Psittacine circovirus infection in parakeets of the genus Eunymphicus and treatment with beta-(1,3/1,6)-D-glucan

Eight captive-bred horned parakeets (Eunymphicus cornutus) and four captive-bred Major Mitchell cockatoos (Cacatua leadbeateri) from the same aviary tested positive for psittacine circovirus (PsCV) DNA in whole blood by nested-polymerase chain reaction (PCR). The chronic form of disease with feather fragility and loss was observed in three horned parakeets. Infection in other individuals was subclinical. Immunosuppression, either hematologically or as susceptibility to secondary infections, was not observed. Treatment consisted of the administration of beta-(1,3/1,6)-D-glucan from oyster mushroom (Pleurotus ostreatus). Excluding two accidentally dead parakeets, four out of the original six horned parakeets, and all Major Mitchell cockatoos were negative for PsCV DNA in whole blood in 7-9 mo after the treatment was started. Even though the absence of PsCV DNA in blood does not signify elimination of the virus from the whole organism, these preliminary results indicate a possible effect of beta-glucan in the treatment of PsCV infection. To the author's knowledge, this is the first report of PsCV in horned parakeets.     

Matrix-driven translocation of cells and nonliving particles

Cells of metazoan organisms produce and react to complex macromolecular microenvironments known as extracellular matrices. Assembly in vitro of native, compositionally nonuniform collagen-fibronectin matrices caused translocation of certain types of cells or polystyrene-latex beads from regions lacking fibronectin into regions containing it. The translocation process was not due to diffusion, convection, or electrostatic distribution effects, but may depend on nonequilibrium phenomena at the interface of contiguous collagen matrices formed in the presence and absence of fibronectin or particles. Extracellular matrix formation alone was sufficient to drive translocation by a biophysical process that may play a role in cellular migration during embryogenesis, as well as in other types of tissue reorganization such as inflammation, wound healing, and tumor invasion.     

Optimum timing of gibberellin A4/7 sprays to promote cone production in jack pine seedlings

Three-year-old jack pine (Pinus banksiana Lamb.) seedlings in pots were sprayed with gibberellin A_4/7 solution during the 1989 growing season. Unsprayed and sprayed controls, and seedlings sprayed with gibberellin A_4/7 at three concentrations (200, 400 and 600 mgL^-1) were tested in each of five different treatment periods based on jack pine morphogenesis. Each spraying period consisted of five weekly applications between May and October. Trees produced significantly more pollen cones than the two controls when sprayed at 400 or 600 mgL^-1 during July and early August. Spraying at 600 mgL^-1 during May–June and June–July produced significantly more seed cones than the two controls, as did spraying at 400 or 600 mgL^-1 during July and early August. The best treatment for both pollen- and seed-cone production was weekly spraying at 400 or 600 mgL^-1 gibberellin A_4/7 from early July, which coincided with the end of terminal shoot elongation, through early August, which coincided with microsporophyll initiation in the pollen-cone buds and initiation of the potential seed-cone buds.     

Core-derived historical records of suspended sediment origin in a mesoscale mountainous catchment: the River Bléone, French Alps

Purpose

Quantifying suspended sediment fluxes and dynamics across mountains, and identifying the origin of sediment in severely eroded areas, are of primary importance for the management of water resources. This contribution aims to generalise previous results from suspended sediment fingerprinting obtained during 2007?C2009 in a mesoscale Alpine catchment (the Bléone River; 905?km²) in France, and to assess variability in sediment sources throughout the second half of the twentieth century.

Materials and methods

Sediment fingerprinting, based on elemental geochemistry and radionuclide measurements, was conducted on a sediment core collected in an alluvial floodplain at the basin outlet. This technique was combined with hydro-sedimentary time-series to reconstruct the origin of suspended sediment deposited at this location over the last 50?years.

