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Kinds of Based Terms modified by Based Selected AbstractsPermeability of receptive fig fruits and its effects on the re-emergence behaviour of pollinatorsECOLOGICAL ENTOMOLOGY, Issue 2 2010HU HAO-YUAN 1. Figs and pollinating fig wasps provide a model system for studying mutualism. The permeability of the syconium changes during receptivity or between seasons, which may affect the behaviour of pollinators. Fig fruits are permeable during receptivity, and in some species, pollinators can enter and re-emerge after oviposition/pollination. We studied the relationship between fig permeability and pollinator re-emergence behaviour with a functional dioecious fig, Ficus hispida and the obligate pollinator Ceratosolen solmsi marchali. 2. The relationship reflects the interaction of figs and pollinators in the mutualism and also the conflicts of interests between the two partners: figs benefit from the enclosed fig fruits which have low permeability, but pollinators benefit from their re-emergence behaviour, which requires high fig permeability. 3. The results showed that at the end of receptivity, the permeability of fig fruits lowered rapidly with changes to the ostiole structures, and re-emergence rate was low, with more re-emerging pollinators trapped in the ostiolar bracts. Our results also showed that in the rainy season, the length of receptivity was shorter and fig permeability was lower. The re-emergence rates were also lower than those in the dry season. The results elucidated that figs' interests dominated in the conflicts between fig and pollinating wasp. 4. Based on a new criteria which employed the classification of pollinators found dead in the ostiolar bracts and which involved a survey of 6 monoecious and 12 dioecious fig species, we found that re-emergence behaviour was prevalent among fig species, and was more prevalent in functional dioecious figs than monoecious ones. [source] The significance of side-arm connectivity for carbon dynamics of the River Danube, AustriaFRESHWATER BIOLOGY, Issue 2 2008S. PREINER Summary 1. Side-arms connected to the main stem of the river are key areas for biogeochemical cycling in fluvial landscapes, exhibiting high rates of carbon processing. 2. This work focused on quantifying autochthonous and allochthonous carbon pools and, thereby, on comparing transport and transformation processes in a restored side-arm system of the River Danube (Regelsbrunn). We established a carbon budget and quantified carbon processing from March to September 2003. In addition, data from previous studies during 1997 to 1999 were assessed. 3. Gross primary production (GPP) and community respiration were estimated by diel oxygen time curves and an oxygen mass balance. Plankton primary production was determined to estimate its contribution to GPP under different hydrological conditions. 4. Based on the degree of connectivity, three hydrological phases were differentiated. Most of the organic matter, dominated by allochthonous carbon, was transported in the main channel and through the side-arm during floods, while at intermediate and low flows (and thus connectivity), transformation processes became more important and autochthonous carbon dominated the carbon pool. The side-arm system functioned as a sink for particulate matter [total suspended solids and particulate organic carbon (POC)] and a source of dissolved organic carbon (DOC) and chlorophyll- a. 5. Autochthonous primary production of 4.2 t C day,1 in the side-arm was equivalent to about 20% of the allochthonous inputs of 20 t C day,1 (POC and DOC) entering the area at mean flow (1% of the discharge of the main channel). Pelagic photosynthesis was generally high at mean flow (1.3,3.8 g C m,2 day,1), and contributed up to 90% of system productivity. During long stagnant periods at low discharge, the side-arm was controlled by biological processes and a shift from planktonic to benthic activity occurred (benthic primary production of 0.4,14 g C m,2 day,1). 6. The transformation of the organic matter that passes through the side-arm under different hydrological conditions, points to the importance of these subsystems in contributing autochthonous carbon to the food web of the main channel. [source] Population genetic structure of three freshwater mussel (Unionidae) species within a small stream system: significant variation at local spatial scalesFRESHWATER BIOLOGY, Issue 8 2007DAVID J. BERG Summary 1. Unionid mussels are highly threatened, but little is known about genetic structure in populations of these organisms. We used allozyme electrophoresis to examine partitioning of genetic variation in three locally abundant and widely distributed species of mussels from a catchment in Ohio. 2. Within-population variation was similar to that previously reported for freshwater mussels, but genotype frequencies exhibited heterozygote deficiencies in many instances. All three species exhibited significant among-population variation. Evidence of isolation-by-distance was found in Elliptio dilatata and Ptychobranchus fasciolaris, while Lampsilis siliquoidea showed no geographical pattern of among-population variation. 3. Our results suggest that the isolating effects of genetic drift were greater in L. siliquoidea than in the other species. Differentiation of populations occurred at a much smaller spatial scale than has previously been found in freshwater mussels. Differences among species may reflect differences in the dispersal abilities of fishes that serve as hosts for the glochidia larvae of mussels. 4. Based on our results, we hypothesise that species of mussels that are common to large rivers exhibit relatively large amounts of within-population genetic variation and little differentiation over large geographical distances. Conversely, species typical of small streams show lower within-population genetic variation and populations will be more isolated. If this hypothesis can be supported, it may prove useful in the design of conservation strategies that maintain the genetic structure of target species. [source] Abundance and microhabitats of freshwater sponges (Spongillidae) in a Danubean floodplain in AustriaFRESHWATER BIOLOGY, Issue 6 2007IRIS DRÖSCHER Summary 1. This study examined the abundance and distribution of freshwater sponges (Spongillidae) at 32 sites in a floodplain on the Danube within the ,Donau-Auen' National Park east of Vienna, Austria. Ranked from abundant to rare, the species inventory comprised Ephydatia fluviatilis, Spongilla lacustris, Ephydatia mülleri, Eunapius fragilis and Trochospongilla horrida. 2. The presence of hard substratum was essential for the growth of sponges. Timber stands near the water and drifting dead wood increased the abundance of E. fragilis, E. fluviatilis and E. mülleri, whereas stony substrata were important for S. lacustris. A small fraction of E. fluviatilis was collected from macrophytes (Phragmites). 