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Par
Kinds of Par Terms modified by Par Selected AbstractsEstimating population attributable risk for hepatitis C seroconversion in injecting drug users in Australia: implications for prevention policy and planningADDICTION, Issue 12 2009Handan Wand ABSTRACT Objective To determine risk factors and estimate their population-level contribution to hepatitis C virus (HCV) burden. Methods Established and potentially modifiable risk factors were estimated using partial population attributable risk (PARp) in a cohort of new injecting drug users (IDUs) in Sydney, Australia. Results A total of 204 hepatitis C seronegative IDUs were recruited through street-based outreach, methadone clinics and needle and syringe programmes (NSPs) and followed-up at 3,6-monthly intervals. A total of 61 HCV seroconversions were observed during the follow-up [overall incidence rate of 45.8 per 100 person-years (95% confidence interval: 35.6,58.8)]. Overall, five potentially modifiable risk factors (sharing needles/syringes, sharing other injecting equipment, assisted injecting, frequency of injection and not being in drug treatment) accounted for approximately 50% of HCV cases observed. Conclusion While sharing needles/syringes or other injecting equipment were associated most strongly with increased risk of HCV infection, the PARp associated with these behaviours was relatively modest (12%) because they are relatively low-prevalence behaviours. Our analyses suggest that more HCV infection could be avoided by changing more common, but less strongly associated behaviours such as assisted injecting or daily injecting. Results suggest that to have a very substantial effect on HCV, a range of risk factors need modifying. The most efficient use of scarce resources in reducing HCV infections will require complex balancing between the PAR for a given risk factor(s), the efficacy of interventions to actually modify the risk factor, and the cost of these interventions. [source] The Preliminary Studies of Electrochemical Behavior of Paracetamol and Its Metabolites on Glassy Carbon Electrode by Voltammetric MethodsELECTROANALYSIS, Issue 10 2009Irena Baranowska Abstract The new, rapid and sensitive method for the determination of paracetamol (PAR) and its glucuronide (PG) and sulfate (PS) metabolites is proposed. The electrochemical properties of the compounds were examined by cyclic voltammetry (CV) on glassy carbon electrode (GCE). All measurements were carried out in Britton,Robinson buffers (BR) with different pH values over the pH range 1.81,7.24. The preliminary research indicated that PAR could be determined simultaneously with one of its metabolites. The linearity of calibration curves was obtained for concentrations between 1.65×10,5 and 1.65×10,4 M for PAR, 1.53×10,5 and 1.53×10,4 M for PG and 2.17×10,5 and 1.52×10,4 M for PS. [source] PLASTICITY TO LIGHT CUES AND RESOURCES IN ARABIDOPSIS THALIANA: TESTING FOR ADAPTIVE VALUE AND COSTSEVOLUTION, Issue 6 2000Lisa A. Dorn Abstract Plants shaded by neighbors or overhead foliage experience both a reduction in the ratio of red to far red light (R:FR), a specific cue perceived by phytochrome, and reduced photosynthetically active radiation (PAR), an essential resource. We tested the adaptive value of plasticity to crowding and to the cue and resource components of foliage shade in the annual plant Arabidopsis thaliana by exposing 36 inbred families from four natural populations to four experimental treatments: (1) high density, full sun; (2) low density, full sun; (3) low density, neutral shade; and (4) low density, low R:FR-simulated foliage shade. Genotypic selection analysis within each treatment revealed strong environmental differences in selection on plastic life-history traits. We used specific contrasts to measure plasticity to density and foliage shade, to partition responses to foliage shade into phytochrome-mediated responses to the R:FR cue and responses to PAR, and to test whether plasticity was adaptive (i.e., in the same direction as selection in each environment). Contrary to expectation, we found no evidence for adaptive plasticity to density. However, we observed both adaptive and maladaptive responses to foliage shade. In general, phytochrome-mediated plasticity to the R:FR cue of foliage shade was adaptive and counteracted maladaptive growth responses to reduced PAR. These results support the prediction that active developmental responses to environmental cues are more likely to be adaptive than are passive resource-mediated responses. Multiple regression analysis detected a few costs of adaptive plasticity and adaptive homeostasis, but such costs were infrequent and their expression depended on the environment. Thus, costs of plasticity may occasionally constrain the evolution of adaptive responses to foliage shade in Arabidopsis, but this constraint may differ among environments and is far from ubiquitous. [source] Chiral alcohol production by NADH-dependent phenylacetaldehyde reductase coupled with in situ regeneration of NADHFEBS JOURNAL, Issue 9 2002Nobuya Itoh Phenylacetaldehyde reductase (PAR) produced by styrene-assimilating Corynebacterium strain ST-10 was used to synthesize chiral alcohols. This enzyme with a broad substrate range reduced various prochiral aromatic ketones and ,-ketoesters to yield optically active secondary alcohols with an enantiomeric purity of more than 98% enantiomeric excess (e.e.). The Escherichia coli recombinant cells which expressed the par gene could efficiently produce important pharmaceutical intermediates; (R)-2-chloro-1-(3-chlorophenyl)ethanol (28 mg·mL,1) from m -chlorophenacyl chloride, ethyl (R)-4-chloro-3-hydroxy butanoate) (28 mg·mL,1) from ethyl 4-chloro-3-oxobutanoate and (S)- N-tert -butoxycarbonyl(Boc)-3-pyrrolidinol from N -Boc-3-pyrrolidinone (51 mg·mL,1), with more than 86% yields. The high yields were due to the fact that PAR could concomitantly reproduce NADH in the presence of 3,7% (v/v) 2-propanol in the reaction mixture. This biocatalytic process provided one of the best asymmetric reductions ever reported. [source] Increase in photosynthetic efficiency as a strategy of planktonic organisms exploiting deep lake layersFRESHWATER BIOLOGY, Issue 2 2004Beatriz Modenutti Summary 1. The photosynthetic efficiencies of the mixotrophic ciliate Ophrydium naumanni and the autotrophic dinoflagellate Gymnodinium paradoxum were investigated using laboratory and field experiments in Lake Moreno Oeste (41°5,S and 71°33,W, 758 m a.s.l.), in the Nahuel Huapi System (North Patagonia, Argentina). 2. The effect of different underwater light intensities on net primary production (NPP) was assessed during one summer. Additionally, laboratory experiments were carried out to obtain photosynthesis-irradiance response curves for each species. 