Results and discussion

Interpretation of sedimentation based on historical hydrological databases corroborates core dating obtained with ¹³⁷Cs and ²¹⁰Pb_xs activity measurements. Black marls and (marly) limestone sources provided the main fraction of sediment throughout the sequence (40 and 22?%, respectively). However, we also found evidence for the occurrence of major floods carrying large quantities of sediment originating from Quaternary deposits and conglomerates (25 and 16?%, respectively). The variability of sediment sources throughout the sequence may reflect the spatial variability of rainfall within the catchment, which in turn reflects its origin. However, the relatively homogeneous sediment composition throughout the sequence confirms that core-derived information is representative of widespread flood events.

Conclusions

These results are consistent with those obtained in previous studies. They also outline the need to take into account the entire grain size range of fine sediment in order to provide an overall picture of sediment sources and transfers within highly erosive catchments. This study also emphasizes the importance of using archival data to validate the results of sediment fingerprinting studies conducted during short contemporary monitoring programmes, and to extend fingerprinting of sediment sources over longer time-scales which include large and widespread floods.     

Electric current in polymer solution jet and spinnability in the needleless electrospinning process

In this study, the electric current of polymer solution jet was measured during a needleless rod electrospinning process using memory oscilloscope recording. According to the results, electric current of solution jet increases as the polyurethane (PU) and tetraethylammonium bromide (TEAB) salt concentration increase. Especially at 17.5 and 20 wt% PU concentrations, electric current increases dramatically with TEAB concentration. Also, there is a strong relationship between the electric current in the solution jet, spinnability and the spinning performance of the roller electrospinning. Thus, the spinnability of polymer solutions can be easily estimated using this simple method.     

Investigating the use of fallout and geogenic radionuclides as potential tracing properties to quantify the sources of suspended sediment in a mining catchment in New Caledonia,South Pacific

Journal of Soils and Sediments - New Caledonia, a French island located in the south-west Pacific Ocean, has vast nickel resources. Open-cast mining has strongly increased soil erosion and the...     

Quantifying suspended sediment sources during runoff events in headwater catchments using spectrocolorimetry

Purpose

Understanding hydro-sedimentary dynamics at the catchment scale requires high temporal resolution data on suspended sediments such as their origin, in addition to the common measurements of sediment concentrations and discharges. Some rapid and low-cost fingerprinting methods based on spectroscopy have recently been developed. We investigated how visible spectra could be used to predict the proportion of various source materials in suspended sediment samples, paying particular attention to the potential alteration of spectrocolorimetric signatures between soils and suspended sediments during transport.

Materials and methods

The 22-km² Galabre catchment, France, is composed of black marls, limestones, molasses, undifferentiated deposits and gypsum. Forty-eight source materials were sampled and 328 suspended sediment samples were collected at the outlet during 23 runoff events. Measurements were taken with a diffuse reflectance spectrophotometer on dried samples. As the erosion processes are particle size selective, five particle size fractions of source material were measured in order to assess the potential alteration of the fingerprint signatures. As the biogeochemical processes occurring in the river could also affect the signatures, source materials were immersed in the river for durations ranging from 1 to 63 days and subsequently measured. Finally, partial least-squares regression models were constructed on 81 artificial laboratory mixtures to predict the proportions of source materials.

Results and discussion

The spectrocolorimetric measurements discriminated the primary source materials but not the Quaternary deposits. As the gypsum was not conservative, only the black marls, molasses and limestones were used in the fingerprinting procedure. The construction of the partial least-squares regression models led to a median absolute error of 1.1%. This error increased to 3.9% when the models were applied to source samples with: (1) different particle sizes; (2) different durations spent in the river; or (3) different origins than those used for their construction. The effect of particle size on the fingerprinting procedure was larger than the effect of biogeochemical reactions or the spatial variability of the spectrocolorimetric signatures. Half of the 23 runoff events analysed exhibited huge variations in the source proportions from one sediment sample to another.

