Florida current volume transports from voltage measurements

The volume transport of the Florida Current is determined from the motionally induced voltage difference between Florida and Grand Bahama Island. Simultaneous measurements of potential differences and of volume transport by velocity profiling have a correlation of 0.97. The calibration factor is 25+/- 0.7 sverdrups per volt, and the root-mean-square discrepancy is 0.7 sverdrup. The induced voltage is about one-half the open-circuit value, implying that the conductance of the sediments and lithosphere is about equal to that of the water column.     

N-acetylcysteine manipulation fails to elicit an increase in glutathione in a teleost model

Levels of oxidative stress can be affected by a range of compounds including toxins and pharmaceuticals. Antioxidants are important protective compounds which counteract the damaging effects of oxidative stress. Glutathione (GSH) is one of the main antioxidants for many organisms and can be synthesized from administered N-acetylcysteine (NAC). NAC has therefore often been used in a wide range of taxa to manipulate levels of GSH. Our objective was to validate this approach in a wild temperate teleost fish model, the brown trout (Salmo trutta). We used intracoelomic injections of NAC in saline and vegetable shortening, at two different concentrations (100 and 400 mg/kg), with the appropriate controls and shams, under controlled laboratory settings. We found that NAC failed to elicit an increase in GSH over three time periods and concluded that NAC is not an effective method to enhance GSH levels in teleost fish using the concentrations and vehicles tested here. We emphasize the importance of validation studies across all new species/taxa when possible and suggest that more investigation is required with regard to NAC manipulation in fish if this approach is to be used.     

Multidisciplinary study of a Lateglacial-Holocene sedimentary sequence near Bologna (Italy): insights on natural and anthropogenic impacts on the landscape dynamics

Journal of Soils and Sediments - This study investigated a Lateglacial to Holocene sedimentary sequence derived from a small catchment located at San Lazzaro di Savena in the surroundings of...     

Induction of porcine post-weaning multisystemic wasting syndrome (PMWS) in pigs from PMWS unaffected herds following mingling with pigs from PMWS-affected herds

In this paper we present the results from two experimental studies (I and II) investigating whether post-weaning multisystemic wasting syndrome (PMWS) can be induced in pigs from PMWS unaffected herds by mingling with pigs from PMWS-affected herds and to observe whether transportation and/or mingling of healthy pigs from unaffected herds could induce PMWS.The studies comprised pigs from 12 different herds. Eight herds had PMWS while four were unaffected. All 12 herds were found to be infected with PCV2. Pigs from PMWS-affected herds were mingled with pigs from unaffected herds in four separate compartments in both study I and study II. In addition, in study II, four groups of pigs from unaffected herds were included. Two groups with pigs transported and mingled from unaffected herds and two groups with pigs which were only transported. The PMWS diagnoses on the individual pigs were based on lymphoid depletion, histiocytic proliferation and the presence of giant cells or inclusion bodies together with the demonstration of PCV2 in lymphoid tissue.Healthy pigs, in both studies, developed PMWS 4–5 weeks after mingling with pigs clinically affected with PMWS. None of the pigs from unaffected herds which had no contact with pigs from PMWS-affected herds developed clinical signs of PMWS. Transportation and mingling of pigs from PMWS unaffected herds in combination or alone was insufficient to provoke PMWS.     

Inter-laboratory and inter-assay comparison on two real-time PCR techniques for quantification of PCV2 nucleic acid extracted from field samples

