Selected Sites (selected + site)

Distribution by Scientific Domains


Selected Abstracts


Scale dependence of diversity measures in a leaf-litter ant assemblage

ECOGRAPHY, Issue 2 2004
Maurice Leponce
A reliable characterization of community diversity and composition, necessary to allow inter-site comparisons and to monitor changes, is especially difficult to reach in speciose invertebrate communities. Spatial components of the sampling design (sampling interval, extent and grain) as well as temporal variations of species density affect the measures of diversity (species richness S, Buzas and Gibson's evenness E and Shannon's heterogeneity H). Our aim was to document the small-scale spatial distribution of leaf litter ants in a subtropical dry forest of the Argentinian Chaco and analyze how the community characterization was best achieved with a minimal sampling effort. The work was based on the recent standardized protocol for collecting ants of the leaf litter ("A.L.L.": 20 samples at intervals of 10 m). To evaluate the consistency of the sampling method in time and space, the selected site was first subject to a preliminary transect, then submitted after a 9-month interval to an 8-fold oversampling campaign (160 samples at interval of 1.25 m). Leaf litter ants were extracted from elementary 1 m2 quadrats with Winkler apparatus. An increase in the number of samples collected increased S and decreased E but did not affect much H. The sampling interval and extent did not affect S and H beyond a distance of 10 m between samples. An increase of the sampling grain had a similar effect on S than a corresponding increase of the number of samples collected, but caused a proportionaly greater increase of H. The density of species m,2 varied twofold after a 9-month interval; the effect on S could only be partially corrected by rarefaction. The measure of species numerical dominance was little affected by the season. A single standardized A.L.L. transect with Winkler samples collected <45% of the species present in the assemblage. All frequent species were included but their relative frequency was not always representative. A log series distribution of species occurrences was oberved. Fisher's , and Shannon's H were the most appropriate diversity indexes. The former was useful to rarefy or abundify S and the latter was robust against sample size effects. Both parametric and Soberón and Llorente extrapolation methods outperformed non-parametric methods and yielded a fair estimate of total species richness along the transect, a minimum value of S for the habitat sampled. [source]


SEAWEED ABUNDANCE AND DIVERSITY IN HIGH ENERGY AND LOW ENERGY AREAS AT PORT ARANSAS, TEXAS JETTIES

JOURNAL OF PHYCOLOGY, Issue 3 2001
Article first published online: 24 SEP 200
Agan, J. C. & Lehman, R. L. Department of Physical and Life Sciences, Texas A&M University-Corpus Christi 6300 Ocean Dr., Corpus Christi, TX 78412 USA Benthic algal sampling from high and low energy zones at a selected site on the south jetty at Port Aransas, Texas was completed between April 1999 and February 2000. Species composition and seasonal periodicity in relation to temperature and salinity fluctuations were determined. Dominant plants throughout the year included Bryocladia cuspidata, Bryocladia thyrsigera, Gelidium pusillum, Centroceras clavulatum, Ulva fasciata, and Padina gymnospora. The Rhodophyta dominated species coverage, along with biomass accumulation, although Chlorophyta species accrued the greatest biomass on the high energy side in April and June sampling. Chlorophyta are important to benthic coverage and biomass in the shallowest of waters, despite being fewer in species richness. Phaeophyta species including Petalonia fascia, Hincksia mitchelliae, and Ectocarpus siliculosus were found only during the cooler months. Padina gymnospora was the one exception as it was collected year-round. Results indicate that a greater Rhodophyta abundance was found on the channel side (low energy), where as, the surf side (high energy) contained a greater Chlorophyta abundance. Phaeophyta abundance for both high and low energy sites were comparable possibly due to the greater depth of water in which they are located. Little variance occurred in average biomass accumulation throughout the year. Highest biomass was in August (216.613g dry weight) with lowest occurring in April (107.4205g dry weight). [source]


SEAWEED ABUNDANCE AND DIVERSITY IN HIGH ENERGY AND LOW ENERGY AREAS AT PORT ARANSAS, TEXAS JETTIES

JOURNAL OF PHYCOLOGY, Issue 2001
Article first published online: 9 OCT 200
Agan, J. C. & Lehman, R. L. Department of Physical and Life Sciences, Texas A&M University-Corpus Christi 6300 Ocean Dr., Corpus Christi, TX 78412 USA Benthic algal sampling from high and low energy zones at a selected site on the south jetty at Port Aransas, Texas was completed between April 1999 and February 2000. Species composition and seasonal periodicity in relation to temperature and salinity fluctuations were determined. Dominant plants throughout the year included Bryocladia cuspidata, Bryocladia thyrsigera, Gelidium pusillum, Centroceras clavulatum, Ulva fasciata, and Padina gymnospora. The Rhodophyta dominated species coverage, along with biomass accumulation, although Chlorophyta species accrued the greatest biomass on the high energy side in April and June sampling. Chlorophyta are important to benthic coverage and biomass in the shallowest of waters, despite being fewer in species richness. Phaeophyta species including Petalonia fascia, Hincksia mitchelliae, and Ectocarpus siliculosus were found only during the cooler months. Padina gymnospora was the one exception as it was collected year-round. Results indicate that a greater Rhodophyta abundance was found on the channel side (low energy), where as, the surf side (high energy) contained a greater Chlorophyta abundance. Phaeophyta abundance for both high and low energy sites were comparable possibly due to the greater depth of water in which they are located. Little variance occurred in average biomass accumulation throughout the year. Highest biomass was in August (216.613g dry weight) with lowest occurring in April (107.4205g dry weight). [source]


