9,293 research outputs found
Circular 20
Since fanning in Alaska first began and especially
since dairy farming became the primary agricultural
industry, there has existed a need for
hardy legumes which would survive Alaska winters
and produce satisfactory yields of high quality
forage. To meet this need hundreds of legume
species and strains have been introduced during
the past 40 or more years. Almost all have lacked
the necessary hardiness or have not been satisfactory
agronomically. The release of Alaskland
red clover in the spring of 1953 is the first time
a hardy legume has been made available to
growers in Alaska.Cooperating with the United States Department of Agriculture, Agricultural Research Administratio
Evidence of late Quaternary environmental change in a continental east Antarctic lake from lacustrine sedimentary pigment distributions
A sediment core from Progress Lake, one of the oldest lacustrine sequences in East Antarctica, contains distinct zones dating from a previous interglacial (most likely Marine Isotope Stage 5e, c. 125-115 kyr BP) and the present interglacial (Marine Isotope Stage 1), separated by a transition zone representing when the lake became sub-glacial. Profiles of fossil pigments, determined using high performance liquid chromatography and liquid chromatography-tandem mass spectrometry, show distinct differences in the photoautotrophic community during these two interglacial periods. The first was dominated by algae and purple phototrophic bacteria, with periods of photic zone euxinia indicated by pigments from anoxygenic phototrophic bacteria. Specific chlorophyll a derivatives reveal periods when grazing pressure impacted significantly on the phytoplankton community. The virtual absence of pigments in the transition zone reflects severe restriction of photoautotrophic activity, consistent with the take having become sub-glacial. Retreat of snow and ice in the late Holocene (3345 C-14 yr Bp) allowed establishment of a less diverse primary producer community, restricted to algae and cyanobacteria. Grazers were severely restricted and oxidative transformation was more important than during the previous interglacial. The pigment data provide a unique and detailed insight in to the evolution of the lake ecology over an interglacial-glacial-interglacial transition and strong evidence that the Marine Isotope Stage 5e interglacial in this region of coastal East Antarctica was several degrees warmer than at present
Drosophila as a model system to study nonautonomous mechanisms affecting tumour growth and cell death
The study of cancer has represented a central focus in medical research for over a century. The great complexity and constant evolution of the pathology require the use of multiple research model systems and interdisciplinary approaches. This is necessary in order to achieve a comprehensive understanding into the mechanisms driving disease initiation and progression, to aid the development of appropriate therapies. In recent decades, the fruit fly Drosophila melanogaster and its associated powerful genetic tools have become a very attractive model system to study tumour-intrinsic and non-tumour-derived processes that mediate tumour development in vivo. In this review, we will summarize recent work on Drosophila as a model system to study cancer biology. We will focus on the interactions between tumours and their microenvironment, including extrinsic mechanisms affecting tumour growth and how tumours impact systemic host physiology
Effect of Photobiomodulation on Vinblastine-Poisoned Murine HERS Cells
Objective: The aim of this study was to investigate the effect of near-infrared (NIR) photobiomodulation on the proliferation and glutathione levels in murine Hertwig\u27s epithelial root sheath (HERS) cells after poisoning with vinblastine. Background: Photobiomodulation has been shown to improve wound healing in a number of animal models. There have been no studies on the effect of photobiomodulation on cancer-related chemotherapy injury to the cells that initiate tooth root growth. Materials and Methods: Control groups consisted of murine HERS cells without vinblastine (VBβ) and cells with vinblastine at 10, 20, and 30βng/mL (VB10, VB20, and VB30). Experimental groups consisted of these same groups with light therapy (VB-L, VB10L, VB20L, and VB30L). The cells were exposed to vinblastine for 1βh. Photobiomodulation consisted of a 75-cm2 gallium-aluminum-arsenide light-emitting diode (LED) array at an energy density of 12.8βJ/cm2, delivered with 50βmW/cm2 power over 256βs. Results: Vinblastine alone significantly decreased HERS cell proliferation and glutathione levels at all concentrations (VB10 [β55%, pβ\u3cβ1.0βΓβ10β8]; VB20 [β72%, pβ\u3cβ1.0βΓβ10β9]; VB30 [β80%, pβ\u3cβ1.0βΓβ10β10]; and VB10 [β36%, pβ\u3cβ0.0001]; VB20 [β49%, pβ\u3cβ1.0βΓβ10β6]; VB30 [β53%, pβ\u3cβ1.0βΓβ10β7] respectively). Photobiomodulation significantly increased cell proliferation at all levels of vinblastine exposure (VB10L [+50%, pβ\u3cβ0.0001]; VB20L [+45%, pβ\u3cβ0.05]; VB30 [+39%, pβ\u3cβ0.05]) but not of the control (+22%, pβ =β0.063). The photobiomodulation significantly increased glutathione production in all concentrations of vinblastine except 20βng/mL (VB10L [+39%, pβ=β0.007]; VB20L [+19%, pβ=β0.087]; VB30 [+14%, pβ=β0.025]) and the control (+12%, pβ=β0.13). Conclusions: Photobiomodulation demonstrated an improvement in proliferation and glutathione levels in vinblastine-poisoned murine HERS cells
Management Recommendations for Soybean Aphid (Hemiptera: Aphididae) in the United States
Soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), is the primary pest of soybean, Glycine max L., in the north central region. After more than a decade of research and extension efforts to manage this pest, several consensus management recommendations have been developed for sustainable and profitable soybean production. A summary of integrated pest management (IPM) tactics for soybean aphid are discussed, including cultural, genetic, economic, and chemical controls. To date, sampling and timely foliar insecticides are routinely recommended to protect yield and delay genetic resistance to insecticides. Host plant resistance is a new tool that can regulate populations and reduce the reliance of insecticides to control soybean aphid. A combination of these management tools also will reduce overall production costs and minimize negative environmental effects such as human exposure, and mortality of beneficial insects and other animals
Orientational Ordering and Dynamics of Rodlike Polyelectrolytes
The interplay between electrostatic interactions and orientational
correlations is studied for a model system of charged rods positioned on a
chain, using Monte Carlo simulation techniques. It is shown that the coupling
brings about the notion of {\em electrostatic frustration}, which in turn
results in: (i) a rich variety of novel orientational orderings such as chiral
phases, and (ii) an inherently slow dynamics characterized by
stretched-exponential behavior in the relaxation functions of the system.Comment: 7 pages, 10 figure
External and internal noise surveys of London primary schools
Internal and external noise surveys have been carried out around schools in London, UK, to provide information on typical levels and sources to which children are exposed while at school. Noise levels were measured outside 142 schools, in areas away from flightpaths into major airports. 86% of the schools surveyed were exposed to noise from road traffic, the average external noise level outside a school being 57 dB LAeq. Detailed internal noise surveys have been carried out in 140 classrooms in 16 schools, together with classroom observations. It was found that noise levels inside classrooms depend upon the activities in which the children are engaged, with a difference of 20 dB LAeq between the 'quietest' and 'noisiest' activities. The average background noise level in classrooms exceeds the level recommended in current standards. The number of children in the classroom was found to affect noise levels. External noise influenced internal noise levels only when children were engaged in the quietest classroom activities. The effects of the age of the school buildings and types of window upon internal noise were examined but results were inconclusive
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