Several real-time PCR assays for quantification of PCV2 DNA (qPCR) have been described in the literature, and different in-house assays are being used by laboratories around the world. A general threshold of 10(7) copies of PCV2 per millilitre serum for postweaning multisystemic wasting syndrome (PMWS) diagnosis has been suggested. However, neither inter-laboratory nor inter-assay comparisons have been published so far. In the present study, two different qPCR probe assays used routinely in two laboratories were compared on DNA extracted from serum, nasal and rectal swabs. Results showed a significant linear association between the assays (p<0.0001), and a systematic difference of 1.4 log10 copies of PCV2 per millilitre of sample (p<0.0001). This difference indicated that the assay from laboratory 1 yielded a higher output than the one from laboratory 2. Results also showed that there was no linear association between the amount of PCV2 DNA and the amount of total DNA, neither in nasal (p=0.86) nor in rectal (p=0.78) swabs, suggesting that normalizing of PCV2 DNA load in swab samples to total DNA concentration is not suitable. The present exploratory study highlights the need for the performance of ring trials on qPCV2 protocols between laboratories. Meanwhile, the proposed thresholds for PMWS diagnosis should only be considered reliable for each particular laboratory and each particular assay.     

Speciation of phytate ion in aqueous solution. Sequestering ability toward mercury(II) cation in NaClaq at different ionic strengths

As a contribution to understanding the speciation of mercury in the environment and to the study of the sequestering ability of phytate (Phy) toward heavy metal and organometal cations, this paper describes the results of an investigation (at t = 25 degrees C by potentiometry, ISE-H+ glass electrode) of its interactions with mercury(II) cation in NaCl aqueous solutions at different ionic strengths (I = 0.15 and 1.0 mol L(-1)), in the pH range 2.5 < or = pH < or = 9.5 and considering metal-to-ligand ratios of 1:1 < or = Hg/Phy < or = 4:1. The formation of 11 HgiHjPhy(12-2i-j)(- species with i = 1 and 0 < or = j < or = 7 and i = 2 and 0 < or = j < or = 2 was observed. Their complex formation constant values proved to be fairly dependent on ionic strength. The speciation of phytic acid and mercury(II) is also dependent on the metal-to-ligand ratio; the dependence of the stability of phytate-mercury(II) species on the phytate protonation step was modeled, and an empirical predictive relationship was proposed. From the results obtained, phytate has very good sequestering ability toward Hg2+, even in the presence of considerable excesses of chloride ion, that is, another ligand strongly interacting with mercury; this supports future studies both on the use of plants that naturally synthesize it for phytoremediation purposes and on its direct application in remediation techniques.     

Flow cytometric patterns in blood from dogs with non-neoplastic and neoplastic hematologic diseases using double labeling for CD18 and CD45

BACKGROUND: In dogs, flow cytometry is used in the phenotyping of immunologic cells and in the diagnosis of hemic neoplasia. However, the paucity of specific antibodies for myeloid cells and B lymphocytes and of labeled antibodies for multicolor techniques limits the ability to detect all leukocyte subpopulations. This is especially true for neoplastic and precursor cells. CD18 and CD45 are expressed on all leukocytes and are involved in cell activation, and together could be useful in helping determine cell lineage. OBJECTIVES: The purpose of this study was to double label canine blood for CD18 and CD45 and to use the differential expression of antigens to identify leukocyte populations in dogs with non-neoplastic and neoplastic hematologic diseases. METHODS: A template was developed using blood samples from 10 clinically healthy dogs and a back-gating technique. Differential leukocyte counts obtained with the template were compared with those obtained by manual and automated methods on blood samples from 17 additional healthy dogs. Blood samples obtained from 9 dogs with non-neoplastic (reactive) hematologic diseases and 27 dogs with hemic neoplasia were double stained for CD18 and CD45 using mouse anticanine CD18 monoclonal antibody (mAb) plus phycoerythrin-conjugated rat anticanine CD45 mAb and fluorescein isothiocyanate-conjugated rabbit antimouse IgG. Hemic neoplasms were diagnosed by cell morphology, and immunophenotypic and cytochemical markers. RESULTS: With the double label, neutrophils, eosinophils, monocytes, and T- and B-lymphocytes were identified. In reactive disorders, a population of activated neutrophils with high CD45 and CD18 expression was detected. In hemic neoplasia, cell lineage was easily determined, even in acute leukemia. CONCLUSIONS: Double labeling for CD18/CD45 may be useful as a screening method to evaluate hematologic diseases and help determine cell lineage, and to aid in the selection of a panel of antibodies that would be useful for further analysis.     

