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Limited Variation (limited + variation)
Selected AbstractsA Work Sampling Study of Provider Activities in School-Based Health CentersJOURNAL OF SCHOOL HEALTH, Issue 6 2009Brian Mavis PhD ABSTRACT Background:, The purpose of this study was to describe provider activities in a convenience sample of School-Based Health Centers (SBHCs). The goal was to determine the relative proportion of time that clinic staff engaged in various patient care and non-patient care activities. Methods:, All provider staff at 4 urban SBHCs participated in this study; 2 were in elementary schools, 1 in a middle school, and 1 in a school with kindergarten through grade 8. The study examined provider activity from 6 days sampled at random from the school year. Participants were asked to document their activities in 15-minute intervals from 8:00 a.m. to 5:00 p.m. A structured recording form was used that included 35 activity categories. Results:, Overall, 1492 records were completed, accounting for 2708 coded activities. Almost half (48%) of all staff activities were coded as direct patient contact, with clinic operations the second largest category. Limited variations in activities were found across clinic sites and according to season. Conclusions:, A significant amount of provider activity was directed at the delivery of health care; direct patient care and clinic operations combined accounted for approximately 75% of clinic activity. Patient, classroom, and group education activities, as well as contacts with parents and school staff accounted for 20% of all clinic activity and represent important SBHC functions that other productivity measures such as billing data might not consistently track. Overall, the method was acceptable to professional staff as a means of tracking activity and was adaptable to meet their needs. [source] A versatile electrophoresis system for the analysis of high- and low-molecular-weight proteinsELECTROPHORESIS, Issue 11 2003Christophe Tastet Abstract A new, versatile, multiphasic buffer system for high-resolution sodium dodecyl sulfate-polyacrylamide gel electrophoresis of proteins in the relative molecular weight range of 300,000,3000 Da is described. The system, based on the theory of multiphasic zone electrophoresis, allows complete stacking and destacking of proteins in the above Mr range. The buffer system uses taurine and chloride as trailing and leading ion, respectively, and Tris, at a pH close to its pKa, as the buffering counterion. Coupled with limited variation in the acrylamide concentration, this electrophoresis system allows to tailor the resolution in the 6,200 kDa Mr range, with minimal difficulties in the post electrophoretic identification processes. [source] Genetic variation in eastern North American and putatively introduced populations of Ceratocystis fimbriata f. plataniMOLECULAR ECOLOGY, Issue 10 2004C. J. B. ENGELBRECHT Abstract The plant pathogenic fungus Ceratocystis fimbriata f. platani attacks Platanus species (London plane, oriental plane and American sycamore) and has killed tens of thousands of plantation trees and street trees in the eastern United States, southern Europe and Modesto, California. Nuclear and mitochondrial DNA fingerprints and alleles of eight polymorphic microsatellite markers of isolates of C. fimbriata from these regions delineated major differences in gene diversities. The 33 isolates from the eastern United States had a moderate degree of gene diversity, and unique genotypes were found at each of seven collection sites. Fingerprints of 27 isolates from 21 collection sites in southern Europe were identical with each other; microsatellite markers were monomorphic within the European population, except that three isolates differed at one locus each, due perhaps to recent mutations. The genetic variability of C. fimbriata f. platani in the eastern United States suggests that the fungus is indigenous to this region. The genetic homogeneity of the fungus in Europe suggests that this population has gone through a recent genetic bottleneck, perhaps from the introduction of a single genotype. This supports the hypothesis that the pathogen was introduced to Europe through Naples, Italy during World War II on infected crating material from the eastern United States. The Californian population may also have resulted from introduction of one or a few related genotypes because it, too, had a single nuclear and mitochondrial genotype and limited variation in microsatellite alleles. [source] Spatial determination of successive spikes in the isolated cat duodenumNEUROGASTROENTEROLOGY & MOTILITY, Issue 6 2004W. J. E. P. Lammers Abstract, In seven isolated segments of the feline duodenum, the timings of all spikes and the locations of all spike patches that occurred after 12,16 successive slow waves were analysed. Simultaneous recordings were performed during 1-min periods using 240 extracellular electrodes (24 × 10 array; interelectrode distance 2 mm) positioned onto the serosal surface. In all seven preparations, spikes always occurred during the first half of the slow wave cycle. From preparation to preparation, and within 1-min periods in each preparation, there was limited variation in the spike,spike intervals, in the times between the spikes and the preceding slow wave and in the number of spikes at each electrode site. In contrast, the number of electrode sites that recorded spikes and the number of spike patches both showed great variability between preparations and