Home About us Contact
|
Home About us Contact | ||
|
|
||
Re-establishment
Selected AbstractsCorrelates of biological soil crust abundance across a continuum of spatial scales: support for a hierarchical conceptual modelJOURNAL OF APPLIED ECOLOGY, Issue 1 2006MATTHEW A. BOWKER Summary 1Desertification negatively impacts a large proportion of the global human population and > 30% of the terrestrial land surface. Better methods are needed to detect areas that are at risk of desertification and to ameliorate desertified areas. Biological soil crusts are an important soil lichen-moss-microbial community that can be used toward these goals, as (i) bioindicators of desertification damage and (ii) promoters of soil stability and fertility. 2We identified environmental factors that correlate with soil crust occurrence on the landscape and might be manipulated to assist recovery of soil crusts in degraded areas. We conducted three studies on the Colorado Plateau, USA, to investigate the hypotheses that soil fertility [particularly phosphorus (P), manganese (Mn) and zinc (Zn)] and/or moisture limit soil crust lichens and mosses at four spatial scales. 3In support of the soil fertility hypothesis, we found that lichen,moss crusts were positively correlated with several nutrients [Mn, Zn, potassium (K) and magnesium (Mg) were most consistent] at three of four spatial scales ranging from 3·5 cm2 in area to c. 800 km2. In contrast, P was negatively correlated with lichen,moss crusts at three scales. 4Community composition varied with micro-aspect on ridges in the soil crust. Three micro-aspects [north-north-west (NNW), east-north-east (ENE) and TOP] supported greater lichen and moss cover than the warmer, windward and more xeric micro-aspects [west-south-west (WSW) and south-south-east (SSE)]. This pattern was poorly related to soil fertility; rather, it was consistent with the moisture limitation hypothesis. 5Synthesis and application. Use of crusts as desertification bioindicators requires knowledge of a site's potential for crust cover in the absence of desertification. We present a multi-scale model of crust potential as a function of site properties. Future quantitative studies can use this model to guide sampling efforts. Also, our results suggest new directions in restoration research: enhancement of moisture residence time and fertilization with key nutrients (Mn, Zn, K and Mg). Re-establishment of soil crusts in desertified lands will help regain lost soil stability and fertility, and facilitate plant re-establishment. [source] Investigations on the Re-establishment of the Positive Feedback of Oestradiol during Anoestrus in the BitchREPRODUCTION IN DOMESTIC ANIMALS, Issue 1 2003R Klein Contents To test for the re-establishment of the positive feedback of oestradiol (E2) during anoestrus in the dog, the hypothalamo,pituitary,ovarian axis of five beagle bitches was challenged by treatments with oestradiol benzoate (EB), mimicking the course of the pro-oestric E2 secretion. Treatments in anoestrus started 7 days following the decline of progesterone (P) <1 ng/ml; they were repeated in 5 week intervals until onset of pro-oestrus; another treatment was performed during dioestrus 50 days after onset of the preceding pro-oestric bleeding. Each dog served as its own control by receiving vehicle-treatments in one of the following cycles. Each observation period covered a time window of 168 h and blood samples were collected for the determination of luteinizing hormone (LH), follicle-stimulating hormone (FSH) and E2 in 6 (0,24 h) and 8 h (24,168 h) intervals. In the control periods and as indicated by the parameters area under curve (AUC), basal and maximal values, the availability of LH, FSH and E2 decreased from dioestrus to early anoestrus to increase again during the course of anoestrus (p < 0.05), indicating a gradual desensitization of the hypothalamus towards the negative feedback of oestradiol. At all times treatments with EB lowered the availability of FSH (decreased AUC and basal levels). A delay in the occurrence of the first LH peak after treatments with EB (p < 0.001) and decreased maximal values (p < 0.001) indicated a suppression of the LH-release. In no case treatment with EB led to a pre-ovulatory like LH-surge. In each dog the last trial with EB in anoestrus passed over into pro-oestrus/oestrus, with a reduced AUC and peak value of the pre-ovulatory LH-surge being the only differences to the control group. The observed differences in the response of LH and FSH to treatments with EB point towards subtle differences in the mechanisms controlling the release of these two hormones during anoestrus. From the data obtained, it may be concluded that the time window for E2 to act via a positive feedback seems to be very small and restricted to the end of anoestrus, and that full follicular function is a pre-requisite to allow for this phenomenon. [source] Dynamics of species-rich upland hay meadows over 15 years and their relation with agricultural management practicesAPPLIED VEGETATION SCIENCE, Issue 3 2007C.N.R. Critchley Stace (1997) Abstract Questions: Has the species-rich vegetation of upland hay meadows been maintained under low intensity management imposed by an agri-environment scheme? Is the target plant community re-establishing where it has been modified previously by intensive agricultural practices? What combinations of management practices and soil properties are associated with changes towards or away from the target community? Location: The Pennines, northern England, UK. Methods: A survey of 116 hay meadows in 1987 was repeated in 2002 by recording plant species in permanent quadrats. Changes in community variables (species richness, Ellenberg values, upland hay meadow community coefficients) were analysed in species-rich, modified species-rich and degraded grassland types. Redundancy Analysis and Generalised Linear Models were used to show the relationship between management practices and soil properties and change in species composition and community variables. Results: Few sites contained the species-rich grassland type, and here forb richness declined. In the modified species-rich type, total and grass species richness increased but Ellenberg N-values also increased. Total and grass species richness increased in the degraded type and the community coefficient increased. Management was weakly related to change in species composition but showed clear relationships with the community variables. Re-establishment of the target species-rich community was more likely with late cutting, in the absence of cattle or prolonged spring grazing, and at lower soil nutrient status. Conclusion: The species-rich community was not maintained but some reversion occurred in degraded grassland. Inorganic fertiliser application and intensive spring grazing should be avoided and cutting delayed until late July. [source] Subcutaneous administration of nitroglycerin to facilitate radial artery cannulationCATHETERIZATION AND CARDIOVASCULAR INTERVENTIONS, Issue 3 2006FSCAI, Samir B. Pancholy MD Abstract Objectives: To study the effect of sublingual versus subcutaneous nitroglycerin on radial artery spasm caused by failed access attempts. Background: Radial artery spasm is the leading reason for failed radial access. We studied the efficacy of systemic versus local nitroglycerin in relieving radial artery spasm caused by needle entry resulting in failed cannulation. Methods: Fifty-two consecutive patients were studied. All patients had failed attempt at radial artery cannulation, resulting in loss of