3. Ophrydium naumanni and G. paradoxum dominated the metalimnetic (30 m depth) deep chlorophyll maximum (DCM) in the lake. 4. Despite these deep higher abundances, the cell-specific production of both species was higher at 10 m than at 30 m (DCM) depth. In addition, at 5 m depth, NPP was reduced by PAR + UV-A radiation. 5. Both species exhibited a positive NPP at very low irradiance but the mixotrophic ciliate was more efficient in exploiting the DCM irradiance level both in situ and at comparable light intensities in laboratory experiments. Light acclimatised O. naumanni showed a higher NPP at lower irradiances and photoinhibition at medium and high irradiances. 6. Under the strong wind-driven turbulence commonly found in Patagonian lakes, organisms cannot select their position in the epilimnetic water column and will be dragged to potentially harmful UV radiation levels. Thus, metalimnetic DCM colonisation by these two species represents a tradeoff between higher survival and lower cell-specific NPP. [source] Modulation of the bacterial response to spectral solar radiation by algae and limiting nutrientsFRESHWATER BIOLOGY, Issue 11 2002J. M. Medina-Sánchez SUMMARY 1. The response of bacterial production (measured as [3H]TdR incorporation rate) to spectral solar radiation was quantified experimentally in an oligotrophic high-mountain lake over 2 years. Bacterial responses were consistent: ultraviolet-B (UVB) was harmful, whereas ultraviolet-A (UVA) + photosynthetically active radiation (PAR) and PAR enhanced bacterial activity. Full sunlight exerted a net stimulatory effect on bacterial activity in mid-summer but a net inhibitory effect towards the end of the ice-free period. 2. Experiments were undertaken to examine whether the bacterial response pattern depended on the presence of algae and/or was modulated by the availability of a limiting inorganic nutrient (phosphorus, P). In the absence of algae, [3H]TdR incorporation rates were significantly lower than when algae were present under all light treatments, and the consistent bacterial response was lost. This suggests that the bacterial response to spectral solar radiation depends on fresh-C released from algae, which determines the net stimulatory outcome of damage and repair in mid-summer. 3. In the absence of algae, UVB radiation inhibited bacteria when they were strongly P-deficient (mean values of N : P ratio: 46.1), whereas it exerted no direct effect on bacterial activity when they were not P-limited. 4. P-enrichment of lake water markedly altered the response of bacteria to spectral solar radiation at the end of ice-free period, when bacteria were strongly P-deficient. Phosphorus enrichment suppressed the inhibitory effect of full sunlight that was observed in October, both in whole lake water (i.e. including algae) and in the absence of algae. This indicates that the bacterial P-deficiency, measured as the cellular N : P ratio, was partly responsible for the net inhibitory effect of full sunlight, implying a high bacterial vulnerability to UVB. [source] Chilean high-altitude hot-spring sinters: a model system for UV screening mechanisms by early Precambrian cyanobacteriaGEOBIOLOGY, Issue 1 2006V. R. PHOENIX ABSTRACT Before the build-up of stratospheric ozone, Archean and early Proterozoic phototrophs existed in an environment subjected to highly elevated levels of ultraviolet (UV) radiation. Therefore, phototrophic life would have required a protective habitat that balanced UV attenuation and photosynthetically active radiation (PAR) transmission. Here we report on aspects of the phototroph geomicrobiology of El Tatio geothermal field, located at 4300 m in the Andes Mountains of northern Chile (22 °S), as an analogue system to early Precambrian environments. El Tatio microbes survive in a geochemical environment of rapidly precipitating amorphous silica (sinter) and unusually high solar radiation (including elevated UV-B flux) due to the high-altitude, low-latitude location. Cyanobacteria produce 10-mm-thick surface mats containing filaments encased in amorphous silica matrices up to 5 µm thick. Relative radiation absorbance of these silica matrices was UV-C > UV-B > UV-A > PAR, suggesting the silica provides a significant UV shield to the cyanobacteria. Cyanobacteria also occur in cryptoendolithic communities 1,10 mm below siliceous sinter surfaces, and in siliceous stromatolites, where viable cyanobacteria are found at least ,10 mm below the sinter surface. UV-B was dramatically attenuated within ,1 mm of the sinter surface, whereas UV-C (a frequency range absent today but present in the early Precambrian) was attenuated even more efficiently. PAR was attenuated the least, and minimum PAR levels required for photosynthesis penetrated 5,10 mm into the sinter. Thus, a favourable niche occurs between approximately 1,10 mm in siliceous sinters where there is a balance between PAR transmission and UV attenuation. These deposits also would have strongly attenuated Archean and early Precambrian levels of UV and thus, by analogy, cyanobacteria of early Precambrian shallow aquatic environments, inhabiting silicified biofilms and silica stromatolites, would have similarly been afforded protection against high-intensity UV radiation. [source] Large annual net ecosystem CO2 uptake of a Mojave Desert ecosystemGLOBAL CHANGE BIOLOGY, Issue 7 2008GEORG WOHLFAHRT Abstract The net ecosystem CO2 exchange (NEE) between a Mojave Desert ecosystem and the atmosphere was measured over the course of 2 years at the Mojave Global Change Facility (MGCF, Nevada, USA) using the eddy covariance method. The investigated desert ecosystem was a sink for CO2, taking up 102±67 and 110±70 g C m,2 during 2005 and 2006, respectively. A comprehensive uncertainty analysis showed that most of the uncertainty of the inferred sink strength was due to the need to account for the effects of air density fluctuations on CO2 densities measured with an open-path infrared gas analyser. In order to keep this uncertainty within acceptable bounds, highest standards with regard to maintenance of instrumentation and flux measurement postprocessing have to be met. Most of the variability in half-hourly NEE was explained by the amount of incident photosynthetically active radiation (PAR). On a seasonal scale, PAR and soil water content were the most important determinants of NEE. Precipitation events resulted in an initial pulse of CO2 to the atmosphere, temporarily reducing NEE or even causing it to switch sign. During summer, when soil moisture was low, a lag of 3,4 days was observed before the correlation between NEE and precipitation switched from positive to negative, as opposed to conditions of high soil water availability in spring, when this transition occurred within the same day the rain took place. Our results indicate that