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Selected AbstractsParticle size of powders under hydrothermal conditionsCRYSTAL RESEARCH AND TECHNOLOGY, Issue 10 2003Wen-Jun Li Abstract Various non-oxide (CuI, AgI, AgCl, PbS, CuS and ZnS) and oxide (ZnO, TiO2, SnO2, CeO2 and ZrO2) powders were prepared under hydrothermal conditions to investigate the effects of temperature, pH and precursors on the particle size of powders. It was found that the particle sizes of PbS, CuS and ZnS powders were much smaller than that of CuI, AgI and AgCl powders prepared under the same conditions. The particle sizes of TiO2, SnO2, CeO2 and ZrO2 powders are much smaller than that of ZnO powders prepared under the same conditions. It is concluded that the solution conditions have a certain effect on the particle size of powders under the hydrothermal conditions. The particle size of powders increased with the rising of temperature. Additional factors affecting the particle size were uncovered through studying the nucleation mechanism. The particle size was mainly related to the Madelung constant and the electric charge number of ions. Powders with smaller particle size resulted from systems that possessed the larger Madelung constant and ionic charge number. (© 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Manipulating subcategory salience: exploring the link between skin tone and social perception of BlacksEUROPEAN JOURNAL OF SOCIAL PSYCHOLOGY, Issue 5 2004Keith B. Maddox Guided by the model of social category salience proposed by M. Blanz (1999), the present paper explores factors affecting the salience of skin tone-based subcategories among Blacks in the United States. Adapting the group discussion paradigm developed by S.E. Taylor and colleagues (1978), Experiment 1 demonstrated that a manipulation of issue relevance enhanced the category salience of skin tone. Participants made more within- than between-category errors when the topic of conversation was related to perceiver's skin tone-based beliefs. Experiment 2 demonstrated that the influence of the issue relevance manipulation was independent of the presence of structural and/or normative fit. Merely discussing the topic of race relations was sufficient to increase encoding and use of skin tone. These studies provide evidence linking skin tone and social beliefs in memory. In addition, they demonstrate support for a category-based perspective in the study of skin tone bias. Additional factors affecting the salience of skin tone are discussed. Copyright © 2004 John Wiley & Sons, Ltd. [source] Cadmium leaching from some New Zealand pasture soilsEUROPEAN JOURNAL OF SOIL SCIENCE, Issue 1 2003C. W. Gray Summary Cadmium (Cd) inputs and losses from agricultural soils are of great importance because of the potential adverse effects Cd can pose to food quality, soil health and the environment in general. One important pathway for Cd losses from soil systems is by leaching. We investigated loss of Cd from a range of contrasting New Zealand pasture soils that had received Cd predominantly from repeated applications of phosphate fertilizer. Annual leaching losses of Cd ranged between 0.27 and 0.86 g ha,l, which are less than most losses recorded elsewhere. These losses equate to between 5 and 15% of the Cd added to soil through a typical annual application of single superphosphate, which in New Zealand contains on average 280 mg Cd kg,1 P. It appears that Cd added to soil from phosphate fertilizer is fairly immobile and Cd tends to accumulate in the topsoil. The pH of the leachate and the total volume of drainage to some extent control the amount of Cd leached. Additional factors, such as the soil sorption capacity, are also important in controlling Cd movement in these pasture soils. The prediction of the amount of Cd leached using the measured concentrations of Cd in the soil solution and rainfall data resulted in an overestimation of Cd losses. Cadmium concentrations in drainage water are substantially less than the current maximum acceptable value of 3 µg l,1 for drinking water in New Zealand set by the Ministry of Health. [source] The implications of solar UV radiation exposure for fish and fisheriesFISH AND FISHERIES, Issue 3 2001Horacio E Zagarese Abstract Ultraviolet radiation (UVR) possesses three important properties that combine to make it a potent environmental force. These include the potential to induce damage: UVR carries more energy per photon than any other wavelength reaching the Earth's surface. Such highly energetic photons are known to damage many biological molecules, such as DNA and proteins. In addition, they can initiate a series of redox reactions to form reactive oxygen species (ROS), which cause oxidative stress to cells and tissues. The second property is ubiquity: owing to their dependence on light, primary producers and most visual predators, such as fish, are also necessarily exposed to damaging levels of UVR. Thirdly, the combined effect of UVR and additional environmental factors may result in synergistic effects, such as the photoactivation of organic pollutants and photosensitisation. In natural environments, the concentration of dissolved organic matter (DOM) and habitat depth are the two main factors controlling the degree of UVR exposure experienced by fish. Additional factors include vegetation coverage, particulate materials in suspension, pH and hydrological characteristics, and site location (latitude, elevation). The range of potential effects on fish includes direct DNA damage resulting in embryo and larval mortality, and adult and juvenile sunburn, as well as indirect oxidative stress, phototoxicity and photosensitisation. [source] Traveling the road to success: A discourse on persistence throughout the science pipeline with African American students at a predominantly white institutionJOURNAL OF RESEARCH IN SCIENCE TEACHING, Issue 6 2005Melody L. Russell This study focuses on 11 African American undergraduate seniors in a biology degree program at a predominantly white research institution in the southeastern United States. These 11 respondents shared their journeys throughout the high school and college science pipeline. Participants described similar precollege factors and experiences that contributed to their academic success and persistence at a predominantly white institution. One of the most critical factors in their academic persistence was participation in advanced science and mathematics courses as part