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Considerable Variation (considerable + variation)
Selected AbstractsBiofilm formation and cellulose expression among diverse environmental Pseudomonas isolatesENVIRONMENTAL MICROBIOLOGY, Issue 11 2006Susanne Ude Summary The ability to form biofilms is seen as an increasingly important colonization strategy among both pathogenic and environmental bacteria. A survey of 185 plant-associated, phytopathogenic, soil and river Pseudomonas isolates resulted in 76% producing biofilms at the air,liquid (A,L) interface after selection in static microcosms. Considerable variation in biofilm phenotype was observed, including waxy aggregations, viscous and floccular masses, and physically cohesive biofilms with continuously varying strengths over 1500-fold. Calcofluor epifluorescent microscopy identified cellulose as the matrix component in biofilms produced by Pseudomonas asplenii, Pseudomonas corrugata, Pseudomonas fluorescens, Pseudomonas marginalis, Pseudomonas putida, Pseudomonas savastanoi and Pseudomonas syringae isolates. Cellulose expression and biofilm formation could be induced by the constitutively active WspR19 mutant of the cyclic-di-GMP-associated, GGDEF domain-containing response regulator involved in the P. fluorescens SBW25 wrinkly spreader phenotype and cellular aggregation in Pseudomonas aeruginosa PA01. WspR19 could also induce P. putida KT2440, which otherwise did not produce a biofilm or express cellulose, as well as Escherichia coli K12 and Salmonella typhimurium LT2, both of which express cellulose yet lack WspR homologues. Statistical analysis of biofilm parameters suggest that biofilm development is a more complex process than that simply described by the production of attachment and matrix components and bacterial growth. This complexity was also seen in multivariate analysis as a species-ecological habitat effect, underscoring the fact that in vitro biofilms are abstractions of those surface and volume colonization processes used by bacteria in their natural environments. [source] THE EVOLUTION OF THE VERTEBRATE ,-GLOBIN GENE PROMOTEREVOLUTION, Issue 2 2002Nadia A. Chuzhanova Abstract Complexity analysis is capable of highlighting those gross evolutionary changes in gene promoter regions (loosely termed "promoter shuffling") that are undetectable by conventional DNA sequence alignment. Complexity analysis was therefore used here to identify the modular components (blocks) of the orthologous ,-globin gene promoter sequences of 22 vertebrate species, from zebrafish to humans. Considerable variation between the ,-globin gene promoters was apparent in terms of block presence/absence, copy number, and relative location. Some sequence blocks appear to be ubiquitous, whereas others are restricted to a specific taxon. Block similarities were also evident between the promoters of the paralogous human ,-like globin genes. It may be inferred that a wide variety of different mutational mechanisms have operated upon the ,-globin gene promoter over evolutionary time. Because these include gross changes such as deletion, duplication, amplification, elongation, contraction, and fusion, as well as the steady accumulation of single base-pair substitutions, it is clear that some redefinition of the term "promoter shuffling" is required. This notwithstanding, and as previously described for the vertebrate growth hormone gene promoter, the modular structure of the ,-globin promoter region and those of its paralogous counterparts have continually been rearranged into new combinations through the alteration, or shuffling, of preexisting blocks. Some of these changes may have had no influence on promoter function, but others could have altered either the level of gene expression or the responsiveness of the promoter to external stimuli. The comparative study of vertebrate ,-globin gene promoter regions described here confirms the generality of the phenomenon of sequence block shuffling and thus supports the view that it could have played an important role in the evolution of differential gene expression. [source] Indices of Drought Tolerance in Wheat Genotypes at Early Stages of Plant GrowthJOURNAL OF AGRONOMY AND CROP SCIENCE, Issue 1 2004S. S. Dhanda Abstract Thirty diverse genotypes of bread wheat were evaluated for seed vigour index, germination percentage, root length, shoot length, root-to-shoot length ratio, coleoptile length and osmotic membrane stability under laboratory conditions. Considerable variation was observed for all the characters. Discrimination among the genotypes on the basis of mean values was better under normal than under moisture stress conditions, indicating suppression of variability under moisture stress conditions. Comparison of mean performance under normal and osmotic stress conditions indicated that the seed vigour index was the most sensitive trait, followed by shoot length, germination percentage and root length. The root-to-shoot length ratio, however, increased under osmotic stress. The magnitude of genetic components of variance and heritability were, in general, lower under osmotic stress than under normal conditions. All the characters except germination percentage, shoot length and coleoptile length showed considerable genetic variability. Heritability in the broad sense was also moderate to high for all the characters under both environments. Due to high heritability and genetic advance great benefit from selection can be expected for the osmotic membrane stability of leaf segments and root-to-shoot length ratio. Moderate progress can be expected from root length and seed vigour index. Correlation studies indicated that the osmotic membrane stability of the leaf segment was the most important trait, followed by root-to-shoot ratio and root length on the basis of their relationships with other traits. [source] Medium, Explant and Genotype Factors Influencing Shoot Regeneration in Oilseed Brassica spp.JOURNAL OF AGRONOMY AND CROP SCIENCE, Issue 5 2003G. X. Tang Abstract The effects of culture media, explants and genotypes on shoot regeneration in oilseed Brassica species were examined in this study. The maximum shoot regeneration frequency was obtained in Murashige and Skoog medium supplemented with 3 mg l,1 6-benzylaminopurine and 0.15 mg l,1 1-naphthaleneacetic acid. The addition