desert ecosystem CO2 exchange may be playing a much larger role in global carbon cycling and in modulating atmospheric CO2 levels than previously assumed , especially since arid and semiarid biomes make up >30% of Earth's land surface. [source] Monoterpene emissions from rubber trees (Hevea brasiliensis) in a changing landscape and climate: chemical speciation and environmental controlGLOBAL CHANGE BIOLOGY, Issue 11 2007YONG-FENG WANG Abstract Emissions of biogenic volatile organic compounds (VOCs) have important roles in ecophysiology and atmospheric chemistry at a wide range of spatial and temporal scales. Tropical regions are a major global source of VOC emissions and magnitude and chemical speciation of VOC emissions are highly plant-species specific. Therefore it is important to study emissions from dominant species in tropical regions undergoing large-scale land-use change, for example, rubber plantations in South East Asia. Rubber trees (Hevea brasiliensis) are strong emitters of light-dependent monoterpenes. Measurements of emissions from leaves were made in the dry season in February 2003 and at the beginning of the wet season in May 2005. Major emitted compounds were sabinene, , -pinene and , -pinene, but , -ocimene and linalool also contributed significantly at low temperature and light. Cis -ocimene was emitted with a circadian course independent of photosynthetic active radiation (PAR) and temperature changes with a maximum in the middle of the day. Total isoprenoid VOC emission potential at the beginning of the wet season (94 ,g gdw,1 h,1) was almost two orders of magnitude higher than measured in the dry season (2 ,g g dw,1 h,1). Composition of total emissions changed with increasing temperature or PAR ramps imposed throughout a day. As well as light and temperature, there was evidence that assimilation rate was also a factor contributing to seasonal regulating emission potential of monoterpenes from rubber trees. Results presented here contribute to a better understanding of an important source of biogenic VOC associated with land-use change in tropical South East Asia. [source] Climatic controls on the carbon and water balances of a boreal aspen forest, 1994,2003GLOBAL CHANGE BIOLOGY, Issue 3 2007ALAN G. BARR Abstract The carbon and water budgets of boreal and temperate broadleaf forests are sensitive to interannual climatic variability and are likely to respond to climate change. This study analyses 9 years of eddy-covariance data from the Boreal Ecosystem Research and Monitoring Sites (BERMS) Southern Old Aspen site in central Saskatchewan, Canada and characterizes the primary climatic controls on evapotranspiration, net ecosystem production (FNEP), gross ecosystem photosynthesis (P) and ecosystem respiration (R). The study period was dominated by two climatic extremes: extreme warm and cool springs, which produced marked contrasts in the canopy duration, and a severe, 3-year drought. Annual FNEP varied among years from 55 to 367 g C m,2 (mean 172, SD 94). Interannual variability in FNEP was controlled primarily by factors that affected the R/P ratio, which varied between 0.74 and 0.96 (mean 0.87, SD 0.06). Canopy duration enhanced P and FNEP with no apparent effect on R. The fraction of annual photosynthetically active radiation (PAR) that was absorbed by the canopy foliage varied from 38% in late leaf-emergence years to 51% in early leaf-emergence years. Photosynthetic light-use efficiency (mean 0.0275, SD 0.026 mol C mol,1 photons) was relatively constant during nondrought years but declined with drought intensity to a minimum of 0.0228 mol C mol,1 photons during the most severe drought year. The impact of drought on FNEP varied with drought intensity. Years of mild-to-moderate drought suppressed R while having little effect on P, so that FNEP was enhanced. Years of severe drought suppressed both R and P, causing either little change or a subtle reduction in FNEP. The analysis produced new insights into the dominance of canopy duration as the most important biophysical control on FNEP. The results suggested a simple conceptual model for annual FNEP in boreal deciduous forests. When water is not limiting, annual P is controlled by canopy duration via its influence on absorbed PAR at constant light-use efficiency. Water stress suppresses P, by reducing light-use efficiency, and R, by limiting growth and/or suppressing microbial respiration. The high photosynthetic light-use efficiency showed this site to be a highly productive boreal deciduous forest, with properties similar to many temperate deciduous forests. [source] Interactive effects of elevated CO2 and soil fertility on isoprene emissions from Quercus roburGLOBAL CHANGE BIOLOGY, Issue 11 2004Malcolm Possell Abstract The effects of global change on the emission rates of isoprene from plants are not clear. A factor that can influence the response of isoprene emission to elevated CO2 concentrations is the availability of nutrients. Isoprene emission rate under standard conditions (leaf temperature: 30°C, photosynthetically active radiation (PAR): 1000 ,mol photons m,2 s,1), photosynthesis, photosynthetic capacity, and leaf nitrogen (N) content were measured in Quercus robur grown in well-ventilated greenhouses at ambient and elevated CO2 (ambient plus 300 ppm) and two different soil fertilities. The results show that elevated CO2 enhanced photosynthesis but leaf respiration rates were not affected by either the CO2 or nutrient treatments. Isoprene emission rates and photosynthetic capacity were found to decrease with elevated CO2, but an increase in nutrient availability had the converse effect. Leaf N content was significantly greater with increased nutrient availability, but unaffected by CO2. Isoprene emission rates measured under these conditions were strongly correlated with photosynthetic capacity across the range of different treatments. This suggests that the effects of CO2 and nutrient levels on allocation of carbon to isoprene production and emission under near-saturating light largely depend on the effects on photosynthetic electron transport capacity. [source] Land-use impact on ecosystem functioning in eastern Colorado, USAGLOBAL CHANGE BIOLOGY, Issue 6 2001J. M. Paruelo Abstract Land-cover change associated with agriculture has had an enormous effect on the structure and functioning of temperate ecosystems. However, the empirical evidence for the impact of land use on ecosystem functioning at the regional scale is scarce. Most of our knowledge on land-use impact has been derived from simulation studies or from small plot experiments. In this article we studied the effects of land use on (i) the seasonal dynamics and (ii) the interannual variability of the Normalized Difference Vegetation Index (NDVI), a variable linearly related to the fraction of the photosynthetically