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Selected AbstractsA Bayesian hierarchical model for over-dispersed count data: a case study for abundance of hake recruitsENVIRONMETRICS, Issue 1 2007Jorge M. Mendes Abstract In this paper, we introduce a Bayesian Hierarchical model to estimate the abundance of hake recruits, as well as to study their spatial distributional patterns in the Portuguese territorial waters. Main objective of the paper is to improve on traditional empirical methods based on sampling averages and variances by using probabilistic models that capture spatial dependence structures. Copyright © 2006 John Wiley & Sons, Ltd. [source] Volume targeted ventilation (volume guarantee) in the weaning phase of premature newborn infantsPEDIATRIC PULMONOLOGY, Issue 10 2007F. Scopesi MD Abstract Objective Several options are currently available in neonatal mechanical ventilation: complete breathing synchronization (patient triggered ventilation, synchronized intermittent positive pressure ventilation,SIPPV); positive pressure flow-cycled ventilation (pressure support ventilation, PSV); and volume targeted positive pressure ventilation (volume guarantee, VG). The software algorithm for the guarantee volume attempts to deliver a tidal volume (Vt) as close as possible to what has been selected by the clinician as the target volume. Main objectives of the present study were to compare patient,ventilator interactions and Vt variability in premature infants recovering from respiratory distress syndrome (RDS) who were weaned by various ventilator modes (SIMV/PSV,+,VG/SIPPV,+,VG and SIMV,+,VG). Methods This was a short-term crossover trial in which each infant served as his/her own control. Ten premature infants born before the 32nd week of gestation in the recovery phase of RDS were enrolled in the study. All recruited infants started ventilation with SIPPV and in the weaning phase were switched to synchronized intermittent mandatory ventilation (SIMV). Baseline data were collected during an initial 20-min period of monitoring with the infant receiving SIMV alone, then they were switched to SIPPV,+,VG for a 20-min period and then switched back to SIMV for 15 min. Next, they were switched to PSV,+,VG for the study period and switched back to SIMV for a further 15 min. Finally, they were switched to SIMV,+,VG and, at the end of monitoring, they were again switched back to SIMV alone. Results Each mode combined with VG discharged comparable Vts, which were very close to the target volume. Among the VG-combined modes, mean variability of Vt from preset Vt was significantly different. Variability from the target value was significantly lower in SIPPV and PSV modes than in SIMV (P,<,0.0001 and P,<,0.04 respectively). SIPPV,+,VG showed greater stability of Vt, fewer large breaths, lower respiratory rate, and allowed for lower peak inspiratory pressure than what was delivered by the ventilator during other modes. No significant changes in blood gases were observed after each of the study periods. Conclusions With regards to the weaning phase, among combined modes, both of the ones in which every breath is supported (SIPPV/PSV) are likely to be the most effective in the delivery of stable Vt using a low working pressure, thus, at least in the short term, likely more gentle for the neonatal lung. In summary, we can suggest that the VG option, when combined with traditional, patient triggered ventilation, adheres very closely to the proposed theoretical algorithm, achieving highly effective ventilation. Pediatr Pulmonol. 2007; 42:864,870. © 2007 Wiley-Liss, Inc. [source] Maximizing revenue in Grid markets using an economically enhanced resource managerCONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 14 2010M. Macías Abstract Traditional resource management has had as its main objective the optimization of throughput, based on parameters such as CPU, memory, and network bandwidth. With the appearance of Grid markets, new variables that determine economic expenditure, benefit and opportunity must be taken into account. The Self-organizing ICT Resource Management (SORMA) project aims at allowing resource owners and consumers to exploit market mechanisms to sell and buy resources across the Grid. SORMA's motivation is to achieve efficient resource utilization by maximizing revenue for resource providers and minimizing the cost of resource consumption within a market environment. An overriding factor in Grid markets is the need to ensure that the desired quality of service levels meet the expectations of market participants. This paper explains the proposed use of an economically enhanced resource manager (EERM) for resource provisioning based on economic models. In particular, this paper describes techniques used by the EERM to support revenue maximization across multiple service level agreements and provides an application scenario to demonstrate its usefulness and effectiveness. Copyright © 2008 John Wiley & Sons, Ltd. [source] Torsional balance of plan-asymmetric structures with frictional dampers: experimental resultsEARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 15 2006Ignacio J. Vial Abstract This investigation deals with the measured seismic response of a six-storey asymmetric structural model with frictional dampers. Its main objective is to experimentally prove the concept of weak torsional balance for mass- and stiffness-eccentric model configurations. The goal is to control the torsional response of these asymmetric structures and to achieve, if possible, a weak form of torsional balance by placing the so-called empirical centre of balance (ECB) of the structure at equal distance from the edges of the building plan. The control of the dynamic response of asymmetric structures is investigated herein by using steel,teflon