Archaeogeophysical study on the site of Tell Toukh El-Qaramous, Sharkia Governorate, East Nile Delta, Egypt

ARCHAEOLOGICAL PROSPECTION, Issue 1 2003
H. Ghazala
Abstract The archaeological site of Tell Toukh El-Qaramous, which is located to the south of Abu Kebir, Sharkiya Governorate, was subjected to detailed geophysical studies using magnetic vertical gradient and geoelectric resistivity survey. The success of these surveys depends on the contrast in the physical properties between the dominant sedimentary deposits (clays and sands) and the buried archeological constructions. The area of study occupies about 80 acres at present. It was subjected firstly to a regional geophysical survey to discover the subsurface conditions above one of the most important military fortress that had been constructed to be vanguard of the eastern entry to Egypt during the Ptolemaic age (323,30 BC). Detailed gridded magnetic (0.5 m grid interval) and geoelectric resistivity surveys (2 m grid interval) were also carried out at a selected site of about 50 × 100 m according to the recommendations of the archaeologists who periodically carried out excavation of the archaeological remains. Such surveys could help mapping of the anomalous features that probably reflect the buried archaeological remains. The integrated results of the magnetic gradient images obtained as well as apparent resistivity maps for depths ranges from 1 to 5 m gave fascinating results. The results indicate that the Tell-Toukh El-Qaramous has been built on a buried sand gezira. Also, groups of ancients walls made of mud bricks and some interesting locations of archeological buried artefacts have been delineated. Both the magnetic and resistivity data supported each other and are in good agreement for the same locations of archeological interest. Copyright © 2002 John Wiley & Sons, Ltd. [source]


Seawater quality along the Adriatic coast, Croatia, based on toxicity data

ENVIRONMENTAL TOXICOLOGY, Issue 2 2004
Nevenka Bihari
Abstract The potential toxicity of organic extracts from 12 seawater samples from each of 24 sampling sites, collected during 1999,2001 along the Adriatic coast, Croatia, was analyzed with the Microtox toxicity bioassay. The results were consistent with the usefulness of Microtox for the detection of accidental toxic events. To determine the water quality of selected areas, cluster analysis for discrimination between groups with similar toxicity load and water quality index as a base for the ranking of sampling sites was introduced. Based on our experimental data, five classes of the quality index were defined, and so areas were ranked in five categories (excellent, good, fair, poor, and very poor) according to their potential toxic influence. The water quality of selected sites for the potential toxicity of organic extracts could be described as excellent at one sampling site, good at 15 sampling sites, and fair at eight sampling sites. Poor and very poor seawater quality was not detected. © 2004 Wiley Periodicals, Inc. Environ Toxicol 19: 109,114, 2004. [source]


Potential multidrug resistance gene POHL: An ecologically relevant indicator in marine sponges

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 1 2001
Anatoli Krasko
Abstract Sponges are sessile filter feeders found in all aquatic habitats from the tropics to the arctic. Against potential environmental hazards, they are provided with efficient defense systems, e.g., protecting chaperones and/or the P-170/multidrug resistance pump system. Here we report on a further multidrug resistance pathway that is related to the pad one homologue (POH1) mechanism recently identified in humans. It is suggested that proteolysis is involved in the inactivation of xenobiotics by the POH1 system. Two cDNAs were cloned, one from the demosponge Geodia cydoniumand a second from the hexactinellid sponge Aphrocallistes vastus. The cDNA from G. cydonium, termed GCPOHL, encodes a deduced polypeptide with a size of 34,591 Da and that from A. vastus, AVPOHL, a protein of a calculated Mr of 34,282. The two sponge cDNAs are highly similar to each other as well as to the known sequences from fungi (Schizosaccharomyces pombe and Saccharomyces cerevisiae) and other Metazoa (from Schistosoma mansoni to humans). Under controlled laboratory conditions, the expression of the potential multidrug resistance gene POHL is, in G. cydonium, strongly upregulated in response to the toxins staurosporin (20 ,M) or taxol (50 ,M); the first detectable transcripts appear after 1 d and reach a maximum after 3 to 5 d of incubation. The relevance of the expression pattern of the G. cydonium gene POHL for the assessment of pollution in the field was determined at differently polluted sites in the area around Rovinj (Croatia; Mediterranean Sea, Adriatic Sea). The load of the selected sites was assessed by measuring the potency of XAD-7 concentrates of water samples taken from those places to induce the level of benzo[a]pyrene monooxygenase (BaPMO) in fish and to impair the multidrug resistance (MDR)/P-170 extrusion pump in clams. These field experiments revealed that the levels of inducible BaPMO activity in fish and of the MDR potential by the water concentrates are highly correlated with the level of expression of the potential multidrug resistance gene POHL in G. cydonium. This report demonstrates that the detoxification POH pathway, here mediated by the G. cydonium GCPOHL gene, is an additional marker for the assessment of the environmental load in a given marine area. [source]


Can macroinvertebrate rapid bioassessment methods be used to assess river health during drought in south eastern Australian streams?