active radiation (PAR) intercepted by the canopy. We also analysed the relative importance of environmental factors and land use on the spatial patterns of NDVI. We compared three cultivated land-cover types against native grasslands. The seasonal dynamics of NDVI was used as a descriptor of ecosystem functioning. In order to reduce the dimensionality of our data we analysed the annual integral (NDVI-I), the date of maximum NDVI (DMAX) and the quarterly average NDVI. These attributes were studied for 7 years and for 346 sites distributed across eastern Colorado (USA). Land use did modify ecosystem functioning at the regional level in eastern Colorado. The seasonal dynamics of NDVI, a surrogate for the fraction of PAR intercepted by the canopy, were significantly altered by agricultural practices. Land use modified both the NDVI integral and the seasonal dynamics of this spectral index. Despite the variability within land-cover categories, land use was the most important factor in explaining regional differences of the NDVI attributes analysed. Within the range of environmental conditions found in eastern Colorado, land use was more important than mean annual precipitation, mean annual temperature and soil texture in determining the seasonal dynamics of NDVI. [source] An empirical model of carbon fluxes in Russian tundraGLOBAL CHANGE BIOLOGY, Issue 2 2001Dmitri G. Zamolodchikov Summary This study presents an empirical model based on a GIS approach, which was constructed to estimate the large-scale carbon fluxes over the entire Russian tundra zone. The model has four main blocks: (i) the computer map of tundra landscapes; (ii) data base of long-term weather records; (iii) the submodel of phytomass seasonal dynamics; and (iv) the submodel of carbon fluxes. The model uses exclusively original in situ diurnal CO2 flux chamber measurements (423 sample plots) conducted during six field seasons (1993,98). The research sites represent the main tundra biome landscapes (arctic, typical, south shrub and mountain tundras) in the latitudinal diapason of 65,74°N and longitudinal profile of 63°E,172°W. The greatest possible diversity of major ecosystem types within the different landscapes was investigated. The majority of the phytomass data used was obtained from the same sample plots. The submodel of carbon fluxes has two dependent [GPP, Gross Respiration (GR)] and several input variables (air temperature, PAR, aboveground phytomass components). The model demonstrates a good correspondence with other independent regional and biome estimates and carbon flux seasonal patterns. The annual GPP of Russian tundra zone for the area of 235 × 106 ha was estimated as ,485.8 ± 34.6 × 106 tC, GR as +474.2 ± 35.0 × 106 tC, and NF as ,11.6 ± 40.8 × 106 tC, which possibly corresponds to an equilibrium state of carbon balance during the climatic period studied (the first half of the 20th century). The results advocate that simple regression-based models are useful for extrapolating carbon fluxes from small to large spatial scales. [source] Prioritizing regions of candidate genes for efficient mutation screening,HUMAN MUTATION, Issue 2 2006Terry A. Braun Abstract The availability of the complete sequence of the human genome has dramatically facilitated the search for disease-causing sequence variations. In fact, the rate-limiting step has shifted from the discovery and characterization of candidate genes to the actual screening of human populations and the subsequent interpretation of observed variations. In this study we tested the hypothesis that some segments of candidate genes are more likely than others to contain disease-causing variations and that these segments can be predicted bioinformatically. A bioinformatic technique, prioritization of annotated regions (PAR), was developed to predict the likelihood that a specific coding region of a gene will harbor a disease-causing mutation based on conserved protein functional domains and protein secondary structures. This method was evaluated by using it to analyze 710 genes that collectively harbor 4,498 previously identified mutations. Nearly 50% of the genes were recognized as disease-associated after screening only 9% of the complete coding sequence. The PAR technique identified 90% of the genes as containing at least one mutation, with less than 40% of the screening resources that traditional approaches would require. These results suggest that prioritization strategies such as PAR can accelerate disease-gene identification through more efficient use of screening resources. Hum Mutat 27(2), 195,200, 2006. © 2006 Wiley-Liss, Inc. [source] Genotype-phenotype analysis in childhood-onset Crohn's disease: NOD2/CARD15 variants consistently predict phenotypic characteristics of severe diseaseINFLAMMATORY BOWEL DISEASES, Issue 11 2005Richard K Russell Abstract Introduction: The incidence of early-onset CD in Scotland is among the highest worldwide. Three single nucleotide polymorphisms (SNPs) R702W, G908R and Leu1007finsC in the NOD2/CARD15 gene predispose to adult CD. We investigated the contribution of these variants to disease susceptibility and phenotype in the Scottish early-onset IBD population. Patients and Methods: 906 individuals including 247 Scottish IBD patients aged <16 years at diagnosis, 414 parents and 245 controls were genotyped. Transmission disequilibrium testing (TDT), case-control analysis and detailed genotype-phenotype analysis were performed. Results: The Leu1007finsC variant was associated with susceptibility to CD by case-control (4.2% versus. 1.4%, P = 0.01) and TDT analysis (P = 0.006). The Population Attributable Risk (PAR) for the 3 NOD2/CARD15 mutations was 7.9%. Carriage of NOD2/CARD15 variants was associated with, at diagnosis: decreased albumin (31.0% versus. 9.0%, P = 0.001) and raised CRP (25% versus. 9.5%, P = 0.04) and at follow up: need for surgery (39.5% versus. 12.8%, P = 0.0002) jejunal involvement (50% versus. 18.4%, P = 0.01) jejunal and ileal involvement (50% versus. 10.7%, P = 0.009), raised CRP (57.1% and 12.8%, P = 0.0009), lower weight/height centile (75.0% versus. 20.2%, P = 0.03, 50.0% versus. 16.0%, P = 0.001 respectively) and stricturing disease (45.5% versus. 