of 2.5 mg l,1 AgNO3 was very beneficial to shoot regeneration in B. napus and Ag2S2O3 (10 mg l,1) was even superior to AgNO3 (2.5 mg l,1). Explant age, explant type and carbon source also significantly affected shoot regeneration. Four-day-old seedlings of cotyledonary explants showed the maximum shoot regeneration frequency and number of shoots per explant. Of the four explants , peduncles, hypocotyls, cotyledons and leaf petioles , cotyledons produced the highest shoot regeneration frequency (56.67 %). Four carbon sources , glucose, maltose, starch and sucrose , were compared for their respective effects on shoot regeneration from cotyledonary explants. Sucrose appeared to be the best carbon source for shoot regeneration with the highest shoot regeneration frequency (76.00 %). Considerable variation in shoot regeneration from cotyledonary explants was observed both between and within Brassica species. The shoot regeneration frequency ranged from 10.00 % for cv. R5 (B. rapa) to 83.61 % for cv. N1 (B. napus). Two B. napus, one B. carinata and one B. juncea cultivars exhibited shoot regeneration frequency higher than 70 %. In terms of the number of shoots produced per explant, B. rapa showed the highest variation, ranging from 5.64 for cv. R3 to 1.33 for cv. R5. Normal plantlets were regenerated from all induced shoots and developed normally. The regenerated plants were fertile and identical with the source plants. [source] New nursing roles: the experience of Scotland's consultant nurse/midwivesJOURNAL OF NURSING MANAGEMENT, Issue 2 2006JOANNE BOOTH BSc Aim, To describe career pathways of consultant nurses/midwives and identify postholders views on key factors in role initiation, development and progression to inform future development and appointment of nurse/midwife consultants in National Health Service Scotland. Background, Nurse/midwife consultants represent the highest levels of clinical practice. Given the Scottish Executive Health Department's aim to treble numbers conditions and circumstances that enable them to flourish must be identified. Method, A postal survey was undertaken of all nurse/midwife consultants in post (n = 16). Results, Key themes emerged around factors that consultant nurse/midwives considered important including mentorship, autonomy and clinical credibility. Barriers to role delivery included lack of understanding of roles and the wide scope of some posts. Considerable variation in support, conditions of service and line management arrangements was found. Conclusions, Development of a recognized career pathway and a consistent approach to employment and support of postholders is recommended. [source] An Economic Analysis of Freshwater Prawn, Macrobrachium rosenbergii, Farming in Mymensingh, BangladeshJOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 1 2008Nesar Ahmed This paper deals with production systems, cost structure, and profitability of freshwater prawn, Macrobrachium rosenbergii, farming in a new area of Mymensingh district in the north-central part of Bangladesh. In the study area, prawn farming practice is still extensive, and only a few farmers (20%) cultivate semiintensively. The costs and returns of extensive and semiintensive farming systems are compared. All farmers in different farming systems made a profit, with seed and feed dominating variable costs. Considerable variation in production costs and profitability was observed. Based on the Cobb,Douglas production function model, return to scale indicates that there is scope to increase production and income from prawn farms in extensive and semiintensive systems by applying more inputs (i.e., seed, feed, and fertilizer). [source] Survey of long-term follow-up programs in the United States for survivors of childhood brain tumors,PEDIATRIC BLOOD & CANCER, Issue 7 2009Daniel C. Bowers MD Abstract Introduction Despite recognition that childhood brain tumor survivors often suffer multiple late effects following therapy, little is known regarding the long-term follow-up (LTFU) programs for these patients. Methods A 16-question survey was mailed to member institutions of the Children's Oncology Group in the United States. Institutions were asked about the size of their brain tumor program, activities of the LTFU programs and perceived barriers to follow-up. Results One hundred forty-five (74%) of 197 institutions returned surveys. Care for patients <21 years old at diagnosis who are >2 years following completion of therapy was provided at a designated neuro-oncology LTFU clinic (31.2%), a general LTFU program for childhood cancer survivors (30.4%), or a general pediatric oncology program (29.7%). Institutions with a neuro-oncology LTFU clinic were more likely to use neuro-psychological testing following radiation therapy (P,=,0.001), have longer duration of continued surveillance imaging (P,=,0.02), use growth hormone replacement for medulloblastoma survivors (P,<,0.001) and continue the use of growth hormone into adulthood (P,=,0.05) than those with a general pediatric oncology program. Perceived barriers to care of brain tumor survivors included limited access and lack of insurance (32.1%), lack of funding or dedicated time for providers (22.9%), patients' uncertainty about need to follow-up (20.6%), and patients' desire to not be followed in a pediatric cancer program (12.2%). Conclusions Considerable variation exists across institutions in the United States in the delivery of follow-up care for survivors of childhood brain tumors. We encourage additional investigation to better define and implement optimal follow-up care for childhood brain tumor survivors. Pediatr Blood Cancer 2009; 53:1295,1301. © 2009 Wiley-Liss, Inc. [source] Growth rates and life histories in twenty-two small-scale societies,AMERICAN JOURNAL OF HUMAN BIOLOGY, Issue 3 2006Robert Walker This study investigates variation in body growth (cross-sectional height and weight velocity) among a sample of 22 small-scale societies. Considerable variation in growth exists among hunter-gatherers that overlaps heavily with growth trajectories present in groups focusing more on horticulture. Intergroup variation tends to track environmental conditions, with societies under more favorable conditions displaying faster growth and earlier puberty. In addition, faster/earlier development in females is correlated