frictional dampers. As expected from theory, experimental results show that the mean-square and peak displacement demand at the flexible and stiff edges of the plan may be similar in magnitude if the dampers are optimally placed. Frictional dampers have proven equally effective in controlling lateral-torsional coupling of torsionally flexible as well as stiff structures. On the other hand, it is shown that impulsive ground motions require larger frictional capacities to achieve weak torsional balance. Copyright © 2006 John Wiley & Sons, Ltd. [source] Process, Responsibility and Inclusion in EU ConstitutionalismEUROPEAN LAW JOURNAL, Issue 1 2003Jo Shaw This paper it looks at some of the normative questions which frame debates about the EU constitutional architecture. Its main objective is to identify the core facets of a ,responsible and inclusive EU constitutionalism', and to argue for a focus on process, freedom, fairness and democracy as well as formal constitution,building within the debates inside and outside the Convention running up to the Intergovernmental Conference anticipated for 2003/2004. A model using the work of Canadian political theorist James Tully is constructed. The paper applies this framework in order to analyse some aspects of the work of the Convention on the Future of the Union, looking especially at questions of autonomy, representativity, internal dynamics, deliberation, receptiveness, and decision,making. The interim conclusion is drawn that the Convention method contains within itself the seeds of a critical and reflexive approach to EU constitutionalism. [source] The General Provisions of the Charter of Fundamental Rights of the European UnionEUROPEAN LAW JOURNAL, Issue 4 2002R. Alonso García The Charter of Fundamental Rights of the European Union provides the Union with a ,more evident' (as the European Council of Cologne asked for) framework of protection of the individuals before the public authorities within the European context, after more than thirty years (since the Stauder Case) of full confidence in the leading role played by the jurisprudence of the Court of Justice of the European Communities. This new normative catalogue of fundamental rights (included the so called ,aspirational fundamental rights') implies one more instrument of protection which has to find its own place with regard to the protection afforded by the national Constitutions and the international agreements on human rights, particularly the European Convention on Human Rights, which are already a privileged source of inspiration for Court of Justice of the European Communities. It is the main objective of the General Provisions of the Charter to clarify which is that place and the relationship with those other levels of protection as managed by their supreme interpreters (i.e., the Constitutional,or Supreme,Courts of the Member States of the Union and the European Court of Human Rights). [source] Nitrogen utilization by Hylocomium splendens in a boreal forest fertilization experimentFUNCTIONAL ECOLOGY, Issue 3 2006Å. FORSUM Summary 1Nitrogen uptake in the terricolous bryophyte Hylocomium splendens (Hedw.) B.S.G. was studied in a boreal forest long-term N-treatment experiment including control plots, N-addition plots (50 kg N ha,1 year,1 for 8 years) and recovery plots (50 kg N ha,1 year,1 for 5 years and thereafter no N addition for 3 years). 2A main objective was to explore whether the N treatments changed bryophyte uptake of different inorganic and organic N forms. In addition, we estimated the contribution of N from throughfall precipitation to the bryophyte N supply. 3The results demonstrated that bryophyte N uptake was similar in all the long-term N-treatment plots. Hylocomium splendens took up more 15N labelled than or glycine when these N forms were applied in situ by the spraying of solutions with N concentrations similar to those in precipitation. 4Analysis of the precipitation collected beneath the closed tree canopy from late May to early October revealed that it contributed 2·0 kg N ha,1 during the period studied, distributed between (78%), amino acid N (17%) and (5%). 5The study highlights that, in addition to analyses of and (normally included in standard environmental monitoring of precipitation), analysis of amino acid N must be performed to account fully for the precipitation N input to bryophytes in boreal forest ecosystems. [source] Design of a Singlet Lens and the Corresponding Aberration Correction Approaches for Cell Phone CameraIEEJ TRANSACTIONS ON ELECTRICAL AND ELECTRONIC ENGINEERING, Issue 4 2010Yupeng Zhang Member Abstract A singlet lens model that is designed for future cell phone camera is discussed. The proposed lens model unavoidably introduces significant optical aberration because of its high field angle (maximum field angle 48°). To correct the aberrations, traditional paraxial aberration and third-order Seidel aberration are no longer applicable because the accuracy will decline dramatically when the field angle reaches a high value. In this paper, the main objective is to find an improved first-order aberration equation and an improved third-order Seidel aberration equation using field-dependent coefficients to correct lateral chromatic aberration (LAT) and distortion, respectively, for a high-field-angle singlet lens. The simulation results suggest that improved higher order aberration equations are more accurate to represent real aberrations than the lower order case. However, the chromatic aberration is still visible in the resultant images even though LAT is corrected, because of the differences of blur between different colors caused by axial chromatic aberration (AX) and other monochromatic aberrations such as field curvature. This poses a new research topic as our future work. Copyright © 2010 