radial pulse. Patients were divided in three groups, group I (n = 11), observed without additional treatment, group II (n = 20), administered 400 mcg of sublingual nitroglycerin, and group III (n = 21), administered 400 mcg of subcutaneous nitroglycerin at the site of the lost radial pulse. All patients were monitored for the return of radial pulse. Demographics, hemodynamics, and time to return of radial pulse as well as ability to successfully cannulate the radial artery were recorded. Results: Seventy-two percent of group I patients, 90% of group II patients, and 100% of group III patients had re-establishment of radial pulse. The time to return of radial pulse was significantly shorter for group III compared with that for group II (3 ± 1 min vs. 8 ± 1 min respectively, P < 0.001). Re-establishment of radial pulse was faster in group II and group III compared with that in group I (18 ± 5 min, P < 0.001). Systolic blood pressure changes and headaches were less common in group III. Conclusion: Subcutaneous administration of nitroglycerin is superior in facilitating radial artery cannulation after initial failed attempt. © 2006 Wiley-Liss, Inc. [source] Effect of crown fracture on the surrounding periodontiumDENTAL TRAUMATOLOGY, Issue 3 2008Janaína Cristina Gomes To reach the long axis of the tooth, an impact device was applied to eight teeth of four adult dogs to produce trauma. Crown fractures involving the enamel and dentin, with or without pulpar exposure and without dislocation, mobility or gingival bleeding were analyzed within the post-trauma periods of 30 min, 1, 3, and 7 days. The force of impact that resulted in coronary fracture, although dissipated at the time of fracture, reverberated in the surrounding periodontium and may generate not only light histological alterations with a rapid re-establishment of the tissues, but also an intense inflammatory condition required as long as 7 days to clear up. The gravity of these inflammatory reactions unleashed in these teeth's periapical tissues depends on the absorption of impact by the periodontal structures and the individual susceptibility of each organism. [source] Involvement of canonical Wnt/Wingless signaling in the determination of the positional values within the leg segment of the cricket Gryllus bimaculatusDEVELOPMENT GROWTH & DIFFERENTIATION, Issue 2 2007Taro Nakamura The cricket Gryllus bimaculatus is a hemimetabolous insect whose nymphs posses the ability to regenerate amputated legs. Previously, we showed that Gryllus orthologues of Drosophila hedgehog (Gb'hh), wingless (Gb'wg) and decapentaplegic (Gb'dpp) are expressed during leg regeneration and play essential roles in the establishment of the proximal-distal axis. Here, we examined their roles during intercalary regeneration: when a distally amputated tibia with disparate positional values is placed next to a proximally amputated host, intercalary growth occurs in order to regenerate the missing part. In this process, we examined expression patterns of Gb'hh and Gb'wg. We found that expressions of Gb'hh and Gb'wg were induced in a regenerate and the host proximal to the amputated region, but not in the grafted donor distal to the regenerate. This directional induction occurs even in the reversed intercalation. Because these results are consistent with a distal-to-proximal respecification of the regenerate, Gb'wg may be involved in the re-establishment of the positional values in the regenerate. Furthermore, we found that no regeneration occurs when Gb'armadillo (the orthologue of beta-catenin) was knocked down by RNA interference. These results indicate that the canonical Wnt/Wingless signaling pathway is involved in the process of leg regeneration and determination of positional information in the leg segment. [source] Learning, Literacy and ICT: What's the Connection?ENGLISH IN EDUCATION, Issue 3 2000Richard Andrews Abstract This article takes the form of a keynote address to delegates at the ,Raising Standards through Literacy and ICT across the Curriculum at Key Stages 3 and 4 conference', held at Middlesex University, London in July 2000. It sets out by defining the terms ,learning', ,literacy' and ,ICT' and then proceeds to make connections between the areas they denote. The main connections are seen to be the increased reciprocity of reading and writing, the contiguity of the verbal and visual in contemporary communication and the re-establishment of composition at the heart of the literacy curriculum. Central to all of these is the importance of transformation in learning, not only in theory but also in the day-to-day practices of classrooms. Recent research into ICT and literacy is reviewed, practical possibilities for cross-curricular collaboration are offered, and implications for the future are considered. [source] High-dose glucose-insulin-potassium treatment reduces myocardial apoptosis in patients with acute myocardial infarctionEUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 3 2005L. Zhang Abstract Background, Several clinical trials have suggested that a metabolic cocktail of glucose-insulin-potassium (GIK) decreases mortality rates in patients with acute myocardial infarction (AMI). It has also been reported that Fas-mediated apoptosis plays an important role in ischaemic/reperfusion injury in the rat model. This study was designed to evaluate the interaction of ischaemic/reperfusion and reperfusion therapy coadministered with high-dose GIK treatment on soluble Fas/APO-1 (sFas) and Fas ligand (sFasL) plasma concentration in patients with AMI. Materials and methods, Seventy-four patients presenting with AMI who underwent reperfusion therapy were randomized into a GIK group (n = 35) receiving high-dose GIK for 24 h or a vehicle group (n = 39). Thirty-four control subjects were also enrolled in the present study. Strepavidin-biotin ELISA was used to determine the soluble sFas and sFasL plasma concentration at baseline, 24 h (h), 3 day (d), 7 d and 14 d. Results, Soluble Fas and sFas-L serum concentrations ([sFas] and [sFas-L]) of patients with AMI were significantly elevated at baseline as compared with normal controls (NCs; P < 0·01 vs. NC). The sFas in the GIK and vehicle groups markedly decreased 24 h after the GIK infusion (10·7,5·9 ng mL,1 and 9·7,6·5 ng mL,1; P < 0·01 vs. baseline) and then increased during the 3,7-d period (5·9,12·1 ng mL,1 and 6·5,11·1 ng mL,1; P < 0·01 vs. 24 h). The GIK group demonstrated reduced sFas (12·1,5·9 ng mL,1) at 14 d (P < 0·01 vs. 7 d), with no concomitant changes in the vehicle group. The sFas-L in the GIK and vehicle groups was not significant different during the 14-d period. Conclusions, These results indicate that the sFas and sFasL in patients with AMI increased significantly compared with NC. Owing to the cardioprotective effects reported here and by others, a high-dose GIK infusion co-administered with the timely re-establishment of nutritive perfusion should be strongly considered as a treatment of choice for AMI. Additionally, sFas may be a valuable marker of the physiological response to ischaemic/reperfusion injury and reperfusion associated with high-dose GIK treatment. [source] Erythropoietin protects the in vitro blood,brain barrier against VEGF-induced permeabilityEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 9 2003Ofelia María Martínez-Estrada Abstract The blood,brain barrier (BBB) ensures the homeostasis of the brain microenvironment, mostly through complex tight junctions between brain endothelial cells that prevent the passage of hydrophilic molecules from blood to brain and vice