3. Based on the area colonised, the abundance of S. lacustris, E. fragilis and E. fluviatilis was highest (94.2,100% of the total) in floodplain waters where hydrological connectivity with the Danube was low (0,6 days year,1), whereas E. mülleri and T. horrida made up 20.3,35.9% of the total at sites connected for up to 179 days year,1. Moreover, the area colonised by T. horrida at a current velocity >0.20 m s,1 was larger than in the remaining species. Sites with E. mülleri and T. horrida had a higher silicon concentration (0.9 mg L,1) than sites where the remaining three species were collected (0.4,0.6 mg L,1). 4. In most species, the length of macroscleres (the larger spicules) was positively correlated with conductivity and negatively with pH. With respect to aberrant macroscleres, hooks were observed most frequently, whereas the proportion of centrotylotes (ie with the one on more globular swellings along the spicule) was lowest. 5. Freshwater sponges have a great deal of potential as bioindicators and restoration measures that improve floodplain connectivity will favour rare species, such as E. mülleri and T. horrida, while impairing others (e.g. E. fragilis, S. lacustris and E. fluviatilis). [source] Undesirable side-effects of water hyacinth control in a shallow tropical reservoirFRESHWATER BIOLOGY, Issue 6 2007DENISE DE C. BICUDO Summary 1. Based on a comprehensive data set collected monthly during 8 years (1997,2004), we evaluated the effects of mechanical removal of Eichhornia crassipes on the limnological characteristics and algal biomass of a polymictic shallow tropical reservoir. 2. Interrupted time series analyses indicated that the limnological responses to macrophyte removal can be classified as an ,abrupt permanent impact' implying that the overall mean of the time-series shifted promptly after intervention. These analyses indicated a significant increase for pH, total phosphorus, total phytoplankton and cyanobacterial biomass, and a decrease in water transparency and CO2 concentrations in the surface water; also, the increase in water stability, increase of bottom soluble reactive phosphorus (SRP) and decrease in bottom oxygen levels. 3. Cyclic anoxic periods previously observed during springs and summers were replaced by a persistent period of anoxic conditions in the sediment overlying water. Anoxic conditions were suitable for SRP release from sediments. Heavy cyanobacterial blooms became more persistent, maximum biomass (4229 mm3 L,1) was 30 times larger, the blooms frequently reached 2 m and sometimes the bottom of the reservoir, contrasting to the preremoval period in which it reached at most 1 m deep. 4. The long-term P dynamics in the system, initially driven by allochthonous nutrient loadings were replaced by internal ecological processes. Water hyacinth removal markedly accelerated the process of eutrophication due to internal feedback mechanisms, leading to a switch to a more turbid state. Biological feedback mechanisms were driven by cyanobacterial blooms by enhancing water stability, oxygen anoxia at the bottom and by increasing suitable conditions for P internal loading. These data support the hypothesis of the role of cyanobacterial blooms as an important factor impairing water quality and driving the ecosystem towards a stable degraded state. 5. These findings have important implications for the restoration of shallow stratifying eutrophic lakes, as the alternative degraded state is most likely to occur when compared with their non-stratifying counterparts. Moreover, feedback mechanisms in tropical and subtropical shallow lakes seem to be stronger than in temperate ones, as stratification events are more likely to occur over the year, intensifying system resilience to restorative strategies. [source] Management options for river conservation planning: condition and conservation re-visitedFRESHWATER BIOLOGY, Issue 5 2007SIMON LINKE Summary 1. Systematic conservation planning is a process widely used in terrestrial and marine environments. A principal goal is to establish a network of protected areas representing the full variety of species or ecosystems. We suggest considering three key attributes of a catchment when planning for aquatic conservation: irreplaceability, condition and vulnerability. 2. Based on observed and modelled distributions of 367 invertebrates in the Australian state of Victoria, conservation value was measured by calculating an irreplaceability coefficient for 1854 subcatchments. Irreplaceability indicates the likelihood of any subcatchment being needed to achieve conservation targets. We estimated it with a bootstrapped heuristic reserve design algorithm, which included upstream,downstream connectivity rules. The selection metric within the algorithm was total summed rarity, corrected for protected area. 3. Condition was estimated using a stressor gradient approach in which two classes of geographical information system Layers were summarised using principal components analysis. The first class was disturbance measures such as nutrient and sediment budgets, salinisation and weed cover. The second class was land use layers, including classes of forestry, agricultural and urban use. The main gradient, explaining 56% of the variation, could be characterised as agricultural disturbance. Seventy-five per cent of the study area was classified as disturbed. 4. Our definition of vulnerability was the likelihood of a catchment being exposed to a land use that degrades its condition. This was estimated by comparing land capability and current land use. If land was capable of supporting a land use that would have a more degrading effect on a river than its current tenure, it was classified vulnerable (66% of the study area). 79% of catchments contained more then 50% vulnerable land. 5. When integrating the three measures, two major groups of catchments requiring urgent conservation measures were identified. Seven per cent of catchments were highly irreplaceable, highly vulnerable but in degraded condition. These catchments were flagged for restoration. While most highly irreplaceable catchments in good condition were already protected, 2.5% of catchments in this category are on vulnerable land. These are priority areas for assigning river reserves. [source] Effects of waterfowl and fish on submerged vegetation and macroinvertebratesFRESHWATER BIOLOGY, Issue 11 2002Ola Marklund SUMMARY 1. With the aim to assess the combined and separate effects of waterfowl and fish on submerged vegetation and macroinvertebrates, we performed a replicated selective exclosure study in a shallow, eutrophic lake in southern Sweden. Our results are presented together with a literature review of the effects of fish and waterfowl on macroinvertebrates and submerged vegetation. 2. Based on our experiment and on published data, we conclude that waterfowl normally will reduce submerged vegetation only at high waterfowl densities, at very low vegetation densities, or in the colonisation phase of the vegetation. 