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [source] Computational mechanics of the steel,concrete interface,INTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS, Issue 2 2002M. R. Ben Romdhane Abstract Concrete cracking in reinforced concrete structures is governed by two mechanisms: the activation of bond forces at the steel,concrete interface and the bridge effects of the reinforcement crossing a macro-crack. The computational modelling of these two mechanisms, acting at different scales, is the main objective of this paper. The starting point is the analysis of the micro-mechanisms, leading to an appropriate choice of (measurable) state variables describing the energy state in the surface systems: on the one side the relative displacement between the steel and the concrete, modelling the bond activation; on the other hand, the crack opening governing the bridge effects. These displacement jumps are implemented in the constitutive model using thermodynamics of surfaces of discontinuity. On the computational side, the constitutive model is implemented in a discrete crack approach. A truss element with slip degrees of freedom is developed. This degree of freedom represents the relative displacement due to bond activation. In turn, the bridge effect is numerically taken into account by modifying the post-cracking behaviour of the contact elements representing discrete concrete cracks crossed by a rebar. First simulation results obtained with this model show a good agreement in crack pattern and steel stress distribution with micro-mechanical results and experimental results. Copyright © 2001 John Wiley & Sons, Ltd. [source] Interior point optimization and limit analysis: an applicationINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING, Issue 10 2003Joseph Pastor Abstract The well-known problem of the height limit of a Tresca or von Mises vertical slope of height h, subjected to the action of gravity stems naturally from Limit Analysis theory under the plane strain condition. Although the exact solution to this problem remains unknown, this paper aims to give new precise bounds using both the static and kinematic approaches and an Interior Point optimizer code. The constituent material is a homogeneous isotropic soil of weight per unit volume ,. It obeys the Tresca or von Mises criterion characterized by C cohesion. We show that the loading parameter to be optimized, ,h/C, is found to be between 3.767 and 3.782, and finally, using a recent result of Lyamin and Sloan (Int. J. Numer. Meth. Engng. 2002; 55: 573), between 3.772 and 3.782. The proposed methods, combined with an Interior Point optimization code, prove that linearizing the problem remains efficient, and both rigorous and global: this point is the main objective of the present paper. Copyright © 2003 John Wiley & Sons, Ltd. [source] Survival and gene expression of enterotoxigenic Escherichia coli during long-term incubation in sea water and freshwaterJOURNAL OF APPLIED MICROBIOLOGY, Issue 4 2010Å. Lothigius Abstract Aims:, In this study, the main objective was to verify the hypothesis of induction of ,viable but non-culturable' (VBNC) forms of enterotoxigenic Escherichia coli (ETEC) during incubation in water. Methods and Results:, Six clinically isolated ETEC strains were studied. Viable counts showed culturable ETEC bacteria for up to 3 months in freshwater but only two out of six strains were culturable in seawater at this time point. Although the bacterial cells remained intact, no production or secretion of heat-labile (LT) or heat-stable (ST) enterotoxins was observed using GM1-ELISA methods. However, genes encoding ETEC toxins (STh and LT), colonization factors (CS7 and CS17), gapA and 16S RNA were expressed during 3 months in both sea water and freshwater microcosms as determined by real-time RT-PCR on cDNA derived from the bacteria. Conclusions:, Clinically isolated ETEC strains can survive for long periods in both sea water and freshwater. The bacterial cells remain intact, and the gene expression of virulence genes and genes involved in metabolic pathways are detected after 3 months. Significance and Impact of the Study:, These results indicate that ETEC bacteria can enter a VBNC state during stressful conditions and suggest that ETEC has the potential to be infectious after long-term incubation in water. [source] Optimized conditions for the grafting reaction of poly(methyl methacrylate) onto oil-palm empty fruit bunch fibersJOURNAL OF APPLIED POLYMER SCIENCE, Issue 2 2008Aznizam Abu Bakar Abstract This article describes the graft copolymerization of poly(methyl methacrylate) (PMMA) onto oil-palm empty fruit bunches (OPEFBs) with a fiber length of less than 75 ,m. The graft copolymerization was carried out under a nitrogen atmosphere by a free-radical initiation technique in an aqueous medium. Hydrogen peroxide and ferrous ions were used as a redox initiator/cocatalyst system. The PMMA homopolymer that formed during the reaction was removed from the grafted copolymers by Soxhlet extraction. Determining the effects of the reaction period, reaction temperature, and monomer concentration on the grafting percentage was the main objective, and they were investigated systematically. The optimum reaction period, reaction temperature, monomer concentration, and initiator concentration were 60 min, 50°C, 47.15 × 10,3 mol, and 3.92 × 10,3 mol, respectively. The maximum percentage of grafting achieved under these optimum conditions was 173%. The presence of PMMA functional groups on OPEFB and the enormous reduction of the hydroxyl-group absorption band in PMMA- g -OPEFB spectra provided evidence of the successful grafting reaction. The improvement of the thermal stability of PMMA- g -OPEFB also showed the optimal achievement of the grafting reaction of PMMA onto OPEFB. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Collation, assessment and analysis of literature in vitro data on hERG receptor blocking potency for subsequent modeling of drugs' cardiotoxic propertiesJOURNAL OF APPLIED TOXICOLOGY, Issue 3 2009Sebastian Polak Abstract The assessment of the torsadogenic potency of a new chemical entity is a crucial issue during lead optimization and the drug development process. It is required by the regulatory agencies during the registration process. In recent years, there has been a considerable interest in developing in silico models, which allow prediction of drug,hERG channel interaction at the early stage of a drug development process. The main mechanism underlying an acquired QT syndrome and a potentially fatal arrhythmia called torsades de pointes is the inhibition of potassium channel encoded by hERG (the human ether-a-go-go-related gene). The concentration producing half-maximal block of the hERG potassium current (IC50) is a surrogate marker for proarrhythmic properties of compounds and is considered a test for cardiac safety of drugs or drug candidates. The IC50 values, obtained from data collected during electrophysiological studies, are highly dependent on experimental conditions (i.e. model, temperature, voltage protocol). For the in silico models' quality and performance, the data quality and consistency is a crucial issue. Therefore the main objective of our work was to collect and assess the hERG IC50 data available in accessible scientific literature to provide a high-quality data set for further studies. Copyright © 2008 John Wiley & Sons, Ltd. [source] Granulocyte colony-stimulating factor produces a decrease in IFN, and increase in IL-4 when administrated to healthy donorsJOURNAL OF CLINICAL APHERESIS, Issue 4 2010Octavio Rodríguez-Cortés Abstract Hematopoietic stem cells transplantation (HSCT) is the leading curative therapy for a variety of hematological and hereditary diseases; however, graft versus host disease (GVHD), an immunologic phenomenon that is favored by Th1 cytokines and cytotoxic cells from donors, is present frequently and is one of the most important causes of transplant related mortality. Peripheral blood HSCT is the preferred source of stem cells in almost 100% of the cases of autologous HSCT and in 70% of allogeneic transplants. The best mobilizing agent to get the stem cells out from the bone marrow is the Granulocyte-Colony Stimulating Factor (G-CSF). In this work, our main objective was to study a possible correlation between the graft cell dose and the patient's clinical outcome. We evaluated the immunologic changes produced by G-CSF in the lymphocyte and cytokine profiles in allogeneic HSC donors. HSC from twelve donors were mobilized with G-CSF at 16 ,g/kg/day, for 5 days. Basal Peripheral Blood (BPB), Mobilized Peripheral Blood (MPB), and aphaeresis mononuclear cells (G-MNC) samples were taken from all donors. Using flow cytometry, we quantified CD19+, CD3+, CD3+CD4+, CD3+CD8+, NK, NKT, DC1, and DC2 cells. Cytokines were determined by ELISA in culture supernatants. CD19+ (p = 0.001), DC1 (p < 0.002) and DC2 (p < 0.001) cells were increased in MPB with respect to BPB. An increase in Th2 cytokines such as (IL-4) and a decrease in Th1 cytokines (IFN,, IL-2) were also found in MPB samples. In conclusion, Th1 and Th2 cytokines are relevant in predicting the clinical outcome after allogeneic peripheral blood HSCT. J. Clin. Apheresis 25:181,187, 2010. © 2010 Wiley-Liss, Inc. [source] Towards a typology of computer use in primary educationJOURNAL OF COMPUTER ASSISTED LEARNING, Issue 3 2007J. Tondeur Abstract, In the present study, we reject the view that computer use can be studied as an isolated variable in a learning environment. Our main objective is to develop an instrumental tool to measure different types of educational computer use in the classroom. This builds on a comprehensive review of the literature about computer use in education. This review helped to construct a questionnaire to identify a typology of computer use in primary education. In addition, the questionnaire was enriched by input of experts in this field. The questionnaire was presented to a sample of 352 primary school teachers. The input from a first subsample was used to carry out an exploratory factor analysis; the second subsample was used to verify the identified factor structure via confirmatory factor analysis. A three-factor structure of computer use in primary education was identified: ,the use of computers as an information tool', ,the use of computers as a learning tool,' and ,learning basic computer skills'. The three-factor structure was confirmed in the confirmatory factor analysis. The results underpin a number of meaningful differences in the current practice of computer use in primary education. [source] Invasive mutualisms and the structure of plant,pollinator interactions in the temperate forests of north-west Patagonia, ArgentinaJOURNAL OF ECOLOGY, Issue 1 2006CAROLINA L. MORALES Summary 1Alien species may form plant,animal mutualistic complexes that contribute to their invasive potential. Using multivariate techniques, we examined the structure of a plant,pollinator web comprising both alien and native plants and flower visitors in the temperate forests of north-west Patagonia, Argentina. Our main objective was to assess whether plant species origin (alien or native) influences the composition of flower visitor assemblages. We also examined the influence of other potential confounding intrinsic factors such as flower symmetry and colour, and extrinsic factors such as flowering time, site and habitat disturbance. 2Flowers of alien and native plant species were visited by a similar number of species and proportion of insects from different orders, but the composition of the assemblages of flower-visiting species differed between alien and native plants. 