with higher mortality. For example, African "Pygmies," Philippine "Negritos," and the Hiwi of Venezuela are characterized by relatively fast child-juvenile growth for their adult body size (used as a proxy for energetic availability). In these societies, subadult survival is low, and puberty, menarche, and first reproduction are relatively early (given their adult body size), suggesting selective pressure for accelerated development in the face of higher mortality. In sum, the origin and maintenance of different human ontogenies may require explanations invoking both environmental constraints and selective pressures. Am. J. Hum. Biol. 18:295,311, 2006. © 2006 Wiley-Liss, Inc. [source] Genetic parameters and QTL analysis of ,13C and ring width in maritime pinePLANT CELL & ENVIRONMENT, Issue 8 2002O. Brendel Abstract Classical quantitative genetics and quantitative trait dissection analysis (QTL) approaches were used in order to investigate the genetic determinism of wood cellulose carbon isotope composition (,13C, a time integrated estimate of water use efficiency) and of diameter growth and their relationship on adult trees (15 years) of a forest tree species (maritime pine). A half diallel experimental set-up was used to (1) estimate heritabilities for ,13C and ring width and (2) to decompose the phenotypic ,13C/growth correlation into its genetic and environmental components. Considerable variation was found for ,13C (range of over 3,) and for ring width (range of over 5 mm) and significant heritabilities (narrow sense 0·17/0·19 for ,13C and ring width, respectively, 100% additivity). The significant phenotypic correlation between ,13C and ring width was not determined by the genetic component, but was attributable to environmental components. Using a genetic linkage map of a full-sib family, four significant and four suggestive QTLs were detected for ,13C, the first for ,13C in a forest tree species, as far as known to the authors. Two significant and four suggestive QTLs were found for ring width. No co-location of QTLs was found between ,13C and growth. [source] Prenatal diagnostic procedures used in pregnancies with congenital malformations in 14 regions of EuropePRENATAL DIAGNOSIS, Issue 11 2004Ester Garne Abstract Objective To investigate outcomes of ultrasound investigations (US) and invasive diagnostic procedures in cases of congenital malformations (CM), and to compare the use of invasive prenatal test techniques (amniocentesis (AC) versus chorionic villus sampling (CVS)) among European populations. Design Analysis of data from population-based registries of CM. Subjects 25 400 cases of CM recorded by 14 EUROCAT registries covering a total population of 1 013 352 births 1995,99. Results US were performed in 91% of cases, and positively detected CM in 35% of cases. AC was performed in 24% of the cases and CVS in 3% of cases. Thirty-eight percent of invasive tests gave positive results. Fifty-two percent of cases with maternal age , 35 years had an invasive test performed compared to 20% of cases with younger mothers. Considerable variation was found between registries in the uptake rate of invasive tests in cases with older maternal age and on the use of invasive tests with only four regions employing CVS techniques in at least a third of the cases having invasive tests. For chromosomal anomalies US gave positive results in 46% of cases with maternal age < 35 years with US performed and in 36% of cases with maternal age , 35 years with US performed. Conclusion Prenatal US was performed in 91% of all pregnancies with CM but the test was only positive in a third of the cases. There was large regional variation in the uptake rate of invasive tests with maternal age of 35 years or more. For every CVS carried out there were nine AC tests. US is an important tool in the prenatal diagnosis of chromosomal anomalies in Europe. Copyright © 2004 John Wiley & Sons, Ltd. [source] Evaluation of Gossypium species for resistance to cotton leaf curl Burewala virusANNALS OF APPLIED BIOLOGY, Issue 1 2010K.P. Akhtar Cotton leaf curl disease (CLCuD), caused by cotton leaf curl Burewala virus (CLCuBV), has emerged as a major threat to cotton production in Pakistan. Resistance to CLCuBV was evaluated in cultivated and wild cotton genotypes representing six Gossypium species by visual symptom scoring and virus assessment using PCR tests. Considerable variation in responses was observed when using whitefly and graft transmission to inoculate Gossypium genotypes with CLCuBV in field and greenhouse experiments. Under field evaluation, all cultivated genotypes of Gossypium hirsutum and three genotypes of G. barbadense were susceptible. Eleven genotypes that represented six wild and cultivated Gossypium species were considered to be highly resistant as they were free from infection. Similar results were obtained when these genotypes were tested using whitefly transmission. To verify these findings, 132 cultivated and wild genotypes were tested by graft inoculation. All G. hirsutum genotypes (116 cultivated, 1 wild, 1 transgenic Coker-312 and 1 non-transgenic Coker-312), three G. barbadense genotypes and one G. thurberi genotype were highly susceptible and exhibited symptoms 9,12 days after grafting. Four genotypes of G. arboreum and one genotype of G. anomalum did not express symptoms but had a detectable level of virus. One genotype of G. herbaceum and three wild genotypes of G. hirsutum showed mild symptoms (severity indexes of 1,2) and exhibited delayed disease development. These genotypes were classified as moderately resistant to resistant. Resistant genotypes that were identified in this study will be useful sources for exploitation of breeding programmes aimed at developing CLCuBV-resistant varieties and increasing genetic diversity. [source] Maintenance costs of serotiny do not explain weak serotinyAUSTRAL ECOLOGY, Issue 6 2009M. D. CRAMER Abstract Considerable variation in the duration of serotiny exists among species of both Australian and South African Proteaceae. ,Weak' serotiny (pre-fire loss after <3 years) could be dictated by the costs (water or carbon) of cone/fruit retention or by benefits accruing from pre-fire seed establishment. We determined that cones/fruits of a range of Australian and south western Cape Proteaceae species (Leucadendron xanthoconus, Aulax