3. Further, we conclude that in shallow temperate eutrophic lakes, a naturally occurring mixed fish assemblage rarely reduces submerged vegetation. Unless the vegetation is very sparse, the risk of severe reduction of submerged vegetation as a result of waterfowl or fish grazing, should thereby be low. 4. Even relatively low densities of fish seem to reduce macroinvertebrate biomass, while a mixed waterfowl assemblage rarely has a significant effect on macroinvertebrate biomass. [source] Distribution and status of medicinal leeches (genus Hirudo) in the Western Palaearctic: anthropogenic, ecological, or historical effects?AQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue 2 2010Serge Utevsky Abstract 1. Distribution and status of medicinal leeches were re-considered in the light of the new taxonomy recognizing four Western Palaearctic species: Hirudo medicinalis, Hirudo verbana, Hirudo orientalis and Hirudo troctina. 2. Recent records and new data obtained on expeditions to Ukraine, Russia, Azerbaijan, Kazakhstan, Uzbekistan and the Western Balkans were mapped to obtain an up-to-date overview of the distribution. 3. Three hypotheses explaining the current ranges of all Hirudo species were tested. The ecological hypothesis, suggesting a strong impact of large-scale environmental factors, received the highest support, while anthropogenic influence was minimal, and no historical patterns of refugia and colonization were detected. 4. Mapped localities of all Hirudo species show extensive, belt-shaped ranges extending from east to west. H. medicinalis is distributed from Britain and southern Norway to the southern Urals and probably as far as the Altai Mountains, occupying the deciduous arboreal zone. H. verbana has been recorded from Switzerland and Italy to Turkey and Uzbekistan, which largely corresponds to the Mediterranean and sub-boreal steppe zone. H. orientalis is associated with mountainous areas in the sub-boreal eremial zone and occurs in Transcaucasian countries, Iran and Central Asia. H. troctina has been found in north-western Africa and Spain in the Mediterranean zone. 5. Based on the data gathered, and considering real and potential threats, global IUCN category Near Threatened is proposed for H. medicinalis, H. verbana, and H. orientalis, while H. troctina can only be assigned to category Data Deficient. Copyright © 2010 John Wiley & Sons, Ltd. [source] Pattern Formation And Rhythm Generation In The Ventral Respiratory GroupCLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 1-2 2000Donald R McCrimmon SUMMARY 1. There is increasing evidence that the kernel of the rhythm-generating circuitry for breathing is located within a discrete subregion of a column of respiratory neurons within the ventrolateral medulla referred to as the ventral respiratory group (VRG). It is less clear how this rhythm is transformed into the precise patterns appearing on the varied motor outflows. 2. Two different approaches were used to test whether subregions of the VRG have distinct roles in rhythm or pattern generation. In one, clusters of VRG neurons were activated or inactivated by pressure injection of small volumes of neuroactive agents to activate or inactivate groups of respiratory neurons and the resulting effects on respiratory rhythm and pattern were determined. The underlying assumption was that if rhythm and pattern are generated by neurons in different VRG subregions, then we should be able to identify regions where activation of neurons predominantly alters rhythm with little effect on pattern and other regions where pattern is altered with little effect on rhythm. 3. Based on the pattern of phrenic nerve responses to injection of an excitatory amino acid (DL -homocysteate), the VRG was divided into four subdivisions arranged along the rostrocaudal axis. Injections into the three rostral regions elicited changes in both respiratory rhythm and pattern. From rostral to caudal the regions included: (i) a rostral bradypnoea region, roughly associated with the Bötzinger complex; (ii) a dysrhythmia/tachypnoea area, roughly associated with the pre-Bötzinger complex (PBC); (iii) a second caudal bradypnoea area; and, most caudally, (iv) a region from which no detectable change in respiratory motor output was elicited. 4. In a second approach, the effect of unilateral lesions of one subregion, the PBC, on the Breuer,Hering reflex changes in rhythm were determined. Activation of this reflex by lung inflation shortens inspiration and lengthens expiration (TE). 5. Unilateral lesions in the PBC attenuated the reflex lengthening of TE, but did not change baseline respiratory rhythm. 6. These findings are consistent with the concept that the VRG is not functionally homogeneous, but consists of rostrocaudally arranged subregions. Neurons within the so-called PBC appear to have a dominant role in rhythm generation. Nevertheless, neurons within other subregions contribute to both rhythm and pattern generation. Thus, at least at an anatomical level resolvable by pressure injection, there appears to be a significant overlap in the circuitry generating respiratory rhythm and pattern. [source] Antidiabetic and toxicological evaluations of naringenin in normoglycaemic and NIDDM rat models and its implications on extra-pancreatic glucose regulationDIABETES OBESITY & METABOLISM, Issue 11 2008R. R Ortiz-Andrade Aim:, The present investigation was designed to determine the in vivo antidiabetic effect of naringenin (NG) in normoglycaemic and diabetic rat models through blood glucose (GLU) measurements following acute and subchronic time periods. Possible modes of action of NG were investigated and its acute toxicity determined. Methods:, Normoglycaemic and non-insulin-dependent diabetes mellitus (NIDDM) rat models were treated for acute and subchronic (5 days) time periods with 50 mg/kg/day of NG. Blood biochemical profiles were determined after 5 days of the treatment in normoglycaemic and NIDDM rats using commercial kits for GLU, triglycerides (TG), total cholesterol (CHOL) and high-density lipoprotein (HDL). In order to elucidate its antidiabetic mode of action, NG was administered intragastrically and an oral glucose tolerance test performed using GLU and sucrose (2 g/kg) as substrates. The inhibitory effect of a single concentration of NG (10 ,M) on 11,-hydroxysteroid dehydrogenase type 1 (11,-HSD1) activity in vitro was determined. Finally, the preclinical safety and tolerability of NG was determined by toxicological evaluation in mice and rats using Organization for Economic Cooperation and Development (OECD) protocols. Results:, Intragastrically administered NG (50 mg/kg) induced a significant decrease in plasma GLU in normoglycaemic and NIDDM rat models (p < 0.05) following acute and subchronic time periods. After 5 days of administration, NG produced