FRESHWATER BIOLOGY, Issue 12 2008
PETER ROSE
Summary 1Despite significant concern about drought impacts in Australia, there have been no broad-scale studies of drought effects on river health. A severe and prolonged drought has been acting on many streams in south eastern Australia over the past decade. EPA Victoria has undertaken rapid bioassessment (RBA) of over 250 stream reference sites since 1990, providing an opportunity for a before-after-control-impact investigation of drought related changes to macroinvertebrate indices and water quality. This study uses data from 1990 to 2004 to critically evaluate the effectiveness of using RBA methods and indices, which were designed for assessment of human impacts, for monitoring streams during drought. 2Reference stream sites across Victoria (those with minimal anthropogenic disturbances and repeatedly sampled) were classified as being ,in drought' or ,not in drought' using the Bureau of Meteorology's rainfall deficiency definition. Four biological indices (SIGNAL, EPT, Family Richness and AUSRIVAS) were calculated for combined autumn and spring samples for edge and riffle habitats for the selected sites. 3General linear models and paired t -tests were used to detect drought related changes to index and water quality values at state-wide and bioregional scales. Changes in taxa constancy were examined to determine which taxa were sensitive to or benefited from drought conditions. Frequency of site failure against biological objectives specified in the State Environment Protection Policy (Waters of Victoria) (herein termed ,SEPP WoV') before and during drought was also examined to detect changes in a management context. 4Few significant changes in index values were detected for riffle habitat samples. Rates of failure against biological objectives were similar before and during drought for riffle samples. In contrast, edge habitat AUSRIVAS and SIGNAL scores were significantly reduced at the state-wide scale and most indices showed significant declines in the lower altitude forests, and foothills and coastal plains bioregions. 5Generally, more pollution tolerant, lentic taxa replaced sensitive and flow-requiring taxa in edge samples during drought. In contrast, there were few reductions in the taxa of riffle samples during drought. However, many pool preferring, but pollution sensitive taxa occurred more frequently in riffle areas. Hence, the riffle community began to resemble that of pools and edges. This was attributed to decreased flow and increased ,lentic' habitat opportunities in riffles. 6Detection of a drought effect was confined to the edge habitat and site failure could be assigned to drought and anthropogenic impacts, in conjunction or alone. The riffle sampling protocol was resistant to detection of drought effects as samples were only taken when sufficient water was present within this habitat. Therefore, biological changes at sites not meeting policy objectives for riffle habitats can be attributed to anthropogenic rather than drought impacts. [source]


Linking flux network measurements to continental scale simulations: ecosystem carbon dioxide exchange capacity under non-water-stressed conditions

GLOBAL CHANGE BIOLOGY, Issue 4 2007
KATHERINE E. OWEN
Abstract This paper examines long-term eddy covariance data from 18 European and 17 North American and Asian forest, wetland, tundra, grassland, and cropland sites under non-water-stressed conditions with an empirical rectangular hyperbolic light response model and a single layer two light-class carboxylase-based model. Relationships according to ecosystem functional type are demonstrated between empirical and physiological parameters, suggesting linkages between easily estimated parameters and those with greater potential for process interpretation. Relatively sparse documentation of leaf area index dynamics at flux tower sites is found to be a major difficulty in model inversion and flux interpretation. Therefore, a simplification of the physiological model is carried out for a subset of European network sites with extensive ancillary data. The results from these selected sites are used to derive a new parameter and means for comparing empirical and physiologically based methods across all sites, regardless of ancillary data. The results from the European analysis are then compared with results from the other Northern Hemisphere sites and similar relationships for the simplified process-based parameter were found to hold for European, North American, and Asian temperate and boreal climate zones. This parameter is useful for bridging between flux network observations and continental scale spatial simulations of vegetation/atmosphere carbon dioxide exchange. [source]


Functional Hydrogel Surfaces: Binding Kinesin-Based Molecular Motor Proteins to Selected Patterned Sites,

ADVANCED FUNCTIONAL MATERIALS, Issue 8 2005
T. Yu
Abstract Hydrogel microstructures with micrometer-scale topography and controllable functionality have great potential for numerous nanobiotechnology applications including, for example, three-dimensional structures that exhibit controlled interactions with proteins and cells. Taking advantage of the strong affinity of histidine (His) residues for metal-ion,nitrilotriacetic acid (NTA) complexes, we have chemically modified hydrogels to enable protein immobilization with retention of activity by incorporating 2-methacrylamidobutyl nitrilotriacetic acid, an NTA-containing monomer that can be copolymerized with a series of monomers to form NTA-containing hydrogels. By varying the NTA-monomer composition in the hydrogels, it is possible to control the amount of protein bound to the hydrogel surface. The retention of biological activity was demonstrated by microtubule gliding assays. Normally, hydrogels are resistant to protein binding, but we have selected these materials because of their porous nature. Bringing together hydrogel functionalization and soft-lithography patterning techniques, it was possible to create a hybrid hydrogel superstructure that possesses binding specificity to His-tagged protein in selected sites. This type of surface and microstructure is not only advantageous for motor protein integration, but it can also be generally applied to the formation of His-tagged molecules for sensors and biochip applications. [source]


A revised Canadian perspective: progress in glacier hydrology

HYDROLOGICAL PROCESSES, Issue 1 2005
D. Scott Munro
Abstract Current research into glacier hydrology is occurring at a time when glaciers around the world, particularly those whose hydrological regimes affect populated areas, are shrinking as they go through a state of perpetual negative annual mass balance. Small glaciers alone are likely to contribute 0·5 to 1 mm year,1 to global sea-level rise, with associated reductions in local freshwater resources, impacts upon freshwater ecosystems and increased risk of hazard due to outburst floods. Changes to the accumulation regimes of glaciers and ice sheets may be partly responsible, so the measurement and distribution of snowfall in glacierized basins, a topic long represented in non-glacierized basin research, is now beginning to receive more attention than it did before, aided by the advent of reliable automatic weather stations that provide data throughout the year. Satellite data continue to be an important information source for summer meltwater estimation, as distributed models, and their need for albedo maps, continue to develop. This further entails the need for simplifications to energy balance components, sacrificing point detail so that spatial calculation may proceed more quickly. The understanding of surface meltwater routing through the glacier to produce stream outflow continues to be a stimulating area of research, as demonstrated by activity at the Trapridge Glacier, Canada, and Canadian involvement in the Haut Glacier d'Arolla, Switzerland. As Canadian glacier monitoring continues to evolve, effort must be directed toward developing situations where mass balance, meltwater generation and flow routing studies can be done together at selected sites. Copyright © 2005 John Wiley & Sons, Ltd. [source]