3The influence of plant species origin on the composition of flower visitor assemblages persisted after accounting for other significant factors such as flowering time, bearing red corollas, and habitat disturbance. This influence was at least in part determined by the fact that alien flower visitors were more closely associated with alien plants than with native plants. The main native flower visitors were, on average, equally associated with native and alien plant species. 4In spite of representing a minor fraction of total species richness (3.6% of all species), alien flower visitors accounted for > 20% of all individuals recorded on flowers. Thus, their high abundance could have a significant impact in terms of pollination. 5The mutualistic web of alien plants and flower-visiting insects is well integrated into the overall community-wide pollination web. However, in addition to their use of the native biota, invasive plants and flower visitors may benefit from differential interactions with their alien partners. The existence of these invader complexes could contribute to the spread of aliens into novel environments. [source] Prediction of species response to atmospheric nitrogen deposition by means of ecological measures and life history traitsJOURNAL OF ECOLOGY, Issue 1 2002Martin Diekmann Summary 1The main objective of this study was to predict the responses of vascular plant species to atmospheric nitrogen deposition and enhanced soil nitrogen levels. The study was carried out in deciduous forests located in three regions of southern Sweden. The abundance of vascular plants, as well as soil pH and nitrogen mineralization rates, were studied in a total of 661 sample plots. 2We calculated an ecological measure (Ndev value) for all species based on their observed vs. expected nitrification ratios at a given soil pH, and compared its accuracy in predicting abundance changes with results using life history traits. Data from long-term field studies and fertilization experiments were used for validation. 3Ndev values were positively correlated between neighbouring regions. Values for the southernmost region (Skåne) were also positively related to the changes in species frequency observed in large-scale flora surveys and permanent plot studies in that area and with species changes reported from Central Europe. Values from one of two other regions were also consistent. Ndev values from Skåne (but no other region) predicted species responses in short-term fertilization experiments. 4No life history trait was as good a predictor as Ndev, although plant height, leaf anatomy, leaf nitrogen concentration and phenology showed significant correlations. Attributes related to taxonomy, life form, relative growth rate and habitat type showed no agreement with the changes in species abundance. 5We predict that species with the following attribute syndrome will increase in abundance in response to enhanced nitrogen levels: those favoured by a high soil nitrification ratio relative to other species at a given soil pH, tall stature, hydro- to helomorph anatomy, high leaf nitrogen concentration and a late phenological development. [source] Factors influencing olive oil brand choice in Spain: an empirical analysis using scanner dataAGRIBUSINESS : AN INTERNATIONAL JOURNAL, Issue 1 2009Juan C. Gázquez-Abad Olive oil consumption is growing all around the world as a consequence of the extension of the Mediterranean diet. Because of limited production, pricing, promotions, and consumer-related variables are essential to explain olive oil consumer behavior. As a consequence of this increasing consumption, it is fundamental to analyze the main factors influencing consumers' olive oil choices for both brands and retailers to be able to compete more efficiently and satisfy consumer needs more closely. But, few such studies are concerned with olive oil (although a great many works in the literature analyze the influence of these factors in other product categories). In a sociocultural context like the Spanish market, in which brand awareness is strong and the use of the product is very high, these factors are even more important. Thus, the main objective of this article is to determine and assess how different marketing variables, such as price, price discounts, use of store flyers and loyalty, explain olive oil brand choice. [Econlit citations: M310, Q130]. © 2009 wiley Periodicals, Inc. [source] The invasive alien leaf miner Cameraria ohridella and the native tree Acer pseudoplatanus: a fatal attraction?AGRICULTURAL AND FOREST ENTOMOLOGY, Issue 2 2010Christelle Péré 1The horse-chestnut leaf miner Cameraria ohridella is an invasive moth in Europe and a serious pest of horse-chestnut Aesculus hippocastanum. The moth also occasionally attacks sycamore maple Acer pseudoplatanus, when situated beside infested horse-chestnuts. 2The main objective of the present study was to provide an overview of the relationship between C. ohridella and A. pseudoplatanus and to determine whether C. ohridella has the potential to shift to this native tree. 3In the field, females oviposit on different deciduous tree species. Although less frequently attacked than A. hippocastanum, A. pseudoplatanus was clearly preferred for oviposition over 12 other woody species investigated. 4Surveys in Europe demonstrated that the majority of A. pseudoplatanus trees found beside infested A. hippocastanum had mines of C. ohridella, even though more than 70% of the larvae died within the first two instars. Attack rates and development success greatly varied from site to site. Attack levels on A. pseudoplatanus were not always correlated with those on A. hippocastanum, and mines on A. pseudoplatanus were sometimes observed beside weakly-infested A. hippocastanum. 