significant diminished blood GLU and TG levels in streptozotocin,nicotinamide,induced diabetic rats. The administration of NG to normal rats significantly increased the levels of TG, CHOL and HDL (p < 0.05). NG (5 and 50 mg/kg) induced a total suppression in the increase of plasma GLU levels after administration of substrates (p < 0.01), but NG did not produce inhibition of ,-glucosidase activity in vitro. However, NG (10 ,M) was shown to inhibit 11,-HSD1 activity by 39.49% in a cellular enzyme assay. Finally, NG showed a Medium Lethal Dose LD50 > 5000 mg/kg and ranking at level five based on OECD protocols. Conclusion:, Our findings suggest that NG may exert its antidiabetic effect by extra-pancreatic action and by suppressing carbohydrate absorption from intestine, thereby reducing the postprandial increase in blood GLU levels. [source] Nuclear morphometry and texture analysis of B-cell non-Hodgkin lymphoma: Utility in subclassification on cytosmearsDIAGNOSTIC CYTOPATHOLOGY, Issue 2 2010Shilpa Gupta M.D. Abstract Non-Hodgkin lymphoma (NHL) is a heterogeneous group of lymphoid neoplasms and accurate subclassification is an essential prerequisite for proper management of patients. This study was aimed at evaluating the utility of nuclear morphometry and textural features on cytology smears to classify the cases of NHL on aspiration cytology. Fine needle aspiration smears of 50 cases of B-cell NHL were included. Various morphometric and texture parameters were obtained by manually tracing the nuclei on digitized images in each case and discriminant analysis performed using various features taken individually as well as all together. The percentage of cells correctly classified to a particular NHL subtype using the discriminant functions so obtained was noted. Our results show that discriminant analysis done on size parameters could correctly classify a greater number of cells than on shape parameters (36.4% vs. 21.2%, respectively). Texture parameters based on single pixel values (first order texture) were inferior (42.8%) to those based on pair of pixels (58.7%) in subtyping of cells. Discriminant analysis based on color parameters was more effective (61.9%) as compared to rest of the morphometric and textural parameters. Using all the morphometric and textural parameters together, 83.3% of cells could be correctly classified to a particular NHL subtype. The present study, perhaps the first study of detailed morphometric analysis on cytosmears, shows that satisfactory classification of NHL on aspiration cytology is possible using nuclear morphometry and textural parameters considered together. These results are promising for further studies on this subject and development of automated cytodiagnosis. Diagn. Cytopathol. 2010. © 2009 Wiley-Liss, Inc. [source] Fluency remediation in dyslexic children: does age make a difference?DYSLEXIA, Issue 2 2008Patrizio E. Tressoldi Abstract This study tested the hypothesis whether older dyslexic children may obtain fewer gains on fluency and accuracy with respect to their younger peers after specific remediation. Changes in accuracy and fluency of a group of children with a diagnosis of dyslexia attending third and fourth grades were compared with those obtained by a group of children attending the sixth, seventh or eighth grade in two different treatments, one based on the Balance model (Bakker) and the second based on the automatization of syllable recognition (sublexical). Among all comparisons between the gains in accuracy and fluency obtained by the two groups, only the younger group in the sublexical treatment obtained a statistically significant gain with respect to their older peers' accuracy in reading words. These outcomes suggest that, at least for the chronological ages and types of treatments considered in this study, older children with dyslexia may obtain comparable gains to their younger peers, suggesting that ,it is never too late' to remediate reading fluency and accuracy. Copyright © 2007 John Wiley & Sons, Ltd. [source] Quantifying sediment storage in a high alpine valley (Turtmanntal, Switzerland)EARTH SURFACE PROCESSES AND LANDFORMS, Issue 13 2009Jan-Christoph Otto Abstract The determination of sediment storage is a critical parameter in sediment budget analyses. But, in many sediment budget studies the quantification of magnitude and time-scale of sediment storage is still the weakest part and often relies on crude estimations only, especially in large drainage basins (>100,km2). We present a new approach to storage quantification in a meso-scale alpine catchment of the Swiss Alps (Turtmann Valley, 110,km2). The quantification of depositional volumes was performed by combining geophysical surveys and geographic information system (GIS) modelling techniques. Mean thickness values of each landform type calculated from these data was used to estimate the sediment volume in the hanging valleys and the trough slopes. Sediment volume of the remaining subsystems was determined by modelling an assumed parabolic bedrock surface using digital elevation model (DEM) data. A total sediment volume of 781·3×106,1005·7×106,m3 is deposited in the Turtmann Valley. Over 60% of this volume is stored in the 13 hanging valleys. Moraine landforms contain over 60% of the deposits in the hanging valleys followed by sediment stored on slopes (20%) and rock glaciers (15%). For the first time, a detailed quantification of different storage types was achieved in a catchment of this size. Sediment volumes have been used to calculate mean denudation rates for the different processes ranging from 0·1 to 2·6,mm/a based on a time span of 10,ka. As the quantification approach includes a number of assumptions and various sources of error the values given represent the order of magnitude of sediment storage that has to be expected in a catchment of this size. Copyright © 2009 John Wiley & Sons, Ltd. [source] Alcohol control policies and alcohol consumption by youth: a multi-national studyADDICTION, Issue 11 2009Mallie J. Paschall ABSTRACT Aims The study examined relationships between alcohol control policies and adolescent alcohol use in 26 countries. Design Cross-sectional analyses of alcohol policy ratings based on the Alcohol Policy Index (API), per capita consumption and national adolescent survey data. Setting Data are from 26 countries. Participants Adolescents (aged 15,17 years) who participated in the 2003 European School Survey Project on Alcohol and Other Drugs (ESPAD) or national secondary school surveys in Spain, Canada, Australia, New Zealand and the United States. Measurements Alcohol control policy ratings based on the API; prevalence of alcohol use, heavy drinking and first drink by age 13 based on national secondary school surveys; per capita alcohol consumption for each country in 2003. Analysis Correlational and linear regression analyses were conducted to examine relationships between alcohol control policy ratings