,Distribution of oxygen-18 and deuterium in river waters across the United States

HYDROLOGICAL PROCESSES, Issue 7 2001
Carol Kendall
Abstract Reconstruction of continental palaeoclimate and palaeohydrology is currently hampered by limited information about isotopic patterns in the modern hydrologic cycle. To remedy this situation and to provide baseline data for other isotope hydrology studies, more than 4800, depth- and width-integrated, stream samples from 391 selected sites within the USGS National Stream Quality Accounting Network (NASQAN) and Hydrologic Benchmark Network (HBN) were analysed for ,18O and ,2H (http://water.usgs.gov/pubs/ofr/ofr00-160/pdf/ofr00-160.pdf). Each site was sampled bimonthly or quarterly for 2·5 to 3 years between 1984 and 1987. The ability of this dataset to serve as a proxy for the isotopic composition of modern precipitation in the USA is supported by the excellent agreement between the river dataset and the isotopic compositions of adjacent precipitation monitoring sites, the strong spatial coherence of the distributions of ,18O and ,2H, the good correlations of the isotopic compositions with climatic parameters, and the good agreement between the ,national' meteoric water line (MWL) generated from unweighted analyses of samples from the 48 contiguous states of ,2H=8·11,18O+8·99 (r2=0·98) and the unweighted global MWL of sites from the Global Network for Isotopes in Precipitation (GNIP) of the International Atomic Energy Agency and the World Meteorological Organization (WMO) of ,2H=8·17,18O+10·35. The national MWL is composed of water samples that arise in diverse local conditions where the local meteoric water lines (LMWLs) usually have much lower slopes. Adjacent sites often have similar LMWLs, allowing the datasets to be combined into regional MWLs. The slopes of regional MWLs probably reflect the humidity of the local air mass, which imparts a distinctive evaporative isotopic signature to rainfall and hence to stream samples. Deuterium excess values range from 6 to 15, in the eastern half of the USA, along the northwest coast and on the Colorado Plateau. In the rest of the USA, these values range from ,2 to 6,, with strong spatial correlations with regional aridity. The river samples have successfully integrated the spatial variability in the meteorological cycle and provide the best available dataset on the spatial distributions of ,18O and ,2H values of meteoric waters in the USA. Published in 2001 by John Wiley & Sons, Ltd. [source]


Comparison of gingival blood flow during healing of simplified papilla preservation and modified Widman flap surgery: a clinical trial using laser Doppler flowmetry

JOURNAL OF CLINICAL PERIODONTOLOGY, Issue 10 2007
M. Retzepi
Abstract Aim: This prospective randomized-controlled clinical trial compared the gingival blood flow responses following simplified papilla preservation (test) versus modified Widman flap (control). Materials and Methods: Twenty contra-lateral upper sites with pocket depth 5 mm after initial treatment in 10 chronic periodontitis patients were randomly assigned to either test or control treatment, using a split-mouth design. Laser Doppler flowmetry recordings were performed pre-operatively, following anaesthesia, immediately post-operatively and on days 1, 2, 3, 4, 7, 15, 30 and 60, at nine selected sites per flap. Results: Significant ischaemia was observed at all sites following anaesthesia and immediately post-operatively. At the mucosal flap basis, a peak hyperaemic response was observed on day 1, which tended to resolve by day 4 at the test sites, but persisted until day 7 at the control sites. The buccal and palatal papillae blood perfusion presented the maximum increase on day 7 in both groups and returned to baseline by day 15. Both surgical modalities yielded significant pocket depth reduction, recession increase and clinical attachment gain. Conclusions: Periodontal access flaps represent an ischaemia,reperfusion flap model. The simplified papilla preservation flap may be associated with faster recovery of the gingival blood flow post-operatively compared with the modified Widman flap. [source]


Antibiotic resistance profile of the subgingival microbiota following systemic or local tetracycline therapy

JOURNAL OF CLINICAL PERIODONTOLOGY, Issue 6 2004
Rosa Maria J. Rodrigues
Abstract Background: Tetracyclines have been extensively used as adjunctives to conventional periodontal therapy. Emergence of resistant strains, however, has been reported. This study evaluated longitudinally the tetracycline resistance patterns of the subgingival microbiota of periodontitis subjects treated with systemic or local tetracycline therapy+scaling and root planing (SRP). Methods: Thirty chronic periodontitis patients were randomly assigned to three groups: SRP+500 mg of systemic tetracycline twice/day for 14 days; SRP alone and SRP+tetracycline fibers (Actsite®) at four selected sites for 10 days. Subgingival plaque samples were obtained from four sites with probing pocket depths (PPD)6 mm in each patient at baseline, 1 week, 3, 6 and 12 months post-therapy. Samples were dispersed and diluted in pre-reduced anaerobically sterilized Ringer's solution, plated on Trypticase Soy Agar (TSA)+5% blood with or without 4 ,g/ml of tetracycline and incubated anaerobically for 10 days. The percentage of resistant microorganisms were determined and the isolates identified by DNA probes and the checkerboard method. Significance of differences among and within groups over time was sought using the Kruskal,Wallis and Friedman tests, respectively. Results: The percentage of resistant microorganisms increased significantly at 1 week in the tetracycline groups, but dropped to baseline levels over time. The SRP+Actsite® group presented the lowest proportions of resistant species at 6 and 12 months. No significant changes were observed in the SRP group. The predominant tetracycline-resistant species included Streptococcus spp., Veillonela parvula, Peptostreptococcus micros, Prevotella intermedia, Gemella morbillorum and Actinobacillus actinomycetemcomitans (Aa). A high percentage of sites with resistant Aa, Porphyromonas gingivalis and Tanerella forsythensis was observed in all groups at baseline. However, T. forsythensis was not detected in any group and P. gingivalis was not present in the SRP+Actsite® group at 1 year post-therapy. Aa was still frequently detected in all groups after therapy. However, the greatest reduction was observed in the SRP+Actsite® group. Conclusion: Local or systemically administered tetracycline results in transitory selection of subgingival species intrinsically resistant to this drug. Although the percentage of sites harboring periodontal pathogens resistant to tetracycline were quite elevated in this population, both therapies were effective in reducing their prevalence over time. [source]