5Field observations, experimental exposure of A. pseudoplatanus saplings and rearing trials in a common garden study showed that individual trees may vary in their susceptibility to C. ohridella, whereas there was no evidence that C. ohridella populations vary in their performance on A. pseudoplatanus. 6To date, there is little evidence that C. ohridella represents a major risk for A. pseudoplatanus. [source] The glutamate/GABA-glutamine cycle: aspects of transport, neurotransmitter homeostasis and ammonia transferJOURNAL OF NEUROCHEMISTRY, Issue 3 2006Lasse K. Bak Abstract Neurons are metabolically handicapped in the sense that they are not able to perform de novo synthesis of neurotransmitter glutamate and ,-aminobutyric acid (GABA) from glucose. A metabolite shuttle known as the glutamate/GABA-glutamine cycle describes the release of neurotransmitter glutamate or GABA from neurons and subsequent uptake into astrocytes. In return, astrocytes release glutamine to be taken up into neurons for use as neurotransmitter precursor. In this review, the basic properties of the glutamate/GABA-glutamine cycle will be discussed, including aspects of transport and metabolism. Discussions of stoichiometry, the relative role of glutamate vs. GABA and pathological conditions affecting the glutamate/GABA-glutamine cycling are presented. Furthermore, a section is devoted to the accompanying ammonia homeostasis of the glutamate/GABA-glutamine cycle, examining the possible means of intercellular transfer of ammonia produced in neurons (when glutamine is deamidated to glutamate) and utilized in astrocytes (for amidation of glutamate) when the glutamate/GABA-glutamine cycle is operating. A main objective of this review is to endorse the view that the glutamate/GABA-glutamine cycle must be seen as a bi-directional transfer of not only carbon units but also nitrogen units. [source] Variation in Aggressiveness of Stagonospora nodorum Isolates in North DakotaJOURNAL OF PHYTOPATHOLOGY, Issue 3 2008S. Ali Abstract Stagonospora nodorum blotch (SNB), caused by Stagonospora nodorum, is an important disease in the northern Great Plains of the United States and in other wheat-producing regions in the world. SNB can be managed by different strategies including the use of resistant cultivars. Genetic variation in the pathogen populations is one of the important factors in the development of durable resistant cultivars. Our main objective was to determine variation in aggressiveness/virulence in the 40 isolates of S. nodorum collected from various locations in North Dakota. To achieve this goal, we tested the isolates on two susceptible wheat cultivars (cvs ,ND495' and ,Alsen') and two resistant wheat cultivars (cvs ,Erik' and ,Salamouni') , two-leaf-stage seedlings under controlled conditions. Aggressiveness of each isolate was characterized by the two epidemiological parameters: percent necrotic leaf area (% NLA) and lesion type (LT) 8 days post-inoculation. The isolates differed significantly (P , 0.05) for % NLA and LT, and were grouped into three aggressiveness groups (AG): low, medium and highly aggressive. Four isolates (S50, S57, S66 and S89) induced 18,26% NLA and were included into the low aggressive group (AG 1). Three isolates (S15, S39 and S89) induced 57,59% NLA and were considered highly aggressive (AG 3). Thirty-three isolates were medium aggressive (AG 2). No relationship between AG and mating types was observed. There were significant (P , 0.05) differences in % NLA and LT among wheat cultivars. Significant wheat cultivars by isolates interaction was also demonstrated, suggesting evidence for the existence of host specificity in this system. Overall, our results indicate that S. nodorum isolates prevalent in North Dakota varied greatly in their aggressiveness and that AG 3 isolates can be utilized in breeding wheat for resistance to SNB. [source] An evidence-based review of therapies for canine chronic kidney diseaseJOURNAL OF SMALL ANIMAL PRACTICE, Issue 5 2010P. Roudebush Successful treatment and prevention of kidney disease in dogs requires a multi-dimensional approach to identify and eliminate causes or exacerbating factors, provide professional evaluation on a regular basis and implement a comprehensive treatment programme when necessary. Over the years, many therapeutic and preventive interventions have been developed or advocated for chronic kidney disease in dogs, but evidence of efficacy or effectiveness is often lacking or highly variable. Accordingly, the main objective of this systematic review was to identify and critically appraise the evidence supporting various aspects of managing canine chronic kidney disease. [source] Glacial vicariance in the Pacific Northwest: evidence from a lodgepole pine mitochondrial DNA minisatellite for multiple genetically distinct and widely separated refugiaMOLECULAR ECOLOGY, Issue 10 2008JULIE GODBOUT Abstract The Canadian side of the Pacific Northwest was almost entirely covered by ice during the last glacial maximum, which has induced vicariance and genetic population structure for several plant and animal taxa. Lodgepole pine (Pinus contorta Dougl. ex. Loud.) has a wide latitudinal and longitudinal distribution in the Pacific Northwest. Our main objective was to identify relictual signatures of glacial vicariance in the population structure of the species and search for evidence of distinct glacial refugia in the Pacific Northwest. A maternally inherited mitochondrial DNA minisatellite-like marker was used to decipher haplotype diversity in 91 populations of lodgepole pine located across the natural range. Overall population differentiation was sizeable (GST = 0.365 and RST = 0.568). Four relatively homogeneous groups of populations, possibly representative of as many genetically distinct