Soil organic matter dynamics and losses in manured maize-based forage systems

Soil organic matter (SOM) produces positive effects on multiple soil properties. Increasing its level also provides an opportunity to reduce atmospheric concentration of carbon dioxide (CO₂). Recycling animal manure and returning crop residue are among the main practices to enhance organic carbon (C) stock in arable croplands. This study analysed data of soil organic carbon (SOC) stocks from a medium-term field trial (established in 1992) through a Hénin–Dupuis-based equation to determine the proportion of different organic materials retained in the soil as SOM.The treatments included in the experiment simulated different typical management techniques and implied the application to the soil of various organic materials, i.e. cattle slurry, cattle farmyard manure, maize straw, root, maize and ley stubble. Soil organic carbon and total nitrogen (N) (Kjeldhal N) were measured in the 0–30 cm layer during spring 1999 and spring 2003. The relationship between SOC and N stocks measured in 1999 and 2003 and the annual additions of C and N was described by the Hénin–Dupuis-based equation, assuming the presence of two C and N pools (stable and fresh).Our results showed that the application of farmyard manure, slurry and maize straw induced higher C and N content compared to the application of urea without return of crop residue. The different levels of urea application did not produce any significant difference in C and N soil content.We found that approximately 2% of SOC is lost to the atmosphere annually. Furthermore, the amount of C and N retained in the soil each year varied by organic materials: 46% C and 44% N with farmyard manure, 26% C and 11% N with slurry, 28% C and 10% N with root and 6% C with maize straw and ley stubble.These results were used to inform an estimate of C lost or removed to/from atmosphere following manure application and crop residue return for the compilation of greenhouse gas inventories. We found that the most C conservative management is the production and spreading of farmyard manure and that increasing amounts of mineral N fertilizer did not affect the C sequestration extent.     

Hybridization between Quercus robur and Q. petraea in a mixed oak stand in Denmark

? Hybridization and mating pattern between Quercus robur and Q. petraea was studied in a 5.8 ha mixed forest stand in Jutland, Denmark which comprises in total 135 Quercus robur and 230 Q. petraea trees. Classification of the oak trees into species was performed using canonical discriminant analysis of a range of leaf morphological traits. Adult trees (365) and offspring (582) were genotyped with eight microsatellite markers. Seedlings were sampled in 2003 and acorns were collected in 2004.

? Mating patterns of Q. robur and Q. petraea are expected to be different in the northern range of the distribution area and a larger hybridization rate is expected. It is further expected, that pollination from outside sources will be relatively less in small fragmented forest management systems compared to large scale oak forest. The conclusions should be verified through repeated year to year analysis of the mating pattern.

? Phenological studies revealed that there was no difference in flowering time between species. Data for the adult trees revealed no significant departures from Hardy-Weinberg proportions and there was weak, but significant spatial genetic structure, which supports the idea that the stand is of natural origin. Spatial genetic structure in the first distance class is stronger for Q. petraea. The genetic composition of the offspring was remarkably consistent from year to year. Paternity analysis revealed that, on average, 85% pollination came from fathers within the stand. The direction of the pollen flow varied from year to year. Inter-specific hybridization was high and ranged from 15–17% and from 48–55% for Q. petraea and Q. robur mothers respectively. Paternity analysis revealed that the population was basically outcrossing and only 3.7% of the analysed progeny were the product of selfing. Over the two years of study, approximately 200 trees contributed to the paternity of the next generations.

? The study confirms earlier studies with a greater tendency for Q. robur mothers to produce hybrid seeds than Q. petraea mothers. The rate of hybridization is higher in this Danish stand than in comparable studies elsewhere in Europe. Gene flow from outside sources are relatively low.