and past 30-day prevalence of adolescent alcohol use, heavy drinking and having first drink by age 13. Per capita consumption of alcohol was included as a covariate in regression analyses. Findings More comprehensive API ratings and alcohol availability and advertising control ratings were related inversely to the past 30-day prevalence of alcohol use and prevalence rates for drinking three to five times and six or more times in the past 30 days. Alcohol advertising control was also related inversely to the prevalence of past 30-day heavy drinking and having first drink by age 13. Most of the relationships between API, alcohol availability and advertising control and drinking prevalence rates were attenuated and no longer statistically significant when controlling for per capita consumption in regression analyses, suggesting that alcohol use in the general population may confound or mediate observed relationships between alcohol control policies and youth alcohol consumption. Several of the inverse relationships remained statistically significant when controlling for per capita consumption. Conclusions More comprehensive and stringent alcohol control policies, particularly policies affecting alcohol availability and marketing, are associated with lower prevalence and frequency of adolescent alcohol consumption and age of first alcohol use. [source] Electrochemical Nitric Oxide Sensors for Biological Samples , Principle, Selected Examples and ApplicationsELECTROANALYSIS, Issue 1 2003Fethi Bedioui Abstract The discoveries made in the 1980s that NO could be synthesized by mammalian cells and could act as physiological messenger and cytotoxic agent had elevated the importance of its detection. The numerous properties of NO, that enable it to carry out its diverse functions, also present considerable problems when attempting its detection and quantification in biological systems. Indeed, its total free concentration in physiological conditions has been established to be in nanomolar range. Thus, detection of nitric oxide remains a challenge, pointing out the difficult dual requirements for specificity and sensitivity. Exception made for the electrochemical techniques, most of the approaches (namely UV-visible spectroscopy, fluorescence, electron paramagnetic resonance spectroscopy) use indirect methods for estimating endogenous NO, relying on measurements of secondary species such as nitrite and nitrate or NO-adducts. They also suffer from allowing only ex situ measurements. So, the only strategies that allow a direct and in vivo detection of NO are those based on the use of ultramicroelectrodes. The reality is that surface electrode modification is needed to make the ultramicroelectrode material selective for NO. Therefore, the design of modified electrode surfaces using organized layers is very attractive and provides the ideal strategy. This review addresses a global description of the various approaches that have involved chemically modified microelectrodes specially designed for the electrochemical detection of NO in biological media. Selected significant examples of applications in biological tissues are also reported in order to highlight the importance of this approach in having new insights into the modulatory role of NO in physiology and pathophysiology. [source] System zones in capillary zone electrophoresis: Moving boundaries caused by freely migrating hydrogen ionsELECTROPHORESIS, Issue 2 2005Jozef L. Beckers Abstract We demonstrate that system zones (SZs) can be expected in background electrolytes (BGEs) with a low buffer capacity. The mobilities of this type of SZ (mSZ) could be determined by calculations both based on a mathematical model and by a simulation program. The values of mSZ are increasing for decreasing buffer capacities and lower concentrations of the BGEs. For completely unbuffered BGEs with a pH below 7, the mSZ reached values up to 350×10,9 m2V,1s,1. This value indicates that the existence of this type of SZ originates from migrating hydrogen ions. Although both the mathematical model and simulation program do not consider the influence of the pH of the sample solution, experiments have shown that the pH of the sample solution is also very important. The lower the pH of the sample solution, the larger the mSZ in a specific BGE for cationic SZs. Using completely unbuffered BGEs the hydrogen ions present in the original sample start to migrate freely through the capillary tube with the mobility of a single hydrogen ion and cause stepwise disturbances in the base line of the detector trace. It is remarkable that this type of SZ appears not to affect the electromigration dispersion (EMD) in a strong way and so far only dips could be obtained experimentally. [source] Quantification of Survival of Escherichia coli O157:H7 on Plants Affected by Contaminated Irrigation Water,ENGINEERING IN LIFE SCIENCES (ELECTRONIC), Issue 6 2006A. M. Ibekwe Abstract Enterohemorrhagic E. coli O157: H7 (EHEC) is a major foodborne pathogen capable of causing diarrhea and vomiting, with further complications such as hemolytic-uremic syndrome (HUS). The aim of this study was to use the real-time PCR method to quantify the survival of Escherichia coli O157:H7/pGFP in phyllosphere (leaf surface), rhizosphere (volume of soil tightly held by plant roots), and non-rhizosphere soils (sand and clay) irrigated with contaminated water and compare the results obtained between real-time PCR method and conventional plate counts. The real-time PCR probe was designed to hybridize with the (eae) gene of E. coli O157:H7. The probe was incorporated into real-time PCR containing DNA extracted from the phyllosphere, rhizosphere, and non-rhizosphere soils irrigated with water artificially contaminated with E. coli O157:H7. The detection limit for E. coli O157:H7 quantification by real-time PCR was 2.3 × 103 in the rhizosphere and phyllosphere samples. E. coli O157:H7 survived longer in rhizosphere soil than the non-rhizosphere soil. The concentration of E. coli O157:H7/pGFP in rhizosphere soils was , 104 CFU/g in both soils at day 12 based on both plate count and real time PCR, with the clay soil significantly (P = 0.05) higher than the sandy soil. This data showed that E. coli O157H:7 can persist in the environment for more than 50 d, and this may pose some risk for both animal and human infection and provides a very significant pathway for pathogen recontamination in the environment. [source] Eukaryotic diversity and phylogeny using small- and large-subunit ribosomal RNA genes from environmental samplesENVIRONMENTAL MICROBIOLOGY, Issue 12 2009William Marande Summary The recent introduction of molecular techniques in eukaryotic microbial diversity studies, in particular those based in the amplification and sequencing of small-subunit ribosomal DNA (SSU rDNA), has revealed the existence of an unexpected variety of new phylotypes. The taxonomic ascription of the organisms