Longitudinal evaluation of GCF IFN-, levels and periodontal status in HIV+ patients

JOURNAL OF CLINICAL PERIODONTOLOGY, Issue 11 2003
T. Alpagot
Abstract Background/Aim: Loss of periodontal support and related tooth loss is a common finding among HIV+ patients. The etiology of this destruction may be an increase in the levels of pro-inflammatory cytokines and subsequent increase in periodontal disease activity. The purpose of this study was to investigate the associations between gingival crevicular fluid interferon gamma (GCF IFN- ,) and clinical measures of periodontal disease in HIV+ individuals. We monitored GCF IFN- , and periodontal status of selected sites in 33 HIV+ subjects over a 6-month period. Method: Clinical measurements including gingival index, plaque index, bleeding on probing, probing depth, attachment loss (AL), and GCF samples were taken from four lower incisors and the upper right posterior sextant of each patient at baseline and 6-month visits by means of sterile paper strips. GCF levels of IFN- , were determined by sandwich ELISA assays. A progressing site was defined as a site that had 2 mm or more AL during the 6-month study period. Results: Twenty-five of the 264 examination sites showed 2 mm or more clinical AL during the 6-month study period. Significantly higher GCF levels of IFN- , were found at progressing sites than in nonprogressing sites (p<0.001). GCF levels of IFN- , were highly correlated with clinical measurements taken at baseline and 6-month visits (0.001[source]


Evaluation of enamel matrix derivative as an adjunct to non-surgical periodontal therapy