19.4%, P < 0.05). Multifactorial analysis demonstrated carriage was associated with need for surgery (P = 0.004, OR 4.9 [1.5-14.7]). Conclusions: These NOD2/CARD 15 variants in the Scottish early onset CD population have a definite, albeit relatively small contribution to CD susceptibility (PAR 7.9%) but a major impact on phenotype. In particular NOD2/CARD15 variants are strongly associated with several markers of disease severity in pediatric CD, notably need for surgery. [source] Priority-based adaptive routing in NGEO satellite networksINTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 3 2007Ömer Korçak Abstract In a non-geostationary satellite constellation with inter satellite links (ISLs), there could be many shortest paths between two satellites in terms of hop count. An efficient routing algorithm should effectively use these paths in order to distribute traffic to ISLs in a balanced way and to improve the performance of the system. This paper presents and evaluates a novel priority-based adaptive shortest path routing (PAR) scheme in order to achieve this goal. PAR sets the path towards the destination in a distributed manner, using a priority mechanism depending on the past utilization and buffering information of the ISLs. Moreover, to avoid unnecessary splitting of a flow and to achieve better utilization of ISLs, enhanced PAR (ePAR) scheme is proposed. This paper evaluates performance of the proposed techniques by employing an extensive set of simulations. Furthermore, since there are a number of ePAR parameters that should be adjusted depending on the network and traffic characteristics, a detailed analysis of ePAR scheme is provided to form a framework for setting the parameters. This paper also includes a method for adaptation of the proposed algorithms to minimum-delay path routing. Copyright © 2006 John Wiley & Sons, Ltd. [source] Delirium and older people: what are the constraints to best practice in acute care?INTERNATIONAL JOURNAL OF OLDER PEOPLE NURSING, Issue 3 2008BHSc (Nursing), Jenny Day ADCHN, MEd (Adult Education) An Australian research team conducted a six-month acute care pilot study in a medical ward of a large hospital in New South Wales. Aim., To explore ways health practitioners might redesign their practice to include prevention, early detection and management of delirium in older people based on the best current practice. Method and design., Participatory action research (PAR) was selected as the best approach for involving ward staff to make sustainable clinical practice decisions. The PAR group comprised research academics and eight clinicians from the ward. Thirteen PAR sessions were held over 5 months. Clinicians described care of patients with delirium. Stories were analysed to identify constraints to best practice. Following PAR group debate about concerns and issues, there were actions toward improved practice taken by clinicians. Relevance to clinical practice., The following constraints to best practice were identified: delayed transfer of patients from the Emergency Department; routine ward activities were not conducive to provision of rest and sleep; assisting with the patient's orientation was not possible as relatives were not able to accompany and/or stay with the older patient. Underreporting of delirium and attributing confusion to dementia was viewed as an education deficit across disciplines. A wide range of assessment skills was identified as prerequisites for working in this acute care ward, with older people and delirium. Clinicians perceived that management driven by length of a patient's stay was incongruent with best practice delirium care which required more time for older patients to recover from delirium. Two significant actions towards practice improvement were undertaken by this PAR group: (i) development of a draft delirium alert prevention protocol and (ii) a separate section of the ward became a dedicated space for the care of patients with delirium. A larger study is being planned across a variety of settings. [source] Effectiveness of the implementation of an evidence-based nursing model using participatory action research in oncohematology: research protocolJOURNAL OF ADVANCED NURSING, Issue 8 2010Eva Abad-Corpa abad-corpa e., meseguer-liza c., martínez-corbalán j.t., zárate-riscal l., caravaca-hernández a., paredes-sidrach de cardona a., carrillo-alcaraz a., delgado-hito p. & cabrero-garcía j. (2010) Effectiveness of the implementation of an evidence-based nursing model using participatory action research in oncohematology: research protocol. Journal of Advanced Nursing,66(8), 1845,1851. Abstract Title.,Effectiveness of the implementation of an evidence-based nursing model using participatory action research in oncohematology: research protocol. Aim., To generate changes in nursing practice introducing an evidence-based clinical practice (EBCP) model through a participatory process. To evaluate the effectiveness of the changes in terms of nurse-sensitive outcome (NSO). Background., For international nursing science, it is necessary to explore the reasons for supporting EBCP and evaluate the real repercussions and effectiveness. Methods., A mixed methods study with a sequential transformative design will be conducted in the bone marrow transplant unit of a tertiary-level Spanish hospital, in two time periods >12 months (date of approval of the protocol: 2006). To evaluate the effectiveness of the intervention, we will use a prospective quasi-experimental design with two non-equivalent and non-concurrent groups. NSO and patient health data will be collected: (a) impact of psycho-social adjustment; (b) patient satisfaction; (c) symptom control; (d) adverse effects. All patients admitted during the period of time will be included, and all staff working on the unit during a participatory action research (PAR). The PAR design will be adopted from a constructivist paradigm perspective, following Checkland's "Soft Systems" theoretical model. Qualitative techniques will be used: 2-hour group meetings with nursing professionals, to be recorded and transcribed. Field diaries (participants and researchers) will be drawn up and data analysis will be carried out by content analysis. Discussion., PAR is a rigorous research method for introducing changes into practice to improve NSO. [source] Multimorbidity and Survival in Older Persons with Colorectal CancerJOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 12 2006Cary P. Gross MD OBJECTIVES: To ascertain the effect of common chronic conditions on mortality in older persons with colorectal cancer. DESIGN: Retrospective cohort study. SETTING: Population-based cancer registry. PARTICIPANTS: Patients in the Surveillance Epidemiology and End Results,Medicare linked database who were aged 67 and older and had a primary diagnosis of Stage 1 to 3 colorectal cancer during 1993 through 1999. MEASUREMENTS: Chronic conditions were identified using claims data, and vital status was determined from the Medicare enrollment files. After estimating the adjusted hazard ratios for mortality associated with each condition using a Cox model, the population attributable risk (PAR) was calculated for the full sample and by age subgroup. RESULTS: The study sample consisted of 29,733 patients, 88% of whom were white and 55% were female. Approximately 9% of deaths were attributable to congestive heart failure (CHF; PAR =9.4%, 95% confidence interval (CI) =8.4,10.5%), more