1,202 research outputs found
Notes on the birds of the tidal lowlands and floodplains of South Sumatra province, Indonesia
During an environmental baseline survey of the tidal lowlands and floodplains of South Sumatra Province in 1988-89, a total of 270 bird species was recorded. This paper focuses on wetland species, including those inhabiting swamp forests. No upland forest habitats are found within the region described. The area supports a diverse avifauna, including some globally threatened species that have a core population here, notably Milky Stork Mycteria cinerea, Storm's Stork Ciconia stormi, Lesser Adjutant Leptoptilos javanicus, Black-headed Ibis Threskiomis melanocephatus and Asian Dowitcher Limnodromus semipalmatus. The coast has vital passage and wintering grounds that rank second in importance only to coastal wetlands in Bangladesh for East Palaearctic waders in terms of numbers of birds. Three species were recorded for the first time in Sumatra: Spotted Eagle Aquila clanga, Steppe/Imperial Eagle Aquila nipalensis/heliaca and Spotted Redshank Tringa erythropa, and first Sumatran breeding records were obtained for Javan Pond-heron Ardeola speciosa and White-headed Stilt Himantopus leucocephalus. A few species were observed outside their previously recorded usual habitats. The paper discusses the principal habitats of the area, and the very rapid rate of development that has occurred during the past two decades. Only one wetland area in the province has protection status, Padang-Sugihan. This Wildlife Reserve does not provide habitat for eight out of the eleven globally threatened species recorded in the study area. Consequently the establishment of two additional swamp reserves and bird sanctuary is strongly recommended
A Formalism for Scattering of Complex Composite Structures. 1 Applications to Branched Structures of Asymmetric Sub-Units
We present a formalism for the scattering of an arbitrary linear or acyclic
branched structure build by joining mutually non-interacting arbitrary
functional sub-units. The formalism consists of three equations expressing the
structural scattering in terms of three equations expressing the sub-unit
scattering. The structural scattering expressions allows a composite structures
to be used as sub-units within the formalism itself. This allows the scattering
expressions for complex hierarchical structures to be derived with great ease.
The formalism is furthermore generic in the sense that the scattering due to
structural connectivity is completely decoupled from internal structure of the
sub-units. This allows sub-units to be replaced by more complex structures. We
illustrate the physical interpretation of the formalism diagrammatically. By
applying a self-consistency requirement we derive the pair distributions of an
ideal flexible polymer sub-unit. We illustrate the formalism by deriving
generic scattering expressions for branched structures such as stars, pom-poms,
bottle-brushes, and dendrimers build out of asymmetric two-functional
sub-units.Comment: Complete rewrite generalizing the formalism to arbitrary functional
sub-units and including a new Feynmann like diagrammatic interpretatio
Sediment supply explains long-term and large-scale patterns in saltmarsh lateral expansion and erosion
Salt marshes often undergo rapid changes in lateral extent, the causes of which lack common explanation. We combine hydrological, sedimentological, and climatological data with analysis of historical maps and photographs to show that long‐term patterns of lateral marsh change can be explained by large‐scale variation in sediment supply and its wave‐driven transport. Over 150 years, northern marshes in Great Britain expanded while most southern marshes eroded. The cause for this pattern was a north to south reduction in sediment flux and fetch‐driven wave sediment resuspension and transport. Our study provides long‐term and large‐scale evidence that sediment supply is a critical regulator of lateral marsh dynamics. Current global declines in sediment flux to the coast are likely to diminish the resilience of salt marshes and other sedimentary ecosystems to sea level rise. Managing sediment supply is not common place but may be critical to mitigating coastal impacts from climate change
External conditions drive optimal planting configurations for salt marsh restoration
Coastal salt marshes are threatened by erosion from storminess and sea level rise, with resulting losses in flood protection, wildlife and recreational space. Although more than $1 billion has been spent to reconcile losses, restoration has had varying success because of poor survival of planted patches in challenging wave and current conditions. Marsh expansion after colonization or replanting is regulated by positive and negative feedbacks between vegetation density and sediment capture. Dense vegetation stimulates sediment capture and vertical patch growth, but negatively constrains patch expansion by concentrating hydrological energy into erosion gullies along patch edges. Conversely, low-density vegetation may not simulate enough sediment capture, which increases plant dislodgement mortality. The strengths of positive and negative feedbacks will vary with wave exposure, but this has never been tested in natural conditions. We observed density-dependent sediment feedbacks, survival and lateral expansion by Sporobolus anglicus patches (0.8 × 0.8 m) planted at three levels of vegetation density, at each of three levels of wave forcing (three sites). We found interactive effects of plant density and forcing on the strength of positive and negative feedbacks. Density-dependent feedbacks only emerged in moderate and exposed conditions: classic marsh tussock patch shapes, which arise due to combined positive (vertical growth) and negative (gullies) feedbacks, were only associated with high density vegetation under exposed conditions. At high exposure, survival was enhanced by dense planting, which diverted energy away from the vegetation. In sheltered conditions, expansion was the greatest at medium density, while dense patches had high mortality and erosion. Synthesis and applications. Success of wetland restoration clearly hinges on considering interactions between environmental stress and planting density. In challenging high-exposure settings, dense planting in large patches should maximize success, as plant facilitation boosts sediment capture and negative edge effects (gullies) will represent a diminished proportion of larger patches. Yet, benefits of dense planting will switch from positive (facilitation) to negative (competition) with reduced environmental stress, when moderate-density planting might be optimal. Switches along stress gradients between positive and negative feedbacks are common across ecosystems. We call for wider integration of facilitation and stress–gradient principles into restoration design to safeguard restoration successes
The blood volumes of the primary and secondary circulatory system in the Atlantic cod Gadus morhua L., using plasma bound Evans Blue and compartmental analysis
The volume of the primary (PCS) and secondary (SCS) circulatory system in the Atlantic cod Gadus morhua was determined using a modified dye dilution technique. Cod (N=10) were chronically cannulated in the second afferent branchial artery with PE-50 tubing. Evans Blue dye was bound to harvested fish plasma at a concentration of 1 mg dye ml(-1) plasma, and injected at a concentration of 1 mg kg(-1) body mass. Serial sampling from the cannula produced a dye dilution curve, which could be described by a double exponential decay equation. Curve analysis enabled the calculation of the primary circulatory and total distribution volume. The difference between these volumes is assumed to be the volume of the SCS. From the dilution curve, it was also possible to calculate flow rates between and within the systems. The results of these experiments suggest a plasma volume in the PCS of 3.42+/-0.89 ml 100 g(-1) body mass, and in the SCS of 1.68+/-0.35 ml 100 g(-1) body mass (mean +/- S.D.) or approximately 50% that of the PCS. Flow rates to the SCS were calculated as 2.7% of the resting cardiac output. There was an allometric relationship between body mass and blood volumes. Increasing condition factor showed a tendency towards smaller blood volumes of the PCS, expressed as percentage body mass, but this was not evident for the volume of the SCS
Prevalence of Cancer in Adult Patients with Atopic Dermatitis:A Nationwide Study
Abstract is missing (Short communication
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