Modelling solute transport in structured soils: performance evaluation of the ADR and TRM models

The movement of chemicals through the soil to the groundwater or discharged to surface waters represents a degradation of these resources. In many cases, serious human and stock health implications are associated with this form of pollution. The chemicals of interest include nutrients, pesticides, salts, and industrial wastes. Recent studies have shown that current models and methods do not adequately describe the leaching of nutrients through soil, often underestimating the risk of groundwater contamination by surface-applied chemicals and overestimating the concentration of resident solutes. This inaccuracy results primarily from ignoring soil structure and nonequilibrium between soil constituents, water, and solutes. A multiple sample percolation system (MSPS), consisting of 25 individual collection wells, was constructed to study the effects of localized soil heterogeneities on the transport of nutrients (NO&minus;3, Cl&minus;, PO3&minus;4) in the vadose zone of an agricultural soil predominantly dominated by clay. Very significant variations in drainage patterns across a small spatial scale were observed (one-way ANOVA, p &lt; 0.001 indicating considerable heterogeneity in water flow patterns and nutrient leaching. Using data collected from the multiple sample percolation experiments, this paper compares the performance of two mathematical models for predicting solute transport, the advective-dispersion model with a reaction term (ADR), and a two-region preferential flow model (TRM) suitable for modelling nonequilibrium transport. These results have implications for modelling solute transport and predicting nutrient loading on a larger scale.<br /

Clinical placement and rurality of career commencement : a pilot study

This article reports on a project that aimed to discover whether rural placement can influence new graduates to take up rural positions, and what factors play a role in the decision-making. This pilot study reports the findings from a pre-survey of students (n = 110) who completed a questionnaire at the end of their rural placement in the Greater Green Triangle region, Australia. Findings are compared with matched questionnaire responses for students who subsequently completed a post-survey after graduation and who commenced work (n = 28). Rural placement appears to be associated with commencing rural practice after graduation. More graduates with an urban home address commenced rural practice than graduates with a rural home address who started their careers in the city. Longer placements may sway those with a city background to start work in a rural area.<br /

A possible cause of misdiagnosis in tumors of the axilla: schwannoma of the brachial plexus

The Authors report a rare case of a 57 years old man affected by a left radial nerve schwannoma that occurred as an asymptomatic lesion of the axilla. At clinical examination the lump was undistinguishable from the most common axillary lymphadenopathy. A lymphoadenopathy was erroneously diagnosed with ultrasonography (US). This mistake was due to the low specificity of the instrumental methodology and to the rarity of an asymptomatic schwannoma of the infraclavicular brachial plexus. The neoplasia was excised without using the microscope. In the early post-operative follow up, a “falling” attitude of the wirst, the hand and the fingers appeared, peculiar for a lesion of the radial nerve. Furthermore a hypoaesthesia of the skin of first finger and of the first interosseus space was associated. The sensitive and motor electromyography showed a radial nerve suffering. The “stupor” of the nerve trunk was treated with steroid therapy for 7 days and the patient underwent to some series of neuro-rehabilitative physical therapy for 12 weeks. The postoperative total body CT, showed that the lesion was unique: therefore it was possible to exclude the diagnosis of neurofibromatosis. After 28 months electromyography and axillary US were performed showing the complete resolution of the motor and sensitive deficit and the absence of local recurrence

Pretend play and parents\u27 view of social competence: the construct validity of the Child-Initiated Pretend Play Assessment.

Background and Aims: Play is the primary means through which children develop skills and socially interact with other children. The aim of this study was to investigate the relationship between pretend play and social competence in 4&ndash;5-year-old typically developing children, thereby adding further knowledge to the construct validity of the Child-Initiated Pretend Play Assessment (ChIPPA). Procedure: The pretend play ability of 35 preschool children aged 4&ndash;5 years was assessed using the ChIPPA. Parent/guardians of the children were interviewed regarding their child\u27s social competence using the Vineland Social&ndash;Emotional Early Childhood Scales (Vineland SEEC Scales). Main Findings: No significant correlations were found between the children\u27s play scores and their Vineland SEEC Scales scores. A significant and negative relationship was found between cooperation and sharing and elaborate play scores, suggesting that children who scored poorly on the play assessment were rated as cooperative by parents. Principal Conclusions: Parent report of social competence cannot be inferred from play scores. Reasons for the negative and significant finding are put forward and clinical implications of the findings are discussed. Additional investigations are necessary to further explore the construct validity of inferring social competence using the ChIPPA. <br /

Analytical approximation for the recession of a sloping aquifer

An approximation is obtained for the recession of a sloping aquifer. The analytical approximation can provide a useful tool to analyze data and obtain physical properties of the aquifer. In contrast to the case of a horizontal aquifer, when plotting the time derivative of the flux versus the flux on a log scale, the result shows that the flux derivative reaches a minimum value and that the curve can have a slope of unity as often observed. Illustration of the application of the analytical results to the Mahantango Creek data is also discussed

Analytical approximation for the recession of a sloping aquifer

An approximation is obtained for the recession of a sloping aquifer. The analytical approximation can provide a useful tool to analyze data and obtain physical properties of the aquifer. In contrast to the case of a horizontal aquifer, when plotting the time derivative of the flux versus the flux on a log scale, the result shows that the flux derivative reaches a minimum value and that the curve can have a slope of unity as often observed. Illustration of the application of the analytical results to the Mahantango Creek data is also discussed