umbellata, L. linifolium, L. gandogeri, Hakea drupacea, H. sericea) are not sealed dead wood, but that they continuously lose H2O and CO2. Water loss from cones/fruits was poorly controlled, occurring in both light and dark. The rates of both H2O and CO2 loss from mature cones/fruits were negatively correlated with the degree of serotiny (r2 = 0.59 and 0.18, respectively, P < 0.001 both). However, the amounts of H2O and CO2 lost per weight were small relative to the fluxes from leaves (13,29% for H2O and 3,10% for CO2). The [N] and [P] in the cones/fruits and seeds was substantial. Despite 25% of N and 38% of P being recovered from the cones/fruits following maturation, the loss of the cones/fruits and seeds would still incur a substantial nutrient cost. The seed [P] was positively correlated with the degree of serotiny (r2 = 0.24, P = 0.001). We suggest that maintenance costs (water and carbon) of serotiny, although exceeding those of soil stored seeds, are relatively low. The correlation between the degree of serotiny and seed [P] indicates that stronger serotiny is required, much like sclerophylly, for survival under low nutrient availability in frequently burnt vegetation. [source] Quality of survival reporting in chemotherapy and surgery trials in patients with metastatic colorectal carcinomaCANCER, Issue 6 2006Robert C. G. Martin M.D. Abstract BACKGROUND Patients with metastatic colorectal carcinoma (MCC) to the liver receive conflicting management recommendations because of the lack of prospective randomized controlled trials (RCTs) clarifying the optimal management in this disease. The oabjective of the current study was to evaluate the reporting of prognostic factors in MCC from chemotherapy and surgery trials and evaluate the ability to compare these results across treatments. METHODS RCTs and retrospective series of greater than 75 MCC patients published between 1980,2004 were reviewed to identify 10 critical prognostic elements of overall survival reported in both types of journals. RESULTS A review 92 RCTs and 116 retrospective reports with 64,898 patients analyzed found 7 (3%) reporting all prognostic factors, with both studies demonstrating no difference in the success of reporting criteria met. The only criterion that was universally reported among both chemotherapy and surgery trials was the mortality rates of the study. All remaining prognostic factors in the evaluation of overall survival were significantly different between both chemotherapy and surgical studies. Considerable variation was observed in the disease-free interval, number of hepatic metastases, size of hepatic metastases, and performance status, and were significantly different among some of the most significant factors for patients evaluating treatment: complication reporting, surgical margin evaluation, and overall response rate. CONCLUSIONS The reporting of results in MCC in chemotherapy trials and surgical reports is limited to general outcomes, with a paucity of prognostic factors, which hinders any ability to compare results across treatments. A mandatory reporting criteria of all metastatic colorectal trials is imperative to optimally manage these patients in both academic and community centers. Cancer 2006. © 2006 American Cancer Society. [source] Morphologic Characteristics of the Left Atrial Appendage, Roof, and Septum: Implications for the Ablation of Atrial FibrillationJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 9 2006WANWARANG WONGCHAROEN M.D. Introduction: The left atrium (LA) ablation in different regions, including LA appendage (LAA), LA roof, and LA septum, has recently been proposed to improve the success rate of treating patients with atrial fibrillation (AF). The purpose of this study was to investigate the anatomy of LAA, LA roof, and LA septum, using computed tomography (CT). Methods and Results: Multidetector CT scan was used to depict the LA in 47 patients with drug-refractory paroxysmal AF (39 males, age = 50 ± 12 years) and 49 control subjects (34 males, age = 54 ± 11 years). The area of LAA orifice, neck, and the length of roof line were greater in AF group than in control subjects. Three types of LAA locations and two types of LAA ridges were observed. Higher incidence of inferior LAA was noted in AF patients. The different morphologies of LA roof were described. Roof pouches were revealed in 15% of AF and 14% of controls. Moreover, we found septal ridge in 32% of AF and 23% of controls. Conclusions: Considerable variations of LAA and LA roof morphologies were demonstrated. Peculiar structures, including roof pouches and septal ridges, were delineated by CT imaging. These findings were important for determining the strategy of AF ablation and avoiding the procedure-related complications. [source] BUSINESS METHOD PATENTS AND U.S. FINANCIAL SERVICESCONTEMPORARY ECONOMIC POLICY, Issue 3 2010ROBERT M. HUNT A decade after the State Street decision, more than 1,000 business method patents are granted each year. Yet, only 1 in 10 is obtained by a financial institution. Most business method patents are also software patents. Have these patents increased innovation in financial services? To address this question, we construct new indicators of research and development intensity based on the occupational composition of financial industries. The financial sector appears more research intensive than official statistics would suggest but less than the private economy taken as a whole. There is considerable variation across industries but little apparent trend. There does not appear to be an obvious effect from business method patents on the sector's research intensity. Looking ahead, three factors suggest that the patent system may affect financial services as it has electronics: (1) the sector's heavy reliance on information technology, (2) the importance of standard setting, and (3) the strong network effects exhibited in many areas of finance. Even today litigation is not uncommon; we sketch a number of significant examples affecting financial exchanges and consumer payments. The legal environment is changing quickly. We review a number of important federal court decisions that will affect how business method patents are obtained and enforced. We also review a number of proposals under consideration in the U.S. Congress. (JEL O31, O34, G20) [source] Validity