4,843 research outputs found
Conservation Evaluation of the Seaside Birds-foot Trefoil, Lotus formosissimus, in Canada
In Canada, Seaside Birds-foot Trefoil, Lotus formosissimus, is restricted to the Victoria area on southeastern Vancouver Island and two adjacent islands. Populations at five sites are extant and have been recently inventoried, whereas populations at two or more sites in Victoria are extirpated. Existing populations represent the northern range limits of L. formosissimus. Although known populations are protected to a certain extent from direct habitat destruction, introduced herbaceous species may pose a serious threat to the continued existence of most populations and may prevent the establishment of L. formosissimus at other sites. Fire suppression, grazing, encroachment and low survivorship are also limiting factors
Conservation Evaluation of the Prairie Lupine, Lupinus lepidus var. lepidus, in Canada
In Canada, Prairie Lupine, Lupinus lepidus var. lepidus, is restricted to southeastern Vancouver Island. Of the nine sites where it has been collected, five are extirpated and the status of two of the populations is uncertain. There are two extant populations; some of the other sites may contain the species in the seed bank. Some of the sites are protected to a certain extent from direct habitat destruction by their remote location, although introduced herbaceous species may pose a serious threat by preventing the establishment of the species at other sites. Fire suppression or the lack of other types of disturbance also likely plays a role in discouraging emergence of Lupinus lepidus
On The Misuse Of Confidence Intervals For Two Means In Testing For The Significance Of The Difference Between The Means
Comparing individual confidence intervals of two population means is an incorrect procedure for determining the statistical significance of the difference between the means. We show conditions where confidence intervals for the means from two independent samples overlap and the difference between the means is in fact significant
The strength relationship between the cube and cylinder
Abstract: Concrete laboratory tests compressive strengths differ in a laboratory depending on whether the shape of the concrete specimen is either a cube or a cylinder. General assumption has defined the cylinder to possesses, approximately 80 % of the cube strength. The validity of this approximation needs to be assessed; as several studies have shown this approximation to be invalid. This investigation assessed the effect of compressive strength and curing age of concrete on the Cylinder–Cube Strength Relationship (CCSR) of South African Concretes. Cubes and cylinders were cast for 7, 28 and 56 day curing ages from 36 concrete mixes varying in strength, aggregate type and cement type. Concrete strength did not influence the CCSR, but rather, the CCSR was influenced by the curing age (r = 0.998). The general CCSR values were 83.66 %, 84.88 % and 86.96 % (on average) for 7, 28 and 56 day concrete, respectively. The overall average CCSR, calculated considering results across all curing ages, was 85.17 %. This research shows that 80 % is not an accurate representative value of the average CCSR for typical concretes varying in composition. In addition, this study also acknowledged that the CCSR cannot simply be represented by a single value. This research does however propose that if there should be a value that provides a better guideline to what can generally be expected, should accuracy not be a requirement, an average CCSR of 85 % should be adopted, as opposed to 80 %
The influence of aggregate on the elastic modulus of concrete
Abstract: Concrete is a heterogeneous material and as a result, there are numerous factors that contribute to its resulting modulus of elasticity (E). One of the major factors is said to be the type of aggregate. This study assesses the influence of aggregate type on concrete E, through the use of 36 mixes each containing one of four commonly used South African aggregates namely, granite, quartzite, andesite and dolomite. The E for each concrete mix was determined for 7, 28 and 56 day concrete and their results were analyzed according to the E of the aggregate type contained. The E values of the concretes were found to decrease with a decrease in the E of the included aggregate, in the order dolomite, quartzite, andesite and granite. The aggregate type significantly influences the E of concrete. In fact, the specific influence of an aggregate on concrete E can be mainly attributed to the E of the included aggregate
Utility of Phylloplanins as Antibiotics, Selective Fungicides and for Enhancing Microbial Resistance in Crop Plants
The invention is directed to methods and compositions that inhibit pathogen proliferation. More particularly, these methods and compositions involve the use of phylloplane proteins as antibiotics against human and animal pathogens
Method Utilizing the Tobacco Phylloplanin Promoter for Expression of Nucleic Acids as Gene Products Directed to Aerial Surfaces of Plants
A method and system is provided for generating excreted gene products in a plant which includes generating a nucleic acid fusion construct comprising a phylloplanin promoter and a selected non-phylloplanin nucleic acid sequence whose transcription product is to be expressed and delivered to an aerial surface of a plant. The method includes transfecting plant cells with the nucleic acid fusion construct and allowing the plant cells to express the non-phylloplanin nucleic acid sequence transcription product which is then excreted from the plant cells to the aerial surfaces
The influence of fly ash and ground granulated blast-furnace slag on the elastic modulus of concrete
Abstract: The typical South African cementitious material used in industry today differs from what was commonly used in the past. With the move toward reducing carbon emissions in the cement manufacturing industry, extenders have now become a staple part of nearly all binder type materials. Along with this shift in cement type manufacturing, it is imperative that the effect of these common modern cement types be assessed in terms of their influence on the Elastic Modulus (E) of concrete. This study includes the assessment of 36 different concrete mixes where each mix differed in strength, aggregate type and cement type. A total of four cement types were utilized and chosen according to the type and proportion of extenders used. These cements were CEM I 52.5N, CEM II A-M 42.5N (15 % FA), CEM II A-M 42.5N additionally extended with 30 % FA, and CEM III A 32.5N (60 % GGBS). The E of concrete was determined for each mix and the results of specimens were grouped according to curing age and cement type for analytical purposes. Specimens were cast for 7, 28 and 56 day tests. The presence of FA had a slight influence on concrete E at early ages whereas GGBS concrete showed no significant differences in E compared to the CEM I concrete, for all ages included in this study. In general, the effect of FA and GGBS can be regarded negligible, except in the case where the E at an early ages is of vital concern
Superactive inhibitors of angiotensin converting enzyme Analogs of BPP9a containing dehydroproline
Protein structural variation in computational models and crystallographic data
Normal mode analysis offers an efficient way of modeling the conformational
flexibility of protein structures. Simple models defined by contact topology,
known as elastic network models, have been used to model a variety of systems,
but the validation is typically limited to individual modes for a single
protein. We use anisotropic displacement parameters from crystallography to
test the quality of prediction of both the magnitude and directionality of
conformational variance. Normal modes from four simple elastic network model
potentials and from the CHARMM forcefield are calculated for a data set of 83
diverse, ultrahigh resolution crystal structures. While all five potentials
provide good predictions of the magnitude of flexibility, the methods that
consider all atoms have a clear edge at prediction of directionality, and the
CHARMM potential produces the best agreement. The low-frequency modes from
different potentials are similar, but those computed from the CHARMM potential
show the greatest difference from the elastic network models. This was
illustrated by computing the dynamic correlation matrices from different
potentials for a PDZ domain structure. Comparison of normal mode results with
anisotropic temperature factors opens the possibility of using ultrahigh
resolution crystallographic data as a quantitative measure of molecular
flexibility. The comprehensive evaluation demonstrates the costs and benefits
of using normal mode potentials of varying complexity. Comparison of the
dynamic correlation matrices suggests that a combination of topological and
chemical potentials may help identify residues in which chemical forces make
large contributions to intramolecular coupling.Comment: 17 pages, 4 figure
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