of their high school college preparatory program. Additional factors that had a significant impact on their persistence and academic success were family support, teacher encouragement, intrinsic motivation, and perseverance. © 2005 Wiley Periodicals, Inc. [source] Blood cultures for febrile patients in the acute care setting: Too quick on the draw?JOURNAL OF THE AMERICAN ACADEMY OF NURSE PRACTITIONERS, Issue 11 2008ACNP-BC, Barbara K. Chesnutt MSN Abstract Purpose: To review the fever literature and determine how 38.3°C was deemed the optimal fever threshold that predicts bacteremia. Data sources: PubMed, MEDLINE, Cochrane database, and the Cumulative Index to Nursing and Allied Health. Conclusions: A temperature of 38.3°C has come to be the threshold value that typically triggers diagnostic fever evaluation for bacteremia in hospitalized patients. Studies that define predictors of bacteremia provide conflicting results, and most bacteremia predictor models have not been externally validated. Therefore, current fever guidelines are based on consensus opinion rather than large clinical trials identifying a specific threshold with high sensitivity and a high negative predictive value. Implications for practice: The use of a single temperature threshold of 38.3°C for the prediction of bacteremia is not sufficient in all patients. Additional factors should be considered, including patient population, supporting clinical signs and symptoms, and the patient's medical history. [source] Growth curves of pediatric patients with biliary atresia following living donor liver transplantation: Factors that influence post-transplantation growthPEDIATRIC TRANSPLANTATION, Issue 7 2007Takeshi Saito Abstract:, We evaluated the growth curves of children with BA after LDLT, and identified factors influencing growth velocity one-yr after LDLT (,Z). The clinical data of 51 children with BA, who had an LDLT at our center from 2001 to 2005, were retrospectively reviewed. The Z scores for height and weight, and ,Z were studied. The correlation between ,Z and various clinical factors was evaluated statistically. Multivariate stepwise analyses were performed for ,Z. The average height and weight Z scores at the time of LDLT were ,1.34 ± 1.36 (±s.d.) and ,0.78 ± 1.15, respectively. Among 30 BA recipients with stable liver function after transplant, weight returned to normal one-yr post-transplantation. However, height did not return to normal even by the third post-transplantation year. On multivariate analyses, 73% of the variance in height ,Z could be accounted for by factors such as standardized height at the time of LDLT (proportion of variance: 38%), number of steroid pulse treatments (17%), donor age (10%), and the presence of HVS (9%). Fifty-four percentage of the variance in weight ,Z could be accounted for by factors such as standardized weight at the time of LDLT (37%) and the total steroid dose given (17%). Height and weight status at the time of LDLT likely have the strongest impact on ,Z. Additional factors include steroid exposure, age of the living donor, and presence of HVS, all of which should be considered to improve post-transplantation growth. [source] School-based health centers: Opportunities and challenges for school psychologistsPSYCHOLOGY IN THE SCHOOLS, Issue 3 2003Adena B. Meyers School psychologists have the potential to contribute to the development and delivery of health and mental health services through school-based health centers (SBHCs). Possible roles for school psychologists within SBHCs are described. Factors that influence school psychologists' efforts within SBHCs are discussed, including factors such as system reforms, school system governance, importance of SBHC to stakeholders, and availability of funding. Knowledge of collaborative problem solving, effective prevention and intervention strategies, and recognition of limitations of traditional mental health programs were also identified as facilitators of the school psychologist's role in a SBHC. Factors that may impede the development of SBHCs are reviewed. These factors include definitional confusion, deemphasis on prevention, community stigma, limited resources, lack of integration and coordination of services, and an emphasis on a narrow role of providing only medical services. Additional factors discussed include the narrow role of school psychologists, space limitations, the challenge of collaboration, role strain, and lack of research on interventions within a SBHC. Strategies for overcoming barriers are suggested. © 2003 Wiley Periodicals, Inc. Psychol Schs 40: 253,264, 2003. [source] Psychological distress and its correlates in ovarian cancer: a systematic reviewPSYCHO-ONCOLOGY, Issue 11 2008Emily Arden-Close Abstract Objective: Ovarian cancer is often diagnosed at an advanced stage, and consequently high levels of distress are often experienced. It is necessary to understand the factors associated with psychological distress in order to guide interventions to target those factors. The purpose of this systematic review was therefore to identify correlates of psychological distress in ovarian cancer. Methods: Included studies had to be quantitative and empirical, with standardized measures of psychological distress (anxiety or depression), and to present results for ovarian cancer patients specifically. Standard systematic search methods were used. Information about design, ovarian cancer sample size, disease stage, time since diagnosis, measures of distress used and findings was extracted from each study. The studies were quality assessed using experimenter-defined criteria as good, average and poor quality. Strength of the evidence (strong, some, inconclusive) was based on the quality and consistency of findings. Results: Eighteen studies meeting the inclusion criteria were identified. There was strong evidence for a relationship between younger age, being diagnosed with more advanced disease, more physical symptoms and shorter time since diagnosis with increased levels of anxiety and/or depression. Additional factors (e.g. immune) tested in a few studies also emerged as correlates of distress. Conclusions: Demographic, disease and quality of life factors correlated with distress. However, too few studies assessed possible psychological and immunological correlates, which could be potentially modified and should be assessed in future studies. Copyright © 2008 John Wiley & Sons, Ltd. [source] Why do older women delay