glacial populations, were identified for the two main subspecies, ssp. latifolia and ssp. contorta. For ssp. contorta, one glacial lineage is suggested to have been located at high latitudes and possibly off the coast of mainland British Columbia (BC), while the other is considered to have been located south of the ice sheet along the Pacific coast. For ssp. latifolia, two genetically distinct glacial populations probably occurred south of the ice sheet: in the area bounded by the Cascades and Rocky Mountains ranges, and on the eastern side of the Rockies. A possible fifth refugium located in the Yukon may have also been present for ssp. latifolia. Zones of contact between these ancestral lineages were also apparent in interior and northern BC. These results indicate the role of the Queen Charlotte Islands and the Alexander Archipelago as a refugial zone for some Pacific Northwest species and the vicariant role played by the Cascades and the American Rocky Mountains during glaciation. [source] Neuroprotective therapy in Parkinson's disease and motor complications: A search for a pathogenesis-targeted, disease-modifying strategyMOVEMENT DISORDERS, Issue S11 2005C. Warren Olanow MD, FRCPC Abstract The introduction of levodopa in the late 1960s represented a landmark in the therapy of Parkinson's disease (PD). However, motor complications of chronic levodopa therapy have emerged as a major limitation of this otherwise effective therapy. Advancing medical and surgical treatment of these complications has been the main objective of clinical trials during the past few decades. In addition, basic research has focused on better understanding of the mechanisms of motor complications and how to prevent them. Slowing or delaying the progression of the disease delays the need for levodopa therapy; therefore, neuroprotective strategies may play an important role in preventing the onset and reducing the severity of levodopa-related adverse effects. In this introductory review, we present the rationale for current and experimental therapies designed to favorably modify the progression of PD. If implemented early in the course of the disease, such treatments, if found effective, may not only alter the natural progression of the disease but may also delay or minimize motor and nonmotor complications associated with levodopa. © 2005 Movement Disorder Society [source] Use of Turkish huntite/hydromagnesite mineral in plastic materials as a flame retardantPOLYMER COMPOSITES, Issue 10 2010Hüsnügül Y, lmaz Atay In this study, the flame retardancy properties of huntite/hydromagnesite mineral in plastic compounds were investigated for potential electrical applications. Before the production of composite materials, huntite/hydromagnesite minerals were ground to particle sizes of 10, 1, and 0.1 ,m. Phase and microstructural analysis of huntite/hydromagnesite mineral powders were undertaken using XRD and SEM-EDS preceding the fabrication of the composite materials. The ground minerals with different particle size and content levels were subsequently added to ethylene vinyl acetate copolymer to produce composite materials. After fabrication of huntite/hydromagnesite reinforced plastic composite samples, they were characterized using DTA-TG, FTIR, and SEM-EDS. Flame retardancy tests were undertaken as a main objective of this research. The size distribution and the mineral content effects are measured regarding the flame retardancy of the polymer composites It was concluded that the flame retardant properties of plastic composites were improved as the mineral content increased and the size was reduced. POLYM. COMPOS., 31:1692,1700, 2010. © 2010 Society of Plastics Engineers. [source] Essential work of fracture (EWF) analysis for compression molded alternating poly(propylene carbonate)POLYMER ENGINEERING & SCIENCE, Issue 3 2004K. L. Fung In this investigation, the main objective was to study the mechanical properties of alternating poly(propylene carbonate) copolymer (PPC). The PPC used in this study was derived from propylene oxide and carbon dioxide using zinc glutarate as catalyst. The molecular weight of the PPC copolymer used in this study has M,n,33,000. The synthesized PPC was compression molded into sheets of thickness ,1mm. The fracture toughness of the PPC films was determined using the essential work of fracture (EWF) technique, at a laboratory temperature of 20°C, and a loading rate of 1 mm/min. During the EWF measurement, a significant amount of plastic deformation has taken place around the initial ligament region. The measured specific total fracture work (wf) was observed to vary in a linear fashion with the specimen ligament (l), and hence satisfied the basic requirement for EWF analysis. The specific essential fracture work (we) for the PPC film was measured to be 11.0 kJ/m2. The PPC showed a prominent recovery behavior. The severely deformed region surrounding the fracture ligament was observed to recover completely 8 days after fracture testing. Polym. Eng. Sci. 44:580,587, 2004. © 2004 Society of Plastics Engineers. [source] Improving the Efficiency of Insemination with Sex-sorted SpermatozoaREPRODUCTION IN DOMESTIC ANIMALS, Issue 2008JM Vazquez Contents The sorting of X- and Y-chromosome-bearing spermatozoa by flow cytometry is nowadays one of the most apt assisted-reproduction technologies in livestock production. Potential economic and biological benefits, as well as those related to easier management of herds, have been reported arising out of the application of this technique, especially in cattle. Yet, the sex-sorting procedure induces damage to spermatozoa, affecting their function and fertilizing ability. Different species present varying degrees of susceptibility to damage from the sorting process and each has its own requirements for sex-sorted