was lost. Electron microscopy did not reveal structural differences between non-infective and infective cultured organisms. Changes in the protein profiles were found by electrophoresis as the organisms were passed in culture.  相似文献   

Insensitivity of soil biological communities to phosphorus fertilization in intensively managed grassland systems          下载免费PDF全文

P. A. Massey  R. E. Creamer  M. J. Whelan  K. Ritz 《Grass and Forage Science》2016,71(1):139-152

Efficient soil P cycling is essential for promoting optimal and sustainable grassland growth. The soil biological community is regarded as an important source of available P to the plant community. However, the effects of P fertilization on the soil biota are unclear. This study aimed to investigate the effects of P fertilization on plant and soil biological communities in two intensively managed grassland sites that had been receiving mineral‐based P fertilization over a 14‐year period. Both pastures had been frequently cut and harvested for plant material and had received only inorganic fertilizers from the establishment of the trial. Both sites were sampled four times from October 2009 to April 2011 and plant and a range of soil biological parameters were determined at each sampling period. The main findings of this study showed that soil chemical measures, such as labile inorganic P and total P concentrations, and plant yield and P contents responded as expected to P fertilization. However, all soil biological parameters either showed no response or inconsistent responses to P fertilization over the experimental period. This study indicates that intensive management regimes, for example intensive plant harvesting and fertilizer regimes, appear to override the relationship between plant and soil biological communities with respect to their response to P fertilization, and thus their productivity is apparently not predicated upon biotic activity.  相似文献   

The effects of earthworms, botanical diversity and fertiliser type on the vertical distribution of soil nutrients and plant nutrient acquisition     

P. A. Massey  R. E. Creamer  R. P. O. Schulte  M. J. Whelan  K. Ritz 《Biology and Fertility of Soils》2013,49(8):1189-1201

The application of phosphorus (P)-based fertiliser to agricultural soils can result in a skewed vertical distribution of P down the soil profile, since the element tends to accumulate at the soil surface. Such accumulation can have detrimental effects on the environment, as the erosion of surface soil can facilitate the transfer of large quantities of P out of the field into water bodies. Earthworm and plant communities are intricately linked to vertical nutrient distributions in soil, with both communities either facilitating or negating the incorporation of nutrients into the soil matrix. This study aimed to investigate the effect of earthworm presence, plant community structure and fertiliser type to affect the distribution of nutrients in experimental mesocosms; with particular emphasis on the vertical distribution of P. Mesocosms were designed to simulate a soil which has a high P concentration at the surface compared to further down the soil profile. It was hypothesised that the presence of earthworms would facilitate the incorporation of P into the soil matrix and the presence of a more botanically diversity community would assimilate a greater quantity of soil nutrients. After 1 year, mesocosms were deconstructed into five depth ranges, and the distribution of nutrients were modelled and analysed. Results indicated that the presence of earthworms did redistribute soil nutrients from the surface into the matrix beneath. This redistribution was apparent from a reduction in nutrient concentrations in the 0–1 cm depth range. The presence of a more botanically diverse community not only assimilated greater soil nutrient concentrations, but also promoted a less even vertical distribution of soil nutrients, demonstrating the importance of soil biota and plant diversity in the redistribution of soil nutrients.  相似文献   

Intranasal peptide-induced peripheral tolerance: the role of IL-10 in regulatory T cell function within the context of experimental autoimmune encephalomyelitis     

Massey EJ  Sundstedt A  Day MJ  Corfield G  Anderton S  Wraith DC 《Veterinary immunology and immunopathology》2002,87(3-4):357-372

Experimental autoimmune encephalomyelitis (EAE) is a T cell-mediated autoimmune disease commonly employed as a model for multiple sclerosis. Extensive studies have demonstrated that EAE may be prevented or ameliorated by the intranasal administration of soluble peptides representing encephalitogenic epitopes. There is increasing evidence that this peptide administration may function via the generation of regulatory cells. The mechanism of action of these cells remains controversial and it seems likely that it may vary between experimental models. At present the majority of work on regulatory cells has centred on characterising naturally occurring regulators, or those generated artificially ex vivo, and less is known about induced regulatory cells produced following peptide administration. This report aims to briefly outline the evidence for the existence of natural regulatory T cells and to introduce the sub-types of induced regulatory T cells now recognised.In several of these regulatory cell systems investigated to date, interleukin-10 (IL-10) has been shown to be important in cell function. This has not been directly investigated in a model employing peptide therapy to induce peripheral tolerance, hence the purpose of this study was to investigate the role of IL-10 in the generation of these regulatory cells. This work has employed both a TCR transgenic mouse system, for predominantly in vitro studies of cell function, and an IL-10 knock-out mouse strain to investigate in vivo disease protection. The results summarised in this report demonstrate that IL-10 is fundamentally important in the generation of disease protection following intranasal peptide therapy.  相似文献   

Three miniature lung ventilators     

L W Hall  G M Massey 《The Veterinary record》1969,85(16):432-437

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