versa. A recent study has shown in vivo that systemic administration of erythropoietin (Epo) protects against brain injury. Using an in vitro model of the bovine BBB, we observed that the expression of the Epo receptor is modulated by its ligand and hypoxic stimuli such as vascular endothelial growth factor (VEGF) treatment. In addition, Epo protects against the VEGF-induced permeability of the BBB, decreases the levels of endothelial nitric oxide synthase and restores junction proteins. The kinetic transport experiments revealed the capacity of Epo to cross the in vitro BBB in a saturable and specific way. Our results suggest a new mechanism for Epo-induced neuroprotection, in which circulating Epo controls and maintains the BBB through an Epo receptor signalling pathway and the re-establishment of cell junctions. [source] Constraints on recovery: using molecular methods to study connectivity of aquatic biota in rivers and streamsFRESHWATER BIOLOGY, Issue 4 2007JANE M. HUGHESArticle first published online: 2 MAR 200 Summary 1. The ,Field of Dreams Hypothesis' states ,if we build it, they will come', referring to the assumption that if habitats are restored, species will recolonise them. However, the ability of a species to recolonise a restored site will depend not only on the appropriate habitat being present, but also on the ability to get there. This is likely to depend on both the species' dispersal behaviour and the position of a site in the landscape. 2. Animals with good potential for dispersal are more likely to be able to disperse to newly restored sites. Similarly, sites in lowland streams with limited altitudinal differences between sites may be easier to reach than upstream sites. This is because upstream sites are connected to one another via lowland streams that have different characteristics and therefore may be difficult for animals to traverse. 3. In this paper, genetic data from a range of freshwater species that have been analysed in my laboratory are used to assess the importance of life cycle and position in the landscape (i.e. upland versus lowland streams) on connectivity patterns (and thus recolonisation potential) among populations. 4. In general, contemporary dispersal across catchment boundaries is negligible, except for aquatic insects with an adult flight stage. Dispersal among streams within catchments appears to be more limited than was predicted from knowledge on life histories, except for fish in lowland rivers and streams. 5. As predicted, dispersal of fish, crustaceans and molluscs among streams within catchments is significantly greater in lowland rivers than in upland streams. 6. Overall, these analyses suggest that, with the exception of most insects, and fishes in lowland rivers, natural recolonisation of restored sites is only likely from sites within the same stream. If a species has disappeared from the whole stream, then restoration of habitat alone may not be sufficient for its re-establishment. [source] Does high nitrogen loading prevent clear-water conditions in shallow lakes at moderately high phosphorus concentrations?FRESHWATER BIOLOGY, Issue 1 2005María A. González Sagrario Summary 1. The effect of total nitrogen (TN) and phosphorus (TP) loading on trophic structure and water clarity was studied during summer in 24 field enclosures fixed in, and kept open to, the sediment in a shallow lake. The experiment involved a control treatment and five treatments to which nutrients were added: (i) high phosphorus, (ii) moderate nitrogen, (iii) high nitrogen, (iv) high phosphorus and moderate nitrogen and (v) high phosphorus and high nitrogen. To reduce zooplankton grazers, 1+ fish (Perca fluviatilis L.) were stocked in all enclosures at a density of 3.7 individuals m,2. 2. With the addition of phosphorus, chlorophyll a and the total biovolume of phytoplankton rose significantly at moderate and high nitrogen. Cyanobacteria or chlorophytes dominated in all enclosures to which we added phosphorus as well as in the high nitrogen treatment, while cryptophytes dominated in the moderate nitrogen enclosures and the controls. 3. At the end of the experiment, the biomass of the submerged macrophytes Elodea canadensis and Potamogeton sp. was significantly lower in the dual treatments (TN, TP) than in single nutrient treatments and controls and the water clarity declined. The shift to a turbid state with low plant coverage occurred at TN >2 mg N L,1 and TP >0.13,0.2 mg P L,1. These results concur with a survey of Danish shallow lakes, showing that high macrophyte coverage occurred only when summer mean TN was below 2 mg N L,1, irrespective of the concentration of TP, which ranged between 0.03 and 1.2 mg P L,1. 4. Zooplankton biomass and the zooplankton : phytoplankton biomass ratio, and probably also the grazing pressure on phytoplankton, remained overall low in all treatments, reflecting the high fish abundance chosen for the experiment. We saw no response to nutrition addition in total zooplankton biomass, indicating that the loss of plants and a shift to the turbid state did not result from changes in zooplankton grazing. Shading by phytoplankton and periphyton was probably the key factor. 5. Nitrogen may play a far more important role than previously appreciated in the loss of submerged macrophytes at increased nutrient loading and for the delay in the re-establishment of the nutrient loading reduction. We cannot yet specify, however, a threshold value for N that would cause a shift to a turbid state as it may vary with fish density and climatic conditions. However, the focus should be widened to use control of both N and P in the restoration of eutrophic shallow lakes. [source] Sedimentary and faunal events revealed by a revised correlation of post-glacial Hirnantian (Late Ordovician) strata in the Welsh Basin, UKGEOLOGICAL JOURNAL, Issue 3 2009Jeremy R. Davies Abstract The discovery of a previously unrecognized unconformity and of new faunas in the type Llandovery area underpins a revised correlation of Hirnantian strata in mid Wales. This has revealed the sedimentary and faunal events which affected the Lower Palaeozoic Welsh Basin during the global rise in sea level that followed the end-Ordovician glacial maximum and has allowed their interpretation in the context of local and global influences. In peri-basinal shelfal settings the onset of post-glacial deepening is recorded by an unfossiliferous, transgressive shoreface sequence (Cwm Clyd Sandstone and Garth House formations) which rests unconformably on Rawtheyan rocks, deformed during an episode of pre-Hirnantian tectonism. In the deep water facies of the basin centre, this same sequence boundary is now recognized as the contact between fine-grained, re-sedimented mudstones and an underlying regressive sequence of turbidite sandstones and conglomerates; it is at a level lower than previously cited and calls into question the established lithostratigraphy. In younger Hirnantian strata, graptolites associated with the newly recognized Ystradwalter Member (Chwefri Formation) demonstrate that this distal shelf unit correlates with the persculptus graptolite-bearing Mottled Mudstone Member of the basinal succession. Together these members record an important macrofaunal recolonization of the Welsh Basin and mark a key event in the post-glacial transgression. Further deepening saw the establishment of a stratified water column and the imposition of anoxic bottom water conditions across the basin floor. These post-glacial Hirnantian events are consistent with the re-establishment of connections between a silled