presentation with breast cancer symptoms?PSYCHO-ONCOLOGY, Issue 11 2006C. C. Burgess Abstract Women who delay their presentation with breast cancer for three months or longer are more likely to be diagnosed with later stage disease and have poorer survival. Older women, who are at greater risk of developing breast cancer, are also more likely to delay their presentation. Factors associated with delayed presentation were assessed in 69 women (>65 years) with breast cancer. Previous factors identified for women of all ages were confirmed (having a non-lump symptom p=0.003) or strengthened (non-disclosure of symptom discovery to a relative or close friend p=0.001). Additional factors for delay in this older group included reservations about seeing their GP (p=0.02) and fear of the consequences of cancer (p=0.04). These factors should inform the design of interventions to reduce delays. Copyright © 2006 John Wiley & Sons, Ltd. [source] Three-dimensional simulation of the ASTEX Lagrangian 1 field experiment with a regional numerical weather prediction modelTHE QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY, Issue 597 2004Robert Sigg Abstract The Atlantic Stratocumulus Transition Experiment (ASTEX) first Lagrangian experiment (Lagrangian 1) is here simulated with a modified version of the regional forecast model HIRLAM (High Resolution Limited Area Model). The main modification is that moist turbulent fluxes are accounted for in the model. Trajectory calculations show good agreement with earlier estimations. The initially rather shallow stratocumulus topped marine boundary layer is deepening along the trajectory, and in the end cumulus clouds are formed that penetrate the boundary-layer top. The model predicts this change in cloudiness, but the boundary layer is too shallow in the model. A simulation with modified initial conditions shows improved results, but is still too slow in increasing the boundary-layer depth. Additional factors that influence the boundary-layer growth are: the increase in sea surface temperatures, lower modelled wind speeds, low entrainment rates due to coarse vertical resolution, and synoptic-scale subsidence. An anticyclone at the surface moved slightly northward during the simulation. The anticyclone was accompanied at 500 hPa by a deepening cyclone and, therefore, one would expect synoptic subsidence in the area of the Lagrangian 1. The modelled negative vertical wind component at the boundary-layer top oscillates, and this is examined using spectral analysis. The results show that the vertical velocity is influenced by cumulus clouds on time-scales up to 15 h with a peak at 9 h. The horizontal and vertical wavelengths of the vertical velocity disturbances are estimated from model output to be 400,500 km and 6,10 km, respectively. Using the estimated vertical wavelength and linear theory for hydrostatic inertia,gravity waves, a horizontal wavelength of 350,550 km was calculated for a frequency of 9 h. The model results thus indicate that these types of waves are responsible for the undulating vertical velocity. Finally, an estimation of the synoptic-scale vertical velocity is calculated by filtering out all scales smaller than 15 h from the vertical velocity signal. This results in subsidence both at the beginning and the end of the Lagrangian with vertical velocities between ,0.1 and ,0.4 cm s,1. Copyright © 2004 Royal Meteorological Society [source] The effects of protective helmet use on physiology and cognition in young cricketersAPPLIED COGNITIVE PSYCHOLOGY, Issue 9 2004Nick Neave Many studies have reported physiological and cognitive decrements following heat stress. Of particular concern in cricket are the possible negative effects of sustained protective helmet use, as this leads to an increase in heat-related stress. Correct and rapid decision making, and focused attention are essential for efficient performance whilst batting, and it is possible that helmet usage could impair such processes. In a repeated-measures, randomized crossover study, physiological, self-report, and cognitive measures were taken from 16 teenage cricketers before and after moderately intense (batting) exercise. Participants underwent the assessments twice, once while wearing a standard protective helmet, and again, when not wearing a helmet (counterbalanced). While helmet use did not lead to significant physiological changes, wearing a helmet led to some cognitive impairments in attention, vigilance and reaction times. These preliminary findings could have significance for cognitively demanding sports (and perhaps military and industrial settings) in which participants perform cognitively demanding operations under conditions of physical exercise whilst wearing protective helmets. Additional factors of hydration, exercise duration, and helmet design are discussed. Copyright © 2004 John Wiley & Sons, Ltd. [source] Morphofunctional patterns in Neotropical felids: species co-existence and historical assemblyBIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 3 2010MIRIAM M. MORALES Extant felids are morphologically homogeneous, probably as a result of recent radiation and constraints from their predatory specializations. The Neotropical assemblage comprises 12 of the 41 extant felid species, which occupy all habitats available, with many species coexisting locally. We studied this assemblage on the basis of 31 craniodental variables reflecting morphofunctional variation, measured from 229 specimens representing all 12 species. Multivariate patterns were summarized allowing for phylogenetic covariation. Additional factors (geographical distribution, use of habitat and stratum, and activity pattern) were coded for each species. As expected, body size accounted for most variation, covarying with membership to three deep clades and, to a lesser extent, with large-scale geographic variation. The species tend to segregate in morphospace plus one or more factors (e.g. habits) that make interspecific overlap in niche space minimal. Using dated phylogenies, biogeographic history, and the fossil record, we reconstructed the historical assembly of the Neotropical felid guild. We found a pattern of successive invasions and speciation in which new lineages occupied previously vacant areas of morphospace, or new species occupied overlapping areas but with contrasting habits. This may be general among antagonistic species of historically structured guilds, and we predict similar patterns in other continents. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 100, 711,724. [source] Origin of planktotrophy,evidence from early molluscsEVOLUTION AND DEVELOPMENT, Issue 4 2006Alexander Nützel SUMMARY The size of early ontogenetic shells (protoconchs) of ancient benthic molluscs suggests that feeding larvae occurred at about 490 myr (approximately, transition from Cambrian to Ordovician). Most studied Ordovician protoconchs were smaller than Cambrian ones, indicating smaller Ordovician eggs and hatchlings. This suggests substitution of nutritious reserve matter such as yolk by plankton as an energy source for larvae. The observed size change represents the first direct empiric evidence for a late Cambrian to Ordovician switch to planktotrophy in invertebrate larvae. It corroborates previous hypotheses about a possible polyphyly of planktotrophy. These hypotheses were primarily based on molecular clock data of extant clades with different types of larva, change in the overall body size, as well as increasing predation pressure on Early Paleozoic sea floors. The Early Ordovician is characterized by an explosive radiation of benthic suspension feeders and it was suggested that planktotrophy would prolongate escape from benthic predation on hatchlings. This biological escalation hypothesis does not fully explain why planktotrophy and suspension feeding became important at the same time, during a major biodiversification. An additional factor that probably included availability of nutrients must have played a role. We speculate that an increasing nutrient supply and availability of photoautotrophic plankton in world oceans have facilitated both planktotrophy and suspension feeding, which does not exclude a contemporaneous predation-driven escalation. It is very likely that the evolution of planktotrophy as well as increasing predation contributed to the Ordovician radiation. [source] The effect of frame figure type and frame size on the line and the circle Ponzo illusionsJAPANESE PSYCHOLOGICAL RESEARCH, Issue 1 2007AKIRA YAMAGAMI Abstract: To examine the determinants of the Ponzo illusion, we compared the perceived size of lines and circles presented within three different frames: two converging lines, two circles, and two squares. Twenty stimulus figures, consisting of two types of objects (lines/circles),× three types of frame figures (Ponzo/circles/squares),× three sizes of lower frames (small/medium/large), and two control figures were presented on a personal computer display. Twelve students performed three measurements (upper-object/lower-object/illusion) for each stimulus figure using the method of adjustment. To analyze the relationship between single object perception and the Ponzo illusion, we compared the calculated values of overestimation magnitude differences between the upper and lower objects with the actual obtained illusion values of the six object-frame conditions. The calculated values of the circle and the square frame figures corresponded to the difference between the upper single object and the lower single object. In contrast, the results of the Ponzo figure need an additional factor to explain the differences between the obtained and the calculated values. These results indicate that two factors are involved in the Ponzo illusion: (a) the framing effect affects the perceived size of the individual single objects, and (b) the comparison factor affects the comparison process of the two objects within the converging lines. [source] Redo-OPCAB via Left Thoracotomy Using Symmetry Aortic Connector System:JOURNAL OF CARDIAC SURGERY, Issue 1 2004A Report of Two Cases This approach has also been successfully used in off-pump coronary artery bypass (OPCAB). Traditionally, the grafts have been anastomosed proximally to the descending thoracic aorta or the left subclavian artery. Recently, proximal connectors have been introduced by various manufacturers for use on ascending aorta during primary CABG and OPCAB. One such device is the Symmetry aortic connector system (St. Jude Medical, Minneapolis, MN). These devices have obviated the need for partial occluding clamps for the construction of the proximal anastomoses and hence are extremely useful when the aorta is heavily calcified. We used this device successfully in two patients undergoing redo-OPCAB, where the proximal anastomosis was constructed on the descending aorta. In so doing, we also used the shortest possible length of vein graft since the descending aorta at that level was much closer than the left subclavian artery. This can be an additional factor in redo-operations where the availability of vein can be an issue. (J Card Surg 2004;19:51-53) [source] Ecological gradients, subdivisions and terminology of north-west European miresJOURNAL OF ECOLOGY, Issue 2 2000B. D. Wheeler Summary 1,The historical development of mire ecology and terminology is reviewed in relation to evolving concepts and perceptions, and the diverse schools and traditions of vegetation and habitat description and research. 2,Most ecological and floristic variation within north-west European mire vegetation is accounted for by three ecological gradients: the acid base-poor vs. neutral, base- and bicarbonate-rich gradient; the gradient in fertility related to availability of the limiting nutrient elements N and P; and the water level gradient. Effects of salinity and the spring,flush,fen gradients are of more local significance, usually easily recognized. Land use is an important additional factor. 3,The mineral-soil-water limit between ombrotrophic and minerotrophically influenced sites is not sharp, and cannot be related to consistent differences in either vegetation or water chemistry. It should be abandoned as a general main division within mires. 4,The most important natural division is between ,bog', with pH generally < 5.0, low Ca2+, and Cl, and SO42, as the main inorganic anions, typically dominated by sphagna, ericoids and calcifuge Cyperaceae, and ,fen', with pH generally > 6.0, high Ca2+ and HCO3,, vegetation rich in dicotyledonous herbs and ,brown mosses'. This division is reflected in a bimodal distribution of pH. 5,The terms oligotrophic, mesotrophic and eutrophic should refer only to nutrient richness (fertility, mainly N and P), not to base richness (metallic cations and pH). 