JOURNAL OF CLINICAL PERIODONTOLOGY, Issue 8 2003
Mauricio A. Gutierrez
Abstract Objectives: The aim of this study was to evaluate the adjunctive use of enamel matrix derivative (EMD) on periodontal healing following nonsurgical periodontal therapy (scaling and root planing , SRP). Material and methods: The study was performed as an intraindividual, longitudinal trial of 3 months duration with a double-blinded, split-mouth, controlled, and randomized design. Twenty-two patients with moderate to severe chronic periodontitis were enrolled in the study. In each patient, two sites with pocket depths 5 mm and with radiographic angular bone defects >3 mm were selected. Baseline examination included measurement of probing pocket depth (PPD) and clinical attachment levels (CAL). The presence or absence of plaque and bleeding on probing at selected sites was also recorded. Following initial examination, full-mouth SRP was performed. Study sites were then treated with 24% EDTA for 2 min, followed by thorough irrigation with sterile saline. The sites were then randomized. The experimental site received subgingival application of enamel matrix derivative (Emdogain®, BIORA AB, Malmo, Sweden). The control site received no additional treatment. At 3 months, all sites were re-examined. The response to therapy in experimental and control sites was evaluated, using change in probing depth and CAL as the primary outcome variables. Statistical analysis (paired t -tests) was used to compare response to treatment in control versus experimental sites. Results: Statistically significant changes in PPD and CAL were seen in both treatment groups from baseline to 3 months. The mean PPD reduction was 2.3±0.5 mm for control sites and 2.0±0.3 mm for experimental sites. The mean CAL gain was 1.8±0.4 mm for control sites, and 1.4±0.3 mm for experimental sites. Statistical analysis, however, revealed no significant difference in PPD reduction or CAL gain between experimental and control groups (p>0.4). In addition, no difference was found between treatment groups in bleeding or plaque indices at 3 months. Conclusion: The findings from the present study do not support the use of EMD during routine, nonsurgical debridement of periodontal pockets as measured 3 months post SRP. Zusammenfassung Ziel: Das Ziel dieser Studie war die Evaluation eines adjunktiven Gebrauchs von Schmelzmatrixderivaten (EMD) auf die parodontale Heilung nach nicht chirurgischer parodontaler Therapie (Wurzelreinigung und ,glättung, scaling und root planing , SRP). Material und Methoden: Die Studie wurde als eine intraindividuelle, für 3 Monate longitudinale Studie mit einem doppelt blinden, split-mouth, kontrolliertem und randomisiertem Protokoll durchgeführt. 22 Patienten mit moderater bis schwerer chronischer Parodontitis wurden in die Studie einbezogen. Bei jedem Patient wurden zwei Flächen mit Sondierungstiefen5 mm und mit radiographisch feststellbaren angulären Knochendefekten>3 mm ausgesucht. Die Basisuntersuchung umfasste die Messung der Sondierungstiefen (PPD) und des klinischen Stützgewebeniveaus (CAL). Die An- oder Abwesenheit von Plaque und Provokationsblutung an den ausgesuchten Flächen wurden auch dokumentiert. Nach der anfänglichen Untersuchung wurde eine alle Zähne betreffende SRP durchgeführt. Die Studienflächen wurden dann mit 24% EDTA für zwei Minuten behandelt, gefolgt von einer sorgsamen Spülung mit steriler Kochsalzlösung. Die Flächen wurden dann randomisiert. Die experimentellen Flächen erhielten eine subgingivale Applikation von Schmelzmatrixderivaten (Emdogain®, BIORA AB, Malmö, Schweden). Die Kontrollflächen erhielten keine zusätzliche Behandlung. Zum dritten Monat wurden alle Flächen reexaminiert. Die Antwort auf die Therapie bei den experimentellen und Kontrollflächen wurden evaluiert in Hinsicht der Veränderung der Sondierungstiefe und CAL als die primären Ergebnisvariablen. Statistische Analysen (gepaarter t -Test) wurden für den Vergleich der Behandlung zwischen experimentellen und Kontrollflächen genutzt. Ergebnisse: Statistisch signifikante Veränderungen bei der PPD und dem CAL wurden in beiden Behandlungsgruppen zwischen Basis und 3 Monaten beobachtet. Die mittlere PPD Reduktion betrug 2.3±0.5 mm für die Kontrollflächen und 2.0±0.3 mm für die experimentellen Flächen. Der mittlere CAL Gewinn betrug 1.8±0.4 mm für die Kontrollflächen und 1.4±0.3 mm für die experimentellen Flächen. Die statistischen Analysen erbrachten jedoch keine signifikanten Differenzen für PPD Reduktion und CAL Gewinn zwischen den experimentellen und Kontrollgruppen (p>0.4). Es wurden auch keine Differenzen zwischen den Gruppen hinsichtlich Provokationsblutung und Plaqueindex zum dritten Monat beobachtet. Schlussfolgerung: Die Ergebnisse von der vorliegenden Studie unterstützen nicht die Anwendung von EMD während der routinemäßigen nicht chirurgischen Reinigung der parodontalen Taschen, wie die Messungen drei Monate nach SRP. Résumé Objectif: Le but de cette étude fut d'évaluer l'utilisation des dérivés de la matrice amellaire (EMD) sur la cicatrisation parodontale après un traitement parodontal non chirurgical (détartrage et surfaçage radiculaire). Matériel et méthodes: L'étude fut conçue en essai longitudinal intra-individuel d'une durée de 3 mois randomisée, contrôlée en double aveugle et en bouche croisée. 22 patients atteints de parodontites chroniques modérées ou sévères furent enrôlés. Pour chaque patient, 2 sites avec des profondeurs de poches5 mm et des lésions osseuses angulaires radiographiques>3 mm furent sélectionnés. L'examen initial comportait la mesure des profondeurs de poche au sondage (PPD) et les niveaux cliniques d'attache (CAL). La présence ou l'absence de plaque et de saignement au sondage sur les sites sélectionnés furent aussi enregistrées. Après l'examen initial, un détartrage et un surfaçage complet étaient réalisés. Les sites étudiés étaient alors traités par de l'EDTA à 24% pendant 2 minutes, puis fortement rinçés avec du serum physiologique. Les sites étaient alors répartis aléatoirement. Le site expérimental recevait une application sous gingivale d'EMD (Emdogain®, BIORA AB, Malmo, Sweden). Le site contrôle ne recevait pas de traitement supplémentaire. A 3 mois, les sites étaient réévalués. La réponse au traitement était évaluée par les modifications de profondeur de poches et de niveau d'attache comme variables primaires. L'analyse statistique (Test t apparié) permit de comparer la réponse au traitement. Résultats: Des modifications statistiquement significatives de PPD et de CAL ont été observées dans les deux groupes de traitement. La réduction de PPD moyenne était de 2.3±0.5 mm pour les sites contrôles et de 2.0±0.3 mm pour les sites expérimentaux. Le gain de CAL moyen était respectivement de 1.8±0.4 mm et de 1.4±0.3 mm.L'analyse statistique, cependant, ne révélait pas de différences significatives entre les deux groupes (p>0.4). De plus, aucune différence n'apparaissait entre les groupes pour le saignement et les indices de plaque au troisième mois. Conclusion: Les données de cette étude n'étayent pas l'utilisation routinière d' EMD lors du débridement non chirurgical des poches parodontales lorsqu'on en mesure les résultats 3 mois après détartrage et surfaçage radiculaire. [source]


Density and habitat associations of Henslow's Sparrows wintering in saline soil barrens in southern Arkansas