Welsh Basin and the open Iapetus Ocean. However, a comparison with other areas suggests that each event records a separate deepening episode within a pulsed glacio-eustatic transgression, while also reflecting changes in post-glacial climate and patterns of oceanic circulation and associated biotic flux. British Geological Survey © NERC 2009. All rights reserved. [source] Increasing representation of localized dung beetles across a chronosequence of regenerating vegetation and natural dune forest in South AfricaGLOBAL ECOLOGY, Issue 3 2002Adrian L. V. Davis Abstract Aim Species assemblages with high proportions of localized taxa occur in regional islands with a history of strong eco-climatic separation from adjacent systems. Current disturbance in such islands of relictualism or endemism disrupts the distinctive local character in favour of regionally distributed taxa with a wider range of tolerances. However, rehabilitation of the system should restore the localized biota. Thus, we used biogeographical composition to assess progress towards restoration of the dung beetle fauna associated with such an island of endemism following dredge-mining. Location The study was conducted in natural coastal dune forest and a 23-year chronosequence of regenerating dune vegetation in the Maputaland centre of endemism, KwaZulu-Natal, South Africa. Methods Dung beetles were trapped in eight stands of regenerating vegetation of different ages (< 1 year to ~21 years) and in four stands of natural dune forest with differing ecological characteristics defined by measurements of vegetative physiognomy and microclimate. Species groups defined from multivariate analysis of biogeographical distribution patterns and vegetation associations were used to demonstrate quantitative compositional changes in the dung beetle assemblages across the chronosequence to natural forest. Results Three biogeographical groups were defined. One group comprised species widespread in southern Africa or both southern and east Africa. The other two groups were endemic, one to the east coast and the other to Maputaland. There was a general trend from dominance by regionally distributed dung beetle taxa to dominance by locally distributed taxa across the chronosequence of regenerating vegetation from grassland, to open Acacia karroo thicket, to dense A. karroo- dominated woodland. However, this trend was linked closely to the relative physiognomic and microclimatic similarity between the regenerating vegetation and natural forest. Thus, proportions of locally distributed taxa were lower in older chronosequence woodland (~18,~21 years) with its low canopy cover and open understorey than in dense early chronosequence woodland (~9,~12 years), which is physiognomically and microclimatically closer to species-diverse natural forest with its dense canopy and understorey. Overall, the present dung beetle community comprises five species groups. Single widespread (21 spp.) and endemic groups (14 spp.) showed similar patterns of association with early chronosequence grassland and open thicket stands. A single widespread (3 spp.) and two endemic shade-associated groups (3 and 11 spp.) showed differing patterns of association centred, respectively, in late chronosequence woodland, natural forest, or all shaded stands. Main conclusions At 23 years, vegetative regeneration is still at an early stage, but abundant activity of most, although not all species recorded in natural forest, is recovered with the closure of the woodland canopy at ~9 years. Compositional differences with respect to natural forest vary closely with vegetative physiognomy and its effect on the microclimate. Therefore, full compositional recovery is dependent on the re-establishment of natural forest physiognomy and microclimate. [source] Implications of ideas on super-hydrophobicity for water repellent soilHYDROLOGICAL PROCESSES, Issue 17 2007G. McHale Abstract Water repellence is an important factor in soil erosion due to its role in inhibiting the re-establishment of vegetation after fire and due to its enhancement of run-off. Water repellence is studied across a range of diverse disciplines, such as chemistry, materials, textiles and soil and reclamation science. In recent years many basic studies of water repellence of materials have focused on the role of the sub-mm surface topography of a material in modifying the intrinsic hydrophobicity imparted by the surface chemistry to create super-hydrophobicity. In this report, we first illustrate the types of hydrophobic effects created by a suitable coupling of small scale surface topography with surface chemistry using three materials: an etched metal, a foam and a micro-fabricated pillar structure. These experiments demonstrate the general applicability of the ideas and suggest that they could apply to a granular material such as, a fine sandy soil, particularly when the grains have become coated with a hydrophobic layer. This applicability is confirmed by contact angle measurements of droplets of water on hydrophobic sand. A theoretical model describing the application of these ideas in a loose-packed, but regular, array of uniform spherical grains is then presented and discussed. When the grains are in a dry state initially, the effect of the surface is to increase the apparent water repellence as observed through the contact angle. However, when the spaces between the grains are filled with water, the effect is to provide greater wetting. To qualitatively confirm the enhancement of contact angle caused by the granular structure, model surfaces using 600 and 250 µm hydrophobic glass beads were created. On these surfaces, the contact angle of droplets of water was increased from 108° to 126° and 140° , respectively. Copyright © 2007 John Wiley & Sons, Ltd. [source] Mobile-initiated network-executed SIP-based handover in IMS over heterogeneous accessesINTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 9-10 2010Wei-Kuo Chiang Abstract The services of next generation networks are envisioned to be potentially capable of seamless mobility in spite of the heterogeneity in underlying access technologies. It is undoubted that to accomplish seamless services across heterogeneous networking environments gets harder in case of simultaneous mobility. In this article, we propose a mobile-initiated network-executed (MINE) session initial protocol (SIP)-based handover mechanism to facilitate simultaneous mobility in IP multimedia subsystem over heterogeneous accesses. The novelty of the proposed approach is that no changes are required to the existing network infrastructure since handover decision is fully made by the mobile host (MH) and handover execution is performed by a new-added application server called mobility server (MS). When the MH decides to initiate a handover and obtains a new IP address, it will send a SIP Publish message to trigger the MS to carry out the handover execution. With the network-executed design of the MINE, the MS can perform third-party registration for security re-association and third-party call control for session re-establishment in parallel. Moreover, the Master,Slave Determination procedures derived from H.245 are used in the MS to handle fairly the racing conditions resulting from simultaneous mobility such that redundant message flows are eliminated. Mathematical analyses present that the MINE can shorten the handover latency and reduce power consumption, as observed from a comparison with the integrated solution of an optimized macro-mobility mechanism and a receiver-side simultaneous mobility