1,565 research outputs found
A novel method of supplying nutrients permits predictable shoot growth and root: shoot ratios of pre-transplant bedding plants
BACKGROUND AND AIMS: Growth of bedding plants, in small peat plugs, relies on nutrients in the irrigation solution. The object of the study was to find a way of modifying the nutrient supply so that good-quality seedlings can be grown rapidly and yet have the high root : shoot ratios essential for efficient transplanting.
METHODS: A new procedure was devised in which the concentrations of nutrients in the irrigation solution were modified during growth according to changing plant demand, instead of maintaining the same concentrations throughout growth. The new procedure depends on published algorithms for the dependence of growth rate and optimal plant nutrient concentrations on shoot dry weight Ws (g m–2), and on measuring evapotranspiration rates and shoot dry weights at weekly intervals. Pansy, Viola tricola ‘Universal plus yellow’ and petunia, Petunia hybrida ‘Multiflora light salmon vein’ were grown in four independent experiments with the expected optimum nutrient concentration and fractions of the optimum. Root and shoot weights were measured during growth.
KEY RESULTS: For each level of nutrient supply Ws increased with time (t) in days, according to the equation {Delta}Ws/{Delta}t=K2Ws/(100+Ws) in which the growth rate coefficient (K2) remained approximately constant throughout growth. The value of K2 for the optimum treatment was defined by incoming radiation and temperature. The value of K2 for each sub-optimum treatment relative to that for the optimum treatment was logarithmically related to the sub-optimal nutrient supply. Provided the aerial environment was optimal, Rsb/Ro{approx}Wo/Wsb where R is the root : shoot ratio, W is the shoot dry weight, and sb and o indicate sub-optimum and optimum nutrient supplies, respectively. Sub-optimal nutrient concentrations also depressed shoot growth without appreciably affecting root growth when the aerial environment was non-limiting.
CONCLUSION: The new procedure can predict the effects of nutrient supply, incoming radiation and temperature on the time course of shoot growth and the root : shoot ratio for a range of growing conditions
HPLC and capillary electrophoresis for determination of acids, terpenes and aldehydes in natural rosins
Rosins are natural compounds derived from pine tree resin. They have many uses in industry, including paints, adhesives and soldering fluxes. In this work HPLC and CE was used to characterise rosin samples which are composed of 90% acidic compounds and 10% neutral compounds including aldehydes and terpenes. Cyclodextrin-modified CE methods were developed for the separation of acids, terpenes and aldehyde groups. The presence and concentration of acids in several rosin samples was investigated
Improving Energy Efficiency by Federal Regulation
This paper examines the scope and nature of federal activities devoted to improving the efficiency of energy utilization in buildings, consumer products, motor vehicles, and industrial processes and equipment. Several forms of regulation are identified and their characteristics are explored. It is postulated that consistency of an overall policy of energy efficiency regulation can be ascertained from the examination of a regulatory policy matrix
Directions in the Work of Black American Artists | Barry Gaither
Poster using the three colors of the Pan-African flag, showing portrait omage of Dr. Barry Gaither, Curator for the Museumof the National Center of African American Artists. Derivation of previous poster (May 5 1970). May 4, 1970 was the date of the Kent State University campus shootings, where 4 anti-war protestors were shot and killed by the Ohio National Guard. RISD, as well as campuses across the U.S., shut down as students went on strike in protest of the Kent State killings. It is likely that the May 5 lecture was canceled and rescheduled for October 20, 1970 [see May 5, 1970 poster for same lecture].
Text reads: Lecture by Barry Gaither DIRECTIONS IN THE WORK OF BLACK AMERICAN ARTISTS Tuesday Oct. 20 8p.m. Museum of Art, Rhode Island School of Design. Curator, Museum of the National Center of Afro-American Artists.
Read more about Barry Gaither at ncaaa.org. Poster designed by Maurice Burns, read more at mauriceburns.com.https://digitalcommons.risd.edu/archives_activism_racialjustice/1022/thumbnail.jp
Mainstreaming climate change adaptation into planning and development: A case study in Northern Ireland
This study outlines the adaptation planning journey undertaken by Derry City and Strabane District Council (DCSDC) in Northern Ireland and reflects how the prevailing policy context and level of organisational adaptive capacity create the conditions for mainstreaming climate adaptation into planning and development. This chapter explores the potential of local government in Northern Ireland to integrate local authority policy drivers such as disaster risk reduction (DRR), emergency planning, risk and assurance, and community resilience. The ability to communicate risks and solutions was identified as an important consideration when undertaking adaptation planning, particularly when discussing the adaptation planning process and securing input or support from colleagues. Moreover, a significant amount of engagement was required with local government agencies to increase understanding of the relevance of climate change and DRR. Embedding DRR and climate change adaptation (CCA) within local authority policy and planning can enable a greater understanding of specific risks to local governments and act as a catalyst for further action
Directions in the Work of Black American Artists | Barry Gaither
Poster using the three colors of the Pan-African flag, showing portrait omage of Dr. Barry Gaither, Curator for the Museumof the National Center of African American Artists. May 4, 1970 was the date of the Kent State University campus shootings, where 4 anti-war protestors were shot and killed by the Ohio National Guard. RISD, as well as campuses across the U.S., shut down as students went on strike in protest of the Kent State killings. It is likely that the May 5 lecture was canceled and rescheduled for the fall [see October 20, 1970 poster for same lecture].