6,It is recommended that ,mire' should embrace both wetlands on peat and related communities on mineral soils, that ,bog' (unqualified) should encompass both ombrotrophic and weakly minerotrophic mires, including ,bog woodland', and that ,fen' should be restricted to base-rich mires but include both herbaceous and wooded vegetation (,fen carr'). 7,Definitions are given for a range of broadly defined categories that should cover most vegetation types commonly encountered. The relation of these to British national vegetation classification types and to major units in European phytosociology is outlined. [source] Association of polymorphisms of glutamate-cystein ligase and microsomal triglyceride transfer protein genes in non-alcoholic fatty liver diseaseJOURNAL OF GASTROENTEROLOGY AND HEPATOLOGY, Issue 2 2010Claudia Pinto Marques Souza Oliveira Abstract Background and Aims:, Although the metabolic risk factors for non-alcoholic fatty liver disease (NAFLD) progression have been recognized, the role of genetic susceptibility remains a field to be explored. The aim of this study was to examine the frequency of two polymorphisms in Brazilian patients with biopsy-proven simple steatosis or non-alcoholic steatohepatitis (NASH): ,493 G/T in the MTP gene, which codes the protein responsible for transferring triglycerides to nascent apolipoprotein B, and ,129 C/T in the GCLC gene, which codes the catalytic subunit of glutamate-cystein ligase in the formation of glutathione. Methods:, One hundred and thirty-one biopsy-proven NAFLD patients (n = 45, simple steatosis; n = 86, NASH) and 141 unrelated healthy volunteers were evaluated. Genomic DNA was extracted from peripheral blood cells, and the ,129 C/T polymorphism of the GCLC gene was determined by restriction fragment length polymorphism (RFLP). The ,493 G/T polymorphism of the MTP gene was determined by direct sequencing of the polymerase chain reaction products. Results:, The presence of at least one T allele in the ,129 C/T polymorphism of the GCLC gene was independently associated with NASH (odds ratio 12.14, 95% confidence interval 2.01,73.35; P = 0.007), whereas, the presence of at least one G allele in the ,493 G/T polymorphism of the MTP gene differed slightly between biopsy-proven NASH and simple steatosis. Conclusion:, This difference clearly warrants further investigation in larger samples. These two polymorphisms could represent an additional factor for consideration in evaluating the risk of NAFLD progression. Further studies involving a larger population are necessary to confirm this notion. [source] Retinal pigment epithelial cells promote spatial reorganization and differentiation of retina photoreceptorsJOURNAL OF NEUROSCIENCE RESEARCH, Issue 16 2008Olga L. German Abstract Retina differentiation involves the acquisition of a precise layered arrangement, with RPE cells in the first layer in intimate contact with photoreceptors in the second layer. Here, we developed an in vitro coculture model, to test the hypothesis that RPE cells play a pivotal role in organizing the spatial structure of the retina. We cocultured rat retinal neurons with ARPE-19 epithelial cells under various experimental conditions. Strikingly, when seeded over RPE cells, photoreceptors attached to their apical surfaces and proceeded with their development, including the increased synthesis of rhodopsin. Conversely, when we seeded RPE cells over neurons, the RPE cells rapidly detached photoreceptors from their substrata and positioned themselves underneath, thus restoring the normal in vivo arrangement. Treatment with the metalloproteinase inhibitor TIMP-1 blocked this reorganization, suggesting the involvement of metalloproteinases in this process. Reorganization was highly selective for photoreceptors because 98% of photoreceptors but very few amacrine neurons were found to redistribute on top of RPE cells. Interestingly, RPE cells were much more efficient than other epithelial or nonepithelial cells in promoting this reorganization. RPE cells also promoted the growth of photoreceptor axons away from them. An additional factor that contributed to the distal arrangement of photoreceptor axons was the migration of photoreceptor cell bodies along their own neurites toward the RPE cells. Our results demonstrate that RPE and photoreceptor cells interact in vitro in very specific ways. They also show that in vitro studies may provide important insights into the process of pattern formation in the retina. © 2008 Wiley-Liss, Inc. [source] Effect of sowing date and straw mulch on virus incidence and aphid infestation in organically grown faba beans (Vicia faba)ANNALS OF APPLIED BIOLOGY, Issue 2 2009H. Saucke Abstract The effect of sowing date on aphid infestation and the incidence of aphid-transmitted viruses were investigated in organically managed, small-scale field experiments with two faba bean cultivars over 3 years (2002,04). As an additional factor, straw mulch was applied in 2 of the 3 years shortly before the start of vector activity in May. Virus incidence was determined using enzyme-linked immunosorbent assay and immunoelectron microscopy. Aphid flight activity was monitored using standard yellow water traps. Bean colonising aphids were assessed throughout the vegetation period by counting the number of plants infested with Acyrthosiphon pisum, Megoura viciae and Aphis fabae. Pea enation mosaic virus and bean yellow mosaic virus were the most abundant aphid-transmitted viruses, being detected in 22,54% and 9,69%, respectively, of the total number of virus-infected plants analysed per year. Further aphid-transmitted viruses found in faba bean were bean leaf roll virus, beet western yellows virus, clover yellow vein virus (in 2002) and soybean dwarf virus (in 2004). A. pisum was the predominant aphid species colonising faba bean plants. Early sowing compared with late sowing led to a significant reduction of the total virus incidence in faba bean in all 3 years. However, significantly decreased levels of A. pisum colonisation as a result of early sowing were observed only in 1 year and one cultivar. Irrespective of sowing date, straw mulching had no significant effects on virus incidence and aphid colonisation. Compared with late sowing, early sowing significantly increased bean yield in all 3 years and kernel weight in 2 years, whereas straw mulching had no effect on yield. [source] Hypermethylation of E-cadherin is an independent predictor of improved survival in head and neck squamous cell carcinoma,CANCER, Issue 7 2008Carmen J. Marsit PhD Abstract BACKGROUND. The loss of E-cadherin (ECAD) protein expression has been linked