JOURNAL OF FIELD ORNITHOLOGY, Issue 4 2008
William C. Holimon
ABSTRACT Although the habitat requirements of breeding populations of Henslow's Sparrow (Ammodramus henslowii) have been examined, less is known about their habitat requirements and ecology during the nonbreeding season. We estimated population densities and quantified habitat associations of Henslow's Sparrows wintering in saline soil barrens in southern Arkansas. Densities of Henslow's Sparrows in the saline soil barrens were similar to those in the Longleaf Pine (Pinus palustris) Ecosystem of the southeastern United States, considered by many to be their primary wintering habitat. Henslow's Sparrows were closely associated with open areas with greater cover of Aristida spp. and globe beaksedge (Rhynchospora globularis), greater stem density at 11,20 cm above ground, more lichens, more herbaceous cover, more bare ground, greater occurrence of little bluestem (Schizacyrium scoparium) as the tallest vegetation, less moss, and less shrub cover than randomly selected sites. In contrast to the results of studies conducted in the Longleaf Pine Ecosystem, the presence of Henslow's Sparrows in our study was not correlated with the height of the tallest vegetation. Our results indicate that saline soil barrens of southern Arkansas support a high density of wintering Henslow's Sparrows and do so for longer postdisturbance periods than longleaf pine savanna. We also found that stem density near the ground was similar to that reported from longleaf pine savanna, but only about half that observed on their breeding grounds. Areas used by Henslow's Sparrows had more lichen and less moss cover, suggesting that those areas were drier than random sites within the barrens. Further research is needed to determine if large populations of Henslow's Sparrows winter in other saline soil barrens and if fire influences habitat associations and densities in the barrens. SINOPSIS Aunque los requisitos de hábitat para las poblaciones reproductivas de Ammodramus henslowii han sido determinadas, se conoce muy poco sobre su ecología y requerimientos de hábitat durante la temporada no-reproductiva. Estimamos la densidad poblacional y cuantificamos el hábitat asociado a Gorrión de Henslow que pasan el invierno en un salitral con suelo empobrecido en el sur de Arkansas. La densidad de las aves en el salitral resultó similar a lo encontrado en Ecosistemas de Pinos (Pinus palustris) en el sureste de los EUA, considerado por muchos como el principal hábitat invernal para la especie. Los gorriones estuvieron altamente asociados a áreas abiertas con covertura de Aristida spp. y Rhynchospora globularis, con mayor densidad de tallos, altura entre 11,20 cm sobre el suelo, mayor cantidad de líquenes, mayor cubierta herbácea, más suelo desnudo, mayor presencia de Schzacyrium scoparium (como la vegetación de mayor tamaño), menos musgos, y menos arbustos que localidades seleccionadas al azar. En contraste a los resultados de estudios conducidos en Ecosistemas de Pinos, la presencia del gorrión en nuestra área de estudio no estuvo correlacionada con la altura de la vegetación de mayor tamaño. Nuestros resultados indican que las salinas en Arkansas sostienen una alta densidad de aves invernales, y lo hacen por periodos más largos, después de disturbios, que en las savanas de pinos. También encontramos que la densidad de tallos, cerca del suelo, era similar a la informada en savanas de pinos, pero tan solo la mitad de lo indicado para lugares en donde las aves se reproducen. Las áreas utilizadas tienen más líquenes, pero menos musgos, lo que sugiere que dichas áreas son más secas que lugares con suelo empobrecido muestreados al azar. Se necesitan más trabajos para determinar si otras grandes poblaciones del gorrión de Henslow pasan el invierno en otras salinas con suelos empobrecidos y si eventos como fuegos incluyen en la asociación del hábitat y densidades en los lugares con suelo empobrecido. [source]


Prevalence of tick-borne encephalitis virus in Ixodes Ricinus from a novel endemic area of North Eastern Italy

JOURNAL OF MEDICAL VIROLOGY, Issue 2 2009
P. D'Agaro
Abstract In Alpine area of extreme North Eastern Italy the first autochthonous case of TBE was reported in 1998 and was followed by 45 cases during the period 2001,2007, thus defining this area as definitely endemic. An ecological survey evaluated the tick density and the Tick-borne encephalitis virus (TBEV) infection prevalence in tick collected in selected sites. In addition, TBE strains were characterized by sequencing and phylogenetic analysis. Overall, 2,361 ticks (2,198 nymphs and 163 adults) of the Ixodes ricinus L. species collected during 2005 and 2006 were examined. Five samples were positive for TBEV, corresponding to an overall prevalence rate of 0.21%. When analyzed by place, TBEV was discovered in three sites where the highest tick density was found. The difference of prevalence between high and low density areas tested to be statistically significant (P,=,0.028). Phylogenetic analysis showed that four sequences clustered with the Neudoerfl prototype, while the other clustered with the Isosaari 17 strain and with a number of Slovenian isolates. In addition, a sequence detected in archival samples from one human case segregated with another variant, namely the Swedish Torö strain. J. Med. Virol. 81:309,316, 2009. © 2008 Wiley-Liss, Inc. [source]


SPECIES COMPOSITION AND SEASONAL PERIODICITY OF MACROALGAL SPECIES IN CORPUS CHRISTI BAY, TEXAS

JOURNAL OF PHYCOLOGY, Issue 2000
J.C. Agan
Benthic algal sampling from selected sites along Corpus Christi Bay and from one site at the Port Aransas, Texas south jetty was completed between April 1999 and February, 2000. Species composition, seasonal periodicity, and fluctuations in temperature and salinity were determined. This is the first comprehensive study of benthic macroalgae conducted in Corpus Christi Bay, which is shallow, turbid, and lacks natural hard substrate. Man-made jetties are necessary for suitable floral attachment. Macroalgae are affected by changes in salinity as freshwater inflows are followed by periods of drought, which increase salinity. These effects are most notable where freshwater enters at the south end near Oso Bay and at the north end at Nueces Bay. Previous Texas algal collections described species of Enteromorpha, Ulva, Gelidium, and Gracilaria as the most dominant plants of the area. This supports the current study with the additions of Hypnea musciformis and Centroceras clavulatum. Dominant plants at the Port Aransas jetty include Ulva fasciata, Padina gymnospora, and Hypnea musciformis. The Rhodophyta including Gracilaria, Gelidium, and Centroceras clavulatum dominate the bay and do so throughout the year. Chlorophytes, although few in species richness, are important to benthic coverage and biomass. Phaeophyta are found predominantly at the Port Aransas jetty with Sargassum, Dictyota dichotoma, and Petalonia fascia being most abundant. A transition occurs in species composition as the water temperature changes seasonally. Hincksia, Ectocarpus, and Petalonia fascia are found only during the cooler months. [source]