approach. Copyright © 2010 John Wiley & Sons, Ltd. [source] Growth factors in periodontal regenerationINTERNATIONAL JOURNAL OF DENTAL HYGIENE, Issue 2 2009S Raja Abstract:, Inflammatory periodontal disease is an almost ubiquitous disorder in the adult population. Cases or sites with moderate to advanced disease often continue to show signs of inflammation after non-surgical approach. Our current understanding of periodontal healing is based on a hypothesis by Melcher who proposed that the cell type that repopulates the exposed root surface at the periodontal repair site will define the nature of the attachment/repair that take place. If mesenchymal cells from periodontal ligament/perivascular region of the bone proliferate and colonize the root surface, regeneration occurs. Growth factors are natural cell products that are released or activated when cell division is needed. This action typically occurs during such events as wound healing or tissue regeneration. Activated platelets at the wound margins release several growth factors such as platelet-derived growth factor (PDGF), transforming growth factor (TGF)-,, epidermal growth factor etc. Cells adjacent to the injured site also are induced to release growth factors such as insulin-like growth factor-I, PDGF, TGF-, and TGF-, within a few hours after injury. In periodontal regeneration, the coronal re-establishment of the periodontal ligament (PDL) is required together with corresponding cementum and supporting alveolar bone. Thus, agents which promote periodontal ligament fibroblast (PLF) proliferation and migration as well as collagen biosynthesis would appear to be mediators for enhancing new PDL formation. When combinations or cocktails of different factors are used, greater repair is achieved than when individual factors are applied. [source] Basis of occlusive therapy in psoriasis: correcting defects in permeability barrier and calcium gradientINTERNATIONAL JOURNAL OF DERMATOLOGY, Issue 3 2001Sang Min Hwang MD Background Although occlusive dressings have great potential in the management of psoriasis vulgaris, the therapeutic mechanism is not completely understood. Occlusion artificially restores and corrects the defective barrier in psoriasis plaques. Additionally, occlusion is know to normalize the epidermal calcium gradients in hyperproliferative murine skin models. Methods To investigate the basis of the therapeutic effect of occlusion on psoriatic plaques, we investigated the ultrastructural morphology of intercorneocyte lipid layers, lamellar bodies, and calcium gradient in chronic plaque-type psoriasis after occlusion with a water vapor-impermeable membrane. The specimens were processed for electron microscopy using: (i) ruthenium tetroxide postfixation; and (ii) ion-capture cytochemistry for calcium localization. Results Occlusion for 7 days resulted in a nearly mature pattern of intercellular multilamellar structures, re-establishment of the near-normal epidermal calcium gradient, and disappearance of calcium precipitates from the stratum corneum interstices. Conclusions The normalization of the permeability barrier and epidermal calcium gradient may play important roles in the therapeutic effects of occlusive dressings in chronic plaque-type psoriasis. [source] Nursing and midwifery management of hypoglycaemia in healthy term neonatesINTERNATIONAL JOURNAL OF EVIDENCE BASED HEALTHCARE, Issue 7 2005Vivien Hewitt BSc(Hons) GradDipLib Executive summary Objectives The primary objective of this review was to determine the best available evidence for maintenance of euglycaemia, in healthy term neonates, and the management of asymptomatic hypoglycaemia in otherwise healthy term neonates. Inclusion criteria Types of studies The review included any relevant published or unpublished studies undertaken between 1995 and 2004. Studies that focus on the diagnostic accuracy of point-of-care devices for blood glucose screening and/or monitoring in the neonate were initially included as a subgroup of this review. However, the technical nature and complexity of the statistical information published in diagnostic studies retrieved during the literature search stage, as well as the considerable volume of published research in this area, suggested that it would be more feasible to analyse diagnostic studies in a separate systematic review. Types of participants The review focused on studies that included healthy term (37- to 42-week gestation) appropriate size for gestational age neonates in the first 72 h after birth. Exclusions ,,preterm or small for gestational age newborns; ,,term neonates with a diagnosed medical or surgical condition, congenital or otherwise; ,,babies of diabetic mothers; ,,neonates with symptomatic hypoglycaemia; ,,large for gestational age neonates (as significant proportion are of diabetic mothers). Types of intervention All interventions that fell within the scope of practice of a midwife/nurse were included: ,,type (breast or breast milk substitutes), amount and/or timing of feeds, for example, initiation of feeding, and frequency; ,,regulation of body temperature; ,,monitoring (including screening) of neonates, including blood or plasma glucose levels and signs and symptoms of hypoglycaemia. Interventions that required initiation by a medical practitioner were excluded from the review. Types of outcome measures Outcomes that were of interest included: ,,occurrence of hypoglycaemia; ,,re-establishment and maintenance of blood or plasma glucose levels at or above set threshold (as defined by the particular study); ,,successful breast-feeding; ,,developmental outcomes. Types of research designs The review initially focused on randomised controlled trials reported from 1995 to 2004. Insufficient randomised controlled trials were identified and the review was expanded to include additional cohort and cross-sectional studies for possible inclusion in a narrative summary. Search strategy The major electronic databases, including MEDLINE/PubMed, CINAHL, EMBASE, LILACS, Cochrane Library, etc., were searched using accepted search techniques to identify relevant published and unpublished studies undertaken between 1995 and 2004. Efforts were made to locate any relevant unpublished materials, such as conference papers, research reports and dissertations. Printed journals were hand-searched and reference lists checked for potentially useful research. The year 1995 was selected as the starting point in order to identify any research that had not been included in the World Health Organisation review, which covered literature published up to 1996. The search was not limited to English language studies. Assessment of quality Three primary reviewers conducted the review assisted by a review panel. The review panel was comprised of nine nurses with expertise in neonatal care drawn from senior staff in several metropolitan neonatal units and education programs. Authorship of journal articles was not concealed from the reviewers. Methodological quality of each study that met the inclusion criteria was assessed by two reviewers, using a quality assessment checklist developed for the review. Disagreements between reviewers were resolved through discussion or with the assistance of a third reviewer. Data extraction and analysis Two reviewers used a data extraction form to independently extract data relating to the study design, setting and participants; study focus and intervention(s); and measurements and outcomes. As only one relevant randomised controlled trial was found, a meta-analysis could not be conducted nor tables constructed to illustrate