Influence of Soil Parameters on the Efficiency of the Attrition Process to Remove Metals,PCP, Dioxins and Furans from Contaminated Soils

The objective of this study was to evaluate the influence of the soil parameters (particle size, initial contamination level, etc.) on the performances of an attrition process to remove As, Cr, Cu, pentachlorophenol (PCP) and dioxins and furans (PCDD/F). Five different contaminated soils were wet-sieved to isolate five soil fractions (<?0.250, 0.250–1, 1–4, 4–12 and >?12 mm). Five attrition steps of 20 min each, carried out in the presence of a biodegradable surfactant ([BW]?=?2%, w w^?1) at room temperature with a pulp density fixed at 40% (w w^?1), were applied to the coarse soil fractions (>?0.250 mm) of different soils. The results showed good performances of the attrition process to simultaneously remove PCP and PCDD/F from contaminated soil fractions initially containing between 1.1 and 13 mg of PCP kg^?1 (dry basis) and between 1795 and 5720 ng TEQ of PCDD/F kg^?1. It appeared that the amounts of contaminants removed were significantly correlated (p value?<?0.05, R ²?=?0.96) with the initial amounts of PCP and PCDD/F, regardless of the particle size of the soils studied. The nature of the soil (granulometric distribution, pH, total organic carbon (TOC) (organic matter) and diverse industrial origin) slightly and negatively influenced the efficiency of organic contaminants removals using attrition. However, the attrition treatment allowed an efficient removal of both PCP and PCDD/F from the coarse fraction of contaminated soil, despite the nature of the soil.     

Improving controlled pollination methodology for breeding <Emphasis Type="Italic">Acacia mangium</Emphasis> Willd.

Acacia mangium is a major plantation species for the pulp and paper industry in south-east Asia and there are a number of active breeding programs. The species is predominantly outcrossing, but with a demonstrated capacity to set selfed seed where outcross pollen is limited, with consequent inbreeding depression in the progeny. Current controlled pollination methods therefore include a time-consuming emasculation step. We used microsatellite genotyping of seedlings to determine the consequences of outcross pollination with and without emasculation. Only 1 of 3 mother trees set a small amount (5%) of selfed seed. Using whole inflorescences from the male parent as the pollen applicator rather than sieved pollen reduced outcross contamination rates from 19.1 to 8.7% and substantially increased worker productivity. Application of sugar solution to the female flowers immediately prior to pollination increased yield of sound seeds per spike. Additional improvements to the pollination protocols are discussed.     

Recovery process of a mountain forest after shifting cultivation in Northwestern Vietnam

The recovery process of fallow stands in the mountainous region of Northwestern Vietnam was studied, based on a chronosequence of 1–26-year-old secondary forests after intensive shifting cultivation. The number of species present in a 26-year-old secondary forest attained 49% of the 72 species present in an old-growth forest. Total stem density decreased gradually from 172,500 ha⁻¹ in a 3-year-old forest to 24,600 ha⁻¹ in the 26-year-old stand, but stem density of larger trees (diameter at breast height (D) ≥ 5 cm) increased from 60 ha⁻¹ in a 7-year-old to 960 ha⁻¹ in the 26-year-old forests, which was similar to that of an old-growth forest. Annual biomass increment of the 26-year-old stand was 4.2 Mg ha⁻¹ year⁻¹. A saturation curve was fitted to biomass accumulation in secondary forests. After an estimated time of 60 years, a secondary forest can achieve 80% of the biomass of old-growth forests (240 Mg ha⁻¹). Species diversity expressed by Shannon Index shows that it takes 60 years for a secondary forest in fallow to achieve a plant species diversity similar to that of old-growth forests.     