The role of the calcar femorale in stress distribution in the proximal femur

ORTHOPAEDIC SURGERY, Issue 4 2009
Qi Zhang MD
Objective:, To investigate the role of the calcar femorale in stress distribution in the proximal femur. Methods:, Twenty-five specimens of proximal femurs were fixed to simulate single-limb stance. Strain gauges were applied to record the strain under different loads. Strain values of 27 selected sites in the proximal femur were recorded and analyzed at the level of 100 N, 200 N, 300 N, 400 N, 500 N, 600 N and 700 N, respectively before and after disruption of the calcar femorale. Results:, When a normal load was being borne, strain values measured in the posterior and medial aspects of the proximal femur were greater than those measured in the anterior and lateral aspects, no matter whether the calcar femorale was disrupted or not. However after disruption of the calcar femorale, strain values in the posterior and medial aspects of the proximal femur increased significantly, whereas those of the anterior and lateral aspects decreased significantly. Conclusion:, The calcar femorale redistributes stress in the proximal femur by decreasing the load in the posterior and medial aspects and increasing the load in the anterior and lateral aspects. [source]


Surface and interface investigations using radioactive atoms

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 12 2004
K. Potzger
Abstract The magnetic behavior of isolated nonmagnetic probe atoms (Cd) at ferromagnetic Ni surfaces and interfaces have been studied using perturbed angular correlation (PAC) spectroscopy. Atomic resolution is achieved making it possible to distinguish between probe atoms at various surface sites, i.e., in/at terraces, atomic steps, kinks. These different atomic surface sites have differing Ni coordination numbers, (i.e., the number of Ni nearest neighbours). With decreasing coordination number, a continuous nonlinear dependent correlation was found with increasing magnetic hyperfine fields (Bhf). Furthermore, experimental evidence is presented, that the induced s-moments on the Cd isolated impurity is independent of the details of the surface symmetry but essentially determined only by the coordination number. Finally, it has been observed that monolayers of Pd on Ni form large unit cells, which offer selected sites to the Cd impurity. We discuss this finding as basic research towards future applications with self-organizing patterned structures. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]


Vectors and alternative hosts of Tobacco yellow dwarf virus in southeastern Australia

ANNALS OF APPLIED BIOLOGY, Issue 1 2010
P. Tr, bicki
Factors that determine the epidemiology of Tobacco yellow dwarf virus (TbYDV), including alternative host plants and insect vector(s), were assessed over three consecutive growing seasons at four field sites in Northeastern Victoria in commercial tobacco growing properties. In addition, these factors were assessed for one growing season at three bean growing properties. Overall, 23 leafhopper species were identified at the 7 sites, with Orosius orientalis as the predominant leafhopper. Of the leafhoppers collected, only O. orientalis and Anzygina zealandica tested positive for TbYDV by polymerase chain reaction (PCR). The population dynamics of O. orientalis was assessed using sweep net sampling over three growing seasons and a trimodal distribution was observed. Despite large numbers of O. orientalis occurring early in the growing season (September,October), TbYDV was only detected in these leafhoppers between late November and end of January. The peaks in the detection of TbYDV in O. orientalis correlated with the observation of disease symptoms in tobacco and bean and were associated with warmer temperatures and lower rainfall. Spatial and temporal distribution of vegetation at selected sites was determined using quadrat sampling. Of the 40 plant species identified, TbYDV was detected only in four dicotyledonous species, Amaranthus retroflexus, Phaseolus vulgaris, Nicotiana tabacum and Raphanus raphanistrum. The proportion of host and non-host availability for leafhoppers was associated with climatic conditions. [source]


Evaluation of mangrove structure and condition in two trans-boundary areas in the Western Indian Ocean

AQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue S1 2009
S. O. Bandeira
Abstract 1.The structure, forest condition and regeneration status of nine mangrove forests in two trans-boundary areas of Mozambique bordering Tanzania and South Africa were studied. The main objective was to estimate the cutting intensity in the selected sites , Saco and Sangala in southern Mozambique; Mecúfi, Pemba, Ibo, Luchete, Ulo in northern Mozambique, and Mngoji 1 and Mngoji 2 in Tanzania. 2.A total of 135, 10,m×10,m quadrats were set in the outer, middle and lower parts of the mangrove forests at all sampling sites. Measurements included stem diameter at breast height (DBH) and height of adult trees (i.e. all trees with stem diameter more than 2.5,cm). Young trees (with stem diameter of less than 2.5,cm) were classified as juveniles. To assess forest condition, trees within the quadrat were classified into intact, partially cut, coppiced, die back and stump. Pole quality was appraised through the classification of the lead stem into three categories,straight, semi-straight and crooked poles. 3.The results indicate different levels of exploitation with Mngoji 1 and Mngoji 2, the most degraded sites, having stump densities of 959,stumps,ha,1 and 592,stumps,ha,1, respectively. Most sites had mostly poles of inferior quality (crooked poles), but high densities of straight and semi-straight poles were found in Mngoji 1 (742,stems,ha,1) and Saco (636,stems,ha,1). 4.Natural regeneration was observed in most sites but not for all species, with adequate regeneration in Saco (14,766 saplings ha,1) and Mecúfi (14,706 saplings ha,1), while low regeneration was recorded in Mngoji 1 and 2 (2212 saplings ha,1 and 4799saplingsha,1, respectively). 5.These results indicate the need for improved mangrove management and replanting especially in mangrove depleted conservation areas of southern Tanzania. Copyright © 2009 John Wiley & Sons, Ltd. [source]