comparisons between studies. Instead, the findings were summarised by a narrative identifying any relevant findings that emerged from the data. Results Seven studies met the inclusion criteria for the objective of this systematic review. The review provided information on the effectiveness of three categories of intervention , type of feeds, timing of feeds and thermoregulation on two of the outcome measures identified in the review protocol , prevention of hypoglycaemia, and re-establishment and maintenance of blood or plasma glucose levels above the set threshold (as determined by the particular study). There was no evidence available on which to base conclusions for effectiveness of monitoring or developmental outcomes, and insufficient evidence for breast-feeding success. Given that only a narrative review was possible, the findings of this review should be interpreted with caution. The findings suggest that the incidence of hypoglycaemia in healthy, breast-fed term infants of appropriate size for gestational age is uncommon and routine screening of these infants is not indicated. The method and timing of early feeding has little or no influence on the neonatal blood glucose measurement at 1 h in normal term babies. In healthy, breast-fed term infants the initiation and timing of feeds in the first 6 h of life has no significant influence on plasma glucose levels. The colostrum of primiparous mothers provides sufficient nutrition for the infant in the first 24 h after birth, and supplemental feeds or extra water is unnecessary. Skin-to-skin contact appears to provide an optimal environment for fetal to neonatal adaptation after birth and can help to maintain body temperature and adequate blood glucose levels in healthy term newborn infants, as well as providing an ideal opportunity to establish early bonding behaviours. Implications for practice The seven studies analysed in this review confirm the World Health Organisation's first three recommendations for prevention and management of asymptomatic hypoglycaemia, namely: 1Early and exclusive breast-feeding is safe to meet the nutritional needs of healthy term newborns worldwide. 2Healthy term newborns that are breast-fed on demand need not have their blood glucose routinely checked and need no supplementary foods or fluids. 3Healthy term newborns do not develop ,symptomatic' hypoglycaemia as a result of simple underfeeding. If an infant develops signs suggesting hypoglycaemia, look for an underlying condition. Detection and treatment of the cause are as important as correction of the blood glucose level. If there are any concerns that the newborn infant might be hypoglycaemic it should be given another feed. Given the importance of thermoregulation, skin-to-skin contact should be promoted and ,kangaroo care' encouraged in the first 24 h after birth. While it is important to main the infant's body temperature care should be taken to ensure that the child does not become overheated. [source] Balancing the funds in the New Cooperative Medical Scheme in rural China: determinants and influencing factors in two provincesINTERNATIONAL JOURNAL OF HEALTH PLANNING AND MANAGEMENT, Issue 2 2010Luying Zhang Abstract In recent years, the central government in China has been leading the re-establishment of its rural health insurance system, but local government institutions have considerable flexibility in the specific design and management of schemes. Maintaining a reasonable balance of funds is critical to ensure that the schemes are sustainable and effective in offering financial protection to members. This paper explores the financial management of the NCMS in China through a case study of the balance of funds and the factors influencing this, in six counties in two Chinese provinces. The main data source is NCMS management data from each county from 2003 to 2005, supplemented by: a household questionnaire survey, qualitative interviews and focus group discussions with all local stakeholders and policy document analysis. The study found that five out of six counties held a large fund surplus, whilst enrolees obtained only partial financial protection. However, in one county greater risk pooling for enrolees was accompanied by relatively high utilisation levels, resulting in a fund deficit. The opportunities to sustainably increase the financial protection offered to NCMS enrolees are limited by the financial pressures on local government, specific political incentives and low technical capacities at the county level and below. Our analysis suggests that in the short term, efforts should be made to improve the management of the current NCMS design, which should be supported through capacity building for NCMS offices. However, further medium-term initiatives may be required including changes to the design of the schemes. Copyright © 2009 John Wiley & Sons, Ltd. [source] Using virtual topologies to manage inter-domain QoS in next-generation networksINTERNATIONAL JOURNAL OF NETWORK MANAGEMENT, Issue 3 2010Ricardo B. Freitas Recently, several computer fields have turned to virtualization as a way to simplify complex problems. In this context, the Virtual Topology Service (VTS) was created to manage the advertisement and acquisition of virtual topologies (abstractions of the network status of a domain) and their use in inter-domain resource reservation to provide end-to-end quality of service (QoS). As an effort to create new network architectures which could attend current requirements like mobility and context-aware applications and support autonomous, heterogeneous and mobile domains next-generation networks (NGNs) emerged, with Ambient Networks (AN) as one of its instances. With an ever increasing multitude of online applications, end-to-end QoS has become increasingly important, especially for media and real-time uses. In this context, in order to better manage inter-domain QoS in these new networks, better coping with mobile nodes and domains, this work presents a new design and implementation of the VTS, adapted to the AN environment. The new VTS stores resource reservation information to enable the reuse of these reservations when re-establishing QoS after a node/domain movement. This implementation was tested on a real NGN prototype and showed considerable time saving when compared to QoS re-establishment without reusing the reservations. Copyright © 2009 John Wiley & Sons, Ltd. [source] The impact of the 2007-2009 crisis on social security and private pension funds: A threat to their financial soundness?INTERNATIONAL SOCIAL SECURITY REVIEW, Issue 2 2010Ariel Pino Abstract Social security and pension funds were affected on an unparalleled scale by the recent financial crisis. They reported massive unrealized investment losses and their governance mechanisms have been challenged, therefore endangering their financial soundness and questioning their capacity to deliver adequate benefits. The year 2009 ended with financial markets recovering, but also with portfolio reallocations and traditional risk management approaches being revisited. Governments have reacted to the crisis and implemented recovery plans that could issue a warning about the mid-term fiscal situation. Post-crisis fiscal stress may generate a trade-off between a re-establishment of a sound fiscal situation and a reduction in social expenditure. This article analyses the impact of the crisis on social security and pension funds and address all the aforementioned issues. [source] Community effects of invasive macrophyte control: role of invasive plant abundance and habitat complexityJOURNAL OF APPLIED ECOLOGY, Issue 2 2010Katya E. Kovalenko Summary 1. The control of invasive species has become a widespread management practice, yet information on the community effects of such efforts is very limited, there is no unified framework for monitoring their success and no guidelines exist to help minimize potential adverse impacts. 