to aggressive head and neck squamous cell carcinoma (HNSCC). Promoter hypermethylation of the cadherin 1, type 1 (CDH1) gene (encoding ECAD) is 1 mechanism by which this protein can be inactivated, although this epigenetic alteration of the gene has not been linked conclusively to poorer patient outcome and, in fact, may be associated with better patient prognosis. METHODS. The authors investigated the prevalence of CDH1 promoter hypermethylation in a population-based case series of 340 primary HNSCC tumors using methylation-specific polymerase chain reaction. They also studied the association between CDH1 hypermethylation and patient demographic characteristics using multivariate analysis and examined the impact of CDH1 hypermethylation on patient survival using both univariate and multivariate methods. RESULTS. Hypermethylation of CDH1 was significantly more prevalent (P < .03) among individuals with a low smoking history independent of whether they were seropositive for human papillomavirus type 16 (HPV-16). Patients who had tumors with CDH1 hypermethylation had significantly better overall survival compared with patients who had tumors without hypermethylation (P < .02; log-rank test). This effect was independent of HPV-16 status and demonstrated a significant hazard ratio of 0.5 (95% confidence interval, 0.3-0.9) in a model that controlled for HPV-16 serology, age, sex, and tumor stage. CONCLUSIONS. The current results suggested that hypermethylation of CDH1 occurs more commonly in patients with HNSCC who are low smokers, suggesting that an additional factor may be driving this epigenetic alteration. Clinically, CDH1 hypermethylation may hold powerful prognostic potential in addition to that observed with HPV serology, and the authors concluded that it should be pursued in additional studies. Cancer 2008. © 2008 American Cancer Society. [source] "Natural restoration" can generate biological complexityCOMPLEXITY, Issue 2 2005Emile ZuckerkandlArticle first published online: 16 DEC 200 Abstract Factor complexes engaged in transcriptional regulation of gene expression and their cognate DNA elements recurrently suffer mutational damage that can result in deadaptations in the mutual fit of interacting macromolecules. Such mutations can spread in populations by drift if their functional consequences are not severe. Mutational restorations of the damaged complexes may ensue and can take many forms. One of these forms would represent spontaneous increases in gene interaction complexity and correlated aspects of organismic complexity. In this particular mode of restoration, restabilization of a factor/factor/DNA complex occurs through the binding of an additional factor. Factors added under such circumstances to regulatory kits of individual genes are thought to be at the origin of a slow but persistent "complexity drive." This drive seems to be resisted in many forms whose developmental outcome has reached a finish line difficult to pass, but imposes itself along other lines of phylogenetic descent. In the process of restoration by an additional factor, the chances are significant that the original regulatory control of a target gene is not recovered exactly and that the restored gene expression has novel spatial, temporal, or quantitative characteristics. These new characteristics, which represent a functional transfer of the gene to a new domain of activity, may be selectable, even when the physicochemical properties of the gene product have remained largely unchanged. As a consequence of such activity transfers under quasi-constancy of the molecular properties of the protein encoded by the regulation's target gene, the activity domain originally covered by that target gene may be left at least in part functionally vacant. At that point, an unmodified duplicate of the target gene and of its original regulatory dependencies probably becomes in turn selectable. A causal link is therefore predicted between the regulatory specialization and selection of one of two duplicates and the regulatory maintenance and selection of the other. A conserved increase in gene number would result indirectly from the regulatory shift in paralogs, and the organism's complexity would be increased in this sense also, complexity as number of genes in addition to complexity as number of regulatory factors per gene. It is thus proposed that increased biological complexity, innovation in the gene regulatory network, and the development of a novel evolutionary potential can be the result, counterintuitively, of conservative forces that intervene when mutations play a survivable form of havoc with the system of gene regulation. Increasing complexity, then, could be seen as one of the side effects of "natural restoration." This phrase designates the mutational re-establishment in the gene whose regulation has been damaged of a functionally effective activity pattern, albeit, perhaps, with changes in its mode of expression in regard to location, time, and rate. The higher complexity, innovation in the gene regulatory network, of higher organisms,their very character of higher organisms,would to a significant extent be a side effect of episodes of natural selection aimed at functional restoration, not at complexity itself. Regulatory impairment, the point of departure of the process outlined, represents a controller gene disease. It thus may well be the case that molecular diseases, the effects on the individual of inheritable structural decay, are among the conditions of the evolution of higher organisms. © 2005 Wiley Periodicals, Inc. Complexity 11: 14,27, 2005 [source] Vastus lateralis surface and single motor unit electromyography during shortening, lengthening and isometric contractions corrected for mode-dependent differences in force-generating capacityACTA PHYSIOLOGICA, Issue 3 2009T. M. Altenburg Abstract Aim:, Knee extensor neuromuscular activity, rectified surface electromyography (rsEMG) and single motor unit EMG was investigated during isometric (60° knee angle), shortening and lengthening contractions (50,70°, 10° s,1) corrected for force,velocity-related differences in force-generating capacity. However, during dynamic contractions additional factors such as shortening-induced force losses and lengthening-induced force gains may also affect force capacity and thereby neuromuscular activity. Therefore, even after correction for force,velocity-related differences in force capacity we expected neuromuscular activity