and reliability of the guidelines of the Surveillance of Cerebral Palsy in Europe for the classification of cerebral palsyDEVELOPMENTAL MEDICINE & CHILD NEUROLOGY, Issue 11 2008Mary Gainsborough MRCPCH The validity and reliability of the guidelines of the Surveillance of Cerebral Palsy in Europe (SCPE) for the classification of cerebral palsy (CP) were tested by administering 10 written case vignettes via an interactive web-based link to 30 SCPE partners. There was a moderately good level of agreement (,=0.59) about inclusion as a CP case on the SCPE database. Classification by CP subtype differed in two main areas: assigning spastic versus dyskinetic and judgement of distribution of spastic involvement. Agreement on Gross Motor Function Classification System (GMFCS) level was less good than reported in previous studies. Twenty respondents repeated the test 5 months later and there was good repeatability for case inclusion (,= 0.72) but considerable variation in assignment of CP subtype and GMFCS level. There is a need for further collaborative work and training to improve harmonization of the classification of CP, including examination, application of SCPE guidelines, and register coding. [source] The assessment of insulin resistance in manDIABETIC MEDICINE, Issue 7 2002T. M. Wallace Abstract Background Insulin resistance exists when a normal concentration of insulin produces a less than normal biological response. The ability to measure insulin resistance is important in order to understand the aetiopathology of Type 2 diabetes, to examine the epidemiology and to assess the effects of intervention. Methods We assess and compare methods of measurement and have undertaken a literature review from 1966 to 2001. Results Quantitative estimates of insulin resistance can be obtained using model assessments, clamps or insulin infusion sensitivity tests. There is considerable variation in the complexity and labour intensity of the various methods. The most well-established methods are the euglycaemic clamp, minimal model assessment and homeostatic model assessment (HOMA). No single test is appropriate under all circumstances. Conclusions There are a number of well-established tests used to measure insulin resistance: the choice of method depends on the size and type of study to be undertaken. Although the so-called ,gold-standard' test, the euglycaemic clamp, is useful for intensive physiological studies on small numbers of subjects, a simpler tool such as HOMA is more appropriate for large epidemiological studies. It is important to be aware that most techniques measure stimulated insulin resistance whereas HOMA gives an estimate of basal insulin resistance. Caution should be exercised when making comparisons between studies due to variations in infusion protocols, sampling procedures and hormone assays used in different studies. [source] Effectiveness of screening and monitoring tests for diabetic retinopathy , a systematic reviewDIABETIC MEDICINE, Issue 7 2000A. Hutchinson SUMMARY Aims To determine which screening and monitoring tests for diabetic retinopathy are most effective and under what circumstances. Methods A systematic review of the English language literature, published from 1983 to April 1999. Results Available studies are generally limited in their ability to answer the important questions on the effectiveness of tests for early detection of diabetic retinopathy. No randomized controlled trials were identified although primary studies exist for two screening tests: ophthalmoscopy, either direct or indirect, and retinal photography, using either mydriasis or non-mydriasis. Retinal photography under mydriasis appears to be the most effective test, with the majority reporting levels of sensitivity in excess of 80%. However effectiveness is compromised when photographs are ungradable. Ophthalmoscopy can also reach acceptable standards of sensitivity and specificity. Conclusion Based on an assessment of available cohort studies, the most effective strategy for testing is the use of mydriatic retinal photography with the additional use of ophthalmoscopy for cases where photographs are ungradable. This does not exclude the use of ophthalmoscopy alone for opportunistic case finding but there is evidence of considerable variation in effectiveness of this test. [source] Phenotypic plasticity, polymorphism and phylogeny within placodermsACTA ZOOLOGICA, Issue 2009K. Trinajstic Abstract Intraspecies variation, polymorphism and asymmetric traits are observed within two families of Arthrodira, the Incisoscutidae and Camuropiscidae, from the Gogo Formation in northern Western Australia. Individual plates of the head and trunk shield show considerable variation between individuals. Plates that show the greatest degree polymorphic traits are the rostral (R), marginal (M), submarginal (SM), preorbital (PrO), anterior dorsolateral, anterior median ventral (AMV) and posterior ventrolateral (PVL) plates. The paths of the sensory line canals are the most variable feature and the dermal plates of the cheek show the greatest asymmetry. It is apparent that if anatomical data in arthrodires are to be interpreted with greater precision, detailed knowledge of intraspecies variation, polymorphic and asymmetric traits is essential. How these variables are treated in cladistic analysis is also critical. Here multistate characters were coded differently in five discrete analyses, each analysis yielding a different number of trees and relationships. It was concluded that including and coding for multistate characters gave the most robust tree. In addition, further morphological characters from a new specimen of Gogosteus sarahae Long (1994) indicates many of the characters used to separate this genus from Incisoscutum are inconsistent and so it is here considered that the genus Gogosteus is a junior synonym of Incisoscutum. [source] Introduced plants of the invasive Solidago gigantea (Asteraceae) are larger and grow denser than conspecifics in the native rangeDIVERSITY AND DISTRIBUTIONS, Issue 1 2004Gabi Jakobs ABSTRACT Introduced plant species that became successful invaders appear often more vigorous and taller than their conspecifics in the native range. Reasons postulated to explain this better performance in the introduced range include more favourable environmental