than 5% were attributable to chronic obstructive pulmonary disease (COPD; PAR =5.3%, 95% CI=4.7,6.6%), and nearly 4% were attributable to diabetes mellitus (PAR =3.9%, 95% CI=3.1,4.8%). The PAR associated with CHF increased with age, from 6.3% (95% CI=4.4,8.8%) in patients aged 67 to 70 to 14.5% (95% CI=12.0,17.5%) in patients aged 81 to 85. Multiple conditions were common. More than half of the patients who had CHF also had diabetes mellitus or COPD. The PAR associated with CHF alone (4.29%, 95% CI=3.68,4.94%) was similar to the PAR for CHF in combination with diabetes mellitus (3.08, 95% CI=2.60,3.61%) or COPD (3.93, 95% CI=3.41,4.54%). CONCLUSION: A substantial proportion of deaths in older persons with colorectal cancer can be attributed to CHF, diabetes mellitus, and COPD. Multimorbidity is common and exerts a substantial effect on colorectal cancer survival. [source] ,Who Did What?': A Participatory Action Research Project to Increase Group Capacity for AdvocacyJOURNAL OF APPLIED RESEARCH IN INTELLECTUAL DISABILITIES, Issue 1 2009E. Garcia-Iriarte Background, This participatory action research (PAR) project involved a collaboration with a self-advocacy group of people with intellectual disabilities that sought to build group capacity for advocacy. Materials and Methods, This study used a focus group, sustained participatory engagement and a reflexive process to gather qualitative and quantitative data over 15 months. All methods were adapted to ensure accessibility and to support active participation. Results, The collaboration generated action products, including tools to support advocacy and an accessible action and reflection process. Research findings suggest that active participation is essential for group control, but alone does not automatically lead to control. The manner in which supports are provided, including member supports, advisor supports, strategy supports and systems supports, influences the extent to which members have a sense of control over decision making and participation and thus, improved capacity for advocacy. Conclusions, A PAR approach can be used to increase a group's capacity for advocacy and meaningfully involve self-advocacy groups in participatory research that leads to change. [source] Association of the VDR Translation Start Site Polymorphism and Fracture Risk in Older Women,,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 5 2007Susan P Moffett PhD Abstract We evaluated the association between the VDR translation start site polymorphism and osteoporotic phenotypes among 6698 older white women. Women with the C/C genotype had lower wrist BMD and an increased risk of wrist and all non-spine/low-trauma fractures. The high frequency of this variant confers a population attributable risk that is similar to several established risk factors for fracture. Introduction: The vitamin D receptor (VDR) is a nuclear receptor that regulates bone formation, bone resorption, and calcium homeostasis. A common C to T polymorphism in exon 2 of the VDR gene introduces a new translation start site and a protein that differs in length by three amino acids (T = 427aa, C = 424aa; rs10735810). Materials and Methods: We conducted genetic association analyses of this polymorphism, BMD, and fracture outcomes in a prospective cohort of 6698 white American women ,65 years of age. Incident fractures were confirmed by physician adjudication of radiology reports. There were 2532 incident nontraumatic/nonvertebral fractures during 13.6 yr of follow-up including 509 wrist and 703 hip fractures. Results: Women with the C/C genotype had somewhat lower distal radius BMD compared with those with the T/T genotype (CC = 0.358 g/cm2, CT = 0.361 g/cm2, TT = 0.369 g/cm2, p = 0.003). The C/C genotype was also associated with increased risk of non-spine, low traumatic fractures (HR: 1.18; 95% CI: 1.04, 1.33) and wrist fractures (HR: 1.33; 95% CI: 1.01, 1.75) compared with the T/T genotype in age-adjusted models. Further adjustments for distal radius BMD only slightly attenuated these associations. The VDR polymorphism was not associated with hip fracture. The population attributable risk (PAR) of the C/C genotype for incident fractures was 6.1%. The PAR for established risk factors for fracture were: low femoral neck BMD (PAR = 16.3%), maternal history of fracture (PAR = 5.1%), low body weight (PAR = 5.3%), corticosteroid use (PAR = 1.3%), and smoking (PAR = 1.6%). Similar PAR results were observed for wrist fractures. Conclusions: The common and potentially functional VDR translation start site polymorphism confers a modestly increased relative risk of fracture among older white women. However, the high frequency of this variant confers a population attributable risk that is similar to or greater than several established risk factors for fracture. [source] Relating Instrumental Texture, Determined by Variable-Blade and Allo-Kramer Shear Attachments, to Sensory Analysis of Rainbow Trout, Oncorhynchus mykiss, FilletsJOURNAL OF FOOD SCIENCE, Issue 7 2010Aunchalee Aussanasuwannakul Abstract:, Texture is one of the most important quality attributes of fish fillets, and accurate assessment of variation in this attribute, as affected by storage and handling, is critical in providing consistent quality product. Trout fillets received 4 treatments: 3-d refrigeration (R3), 7-d refrigeration (R7), 3-d refrigeration followed by 30-d frozen storage (R3F30), and 7-d refrigeration followed by 30-d frozen storage (R7F30). Instrumental texture of raw and cooked fillets was determined by 3 approaches: 5-blade Allo-Kramer (AK) and variable-blade (VB) attachment with 12 blades arranged in perpendicular (PER) and parallel (PAR) orientations to muscle fibers. Correlation between instrumental texture and sensory hardness, juiciness, elasticity, fatness, and coarseness was determined. Muscle pH remained constant at 6.54 to 6.64. Raw fillets lost 3.66% of their original weight after 30-d frozen storage. After cooking, weight loss further increased to 15.97%. Moisture content decreased from 69.11 to 65.02%, while fat content remained constant at 10.41%. VBPER detected differences in muscle sample strength (P= 0.0019) and demonstrated effect of shear direction reported as maximum force (g force/g sample). AKPER detected differences in energy of shear (g × mm; P= 0.0001). Fillets that received F30 treatments were less extensible. Cooking increased muscle strength and toughness. Force determined by VBPER was correlated with sensory hardness (r= 0.423, P= 0.0394) and cook loss (r= 0.412, P= 0.0450). VB attachment is accurate, valid, and less destructive in fillet texture analysis. Practical Application:, A new shearing device was validated with sensory analysis. Settings and parameters obtained could be used to define fillet texture quality associated with muscle fiber