bearing those sequences is generally deduced from phylogenetic analysis. Unfortunately, the SSU rDNA sequence alone has often not enough phylogenetic information to resolve the phylogeny of fast-evolving or very divergent sequences, leading to their misclassification. To address this problem, we tried to increase the phylogenetic signal by amplifying the complete eukaryotic rDNA cluster [i.e. the SSU rDNA, the internal transcribed spacers, the 5.8S rDNA and the large-subunit (LSU) rDNA] from environmental samples, and sequencing the SSU and LSU rDNA part of the clones. Using marine planktonic samples, we showed that surveys based on either SSU or SSU + LSU rDNA retrieved comparable diversity patterns. In addition, phylogenetic trees based on the concatenated SSU + LSU rDNA sequences showed better resolution, yielding good support for major eukaryotic groups such as the Opisthokonta, Rhizaria and Excavata. Finally, highly divergent SSU rDNA sequences, whose phylogenetic position was impossible to determine with the SSU rDNA data alone, could be placed correctly with the SSU + LSU rDNA approach. These results suggest that this method can be useful, in particular for the analysis of eukaryotic microbial communities rich in phylotypes of difficult phylogenetic ascription. [source] Estrogenic effect of leachates and soil extracts from lysimeters spiked with sewage sludge and reference endocrine disruptersENVIRONMENTAL TOXICOLOGY, Issue 2 2002Halim Dizer Abstract Several experiments were conducted to evaluate the behavior and performance of some potential endocrine disrupters (ECDs). Two in vitro screening assays, one based on MCF7-cell proliferation (E-screen test) and the other on estrogenic receptor activity [enzyme-linked receptor assay (ELRA)], were used for the tests, which were done in lysimeters 80 cm in diameter with depths of 30 cm (shallow) or 90 cm (deep). A sandy soil was used to fill in all lysimeters, which were spiked on the surface with either: (a) a sewage sludge (SS) at a dose equivalent to 20 tons ha,1; (b) a mixture of reference ECDs, comprising 17,- and 17,-estradiol (E2), nonylphenol, octylphenol, and bisphenol A at doses 100 times higher than the maximum concentrations respectively found in the applied SS; or (c) a mixture of ECDs and SS. After percolation of the lysimeters with rain and/or artificial water, five leachates were sampled from each lysimeter during a period of 210 days. Immediately after the lysimeter percolation experiments, four and six soil fractions were dissected from, respectively, the 30-cm and 90-cm lysimeters and extracted by water. Both the leachate and soil extract samples were analyzed for their estrogenicity using the assays indicated above. The E-screen assay was highly sensitive only for some leachate and extract samples but gave no response for most leachates and soil extracts. The results of the ELRA assay suggests a significantly higher estrogenicity of leachate samples from shallow lysimeters compared with that of leachates from deep lysimeters. In contrast, the estrogenic effect measured for soil extracts of shallow lysimeters was lower than that measured for soil extracts of deep lysimeters. The results of the E-screen assay suggests the occurrence of a fast mobilization of applied ECDs and a moderate retardation effect of native ECDs contained in applied SS in the sandy soil used in the lysimeters. In lysimeters spiked with a mixture of SS and ECDs, the washing-out effect of ECDs in the first leachate fraction decreased, but the distribution of ECDs in the lysimeters increased. The relatively high estrogenic impact measured for soil water extracts suggests that the ECDs were mostly associated with water-soluble fractions of organic matter and/or water-suspended fractions of the mineral soil matrix. The application of SS to agricultural and forest fields may determine the immobilization of ECDs in soil or their movement to surface and/or groundwater. Therefore, an endocrine risk of exposure exists for the water and soil organisms. © 2002 Wiley Periodicals, Inc. Environ Toxicol 17: 105,112, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/tox.10038 [source] A multivariate biomarker-based model predicting population-level responses of Daphnia magnaENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 9 2003Wim M. De Coen Abstract A multivariate model is proposed relating short-term biomarker measurements in Daphnia magna to chronic effects (21-d exposure) occurring at the population level (time to death, mean brood size, mean total young per female, intrinsic rate of natural increase, net reproductive rate, and growth). The results of the short-term exposure (48h-96 h) to eight model toxicants (cadmium, chromium, mercury, tributyl tin, linear alkylsulfonic acid, sodium pentachlorophenolate, lindane, and 2,4-dichloro-phenoxyacetic acid) on the following biomarkers were used for the multivariate model: digestive enzymes (amylase, cellulase, ,-galactosidase, trypsin, and esterase), enzymes of the intermediary metabolism (glycogen phosphorylase, glucose-6-phosphate de-hydrogenase, pyruvate kinase, lactate dehydrogenase, and isocitrate dehydrogenase), cellular energy allocation (CEA) (protein, carbohydrate, and lipid content and electron transport activity), and DNA damage and antioxidative stress activity. Using partial least squares to latent structures (PLS), a two-component model was obtained with R2 of 0.68 and a Q2 value of 0.60 based on the combined analysis of a limited number of the 48- and 96-h biomarker responses. For the individual population-level responses, the R2 values varied from 0.66 to 0.77 and the Q2 values from 0.52 to 0.69. Energy-related biomarkers (cellular energy allocation, lipid contents, anaerobic metabolic activity,pyruvate kinase, and lactate dehydrogenase), combined with parameters related to oxidative stress (catalase) and DNA damage measured after 48 and 96 h of exposure, were able to predict long-term effects at higher levels of biological organization. [source] Improved likelihood inference for the roughness parameter of the GA0 distributionENVIRONMETRICS, Issue 4 2008Michel Ferreira da Silva Abstract This paper presents adjusted profile likelihoods for ,, the roughness parameter of the distribution. This distribution has been widely used in the modeling, processing and analysis of data corrupted by speckle noise, e.g., synthetic aperture radar images. Specifically, we consider the following modified profile likelihoods: (i) the one proposed by Cox and Reid, and (ii) approximations to adjusted profile likelihood proposed by Barndorff,Nielsen, namely the approximations proposed by Severini and one based on results by Fraser, Reid and Wu. We focus on point estimation and on signalized likelihood ratio tests, the parameter of interest being the roughness parameter that indexes the distribution. As far as point estimation is concerned, the numerical evidence presented in