A Revision of the Allium Fimbriatum (Alliaceae) Complex

Allium fimbriatum in California and northern Baja California causes frequent difficulty in identification. The species, as defined by Ownbey, comprises nine varieties and is characterized by great morphologic diversity. No single character or suite of characters separates this species from others in the A. sanbornii alliance. This investigation was undertaken to survey the large number of herbarium specimens that have accumulated since Ownbey\u27s study and to observe all of the taxa in the field or garden, something not accomplished by Ownbey. Orientation of the perianth segments, visible only in living material, along with shape and presence or absence of denticulation, is valuable in distinguishing between taxa. Characters of the ovarian crest processes, including the presence or absence and location of surface ornamentation and the degree to which the margins of the processes are denticulate or fimbriate, are also important. Based on these characters, along with habit, edaphic preference, and geographic distribution, seven species and two varieties are recognized. Of these, A. abramsii, A. denticulatum, A. diabolense, A. munzii, A. parryi, and A. sharsmithae were previously classified by Ownbey as varieties of A. fimbriatum. Chromosome numbers (all n = 7) are reported for each taxon. Line drawings of representative ovarian crests and perianth segments, a key, and distribution maps of the taxa are presented

The Locus of Control Issue in Standards-Based Accountability

Many states have developed complex approaches to standards-based accountability because both policymakers and educators recognize that accountability requires credible assessment tasks – tasks that clearly reflect the language of the standards and that articulate good classroom instruction

Taxonomy of the Allium Tribracteatum (Alliaceae) Complex

Allium tribracteatum and related species present a confusing array in California. Previous attempts at classification have been largely unsuccessful and keys that are available are unworkable. Herbarium and field studies were initiated to ascertain if previously overlooked characteristics could be found that would elucidate relationships within the group. Members of the complex were examined morphologically and cytologically. Based on these investigations four of the seven previously described taxa are considered valid: A. cratericola, A. obtusum, A. tribracteatum, and A. yosemitense. Allium tribracteatum is redefined and A. obtusum is divided into two varieties. Allium obtusum var. conspicuum var. n. is described. A key to the species is presented and relationships within the complex are discussed

Parallel Loss of Plastid Introns and Their Maturase in the Genus Cuscuta

Plastid genome content and arrangement are highly conserved across most land plants and their closest relatives, streptophyte algae, with nearly all plastid introns having invaded the genome in their common ancestor at least 450 million years ago. One such intron, within the transfer RNA trnK-UUU, contains a large open reading frame that encodes a presumed intron maturase, matK. This gene is missing from the plastid genomes of two species in the parasitic plant genus Cuscuta but is found in all other published land plant and streptophyte algal plastid genomes, including that of the nonphotosynthetic angiosperm Epifagus virginiana and two other species of Cuscuta. By examining matK and plastid intron distribution in Cuscuta, we add support to the hypothesis that its normal role is in splicing seven of the eight group IIA introns in the genome. We also analyze matK nucleotide sequences from Cuscuta species and relatives that retain matK to test whether changes in selective pressure in the maturase are associated with intron deletion. Stepwise loss of most group IIA introns from the plastid genome results in substantial change in selective pressure within the hypothetical RNA-binding domain of matK in both Cuscuta and Epifagus, either through evolution from a generalist to a specialist intron splicer or due to loss of a particular intron responsible for most of the constraint on the binding region. The possibility of intron-specific specialization in the X-domain is implicated by evidence of positive selection on the lineage leading to C. nitida in association with the loss of six of seven introns putatively spliced by matK. Moreover, transfer RNA gene deletion facilitated by parasitism combined with an unusually high rate of intron loss from remaining functional plastid genes created a unique circumstance on the lineage leading to Cuscuta subgenus Grammica that allowed elimination of matK in the most species-rich lineage of Cuscuta

Biochemical Characterization of a Filtered Synaptoneurosome Preparation from Guinea Pig Cerebral Cortex: Cyclic Adenosine 3’:5’-Monophosphate-generating Systems, Receptors, and Enzymes

A particulate preparation was obtained by low speed centrifugation of guinea pig cerebral cortical homogenates prepared with a Krebs-Henseleit buffer. Light microscopic examination, using a reflected light differential interference contrast system, reveals the presence of intact neurons, axonal fragments, glial cells, and erythrocytes along with an abundance of small spherical entities (diameter about 1.1 μm) and snowman-shaped entities (diameter of larger sphere about 1.1 μm, diameter of attached smaller sphere about 0.6 μm). Many unattached smaller spherical entities are also present (diameter about 0.6 μm). Pressure filtration through 5 or l0-μm Millipore filters, followed by low speed centrifugation and resuspension, removes most of the larger entities to afford a suspension composed mainly of the small spherical and snowman-shaped entities. Electron microscopic examination reveals the presence of many synaptosomes with attached resealed postsynaptic entities. It is proposed that these correspond to the snowman-shaped entities to be termed synaptoneurosomes. Accumulations of cyclic AMP elicited by 2-chloroadenosine and histamine, and by combinations of 2-chloroadenosine, histamine, norepinephrine, and forskolin, are lower in filtered than in unfiltered preparations, whereas accumulations elicited by forskolin are unchanged. Levels of adenylate cyclase are reduced by filtration, whereas levels of phosphodiesterase are unchanged. Filtration reduces levels of markers for whole cells and endothelial cells, whereas neuronal markers such as acetylcholinesterase activity and norepinephrine uptake are increased. Levels of S-100 protein, a marker for glial cells, are not significantly decreased. There is no apparent change in the density of many receptors or ion channels. Levels of A1-adenosine and H1-histamine receptors are increased, whereas levels of so-called peripheral benzodiazepine-binding sites are decreased

Television viewing and consumer behaviour

Looks at the influence of television on children’s development as consumers,beginning with a literature review of consumer socialisation which establishes the importance of television as an influential model for children’s expressions of nonverbal behaviour and emotion.Explains the results of a survey of Malaysian schoolchildren which considers demographic variables such as gender and family income, and also personality traits, in relation to television viewing habits and consumer behaviour, including propensity to buy, time spent watching television, preferred type of programme etc.Discusses the results, which indicate the importance of family income as a predictor of differences in socialisation; gender is less influential, and of the six personality traits studied, the aggressive - passive is the most influential on socialisation

Carleson Measures and Toeplitz Operators

In this last chapter we shall describe an application of the Kobayashi distance to geometric function theory and functional analysis of holomorphic functions

Methods for Obtaining and Analyzing Whole Chloroplast Genome Sequences

During the past decade there has been a rapid increase in our understanding of plastid genome organization and evolution due to the availability of many new completely sequenced genomes. Currently there are 43 complete genomes published and ongoing projects are likely to increase this sampling to nearly 200 genomes during the next five years. Several groups of researchers including ours have been developing new techniques for gathering and analyzing entire plastid genome sequences and details of these developments are summarized in this chapter. The most important recent developments that enhance our ability to generate whole chloroplast genome sequences involve the generation of pure fractions of chloroplast genomes by whole genome amplification using rolling circular amplification, cloning genomes into Fosmid or BAC vectors, and the development of an organellar annotation program (DOGMA). In addition to providing details of these methods, we provide an overview of methods for analyzing complete plastid genome sequences for repeats and gene content, as well as approaches for using gene order and sequence data for phylogeny reconstruction. This explosive increase in the number of sequenced plastid genomes and improved computational tools will provide many insights into the evolution of these genomes and much new data for assessing relationships at deep nodes in plants and other photosynthetic organisms