Characterization and implication of phytolith-associated potassium in rice straw and paddy soils

Rice straw contains up to 2.3% K in dry matter, including potassium (K) subcompartmented in phytoliths, complex siliceous structures formed in plant tissue via precipitation of Si. Rice straw is usually returned to the soil as a conventional practice to sustain soil nutrients, and therefore, the K pool accompanied with rice straw phytoliths is also cycled. Based on phytoliths obtained by ashing of rice straw at 400 °C and dissolution experiments using batch extraction in combination with physical separation of phytoliths by heavy liquid, this study evaluated the phytolith K(phytK) pool in rice straw and aged phytoliths in paddy soils. Entrapped organic matter containing K within phytolith silica cells was visualized by X-ray tomographic microscopy, and releases of this phytK pool accompanying phytolith dissolution were quantified. A 1% Na₂CO₃ solution, which has been commonly used to extract amorphous Si and to quantify soil phytoliths, showed obvious responses for K derived from phytolith dissolution, indicating that the Na₂CO₃ method can be developed for measurement of phytK. In 13 soil samples, Na₂CO₃-dissolvable K content assignable to phytK was 0.55 ± 0.39 g kg^?1 in the puddled horizon, suggesting the phytK pool is of high significance for the management of K in paddy soils.     

Effect of fishmeal replacement with Artemia biomass as a protein source in practical diets for the giant freshwater prawn Macrobrachium rosenbergii

A 30-day feeding experiment was conducted in 160-L plastic tanks to evaluate the potential use of Artemia biomass as a protein source in practical diets for postlarval Macrobrachium rosenbergii (initial mean weight of 12.12–12.29 mg). Nine isoenergetic and isonitrogenous experimental diets (approximately 40% crude protein) were formulated by replacing levels of the fishmeal (FM) protein difference either with dried or frozen Artemia (0, 25, 50, 75 and 100%). The 0% Artemia treatment, in which Peruvian FM was the only main protein source, was considered to be the control diet. The results showed that prawn postlarvae (PLs) fed the FM control diet had a lower survival (46%) compared with all Artemia diets. Significant differences ( P <0.05) were, however, only found at 75% and 100% Artemia protein inclusion levels (survival of 68–77%). A gradual increase in growth performance (live weight gain, specific growth rate and total length) of the prawns was achieved on increasing dietary inclusion of Artemia protein. Additionally, the size distribution exhibited the same response as growth performance. However, prawns fed the frozen Artemia diets showed a better performance than the ones fed the dried Artemia diets. It can be suggested that Artemia biomass may totally replace FM in practical diets for PLs of the freshwater prawn M. rosenbergii .     

Factors that influence passive transfer of immunoglobulins in foals.

Effects of farm management, breed, mare age, gestation duration, and climatologic factors on colostral specific gravity, colostral IgG concentration, and foal serum IgG concentration were evaluated. Climatologic variables measured were daily maximal, minimal, and mean air temperature, precipitation, average relative humidity, and total solar radiation. Presuckle, postpartum colostrum samples were collected from 140 Standardbred, 94 Thoroughbred, and 59 Arabian mares from January through June during 1985 and 1986. Thoroughbred (farm A, n = 61; farm B, n = 33) and Arabian (farm C, n = 45; farm D, n = 14) mares were located in Ocala, Fla; Standardbred mares (farm E) were in Montgomery, NY. Mares from farms A, B, D, and E foaled in box stalls, and mares from farm C foaled in sand paddocks. Mares with premature lactation greater than 12 hours were not included in the study. Foals were clinically normal at birth and suckled colostrum without assistance within 2 hours of parturition. Specific gravity of presuckle colostrum samples was measured by use of an equine colostrometer. Blood samples were collected 18 hours after parturition from 253 of the 293 foals (n = 45, 25, 32, 13, 138 on farms A through E, respectively) to determine serum concentration of IgG. The IgG concentrations in colostrum and serum were measured by single radial immunodiffusion. Data were analyzed by multiple regression or chi 2 analysis. The most important determinants of foal serum IgG concentration were the IgG content and specific gravity of presuckle colostrum samples (P less than 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)     

