The implications of sample preparation on the particle size distribution of soil

Particle size distribution (PSD) is among basic parameters in soil and sediment characterization and provides essential information in sedimentological and environmental studies. The problem with the PSD determination is that for any given sample the result depends not only on the method used but also on the sample pre‐treatment, making them seldom comparable. In this study, the PSD of seven non‐treated and pre‐treated soil samples were determined by four granulometric methods (pipette, sedigraph, particle counter and laser diffraction analysis). Samples were subjected to pre‐treatments commonly used in sample preparation for the PSD determination, i.e., addition of dispersant (sodium metaphosphate) and removal of the organic matter (with hydrogen peroxide). The total organic carbon (TOC) analysis was used to estimate the content of organic matter before and after its removal. The effect of different pre‐treatments was evaluated based on the PSD variations and the changes in the specific surface area (SSA) of the samples. The results highlighted differences in the PSD curves of samples depending on the granulometric method and pre‐treatment applied. The most pronounced difference was the higher amount of clay fraction determined by settling techniques. The role of hydrogen peroxide in disruption of aggregates was evident in the increase in the SSA as well as the share of fine fraction determined by all four techniques, while sodium metaphosphate made no modifications of the SSA but acted in favour of prolonging settling of clay particles and increasing its content obtained by settling techniques.     

Pore water geochemistry and diagenesis of estuary sediments—an example of the Zrmanja River estuary (Adriatic coast,Croatia)

Journal of Soils and Sediments - The geochemistry of pore waters from sediments deposited in the semi-enclosed bay of the Zrmanja River estuary, encompassing two small interconnected basins, the...     

Neospora caninurn Infection in English Springer Spaniel Littermates

Progressive paraparesis developed in four male English Springer Spaniel pups from a litter of five during the first 10 weeks of life. Two of the pups, which had the earliest onset of neurologic signs, were euthanatized without further workup. However, a detailed investigation was completed on the remaining two littermates at 12 weeks of age. Both pups had progressive paraparesis for 3 to 4 weeks before presentation, with one dog developing subsequent asymmetric pelvic limb extensor rigidity. Based on results from neurologic examination, cerebrospinal fluid (CSF) analysis, electrophysiology, and muscle/nerve biopsy, a presumptive diagnosis of protozoal polyradiculitis and polymyositis was made. Necropsy of the most severely affected pup confirmed the clinical diagnosis of inflammatory nerve root and muscle disease but no organisms were found. To increase the potential yield of organisms, the second pup was placed on immunosuppressive doses of corticosteroids and euthanatized 2 weeks later. Numerous organisms were found in lesions in muscle and the central nervous system. Organisms grew in tissue culture and were isolated from the peritoneal fluid of gerbils inoculated with infected tissue. Organisms were not isolated from inoculated mice, guinea pigs, rabbits, and hamsters. No parasites were seen in feces or tissues of three cats fed infected dog tissues. Serologic testing demonstrated a strong positive titer to Neospora caninum in both pups, and electron microscopy showed the characteristic morphology of this parasite.     

Detection of apple proliferation phytoplasma by ELISA and PCR in growing and dormant apple trees

Journal of Plant Diseases and Protection - Apple proliferation (AP), caused by a phytoplasma belonging to AP group, is an important vector-borne and graft-transmissible disease of apple trees in...     

Evaluation of the dynamic predictors of fluid responsiveness in dogs receiving goal-directed fluid therapy

Objectives

Goal-directed fluid therapy (GDFT) based on pulse pressure variation (PPV) was used in anaesthetized dogs undergoing abdominal surgeries. The aims were 1) to evaluate the success rate of the PPV ≥13% in detecting fluid responsiveness [delta stroke volume (ΔSV) ≥10%]; 2) to assess the correlation between PPV, systolic pressure variation (SPV), Plethysmograph Variability Index (PVI) and central venous pressure (CVP) and 3) to establish the threshold value for the PVI that would predict a PPV value of ≥13% and indirectly discriminate responders from nonresponders to fluid therapy.

In vitro Germination of Early Ripening Sweet Cherry Varieties (Prunus avium L.) at Different Fruit Ripening Stages

In vitro embryo culture enabled satisfactory germination of immature seeds produced in crosses from early ripening sweet cherry varieties (Prunus avium L.). Three varieties —‘Rita’, ‘Bigarreau Burlat’ and ‘Carmen’— were crossed with ‘Early Star’ as male parent. Germination rate was affected by the developmental stage of both fruit and embryo. Fruit ripening stage was a critical factor for culture infection rate that increased with maturity. In-ovule embryo culture on Murashige and Skoog medium without hormones improved the embryo size but did not increase the germination rate due to a further increase in infection rate. Ex-ovule embryo culture on Murashige and Skoog medium supplemented with BA 1 mg L^?1, NAA 0.5 mg L^?1, 20 g L^?1sucrose, 10 g L^?1 sorbitol and 6 g L^?1agar during the stratification time increased embryo length. Germination was performed on Brooks and Hough medium at the 22?±?1?°C with 16/8 h light/dark photoperiod. The highest germination rate (75?%) was reached in embryos that were 3?4 mm in length, after 30-days stratification at 4?°C. Embryos in fruits at green-yellow stage that were 3?4 mm long were morpho-physiologically developed to produce bipolar seedlings, without combined application of embryo culture and micropropagation.     

酵母可给动物机体提供抗病保护

试验时期:2006年3月至8月; 针对问题:产蛋母鸡对疾病感染比较敏感,并且可用于预防和治疗的措施非常有限.一个可能的方法是使用广泛用于提高肉鸡、火鸡、肉种鸡和猎鸟肠道健康的饲料添加剂.为了对此方法进行评估,我们给一组散养蛋鸡饲喂酵母型饲料添加剂(Alphamune).