orientation. [source] Health Promotion and Participatory Action Research with South Asian WomenJOURNAL OF NURSING SCHOLARSHIP, Issue 1 2002U.K. Choudhry Purpose: To examine South Asian immigrant women's health promotion issues and to facilitate the creation of emancipatory knowledge and self-understanding regarding health-promoting practices; to promote health education and mobilization for culturally relevant action. Method: The study was based on critical social theory; the research model was participatory action research (PAR). Two groups of South Asian women (women from India and of Indian origin) who had immigrated to Canada participated in the project. The qualitative data were generated through focus groups. Reflexive and dialectical critique were used as methods of analyzing qualitative data. The data were interpreted through reiterative process, and dominant themes were identified. Findings: Three themes that were extracted from the data were: (a) the importance of maintaining culture and tradition, (b) placing family needs before self, and (c) surviving by being strong. An issue for action was the risk of intergenerational conflicts leading to alienation of family members. Over a period of 3 years, the following action plans were carried out: (a) workshops for parents and children, (b) sharing of project findings with the community, and (c) a presentation at an annual public health conference. Conclusions and Implications: The project activities empowered participants to create and share knowledge, which was then applied toward action for change. Health and health promotion were viewed as functions of the women's relationships to the world around them. [source] IMPACTS OF SOLAR UV RADIATION ON THE PHOTOSYNTHESIS, GROWTH, AND UV-ABSORBING COMPOUNDS IN GRACILARIA LEMANEIFORMIS (RHODOPHYTA) GROWN AT DIFFERENT NITRATE CONCENTRATIONS,JOURNAL OF PHYCOLOGY, Issue 2 2009Yangqiao Zheng Solar ultraviolet radiation (UVR, 280,400 nm) is known to affect macroalgal physiology negatively, while nutrient availability may affect UV-absorbing compounds (UVACs) and sensitivity to UVR. However, little is known about the interactive effects of UVR and nitrate availability on macroalgal growth and photosynthesis. We investigated the growth and photosynthesis of the red alga Gracilaria lemaneiformis (Bory) Grev. at different levels of nitrate (natural or enriched nitrate levels of 41 or 300 and 600 ,M) under different solar radiation treatments with or without UVR. Nitrate-enrichment enhanced the growth, resulted in higher concentrations of UVACs, and led to negligible photoinhibition of photosynthesis even at noon in the presence of UVR. Net photosynthesis during the noon period was severely inhibited by both ultraviolet-A radiation (UVA) and ultraviolet-B radiation (UVB) in the thalli grown in seawater without enriched nitrate. The absorptivity of UVACs changed in response to changes in the PAR dose when the thalli were shifted back and forth from solar radiation to indoor low light, and exposure to UVR significantly induced the synthesis of UVACs. The thalli exposed to PAR alone exhibited higher growth rates than those that received PAR + UVA or PAR + UVA + UVB at the ambient or enriched nitrate concentrations. UVR inhibited growth approximately five times as much as it inhibited photosynthesis within a range of 60,120 ,g UVACs · g,1 (fwt) when the thalli were grown under nitrate-enriched conditions. Such differential inhibition implies that other metabolic processes are more sensitive to solar UVR than photosynthesis. [source] PHOTOSYNTHETIC INSENSITIVITY OF THE TERRESTRIAL CYANOBACTERIUM NOSTOC FLAGELLIFORME TO SOLAR UV RADIATION WHILE REHYDRATED OR DESICCATED,JOURNAL OF PHYCOLOGY, Issue 4 2007Kunshan Gao Photosynthetic performance of the terrestrial cyanobacterium Nostoc flagelliforme (M. J. Berkeley et M. A. Curtis) Bornet et Flahault during rehydration and desiccation has been previously characterized, but little is known about the effects of solar UV radiation (280,400 nm) on this species. We investigated the photochemical activity during rehydration and subsequent desiccation while exposing the filamentous colonies to different solar radiation treatments. Photochemical activity could be reactivated by rehydration under full-spectrum solar radiation, the species being insensitive to both ultraviolet-A radiation (UVAR; 315,400 nm) and ultraviolet-B radiation (UVBR). When the rehydrated colonies were exposed for desiccation, the effective PSII photochemical yield was inhibited by visible radiation (PAR) at the initial stage of water loss, then increased with further decrease in water content, and reached its highest value at the water content of 10%,30%. However, no significant difference was observed among the radiation treatments except for the moment when they were desiccated to critical water content of about 2%,3%. At such a critical water content, significant reduction by UVBR of the effective quantum yield was observed in the colonies that were previously rehydrated under indoor light [without ultraviolet radiation (UVR)], but not in those reactivated under scattered or direct solar radiation (with UVR), indicating that preexposure to UVR during rehydration led to higher resistance to UVR during desiccation. The photosynthetic CO2 uptake by the desiccated colonies was enhanced by elevation of CO2 but was not affected by both UVAR and UVBR. It increased with enhanced desiccation to reach the maximal values at water content of 40%,50%. The UV-absorbing compounds and the colony sheath were suggested to play an important role in screening harmful UVR. [source] SHORT-TERM AND LONG-TERM EFFECTS OF TEMPERATURE ON PHOTOSYNTHESIS IN THE DIATOM THALASSIOSIRA PSEUDONANA UNDER UVR EXPOSURES,JOURNAL OF PHYCOLOGY, Issue 3 2007Cristina Sobrino Temperature is expected to modify the effects of ultraviolet radiation (UVR) on photosynthesis by affecting the rate of repair. We studied the effect of short-term (1 h) and long-term (days) acclimation to temperature on UVR photoinhibition in the diatom Thalassiosira pseudonana Hasle et Heimdal. Photosynthesis was measured during 1 h exposures to varying irradiances of PAR and UVR + PAR at 15, 20, and 25°C, the latter corresponding to the upper temperature limit for optimal growth in T. pseudonana. The exposures allowed the estimation of photosynthesis,irradiance (P,E) curves and biological weighting functions (BWFs) for photoinhibition. For the growth conditions used, temperature did not affect photosynthesis under PAR. However, photoinhibition by UVR was highly affected by temperature. For cultures preacclimated to 20°C, the extent of UVR photoinhibition increased with decreasing temperature, from 63% inhibition of PAR-only photosynthesis at 25°C to 71% at 20°C and 85% at 15°C. These effects were slightly modified after several