SCINTIGRAPHIC MEASUREMENT OF UTERINE CLEARANCE IN MARES

Uterine clearance of technetium 99m-albumin colloid (^99mTc-μAA) was qualitatively and quantitatively measured in 5 reproductively normal mares and 5 mares susceptible to endometritis (infertile). The percentage of 370 MBq ^99mTc-μAA cleared from the uterine lumen within 2 hr of intrauterine infusion was measured in 10 mares on day 3 of estrus and 48 hr after ovulation. The procedure was repeated 3 times on day 3 of estrus in 6 mares to determine repeatability. Six mares were infused with 1110 MBq ^99mTc-μAA on day 3 of estrus to evaluate the effect of increasing the dose to reduce the imaging time. There was no statistically significant difference in the mean percentage of radiocolloid cleared from the uterus during day 3 of estrus or 48 hr after ovulation or in the percent cleared when the studies were repeated in individual mares. There was no statistically significant difference in uterine clearance between the 370 and 1110 MBq dose studies in each mare from 15 to 120 min. Reproductively normal mares cleared approximately 50% of the radiocolloid from the uterus by 120 min while susceptible mares cleared less than 15%.     

Isolation and Characterisation of Single Chain Amylose

Five amylose preparations of different origins (cassava, potato, smooth seeded pea, wheat and maize), obtained from native starch granules by thymol complexation, were ultracentrifuged as the final decontamination step to remove a high molecular weight population contaminating the amylose solutions. The efficiency of this ultracentrifugation procedure was assessed by dynamic light scattering (DLS): decreases in apparent hydrodynamic radii,R?_H, from 46·1–72·6 nm before ultracentrifugation to 16·1–29·3 nm after were observed. Amylose solutions were then characterised by size exclusion chromatography coupled on-line to multi-angle laser light scattering (SEC–MALLS). Under these conditionsM?_wof cassava, potato, smooth seeded pea, wheat and maize amyloses were, respectively, 1·05×10⁶, 7×10⁵, 6·2×10⁵, 5·1×10⁵and 3·4×10⁵g/mol. Using a specific optimisation algorithm, experimental molecular weight distributions (MWD) were fitted by two mathematical models of ‘Most Probable’ distribution and ‘log-normal’ distribution. The best fit was obtained for the second model, but fittedM?_wwere higher than experimentalM?_w. When a ‘Most Probable’ model was used, the fittedM?_wwere consistent with experimentalM?_wbut with a lower quality of fit. Exponentscin the power lawR_G=KM^cwere between 0·6 and 0·7, indicating an extended linear random coil in the range of MW analysed (3×10⁵–9×10⁶g/mol). This procedure was also applied to the characterisation of different commercial amylose products.     

Relationship between metabolic status and results of embryo collection in high-producing cows

Blood samples were taken from 58 high-performance cows earmarked as donors for embryo transfer, one day before artificial insemination and following superovulation. An evaluation of 16 major indices showed the yield of transferable embryos to be clearly reduced by hypocholesterolemia, hyperproteinemia, and even more by hypophosphatemia. More than one deviating metabolic findings were obtained only from few animals which had the desired high number of embryos, that is above seven.     

Production of antibodies in murine mucosal immunization with Toxoplasma gondii excreted/secreted antigens

Toxoplasmagondii RH strain excreted/secreted antigens (ESA) were administrated weekly by the oral route, to two groups of 40 OF1 mice for 4 weeks. One group received ESA associated with cholera toxin (CT+) and the other, ESA only (CT-). Five animals from each group were sacrificed from day 4 (D4) to D49 following the first immunization and their feces and sera were collected and tested by ELISA for IgA, IgG and IgM antibody detection. In feces, IgA antibodies were detected on D4 and on D12 in the CT+ and CT- groups, respectively, and they persisted up to D49. IgG antibodies were detected from D12 to D41 in the CT+ group and on D12 only in the CT- group. No IgM antibodies were detected. In sera, IgA antibodies were detected on D27, D41 and D49 only in the CT+ group. IgG and IgM antibodies were found on D12 and D4, respectively, in the CT+ group and starting from D27 in the CT- group. To our knowledge, this is the first demonstration that ESA, with or without CT, are immunogenic when administrated by the oral route.