the paper favors the Cox and Reid adjustment, and in what concerns signalized likelihood ratio tests, the results favor the approximation to Barndorff7mdash;Nielsen's adjustment based on the results by Fraser, Reid and Wu. An application to real synthetic aperture radar imagery is presented and discussed. Copyright © 2007 John Wiley & Sons, Ltd. [source] Age,environment model for breast cancerENVIRONMETRICS, Issue 3 2004Nobutane Hanayama Abstract In the field of breast cancer study, it has become accepted that crucial exposures to environmental risks might have occurred years before a malignant tumor is evident in human breasts, while age factors such as ages at menstruation have been known as risks for the disease already. To project trends in two such kinds of risks for the disease, the concept of environment effects is introduced for (age, period)-specific breast cancer mortality rates. Also, a new model, named the age,environment (AE) model, which assumes that the logarithm of the expected rate is a linear function of environment effects and age effects, is proposed. It is shown that, although environment effects have different meanings from period effects or cohort effects, in the age,period,cohort (APC) model, the range space of the design matrix for the AE model is included in that for APC model. It is seen, however, that the AE model provides a better fit to the data for females in Japan and the four Nordic countries than does the APC model in terms of AIC. From the results of ML estimation of the parameters in the AE model based on the data obtained in Japan, we see high levels of environment effects associated with the Sino,Japanese war, World War II and the environmental pollution due to the economy in the recovery period from the defeat. Besides, from those based on the data obtained in the four Nordic countries, we see high levels of environment effects associated with the environment becoming worse after the year of Helsinki Olympics and low levels of them associated with the period including the year of ,Miracle of the Winter War' in Finland. Copyright © 2004 John Wiley & Sons, Ltd. [source] Outcome of psychological treatments of pathological gambling: a review and meta-analysisADDICTION, Issue 10 2005Ståle Pallesen ABSTRACT Aims To investigate the short- and long-term effect of psychological treatments of pathological gambling and factors relating to treatment outcome. Design and setting This study provides a quantitative meta-analytical review of psychotherapeutic treatments of pathological gambling. Studies were identified by computer search in the PsycINFO and Medline databases covering the period from 1966 to 2004, as well as from relevant reference lists. Inclusion criteria The target problem was pathological gambling, the treatment was psychological, the study was published in English and outcomes directly pertaining to gambling were employed. Single case studies, studies where elimination of gambling not was the priority and studies with insufficient statistical information were excluded from the present meta-analysis. Participants A total of 37 outcome studies, published or reported between 1968 and 2004, were identified. Of these 15 were excluded, thus 22 studies were included, involving 1434 subjects. The grand mean age was 40.1 years. The overall proportion of men was 71.5%. Measurements The included studies were coded for outcome measures of pathological gambling. For each condition, means and standard deviations for gambling-related outcome measures, all based upon self-reports or therapist ratings, were compiled at three points in time: baseline, post-treatment and the last follow-up reported. Findings Effect sizes represent the difference between the mean score in a treatment condition and a control condition or the difference between mean scores at separated points in time for one group, expressed in terms of standard deviation units. At post-treatment the analysis indicated that psychological treatments were more effective than no treatment, yielding an overall effect size of 2.01 (P < 0.01). At follow-up (averaging 17.0 months) the corresponding effect size was 1.59 (P < 0.01). A multiple regression analysis showed that the magnitude of effect sizes at post-treatment were lower in studies including patients with a formal diagnosis of pathological gambling only, compared to studies not employing such inclusion criteria. Effect sizes were also higher in randomized controlled trials compared to not randomized controlled trials, higher in within subjects designs compared to between subjects designs and also positively related to number of therapy sessions. No mediator variables were significantly related to the magnitude of the effect sizes at follow-up. Conclusion Psychological interventions for pathological gamble seem to be yield very favourable short- and long-term outcomes. [source] Alcohol and mortality: methodological and analytical issues in aggregate analysesADDICTION, Issue 1s1 2001Thor Norström This supplement includes a collection of papers that aim at estimating the relationship between per capita alcohol consumption and various forms of mortality, including mortality from liver cirrhosis, accidents, suicide, homicide, ischaemic heart disease, and total mortality. The papers apply a uniform methodological protocol, and they are all based on time series data covering the post-war period in the present EU countries and Norway. In this paper we discuss various methodological and analytical issues that are common to these papers. We argue that analysis of time series data is the most feasible approach for assessing the aggregate health consequences of changes in population drinking. We further discuss how aggregate data may also be useful for judging the plausibility of individual-level relationships, particularly those prone to be confounded by selection effects. The aggregation of linear and curvilinear risk curves is treated as well as various methods for dealing with the time-lag problem. With regard to estimation techniques we find country specific analyses preferable to pooled cross-sectional/time series models since the latter incorporate the dubious element of geographical co-variation, and conceal potentially interesting variations in alcohol effects. The approach taken in the papers at hand is instead to pool the country specific results into three groups of countries that represent different drinking cultures; traditional wine countries of southern Europe, beer countries of central Europe and the British Isles and spirits countries of northern Europe. The findings of the papers reinforce the central tenet of the public health perspective that overall consumption is an important determinant of alcohol-related harm rates. However, there is a variation across country groups in alcohol effects, particularly those on violent deaths, that indicates the potential importance of drinking patterns. There is no