conditions and release from natural enemies and pathogens. According to the Evolution of Increased Competitive Ability hypothesis (EICA hypothesis) there is a trade-off between investment into defence against herbivores and pathogens, and investment into a stronger competitive ability. In this study, we conducted field surveys to investigate whether populations of the invasive perennial Solidago gigantea Ait (Asteraceae) differ with respect to growth and size in the native and introduced range, respectively. We assessed size and morphological variation of 46 populations in the native North American range and 45 populations in the introduced European range. Despite considerable variation between populations within continents, there were pronounced differences between continents. The average population size, density and total plant biomass were larger in European than in American populations. Climatic differences and latitude explained only a small proportion of the total variation between the two continents. The results show that introduced plants can be very distinct in their growth form and size from conspecifics in the native range. The apparently better performance of this invasive species in Europe may be the result of changed selection pressures, as implied by the EICA hypothesis. [source] The factors influencing the abrasion efficiency of saltating grains on a clay-crusted playaEARTH SURFACE PROCESSES AND LANDFORMS, Issue 5 2001Christopher A. Houser Abstract The entrainment and subsequent transport of PM10 (particulate matter <10,µm) has become an important and challenging focus of research for both scientific and practical applications. Arid and semi-arid environments are important sources for the atmospheric loading of PM10, although the emission of this material is often limited by surface crusts. It has been suggested that the primary mechanisms through which PM10 is released from a crusted surface are abrasion by saltating grains or disturbance by agricultural and recreational activities. To examine the importance of saltation abrasion in the emission of PM10, a series of field wind tunnel tests were conducted on a clay-crusted surface near Desert Wells, Arizona. In a previous part of this study it was found that the emission rate varies linearly with the saltation transport rate, although there can be considerable variation in this relationship. This paper more closely examines the source of the variability in the abrasion efficiency, the amount of PM10 emitted by a given quantity of saltating grains. The abrasion efficiency was found to vary with the susceptibility of the surface to abrasion, the ability of the sand to abrade that surface and the availability of material with a caliper size <10,µm within the crust. Specifically, the results of the study show that the abrasion efficiency is related to the crust strength, the amount of surface disturbance and the velocity of the saltating grains. It is concluded that the spatial and temporal variability of these controls on the abrasion efficiency imposes severe contextual limitations on experimentally derived models, and can make theoretical models too complex and impractical to be of use. Copyright© 2001 John Wiley & Sons, Ltd. [source] Genetic and environmental influences on cannabis use initiation and problematic use: a meta-analysis of twin studiesADDICTION, Issue 3 2010Karin J. H. Verweij ABSTRACT Background Because cannabis use is associated with social, physical and psychological problems, it is important to know what causes some individuals to initiate cannabis use and a subset of those to become problematic users. Previous twin studies found evidence for both genetic and environmental influences on vulnerability, but due to considerable variation in the results it is difficult to draw clear conclusions regarding the relative magnitude of these influences. Methods A systematic literature search identified 28 twin studies on cannabis use initiation and 24 studies on problematic cannabis use. The proportion of total variance accounted for by genes (A), shared environment (C) and unshared environment (E) in (i) initiation of cannabis use and (ii) problematic cannabis use was calculated by averaging corresponding A, C and E estimates across studies from independent cohorts and weighting by sample size. Results For cannabis use initiation, A, C and E estimates were 48%, 25% and 27% in males and 40%, 39% and 21% in females. For problematic cannabis use A, C and E estimates were 51%, 20% and 29% for males and 59%, 15% and 26% for females. Confidence intervals of these estimates are considerably narrower than those in the source studies. Conclusions Our results indicate that vulnerability to both cannabis use initiation and problematic use was influenced significantly by A, C and E. There was a trend for a greater C and lesser A component for cannabis use initiation compared to problematic use for females. [source] Sexual orientation, substance use behaviors and substance dependence in the United StatesADDICTION, Issue 8 2009Sean Esteban McCabe ABSTRACT Aims To assess past-year prevalence rates of substance use behaviors and substance dependence across three major dimensions of sexual orientation (identity, attraction and behavior) in a large national sample of adult women and men in the United States. Design Data were collected from structured diagnostic face-to-face interviews using the Alcohol Use Disorder and Associated Disabilities Interview Schedule DSM-IV version IV (AUDADIS-IV). Setting Prevalence estimates were based on data collected from the 2004,2005 (wave 2) National Epidemiologic Survey on Alcohol and Related Conditions (NESARC). Participants A large national sample of 34 653 adults aged 20 years and older: 52% female, 71% white, 12% Hispanic, 11% African American, 4% Asian and 2% Native American. Findings Approximately 2% of the population self-identified as lesbian, gay or bisexual; 4% reported at least one life-time same-sex sexual partner and 6% reported same-sex sexual attraction. Although non-heterosexual orientation was generally associated with a higher risk of substance use and substance dependence, the majority of sexual minority respondents did not report substance use or meet criteria for DSM-IV substance dependence. There was considerable variation in substance use outcomes