days of acclimation: UVR photoinhibition increased from 63% to 75% at 25°C and decreased from 85% to 80% at 15°C. Time courses of photochemical efficiency (,PSII) under UVR + PAR were also fitted to a model of UVR photoinhibition, allowing the estimation of the rates of damage (k) and repair (r). The r/k values obtained for each temperature treatment verified the responses observed with the BWF (R2 = 0.94). The results demonstrated the relevance of temperature in determining primary productivity under UVR exposures. However, the results suggested that temperature and UVR interact mainly over short (hours) rather than long (days) timescales. [source] UV-A/BLUE LIGHT,INDUCED REACTIVATION OF SPORE GERMINATION IN UV-B IRRADIATED ULVA PERTUSA (CHLOROPHYTA),JOURNAL OF PHYCOLOGY, Issue 2 2004Taejun Han Recent reduction in the ozone shield due to manufactured chlorofluorocarbons raised considerable interest in the ecological and physiological consequences of UV-B radiation (,=280,315 nm) in macroalgae. However, early life stages of macroalgae have received little attention in regard to their UV-B sensitivity and UV-B defensive mechanisms. Germination of UV-B irradiated spores of the intertidal green alga Ulva pertusa Kjellman was significantly lower than in unexposed controls, and the degree of reduction correlated with the UV doses. After exposure to moderate levels of UV-B irradiation, subsequent exposure to visible light caused differential germination in an irradiance- and wavelength-dependent manner. Significantly higher germination was found at higher photon irradiances and in blue light compared with white and red light. The action spectrum for photoreactivation of germination in UV-B irradiated U. pertusa spores shows a major peak at 435 nm with a smaller but significant peak at 385 nm. When exposed to December sunlight, the germination percentage of U. pertusa spores exposed to 1 h of solar radiation reached 100% regardless of the irradiation treatment conditions. After a 2-h exposure to sunlight, however, there was complete inhibition of germination in PAR+UV-A+UV-B in contrast to 100% germination in PAR or PAR+UV-A. In addition to mat-forming characteristics that would act as a selective UV-B filter for settled spores under the parental canopy, light-driven repair of germination after UV-B exposure could explain successful continuation of U. pertusa spore germination in intertidal settings possibly affected by intense solar UV-B radiation. [source] Melatonin limits lung injury in bleomycin treated miceJOURNAL OF PINEAL RESEARCH, Issue 2 2005Tiziana Genovese Abstract:, Melatonin is the principal secretory product of the pineal gland and its role as an immuno-modulator is well established. Recent evidence shows that melatonin is a scavenger of oxyradicals and peroxynitrite and exerts protective effects in septic shock, hemorrhagic shock and inflammation. The aim of this study was to investigate the effect of melatonin on the lung injury caused by bleomycin (BLM) administration. Mice subjected to intratracheal administration of BLM developed significant lung injury characterized by a marked neutrophil infiltration [assessed by myeloperoxidase (MPO) activity] and by tissue edema. In addition, an increase of immunoreactivity to nitrotyrosine, poly-ADP-ribose (PAR) was also observed in the lung of BLM-treated mice. Also, lung injury induced by BLM administration was correlated with a significant loss of body weight and with a significant mortality. Administration of melatonin (10 mg/kg i.p.) daily significantly reduced the (i) loss of body weight, (ii) mortality rate, (iii) infiltration of the lung with polymorphonuclear neutrophils (MPO activity), (iv) edema formation and (v) histological evidence of lung injury. Administration of melatonin also markedly reduced the nitrotyrosine and PAR formation. Taken together, our results demonstrate that treatment with melatonin significantly reduces lung injury induced by BLM in the mice. [source] Is the Child Oral Health Quality of Life Questionnaire Sensitive to Change in the Context of Orthodontic Treatment?JOURNAL OF PUBLIC HEALTH DENTISTRY, Issue 4 2008A Brief Communication Abstract Objective: This study aimed to assess the ability of the Child Oral Health Quality of Life Questionnaire (COHQoL) to detect change following provision of orthodontic treatment. Methods: Children were recruited from an orthodontic clinic just prior to starting orthodontic treatment. They completed a copy of the Child Perception Questionnaire, while their parents completed a copy of the Parents Perception Questionnaire and the Family Impact Scale. Normative outcomes were assessed using the Dental Aesthetic Index (DAI) and the Peer Assessment Rating (PAR) index. Change scores and effect sizes were calculated for all scales. Results: Complete data were collected for 45 children and 26 parents. The mean age was 12.6 years (standard deviation = 1.4). There were significant pre-/posttreatment changes in DAI and PAR scores and significant changes in scores on all three questionnaires (P < 0.05). Effect sizes for the latter were moderate. Global transition judgments also confirmed pre-/posttreatment improvements in oral health and well-being. Conclusion: The results provide preliminary evidence of the sensitivity to change of the COHQoL questionnaires when used with children receiving orthodontic treatment. However, the study needs to be repeated in different treatment settings and with a larger sample size in order to confirm the utility of the measure. [source] Comparison of Treatment Result and Compliance between Private Practice Medicaid and Non-Medicaid Orthodontic Patients , A Brief CommunicationJOURNAL OF PUBLIC HEALTH DENTISTRY, Issue 3 2008Steven Dickens Abstract Treatment result and compliance for orthodontic Medicaid patients were assessed and compared to non-Medicaid patients of similar initial severity. All 55 North Carolina practices providing orthodontic treatment covered by Medicaid were asked to submit their last five Medicaid cases and five non-Medicaid cases of similar initial treatment complexity. Nine practices agreed to participate. Initial models, final models, and progress notes were obtained for all subjects. Casts were scored using the Peer Assessment Rating (PAR) Index to assess initial and posttreatment orthodontic status, and progress notes were reviewed for compliance data. No clinically important differences were seen between the Medicaid and non-Medicaid groups with respect to initial PAR, final PAR, percent PAR reduction, broken appointments, broken appliances, or poor oral hygiene. In this study, Medicaid and non-Medicaid patients did not differ substantially with respect to effectiveness of treatment received or their compliance with treatment. [source] | ||||||||||||||||||||||||||||||||||||||||||||||||||||