support for the notion that increases in per capita consumption have any cardioprotective effects at the population level. [source] Nitroamino Triazoles: Nitrogen-Rich Precursors of Stable Energetic SaltsEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 16 2008Yangen Huang Abstract 1-Nitroamino-1,2,3-triazole (5) was synthesized and its zwitterionic structure was established using single-crystal X-ray diffraction. The calculated detonation properties for 4-nitroamino-1,2,4-triazole (2) (P = 33.4 GPa, vD = 8793 m/s) and 1-nitroamino-1,2,3-triazole (5) (P = 33.0 GPa, vD = 8743 m/s) are comparable with RDX. A new family of energetic salts 7,21 based on either the 1-nitroamino-1,2,3-triazolate or the 4-nitroamino-1,2,4-triazolate anion were prepared and characterized by vibrational spectroscopy (IR), multinuclear NMR spectra, elemental analyses, density, TGA and DSC. The heats of formation (,fH°298) and detonation properties for these stable salts were calculated using Gaussian 03 and Cheetah 4.0, respectively. Comparison of the properties of the 1,2,3- and 1,2,4-triazolate salts indicates that while the 1,2,4-derivatives are more stable thermally, the 1,2,3-analogs invariably have higher heats of formation. In contrast to its salts, 1-nitroamino-1,2,3-triazole (5) is extremely shock-sensitive with an impact sensitivty of <1 J. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] Prevalence of cervical spinal pain in craniomandibular pain patientsEUROPEAN JOURNAL OF ORAL SCIENCES, Issue 2 2001Corine M. Visscher It has often been suggested that patients with a craniomandibular disorder (CMD) more often suffer from a cervical spine disorder (CSD) than persons without a CMD. However, in most studies no controlled, blind design was used, and conclusions were based on differing signs and symptoms. In this study, the recognition of CMD and CSD was based upon the presence of pain. The aim of this study was to determine the prevalence of cervical spinal pain in persons with or without craniomandibular pain, using a controlled, single-blind design. From 250 persons, a standardised oral history was taken, and a physical examination of the masticatory system and the neck was performed. Three classification models were used: one based on symptoms only; a second on signs only; and a third one based on a combination of symptoms and signs. The CMD patients were also subdivided in three subgroups: patients with mainly myogenous pain; mainly arthrogenous pain; and both myogenous and arthrogenous pain. Craniomandibular pain patients more often showed cervical spinal pain than persons without craniomandibular pain, independent of the classification model used. No difference in the prevalence of cervical spinal pain was found between the three subgroups of craniomandibular pain patients. [source] Synthesis of "V-Shaped" syn -Bidentate Ligands Based on Mesitylene-Derived [1.1.1.1]Metacyclophane Blocked in a 1,3-Alternate ConformationEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 2 2003Cédric Klein Abstract A series of five new syn -bidentate ligands 14,18 based on the [1.1.1.1]metacyclophane backbone blocked in a 1,3-alternate conformation was achieved. The common building block for the preparation of ligands bearing two interaction sites located in a syn fashion (CN, SMe, p -pyridyl, p -methoxyphenyl and p -methylthiophenyl) is the dibromo derivative 12. All reported ligands were fully characterised by classical analytical methods and their 1,3-alternate conformation demonstrated. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003) [source] On the bounded rationality of gender stereotyping in fame judgmentsEUROPEAN JOURNAL OF SOCIAL PSYCHOLOGY, Issue 4 2004Melanie C. Steffens The false-fame effect is the phenomenon that familiar names are falsely judged famous more often than unfamiliar names. M.R. Banaji and A.G. Greenwald (1995) demonstrated a gender bias in the false-fame effect: In line with existing gender stereotypes, the false-fame effect was larger for male than for female names. A more general explanation for gender biasing in fame judgments is based on cognitive availability. Name gender could be used as an ecologically valid cue when making fame judgments. If the relevant universe of famous names contained more male than female names, a gender bias in fame judgments should be observed, if it contained more female names, the gender bias should be reversed. Indeed, this pattern could be demonstrated experimentally, and we argue that it is not compatible with an account that draws on gender stereotyping but with one based on cognitive availability. Copyright © 2004 John Wiley & Sons, Ltd. [source] CASE STUDIES AND MATHEMATICAL MODELS OF ECOLOGICAL SPECIATION.EVOLUTION, Issue 10 2009We build a spatial individual-based multilocus model of homoploid hybrid speciation tailored for a tentative case of hybrid origin of Heliconius heurippa from H. melpomene and H. cydno in South America. Our model attempts to account for empirical patterns and data on genetic incompatibility, mating preferences and selection by predation (both based on coloration patterns), habitat preference, and local adaptation for all three Heliconius species. Using this model, we study the likelihood of recombinational speciation and identify the effects of various ecological and genetic parameters on the dynamics, patterns, and consequences of hybrid ecological speciation. Overall, our model supports the possibility of hybrid origin of H. heurippa under certain conditions. The most plausible scenario would include hybridization between H. melpomene and H. cydno in an area geographically isolated from the rest of both parental species with subsequent long-lasting geographic isolation of the new hybrid species, followed by changes in the species ranges, the secondary contact, and disappearance of H. melpomene -type ecomorph in the hybrid species. However, much more work (both empirical and theoretical) is necessary to be able to make more definite conclusions on the importance of homoploid hybrid speciation in animals. [source] Context-aware environments: from specification to implementationEXPERT SYSTEMS, Issue 5 2007Patrick Reignier Abstract: This paper deals with the problem of implementing a context model for a smart environment. The problem has already been addressed several times using many different data- or problem-driven methods. In order to separate the modelling phase from implementation, we first represent the context model by a network of situations. Then, different implementations can be automatically generated from this context model depending on user needs and underlying perceptual components. Two different implementations are proposed in this paper: a deterministic one based on Petri nets and a probabilistic one based on hidden Markov models. Both implementations are illustrated and applied to real-world problems. [source] | ||||||||||||||||||||||||||||||||||||||||||||||