across sexual orientation dimensions; these variations were more pronounced among women than among men. Conclusions Results support previous research findings of heightened risk of substance use and substance dependence among some sexual minority groups and point to the need for research that examines the reasons for such differences. Results also highlight important gender differences and question previous findings indicating uniformly higher risk for substance dependence among sexual minorities. Risks appear to vary based on gender and how sexual orientation is defined. Findings have implications for more effective prevention and intervention efforts that target subgroups at greatest risk. [source] Exposure of children and adolescents to alcohol advertising on Australian metropolitan free-to-air televisionADDICTION, Issue 7 2009Lynda Fielder ABSTRACT Aim This study investigated the exposure of underage youth to alcohol television advertising on metropolitan free-to-air television in the five mainland capital city markets of Australia. Design Exposure levels (target audience rating points; TARPs) were obtained for all alcohol advertisements screened from November 2005 to October 2006 in each capital city market for: children 0,12 years; underage teens 13,17 years; young adults 18,24 years; and mature adults 25+ years. The 30 most exposed advertisements across age groups were then content-analysed for elements appealing to children and underage youth. Results In each of the five metropolitan markets, mature adults were most exposed to alcohol advertising. Children were exposed to one-third the level of mature adults and underage teens to approximately the same level as young adults. However, there was considerable variation in media weight between markets, such that underage teens in two markets had higher advertising TARPs than young adults in other markets. All 30 highest exposed advertisements contained at least one element known to appeal to children and underage youth, with 23 containing two or more such elements. Fifteen of the 30 advertisements featured an animal. Conclusions The self-regulation system in Australia does not protect children and youth from exposure to alcohol advertising, much of which contains elements appealing to these groups. [source] Diversity of rice glutelin polypeptides in wild species assessed by the higher-temperature sodium dodecyl sulfate-polyacrylamide gel electrophoresis and subunit-specific antibodiesELECTROPHORESIS, Issue 6 2008Nadar Khan Abstract In efforts to find genetic resources with high nutritional value of rice seed, we assessed the diversity of the major storage protein glutelin in 13 wild and 2 cultivated rice species by a unique SDS-PAGE method and subunit-specific antibodies. Maximum separation of microheterogeneous glutelin ,-polypeptides, which is a prerequisite for the diversity evaluation, could be attained by SDS-PAGE performed at higher temperature (45°C) than the generally employed temperatures (4,25°C). Seven antipeptide antibodies were raised against subunit-specific epitope sequences designed at five sites from four variable regions spanning the glutelin ,-polypeptides. High specificity of each antibody was confirmed using rice glutelin mutants, and demonstrated considerable variation in amino acid sequence and accumulation level of glutelin subunit in wild species, in combination with the higher-temperature SDS-PAGE. The degree of the variation was, however, changed according to the site of variable regions and the type of subunit. Some wild species accumulated nutritious GluB subunits more than cultivated rice. The wild species Oryza longiglumis and O. brachyantha had glutelin with low reactivity against most antibodies examined in this study, reflecting the significant divergence. Such wild species may hopefully serve as important genetic resources for nutritional improvement of cultivated rice. [source] Sinusoidal modeling applied to spatially variant tropospheric ozone air pollutionENVIRONMETRICS, Issue 6 2008Nicholas Z. Muller Abstract This paper demonstrates how parsimonious models of sinusoidal functions can be used to fit spatially variant time series in which there is considerable variation of a periodic type. A typical shortcoming of such tools relates to the difficulty in capturing idiosyncratic variation in periodic models. The strategy developed here addresses this deficiency. While previous work has sought to overcome the shortcoming by augmenting sinusoids with other techniques, the present approach employs station-specific sinusoids to supplement a common regional component, which succeeds in capturing local idiosyncratic behavior in a parsimonious manner. The experiments conducted herein reveal that a semi-parametric approach enables such models to fit spatially varying time series with periodic behavior in a remarkably tight fashion. The methods are applied to a panel data set consisting of hourly air pollution measurements. The augmented sinusoidal models produce an excellent fit to these data at three different levels of spatial detail. Copyright © 2007 John Wiley & Sons, Ltd. [source] Temporal and Geographic Variation in the Advertisement Call of the Booroolong Frog (Litoria booroolongensis: Anura: Hylidae)ETHOLOGY, Issue 12 2005Michael J. Smith The mechanisms that underlie sexual selection rely upon within- and among-individual variability in the targeted traits. In this study, we examined variation in the advertisement call of the booroolong frog (Litoria booroolongensis) at several different levels: between populations, between breeding seasons in the same population, among males within a population, within males between nights and within males in a single calling bout. The call of L. booroolongensis has multiple notes with a pulsed structure. We detected considerable variation in advertisement call structure between breeding seasons and between populations. The measured call properties ranged from static to dynamic; however, most properties were intermediate between the criteria that have been traditionally used to define call traits as static or dynamic (,5 and ,12% respectively). We compared actual and relative repeatabilities and found that the temporal call properties associated with the structure of the note had the highest values, suggesting that these characters in particular