to be higher and lower during shortening and lengthening, respectively, compared to isometric contractions. Methods:, rsEMG of the three superficial muscle heads was obtained in a first session [10 and 50% maximal voluntary contraction (MVC)] and additionally EMG of (46) vastus lateralis motor units was recorded during a second session (4,76% MVC). Using superimposed electrical stimulation, force-generating capacity for shortening and lengthening contractions was found to be 0.96 and 1.16 times isometric (Iso) force capacity respectively. Therefore, neuromuscular activity during submaximal shortening and lengthening was compared with isometric contractions of respectively 1.04Iso (=1/0.96) and 0.86Iso (=1/1.16). rsEMG and discharge rates were normalized to isometric values. Results:, rsEMG behaviour was similar (P > 0.05) during both sessions. Shortening rsEMG (1.30 ± 0.11) and discharge rate (1.22 ± 0.13) were higher (P < 0.05) than 1.04Iso values (1.05 ± 0.05 and 1.03 ± 0.04 respectively), but lengthening rsEMG (1.05 ± 0.12) and discharge rate (0.90 ± 0.08) were not lower (P > 0.05) than 0.86Iso values (0.76 ± 0.04 and 0.91 ± 0.07 respectively). Conclusion:, When force,velocity-related differences in force capacity were taken into account, neuromuscular activity was not lower during lengthening but was still higher during shortening compared with isometric contractions. [source] Squamous Cell Carcinoma in Chronic Lymphedema: Case Report and Review of the LiteratureDERMATOLOGIC SURGERY, Issue 10 2002Hiroshi Furukawa MD background. Squamous cell carcinoma (SCC) arising in chronic lymphedema is rare; only nine cases have been reported. objective. To present the evolution of SCC in chronic lymphedema. methods. Case report and literature review. results. The tumor was treated by wide excision and covered by a skin graft. conclusion. In most of the other reported SCC cases in lymphedema, there are additional factors for carcinogenesis. There is no additional carcinogenic factor except for chronic lymphedema in our case. This strongly supports that lymphedema itself is one of the carcinogenic factors for not only angiosarcoma but also SCC. [source] Cell-type-specific limitation on in vivo serotonin storage following ectopic expression of the Drosophila serotonin transporter, dSERTDEVELOPMENTAL NEUROBIOLOGY, Issue 5 2006Sang Ki Park Abstract The synaptic machinery for neurotransmitter storage is cell-type specific. Although most elements of biosynthesis and transport have been identified, it remains unclear whether additional factors may be required to maintain this specificity. The Drosophila serotonin transporter (dSERT) is normally expressed exclusively in serotonin (5-HT) neurons in the CNS. Here we examine the effects of ectopic transcriptional expression of dSERT in the Drosophila larval CNS. We find a surprising limitation on 5-HT storage following ectopic expression of dSERT and green fluorescence protein-tagged dSERT (GFP-dSERT). When dSERT transcription is driven ectopically in the CNS, 5-HT is detectable only in 5-HT, dopamine (DA), and a very limited number of additional neurons. Addition of exogenous 5-HT does not dramatically broaden neuronal storage sites, so this limitation is only partly due to restricted intercellular diffusion of 5-HT. Furthermore, this limitation is not due to gross mislocalization of dSERT, because cells lacking or containing 5-HT show similar levels and subcellular distribution of GFP-dSERT protein, nor is it due to lack of the vesicular transporter, dVMAT. These data suggest that a small number of neurons selectively express factor(s) required for 5-HT storage, and potentially for function of dSERT. © 2006 Wiley Periodicals, Inc. J Neurobiol, 2006 [source] Robust principal component analysis and outlier detection with ecological dataENVIRONMETRICS, Issue 2 2004Donald A. Jackson Abstract Ecological studies frequently involve large numbers of variables and observations, and these are often subject to various errors. If some data are not representative of the study population, they tend to bias the interpretation and conclusion of an ecological study. Because of the multivariate nature of ecological data, it is very difficult to identify atypical observations using approaches such as univariate or bivariate plots. This difficulty calls for the application of robust statistical methods in identifying atypical observations. Our study provides a comparison of a standard method, based on the Mahalanobis distance, used in multivariate approaches to a robust method based on the minimum volume ellipsoid as a means of determining whether data sets contain outliers or not. We evaluate both methods using simulations varying conditions of the data, and show that the minimum volume ellipsoid approach is superior in detecting outliers where present. We show that, as the sample size parameter, h, used in the robust approach increases in value, there is a decrease in the accuracy and precision of the associated estimate of the number of outliers present, in particular as the number of outliers increases. Conversely, where no outliers are present, large values for the parameter provide the most accurate results. In addition to the simulation results, we demonstrate the use of the robust principal component analysis with a data set of lake-water chemistry variables to illustrate the additional insight available. We suggest that ecologists consider that their data may contain atypical points. Following checks associated with normality, bivariate linearity and other traditional aspects, we advocate that ecologists examine their data sets using robust multivariate methods. Points identified as being atypical should be carefully evaluated based on background information to determine their suitability for inclusion in further multivariate analyses and whether additional factors explain their unusual characteristics. Copyright © 2004 John Wiley & Sons, Ltd. [source] Sex, Rank and Age Differences in the Japanese Macaque (Macaca fuscata yakui) Participation in Inter-Group EncountersETHOLOGY, Issue 5 2005Bonaventura Majolo In many species interactions among group are often characterized by agonistic behaviour. Although animals may participate in inter-group encounters in different ways, depending on their energetic requirements, reproductive tactics, and/or developmental stage, the proximate causes affecting an animal's participation in inter-group encounters are still poorly understood. Indeed, many