Text reads: Lecture: DIRECTIONS IN THE WORK OF BLACK AMERICAN ARTISTS by Barry Gaither, Curator, Museum of the National Center of Afro-American Artists. Tuesday, May 5, 1970 8 p.m. Museum of Art, Rhode Island School of Design, Memorial Hall, Entrance through the museum.
Read more about Barry Gaither at ncaaa.org. Poster designed by Maurice Burns, read more at mauriceburns.com.https://digitalcommons.risd.edu/archives_activism_racialjustice/1021/thumbnail.jp
Determination of the composition of natural rosins using cyclodextrin-modified capillary electrophoresis
Natural rosins are derived from pine tree resin. Their composition is complex and varied depending on the geographical source of the rosin and the part of the tree it is sourced from. They are used widely in industry in paints and varnishes, drug coating and as flux in soldering. Random crystallization of rosins in finished products results in problems e.g. in circuit boards, and the cause is still unclear.
Rosins are composed of 90% acidic compounds and 10% neutrals. The acidic compounds are primarily abietic acid, neoabietic acid, dehydroabietic acid palustric acid and pimaric acid. The neutral compounds compose mainly of aldehydes and terpenes. The acidic composition of rosins has been reported on widely since the early 90’s through the analysis of their methyl esters by GC-MS. However, the neutral compounds of rosins have not been thoroughly investigated.
In this project, rosin samples were analysed by Capillary Electrophoresis (CE) and High Performance Liquid Chromatography (HPLC). A CE method using cyclodextrin-modified buffers was developed and optimised in order to achieve the best separation of the three chemical groups of compounds present in this complex matrix. Having previously identified and quantified the acids present in the samples, this talk focuses on the identification of the neutral compounds present. Spiked samples and various simultaneous UV detection wavelengths were used to determine the identity of compound peaks. Possible links between the differences in composition of rosin samples, and their uses in industry were also addressed
Carnegie Hubble Program: A Mid-Infrared Calibration of the Hubble Constant
Using a mid-infrared calibration of the Cepheid distance scale based on
recent observations at 3.6 um with the Spitzer Space Telescope, we have
obtained a new, high-accuracy calibration of the Hubble constant. We have
established the mid-IR zero point of the Leavitt Law (the Cepheid
Period-Luminosity relation) using time-averaged 3.6 um data for ten
high-metallicity, Milky Way Cepheids having independently-measured
trigonometric parallaxes. We have adopted the slope of the PL relation using
time-averaged 3.6 um data for 80 long-period Large Magellanic Cloud (LMC)
Cepheids falling in the period range 0.8 < log(P) < 1.8. We find a new
reddening-corrected distance to the LMC of 18.477 +/- 0.033 (systematic) mag.
We re-examine the systematic uncertainties in H0, also taking into account new
data over the past decade. In combination with the new Spitzer calibration, the
systematic uncertainty in H0 over that obtained by the Hubble Space Telescope
(HST) Key Project has decreased by over a factor of three. Applying the Spitzer
calibration to the Key Project sample, we find a value of H0 = 74.3 with a
systematic uncertainty of +/-2.1 (systematic) km/s/Mpc, corresponding to a 2.8%
systematic uncertainty in the Hubble constant. This result, in combination with
WMAP7 measurements of the cosmic microwave background anisotropies and assuming
a flat universe, yields a value of the equation of state for dark energy, w0 =
-1.09 +/- 0.10. Alternatively, relaxing the constraints on flatness and the
numbers of relativistic species, and combining our results with those of WMAP7,
Type Ia supernovae and baryon acoustic oscillations yields w0 = -1.08 +/- 0.10
and a value of N_eff = 4.13 +/- 0.67, mildly consistent with the existence of a
fourth neutrino species.Comment: 27 pages, 8 figures, Accepted for publication in Ap
American Institute of Ultrasound in Medicine Recommendations for Contrast‐Enhanced Liver Ultrasound Imaging Clinical Trials
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/135306/1/jum2007266705.pd
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