may respond to selection. We argue that relative repeatabilities are a particularly useful measure of the potential for evolutionary response to selection as they account for an individual's relative performance during the period of assessment in an ever-changing breeding arena. [source] Cancer patients' satisfaction with communication, information and quality of care in a UK regionEUROPEAN JOURNAL OF CANCER CARE, Issue 1 2005R. DAVIDSON bsc, abps. consultant clinical psychologist , dphil., msc (clin. psych.) Effective patient,professional communication can be of crucial importance to long-term psycho-social outcomes in patients with cancer. This study identifies patient satisfaction with regard to various aspects of communication and perceived quality of care. A well-validated questionnaire was administered to 435 cancer patients throughout Northern Ireland during a 3-month period. Northern Ireland can be regarded as a typical UK region in terms of cancer service configuration. The cohort consisted of patients with breast, colorectal, lung, prostate, gynaecological and gastric cancers. There was a 78% response rate. Satisfaction scores were individually calculated for various aspects of care, particularly diagnosis, treatment, follow-up and overall care. Non-parametric analysis examined the interaction between satisfaction scores and primary tumour site, age and gender. While overall satisfaction scores were relatively high, there was considerable variation. Of particular note was the interaction between perceived satisfaction and quality of care, communication, tumour site and age. Key findings are that there are a number of issues with regard to information and communication which can be clearly improved within Northern Ireland cancer services. The paper concludes that patient,professional communication should be tailored to meet individual need. [source] External Examiners and Immediate Post Qualification Clinical Dental Training in EuropeEUROPEAN JOURNAL OF DENTAL EDUCATION, Issue 2 2004G. H. Moody Background: A conversation at the ADEE Conference in Bern, 2001, revealed an apparent diversity in the use and role of External Examiners in dental undergraduate examinations in ADEE-associated schools. There also appeared to be considerable variation in the amount of post-graduate supervised clinical training. Aims: (i) To elicit information on the use of External Examiners in dental undergraduate examinations. (ii) To acquire information about immediate post-qualifying supervised clinical experience and training. Method: Questionnaire to the 205 Dental Schools listed in the ADEE Directory in 35 European countries. Results: Eighty-two (40%) completed questionnaires were returned. Of these 82 schools, 43 (52.4%) did not use External Examiners. The remaining 39 (47.6%) used an External Examiner at least once during the under-graduate course. All 39 used an External Examiner in ,Finals', 34 in all clinical examinations and 30 in pre-clinical examinations. Thirty out of 39 allowed external examiners to scrutinize papers before the examination. Although 31/39 were asked to advise on problems during examinations, only 26/39 were consulted about the fate of ,failed' candidates and 23/39 asked to adjudicate in such instances. Following qualification, graduates from 38/82 schools experienced some form of supervised further clinical training ranging from 3 months to 2 years. The majority (21/38) were trained for 1 year and 13 for 2 years. However, 30/82 (36.5%) schools produced graduates who qualified without any external assessment and without the benefit of any post-qualifying supervised training. Conclusions: Although the questionnaire response rate is low, it is clear that there are disparities in practice with regard to the use of external examiners and post-graduate training, which need to be evaluated if dental undergraduate standards in Europe are to converge. [source] Changes in mu opioid receptors and rheological properties of erythrocytes among opioid abusersADDICTION BIOLOGY, Issue 2 2002ALLEN R. ZEIGER The high prevalence of anemia among chronic opioid users leads us to propose that chronic opiate use results in elevated mu opioid receptor levels on human erythrocytes and that these receptor changes may affect erythrocyte membrane properties. Blood samples from 17 opioid-dependent subjects (based on the Diagnostic and Statistical Manual of Mental Disorders, 4th edition or DSM-IV) and 15 drug-free controls were assayed for mu opioid receptors on erythrocytes using a flow cytometry immunoassay. Deformability and the hydration status of erythrocytes were studied by ektacytometry. Data were analyzed by independent t-tests, tests of correlation, chi square and cluster analyses. As expected, the percentage of erythrocytes from opioiddependent subjects with opioid receptors (opioid receptor levels) was significantly higher (47.4 ± 38.3%) than controls (22.8 ± 30.1%) (t = 2.01, df = 30, p < 0.05). Also, the opioid-dependent patients showed a wide variation in the percentage of erythrocytes bearing opioid receptors and data analyses of these patients showed two strongly defined clusters. One subgroup consisted of nine individuals with very high receptor levels (mean = 81.5%) while the other had eight patients with low receptor levels (mean = 9.1%) that were not significantly different than the receptor levels of controls. Ektacytometry of opioid dependent patients with high opioid receptor levels showed changes in rheological parameters of erythrocytes, such as deformability index and cellular hydration. For example, a positive correlation was observed between opioid receptor levels and deformability indices among opioid-dependent patients (r = 0.74, p < 0.005). Our findings indicate that the mu opioid receptor is present on human erythrocytes, although with considerable variation in receptor levels, and that the levels of this receptor are significantly elevated with chronic opioid exposure. Moreover, erythrocytes with high opioid receptor levels from chronic opiate users seem to have high deformability. This study may offer clues to the biological properties of peripheral blood cells that may be mediated by mu opioid receptors and lead to a better understanding of some of the clinical effects of opioid use. [source] | |||||||||||||||||||||||||||||||||||||||||||