studies have analysed the behaviour of males and females during inter-group encounters without considering the importance of additional factors (e.g. rank). This study focuses on wild non-provisioned Japanese macaques (Macaca fuscata yakui) living on Yakushima Island, Japan. It aims to determine how monkeys of different sex, age, and rank behave during inter-group encounters and it discusses the implications and consequences of their behaviour on group composition and male dispersal. Males participated significantly more than females in inter-group encounters, by displaying more aggressive or affiliative behaviour. High-ranking and/or adult males were more aggressive than low-ranking and/or subadult males during encounters occurring in the mating season and they also showed more herding behaviour. This trend was not found in inter-group encounters occurring during the non-mating season. Finally, males which then emigrated to new groups were low-ranking and/or subadult individuals. Those males displayed more affiliative behaviour towards foreign males than males which did emigrate. These data indicate that in non-territorial species with male dominance over female and high competition for mating partners males play an active, and often aggressive, role during inter-group encounter while female participation is scarce. Factors such as age, rank and period of the year (in seasonally breeding species) have to be taken into considerations when analysing interactions between groups and their effects on group composition and social behaviour. [source] Regulation of cerebral blood flow in mammals during chronic hypoxia: a matter of balanceEXPERIMENTAL PHYSIOLOGY, Issue 2 2010Philip N. Ainslie Respiratory-induced changes in the partial pressures of arterial carbon dioxide and oxygen play a major role in cerebral blood flow (CBF) regulation. Elevations in (hypercapnia) lead to vasodilatation and increases in CBF, whereas reductions in (hypocapnia) lead to vasoconstriction and decreases in CBF. A fall in (hypoxia) below a certain threshold (<40,45 mmHg) also produces cerebral vasodilatation. Upon initial exposure to hypoxia, CBF is elevated via a greater relative degree of hypoxia compared with hypocapnia. At this point, hypoxia-induced elevations in blood pressure and loss of cerebral autoregulation, stimulation of neuronal pathways, angiogenesis, release of adenosine, endothelium-derived NO and a variety of autocoids and cytokines are additional factors acting to increase CBF. Following 2,3 days, however, the process of ventilatory acclimatization results in a progressive rise in ventilation, which increases and reduces , collectively acting to attenuate the initial rise in CBF. Other factors acting to lower CBF include elevations in haematocrit, sympathetic nerve activity and local and endothelium-derived vasoconstrictors. Hypoxia-induced alterations of cerebrovascular reactivity, autoregulation and pulmonary vascular tone may also affect CBF. Thus, the extent of change in CBF during exposure to hypoxia is dependent on the balance between the myriad of vasodilators and constrictors derived from the endothelium, neuronal innervations and perfusion pressure. This review examines the extent and mechanisms by which hypoxia regulates CBF. Particular focus will be given to the marked influence of hypoxia associated with exposure to high altitude and chronic lung disease. The associated implications of these hypoxia-induced integrative alterations for the regulation of CBF are discussed, and future avenues for research are proposed. [source] The impact of politeness and relationship on perceived quality of advice about a problemHUMAN COMMUNICATION RESEARCH, Issue 2 2000DJ Goldsmith Advice is a common but potentially problematic way to respond to someone who is distressed. Politeness theory (Brown & Levinson, 1987) suggests advice threatens a hearer's face and predicts that the speaker-hearer relationship and the use of politeness strategies can mitigate face threat and enhance the effectiveness of advice messages. Students (N=384) read 1 of 16 hypothetical situations that varied in speaker power and closeness of the speaker-hearer relationship. Students then read 1 of 48 advice messages representing different politeness strategies and rated the message for regard shown for face and for effectiveness. However, neither speaker-hearer relationship nor politeness strategies was consistently associated with perceived threat to face or perceived advice effectiveness. We suggest revisions to politeness theory and additional factors that may affect judgments of face sensitivity and advice effectiveness. [source] LDL-receptor mutations in Europe,HUMAN MUTATION, Issue 6 2004George V.Z. Dedoussis Abstract Familial hypercholesterolemia (FH) is a clinical definition for a remarkable increase of cholesterol serum concentration, presence of xanthomas, and an autosomal dominant trait of either increased serum cholesterol or premature coronary artery disease (CAD). The identification of the low-density lipoprotein (LDL)-receptor (LDLR) as the underlying cause and its genetic characterization in FH patients revealed more insights in the trafficking of LDL, which primarily transports cholesterol to hepatic and peripheral cells. Mutations within LDLR result in hypercholesterolemia and, subsequently, cholesterol deposition in humans to a variable degree. This confirms the pathogenetic role of LDLR and also highlights the existence of additional factors in determining the phenotype. Autosomal dominant FH is caused by LDLR deficiency and defective apolipoprotein B-100 (APOB), respectively. Heterozygosity of the LDLR is relatively common (1:500). Clinical diagnosis is highly important and genetic diagnosis may be helpful, since treatment is usually effective for this otherwise fatal disease. Very recently, mutations in PCSK9 have been also shown to cause autosomal dominant hypercholesterolemia. For autosomal recessive hypercholesterolemia, mutations within the so-called ARH gene encoding a cellular adaptor protein required for LDL transport have been identified. These insights emphasize the crucial importance of LDL metabolism intra- and extracellularly in determining LDL-cholesterol serum concentration. Herein, we focus on the published European LDLR mutation data that reflect its heterogeneity and phenotypic penetrance. Hum Mutat 24:443,459, 2004. © 2004 Wiley-Liss, Inc. [source] | |||||||||||||||||||||||||||||||||||||