2. This study was conducted to determine how long-term efforts to control a widespread invasive macrophyte, Eurasian watermilfoil, affect native macrophytes, fish and macroinvertebrates. In addition, we examined how members of the aquatic fauna respond to changes in invasive macrophyte abundance and habitat complexity to understand the mechanisms underlying any potential community response. 3. Selective control of the invasive macrophyte had minor effects on habitat complexity due to timely recolonization by native macrophytes and it did not affect littoral fish richness and abundance. Macroinvertebrate communities were highly variable and some of that variation could be attributed to characteristics of the macrophyte community. Fish and macroinvertebrates were more affected by habitat complexity than by other attributes of the macrophyte assemblage. 4.Synthesis and applications. Management plans to control invasive species need to prioritize selective removal and timely restoration of the native assemblage. In this study, the invasive macrophyte was used by aquatic fauna, which emphasizes the need for immediate restoration of the native macrophyte community to mitigate for the lost habitat after invasive plant control efforts. As both fish and macroinvertebrates were more affected by complexity than other attributes of the macrophyte assemblage, re-establishment of habitat complexity appears to be a promising restoration strategy. On a more general note, we highlight the importance of assessing community response to the habitat provided by the invader and invader's function in the community when evaluating strategies to control invasive species. [source] Habitat differentiation within the large-carnivore community of Norway's multiple-use landscapesJOURNAL OF APPLIED ECOLOGY, Issue 5 2008Roel May Summary 1The re-establishment of large carnivores in Norway has led to increased conflicts and the adoption of regional zoning for these predators. When planning the future distribution of large carnivores, it is important to consider details of their potential habitat tolerances and strength of inter-specific differentiation. We studied differentiation in habitat and kill sites within the large-carnivore community of south-eastern Norway. 2We compared habitat selection of the brown bear Ursus arctos L., Eurasian lynx Lynx lynx L., wolf Canis lupus L. and wolverine Gulo gulo L., based on radio-tracking data. Differences in kill site locations were explored using locations of documented predator-killed sheep Ovis aries L. We modelled each species' selection for, and differentiation in, habitat and kill sites on a landscape scale using resource selection functions and multinomial logistic regression. Based on projected probability of occurrence maps, we estimated continuous patches of habitat within the study area. 3Although bears, lynx, wolves and wolverines had overlapping distributions, we found a clear differentiation for all four species in both habitat and kill sites. The presence of bears, wolves and lynx was generally associated with rugged, forested areas at lower elevations, whereas wolverines selected rugged terrain at higher elevations. Some degree of sympatry was possible in over 40% of the study area, although only 1·5% could hold all four large carnivores together. 4Synthesis and applications. A geographically differentiated management policy has been adopted in Norway, aimed at conserving viable populations of large carnivores while minimizing the potential for conflicts. Sympatry of all four carnivores will be most successful if regional zones are established of adequate size spanning an elevational gradient. High prey densities, low carnivore densities, low dietary overlap and scavenging opportunities have most probably led to reduced competitive exclusion. Although regional sympatry enhances the conservation of an intact guild of large carnivores, it may well increase conflict levels and resistance to carnivore conservation locally. [source] Correlates of biological soil crust abundance across a continuum of spatial scales: support for a hierarchical conceptual modelJOURNAL OF APPLIED ECOLOGY, Issue 1 2006MATTHEW A. BOWKER Summary 1Desertification negatively impacts a large proportion of the global human population and > 30% of the terrestrial land surface. Better methods are needed to detect areas that are at risk of desertification and to ameliorate desertified areas. Biological soil crusts are an important soil lichen-moss-microbial community that can be used toward these goals, as (i) bioindicators of desertification damage and (ii) promoters of soil stability and fertility. 2We identified environmental factors that correlate with soil crust occurrence on the landscape and might be manipulated to assist recovery of soil crusts in degraded areas. We conducted three studies on the Colorado Plateau, USA, to investigate the hypotheses that soil fertility [particularly phosphorus (P), manganese (Mn) and zinc (Zn)] and/or moisture limit soil crust lichens and mosses at four spatial scales. 3In support of the soil fertility hypothesis, we found that lichen,moss crusts were positively correlated with several nutrients [Mn, Zn, potassium (K) and magnesium (Mg) were most consistent] at three of four spatial scales ranging from 3·5 cm2 in area to c. 800 km2. In contrast, P was negatively correlated with lichen,moss crusts at three scales. 4Community composition varied with micro-aspect on ridges in the soil crust. Three micro-aspects [north-north-west (NNW), east-north-east (ENE) and TOP] supported greater lichen and moss cover than the warmer, windward and more xeric micro-aspects [west-south-west (WSW) and south-south-east (SSE)]. This pattern was poorly related to soil fertility; rather, it was consistent with the moisture limitation hypothesis. 5Synthesis and application. Use of crusts as desertification bioindicators requires knowledge of a site's potential for crust cover in the absence of desertification. We present a multi-scale model of crust potential as a function of site properties. Future quantitative studies can use this model to guide sampling efforts. Also, our results suggest new directions in restoration research: enhancement of moisture residence time and fertilization with key nutrients (Mn, Zn, K and Mg). Re-establishment of soil crusts in desertified lands will help regain lost soil stability and fertility, and facilitate plant re-establishment. [source] The development of vegetative zonation patterns in restored prairie pothole wetlandsJOURNAL OF APPLIED ECOLOGY, Issue 1 2003Eric W. Seabloom Summary 1The spatial structure of plant communities can have strong impacts on ecosystem functions and on associated animal communities. None the less, spatial structure is rarely used as a measure of restoration success. 2The restoration of hundreds of wetlands in the prairie pothole region in the mid-western USA provided an excellent opportunity to determine whether the re-establishment of abiotic conditions is sufficient to restore structure, composition and spatial patterning of the vegetation. 3We mapped the topography and vegetative distributions in 17 restored and nine natural wetlands. We used these data to compare the composition and spatial structure of the vegetation in both wetlands types. 