insemination procedures. Thus, several new protocols and strategies have been designed for the handling of sorted spermatozoa, with the main objective of optimizing their fertilizing ability and the consequent application of flow-cytometric sex-sorting technology. This article reviews current advances in this technology, pointing out the components to be improved before this technology may be widely applied in different domestic species. [source] Indigenous School Policies and Politics: The Sociopolitical Relationship of Wayãpi Amerindians to Brazilian and French Guianan SchoolingANTHROPOLOGY & EDUCATION QUARTERLY, Issue 2 2009Silvia Lopes Da Silva Macedo In this article, I aim to demonstrate the relationships between the educational policies of the Brazilian and French Guyana governments and the sociopolitical structure of the Wayãpi in respect to these educational practices. My main objective is to go beyond the normal concept that the school is an external interference that catalyzes processes of "Indigenous acculturation," to make clear that the Wayãpi sociopolitical forms of interaction that govern their relationships with alterity also govern their relationships with the state and its representatives. This article is based on my ethnographic study of the school experiences among the Wayãpi living in villages in both countries.,[Wayãpi Amerindians, Brazil, schooling, sociopolitical interaction, alterity] [source] Interleukin-12 induces salivary gland dysfunction in transgenic mice, providing a new model of Sjögren's syndromeARTHRITIS & RHEUMATISM, Issue 12 2009Jelle L. Vosters Objective Interleukin-12 (IL-12) is a pleiotropic cytokine that is elevated in the affected organs of patients with Sjögren's syndrome (SS). We have previously reported that overexpression of IL-12 in CBA mice leads to mononuclear infiltration of salivary and lacrimal glands, as well as to expansion of bronchial lymphoid tissue and decreased mucociliary clearance. Because xerostomia is one of the most important clinical features in SS patients, our main objective in the current study was to evaluate salivary gland function in IL-12,transgenic mice. Our secondary objective was to further characterize this animal model and to determine if the changes observed in these mice are representative of those observed in patients with SS overall. Methods Pilocarpine-stimulated salivary flow was used to address salivary gland function in a large group of IL-12,transgenic mice bred onto the autoimmune-prone SJL background. Furthermore, salivary glands were removed to assess the formation of infiltrates in the glands and gland morphology. Serum was also collected from these animals to investigate the formation of autoantibodies. Results Pilocarpine-stimulated salivary flow was significantly lower in IL-12,transgenic mice than in wild-type controls. Salivary glands from transgenic mice exhibited an increase in both the number and the size of lymphocytic foci, versus glands from age-matched controls. Furthermore, the acini in transgenic mice were fewer in number and larger in size compared with acini in controls. An age-dependent increase in anti-SSB/La antibodies was observed in IL-12,transgenic mice and was accompanied by an increase in antinuclear antibodies. Conclusion Our findings indicate that a number of conditions associated with SS are exhibited by IL-12,transgenic SJL mice and that this model might be useful in researching multiple aspects of the disease. [source] Course of the modified Rodnan skin thickness score in systemic sclerosis clinical trials: Analysis of three large multicenter, double-blind, randomized controlled trialsARTHRITIS & RHEUMATISM, Issue 8 2009Sogol Amjadi Objective To assess the course of the modified Rodnan skin thickness score (MRSS) in 3 large, multicenter, double-blind, randomized controlled trials (RCTs) of patients with diffuse cutaneous systemic sclerosis (dcSSc) with different baseline disease durations, as defined from the date of onset of the first dcSSc symptom (excluding Raynaud's phenomenon) or from the date of onset of the first dcSSc-related symptom (including Raynaud's phenomenon). Methods Data from 3 RCTs examining high-dose versus low-dose D-penicillamine (D-Pen Trial), recombinant human relaxin versus placebo (Relaxin Trial), and oral bovine type I collagen versus placebo (Collagen Trial) treatment in patients with dcSSc were pooled and analyzed. Patients were divided into 5 groups according to their disease duration at baseline. The linear mixed model for correlated data was used to model the 2 predictors of MRSS: time in study (expressed in months after baseline) and baseline disease duration (expressed in months, calculated from the date of onset of the first symptom characteristic of dcSSc with and without Raynaud's phenomenon). Results At study entry, the mean MRSS value was 21.0 in the D-Pen Trial cohort, 27.3 in the Relaxin Trial cohort, and 26.1 in the Collagen Trial cohort. Time in study was a significant predictor of improvement in MRSS regardless of the disease duration at baseline (P < 0.0001). Patients with a disease duration of ,24 months showed a greater rate of decline as compared with patients with a disease duration of <24 months (P < 0.05). Similar results were obtained when disease duration was reclassified by including the time of the first Raynaud's phenomenon symptom in the definition. Conclusion Our study confirms recent findings that in patients entered into these 3 RCTs, skin thickening did not follow the same trend in natural history as that seen in the dcSSc populations entered into early, open longitudinal studies previously reported. These findings have important implications for study design, in which "prevention of worsening" is the main objective. [source] | ||||||||||||||||||||||||||||||||||||||||