sometimes within a single preparation. In addition, the location of spikes and spike patches was not random but was significantly concentrated in certain areas, often located along the anti-mesenteric border, while other sites showed little or no spike activity. In conclusion, spikes and spike patches tend to occur significantly in some areas and not in others. This spatial heterogeneity will play a role in intestinal motility. [source] Genetic variation in populations of the cacao wilt pathogen, Ceratocystis cacaofunestaPLANT PATHOLOGY, Issue 6 2007C. J. B. Engelbrecht Ceratocystis cacaofunesta (= Ceratocystis fimbriata) causes a lethal wilt disease of cacao (Theobroma cacao) in Latin America. Polymorphic microsatellite markers, (CAT)5 nuclear DNA fingerprints and Hae III mitochondrial DNA fingerprints were used to compare genetic diversity among isolates of C. cacaofunesta collected from populations in western Ecuador, Costa Rica, Colombia, and Rondônia and Bahia in Brazil. Microsatellite markers and nuclear DNA fingerprints separated Ecuadorian isolates from isolates of the other four populations, and these two major groups correspond to genetic lineages already identified from ITS-rDNA sequences and intersterility groupings. Mitochondrial DNA fingerprints also demonstrated substantial diversity and split the Ecuadorian isolates into two groups. All marker types showed limited variation in the Colombian, Costa Rican and Bahian populations, as might be expected for introduced populations that have gone through recent genetic bottlenecks. In contrast, the Rondonian and western Ecuadorian populations showed gene diversity values similar to natural populations of other Ceratocystis species. The Rondonian population was the only sampled population in the native range of T. cacao (the Upper Amazon), and the putatively introduced populations were more closely related to the Rondonian population than to the western Ecuadorian population. The Ecuadorian population is in an area with other native Theobroma species, which may serve as natural hosts. [source] Intercalary Elements, Treefrogs, and the Early Differentiation of a Complex System in the NeobatrachiaTHE ANATOMICAL RECORD : ADVANCES IN INTEGRATIVE ANATOMY AND EVOLUTIONARY BIOLOGY, Issue 12 2007Adriana S. Manzano Abstract Intercalary elements are additional skeletal structures of digits of many anuran amphibians. Twelve terminal clades in the neobatrachian lineage of frogs have intercalary elements revealing it is a homoplastic character with five to seven gains and two to four losses along a consensus phylogeny of the Neobatrachia. We analyzed anatomical variation of intercalary elements, related structures (distal phalanges, tendons, and muscles), and articulations of digits of 45 anuran species, representing eight suprageneric terminal taxa. The intercalary elements are integrated in a complex system that is probably related to different types of movements, which are produced by a similar set of muscles and tendons with limited variation among the studied taxa. Species in the clades Hyloides and Ranoides show distinctive patterns of morphostructural features in their intercalary elements that are usually wedge-shaped and composed of hyaline cartilage in Ranoides, and biconcave and composed of embryonic cartilage in Hyloides. Features derived from the typical hyloid condition may only be interpreted in some Hylidae (Pseudis and Lysapsus) and Centrolenidae. In Ranoides, the described features of the intercalary elements are found in all taxa examined with the exception of Leptopelis, which have an intercalary element similar to the other Ranoides but formed by connective tissue. Several features are shared by all taxa having intercalary elements: (1) the intercalary elements differ from the phalanges by lacking terminal epiphyses, (2) they are present in hands and feet, and (3) they appear in all digits. This finding suggests that the genetic basis for presence of intercalary elements may be homologous in all these taxa and may have evolved only once early in neobatrachian history. Anat Rec, 2007. © 2007 Wiley-Liss, Inc. [source] Local DNA features affect RNA-directed transcriptional gene silencing and DNA methylationTHE PLANT JOURNAL, Issue 1 2008Ute Fischer Summary Transcription of a nopaline synthase promoter (pNOS) inverted repeat provides an RNA signal that can trigger transcriptional gene silencing and methylation of pNOS promoters in trans. The degree of silencing is influenced by the local DNA features close to the target promoter integration sites. Among 26 transgenic Arabidopsis thaliana lines harbouring single copies of a T-DNA including a pNOS- NPTII reporter gene at different chromosomal loci, NPTII RNA levels showed limited variation. When challenged by the silencer transgene providing the pNOS RNA signal, reduction of the NPTII RNA levels in the F1 generation varied by more than 100-fold, ranging from no reduction to reduction to <1% of the non-silenced level. Silencing was generally correlated with proportional DNA methylation in the pNOS region, except for one target transgene showing substantial DNA methylation without adequate silencing. Silencing was progressive through generations. Differences in the degree of silencing among the target transgenes were transmitted at least to the F3 generation, and seemed to be influenced by transgene-flanking sequences. Apparently, close-by repeats promoted, whereas close-by functional genes diminished, the response to the silencing signal. [source] | |||||||||||||