4The composition of the plant communities differed between restored and natural wetlands; the restored wetlands lacked the well-developed sedge-meadow community found in most natural wetlands. However, the spatial heterogeneity was similar, although the zonation patterns were less well-developed in the restored wetlands. 5Although the overall structure was similar, species distributions differed among wetland types, such that species were found more than 10 cm higher in restored wetlands than in natural wetlands. 6Synthesis and applications. This study illustrates that restored plant community composition and spatial structure may converge on their targets at different rates. Evaluations of restoration success should consider spatial structure of communities along with compositional and functional metrics. [source] The dynamics of nitrogen movement in an Arctic salt marsh in response to goose herbivory: a parameterized model with alternate stable statesJOURNAL OF ECOLOGY, Issue 4 2003N. A. Walker Summary 1LPBN is a parameterized simulation model of flows of nitrogen (N) in an ecosystem of cyanobacteria, grass and grazers, based on the N dynamics of a grazed Puccinellia lawn in an intertidal marsh on Hudson Bay. This system shows two alternate stable states: (a) lawns that either support a foraging population of lesser snow geese, or are not grazed by geese; and (b) exposed saline sediments that support little or no vegetation. The model represents the flow of N from cyanobacterial fixation, the major N input into the system, to the geese that migrate in autumn; those that do not return represent the major N output from the system. We have modelled N fixation, the transformations of N in the soil, plant growth, lawn regeneration, and goose grazing and grubbing. 2The model simulates steady-state flows of N similar to those observed in the field at zero and at moderate goose density, and it also simulates the transition to the state of zero plant biomass, a consequence of increased grubbing at high goose density. The simulated steady-state flows are found to be more sensitive to changes in the parameters that describe N fixation and goose biology, than to similar changes in the parameters describing plant biology. 3Because the model shows the alternate stable states and the transition between them, with values for the state variables that are consistent with field data, we conclude that N dynamics are crucial in determining the stability of the real salt marsh-goose system. The determining factor is the loss of the input of N from fixation when lawn area is reduced because the rate of goose grubbing exceeds that of plant re-establishment. [source] THE INFLUENCE OF FUNDAMENTALS ON EXCHANGE RATES: FINDINGS FROM ANALYSES OF NEWS EFFECTSJOURNAL OF ECONOMIC SURVEYS, Issue 4 2010Rafael R. Rebitzky Abstract As we survey the literature of macroeconomic news in the foreign exchange market, we can by now look back on nearly 30 years of research. The first studies which analysed news effects on exchange rates were established in the early 1990s (see, for example, Dornbusch). Almost at the same time Meese and Rogoff published their influential paper, revealing the forecasting inferiority in exchange rates of structural models against the random walk. This finding has shocked the pillars of exchange rate economics and thus cast general suspicion on research focusing on fundamentals in this field. The eventual rising popularity of event studies can partly be attributed to the re-establishment of the,raison d'être,of exchange rate economics. This work focuses on systematically surveying this literature with particular respect to its primary goal, i.e. shedding light on the analytical value of fundamental research. Thus, its major findings are, first, fundamental news does matter, whereas non-fundamental news matters to a lesser degree. Second, news influences exchange rates via two separated channels, i.e. incorporating common information into prices directly or indirectly based upon order flow. Third, with a few exceptions the impact of fundamental news on exchange rates is fairly stable over time. [source] Preparation of high specific activity tritium labeled 6,,9,-difluoro-11,,21-dihydroxy-16,,17-[(1-methylethylidene)bis(oxy)]pregna-1,4-diene-3,20-one, fluocinolone acetonideJOURNAL OF LABELLED COMPOUNDS AND RADIOPHARMACEUTICALS, Issue 4 2009D. Zhong Abstract Fluocinolone acetonide was tritiated by selective reduction of the 1,2-double bond of the O -protected analog under tritium, followed by re-establishment of the 1,2-double bond and deprotection. Protection of both hydroxyl functionalities was required. The product was obtained with specific activity 36.8,Ci/mmol. Copyright © 2009 John Wiley & Sons, Ltd. [source] A CLASS OF MODELS DESCRIBING AGE STRUCTURE DYNAMICS IN A NATURAL FORESTNATURAL RESOURCE MODELING, Issue 2 2002MICHAEL A. KRAEMER ABSTRACT. The age dynamics of a natural forest is modeled by the von-Foerster partial differential equation for the age density, while the seedling density is obtained as a solution of an integro-differential equation. This seedling density equation contains a small parameter, the ratio of seedling re-establishment time and the life span of an average tree in the forest. Several models are introduced that take into account various mortality curves and growth functions of trees, the dependence of seedlings carrying capacity on forest size, and different types of seedlings re-establishment. Asymptotic, analytic and numerical methods are used to solve typical example problems. [source] Impact of released Eurasian otters on a population of American mink: a test using an experimental approachOIKOS, Issue 1 2004L. Bonesi Competition is considered to be a major evolutionary driving force within assemblages of related and morphologically similar species, but it is notoriously difficult to test and quantify especially amongst species that cannot be easily manipulated in a laboratory or in the field. By exploiting a re-introduction of Eurasian otters (Lutra lutra) in the Upper Thames catchment (UK) in 1999 we performed an experiment to test whether there was evidence of competition between otters and American mink (Mustela vison). Mink and otters are semi-aquatic mustelids belonging to the same guild. Otters are expected to be the dominant competitor because they are larger and better adapted at exploiting aquatic resources. Our hypothesis was that mink declines when the density of otters increases. We measured the effect of competition at the population level, by observing whether mink distribution and densities changed in an area of 1353 km2 in association with the arrival of its putative competitor. We estimated distribution and densities by means of sign surveys and trapping. The results showed that otters were associated with a significant and rapid reduction in the densities of mink, while mink occupancy remained approximately the same in an area of 2464 km2 that was used as a control. We observed that the spatial distribution of the mink population throughout its decline was influenced by the yearly cycle of mink activities, with areas being temporarily re-colonized during the dispersal season. Mink is an invasive species in the UK threatening the survival of some native species. Our findings suggest that the re-establishment of otter populations is likely to lead to a decline of mink that may, in turn, be beneficial to native species threatened by this invasive. [source] | ||||||||||||||||||||||||||||