Conclusions

The spectrocolorimetric fingerprinting approach was able to quantify routinely the proportion of primary source materials in all suspended sediment samples collected during runoff events. The high temporal resolution of the predicted proportions revealed that only analysing three or four suspended sediment samples during a runoff event could lead to a misunderstanding of the hydro-sedimentary processes for more than half of the investigated runoff events.     

An investigation to enhance understanding of the stimulation of weed seedling emergence by soil disturbance

Enhanced understanding of soil disturbance effects on weed seedling recruitment will help guide improved management approaches. Field experiments were conducted at 16 site‐years at 10 research farms across Europe and North America to (i) quantify superficial soil disturbance (SSD) effects on Chenopodium album emergence and (ii) clarify adaptive emergence behaviour in frequently disturbed environments. Each site‐year contained factorial combinations of two seed populations (local and common, with the common population studied at all site‐years) and six SSD timings [0, 50, 100, 150, 200 day‐degrees (d°C, base temperature 3°C) after first emergence from undisturbed soil]. Analytical units in this study were emergence flushes. Flush magnitudes (maximum weekly emergence per count flush) and flush frequencies (flushes year^?1) were compared between disturbed and undisturbed seedbanks. One year after burial, SSD promoted seedling emergence relative to undisturbed seedbanks by increasing flush magnitude rather than increasing flush frequency. Two years after burial, SSD promoted emergence through increased flush magnitude and flush frequency. The promotional effects of SSD on emergence were strongest within 500 d°C following SSD; however, low levels of SSD‐induced emergence were detected as late as 3000 d°C following SSD. Accordingly, stale seedbed practices that eliminate weed seedlings should occur within 500 d°C of disturbance, because few seedlings emerge after this time. However, implementation of stale seedbed practices will probably cause slight increases in weed population densities throughout the year. Compared with the common population, local populations exhibited reduced variance in total emergence measured within sites and across SSD treatments, suggesting that C. album adaptation to local pedo‐climatic conditions involves increased consistency in SSD‐induced emergence.     

Effect of cutting frequency on species richness and dry matter yield of permanent grassland after grazing cessation

The effect of grazing cessation management has only rarely been investigated. In this study, the influence of cutting regime in the absence of fertilization was examined during 2005–2011 on a semi-natural grassland in Rapotin (Czech Republic) which had been grazed for more than 30 years before the start of the trial. This was conducted as a randomized plot design with five levels of treatment: 4 C – intensive (four cuts per year); 3 C – medium intensive (three cuts per year); 2 C – low intensive (two cuts per year); 1 C – extensive (one cut per year); 0 C – abandoned (control; without any management). Species richness was significantly lower in treatments 1 C and 0 C than in other treatments. Management and year had similar and significant influence on species composition and explained 23% of its variability. Dry matter (DM) yields were found to be lower in three-cut than in two-cut treatments (5.56 t ha^?1 and 6.22 t ha^?1, respectively). In the case of grazing cessation, a suitable compromise of three cuts per year can be recommended to guarantee maintenance of species richness, botanical composition, and appropriate grass forage yield under similar site conditions.     

Genetics of a butterfly relocation: large, small and introduced populations of the mountain endemic Erebia epiphron silesiana

Species specific levels of genetic diversity are necessary for the viability of populations. Erebia epiphron (Lepidoptera: Satyrinae) is a relic species in the Sudetan Mountains, Czech Republic. These populations represent a suitable study object to test the population genetic effects of large, small and introduced populations by means of allozyme electrophoresis. A large continuous and viable population (>100,000 individuals) shows a significantly higher genetic diversity than a small isolated and declining population (ca. 5000 individuals), which most probably was founded during the Little Ice Age in the 17th and 18th centuries and became isolated afterwards. In 1932 and 1933, 50 females were transferred from the large population to the Krkonose Mountains, where they established a viable and quickly expanding population. The number of transferred individuals was sufficient to transfer most of the allozyme diversity of the large natural population. Due to the higher elevation of the Krkonose in comparison to the native range, this allocation might safeguard the survival of the Czech race of E. epiphron even under conditions of global warming.