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−3, Cl−, PO3−4) 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 < 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.

Changing violent behaviour : forensic mental health and criminological models compared

Evidence-based interventions designed to reduce the risk of re-offending, particularly violent re-offending, are commonly offered in correctional systems around the world. The interventions are often based upon the application of several principles of service delivery that have become widely known as the 'what works' approach to offender rehabilitation. The applicability of these principles to forensic psychiatric services has yet to be determined. The aims are to examine the possible application of the 'what works' approach and its implications for forensic mental health practice. The method used was a review of relevant research from both the general offender and forensic psychiatry literature. The principles underlying the 'what works' approach are likely to have utility in service delivery in forensic psychiatry, particularly when a treatment target is a reduction in risk of harm to others. The individualized models of patient care practiced in forensic psychiatry are also likely to have utility in improving treatment outcomes in correctional settings. The conclusion is that an increased interchange of ideas and interventions between the two areas of practice is likely to be of mutual benefit. This is an area that requires significant development.

High rate filtration using buoyant medium : experiments and mathematical models

In this study, the high rate filtration system using buoyant medium of polypropylene or polystyrene was introduced with the study on its performance evaluation via: (i) specific surface coverage, (ii) ultimate specific deposit, (iii) blocking effect and (iv) particle detachment. The filter system was arranged in the downflow mode with an in-line flocculation. Experimental results obtained were analyzed using filtration models. This study showed that: (i) the specific surface coverage increased with the increase in the velocity; (ii) the ultimate specific deposit changed slightly at different filtration velocities and different flocculants; (iii) the blocking effect was significant in the transient stage removal of flocs; and (iv) the detachment model parameter was found to decrease with the increase in the adhesive force, Fad that acts on the flocs (above-micron size).

Freedom and conditionality: analysing mental and yogic models of freedom

This thesis asks: Is freedom possible on a cognitive level, or do particular emotions negate freedom? It examines various theories of emotion, from both a cognitive and a physiological perspective, ultimately demonstrating a resonance between particular Eastern and Western theories of emotional life.

Certificateless ignatures: New schemes and security models

We present a study of security in certificateless signatures. We divide potential adversaries according to their attack power, and for the first time, three new kinds of adversaries are introduced into certificateless signatures. They are Normal Adversary, Strong Adversary and Super Adversary (ordered by their attack power). Combined with the known Type I Adversary and Type II Adversary in certificateless cryptography, we then define the security of certificateless signatures in different attack scenarios. Our new security models, together with others in the literature, provide a clear definition of the security in certificateless signatures. Two concrete schemes with different security levels are also proposed in this paper. The first scheme, which is proven secure (in the random oracle model) against Normal Type I and Super Type II adversaries, has the shortest signature length among all known certificateless signature schemes. The second scheme is secure (in the random oracle model) against Super Type I and Type II adversaries. Compared with another scheme that has a similar security level, our second scheme requires less operational cost but a little longer signature length. Two server-aided verification protocols are also proposed to reduce the verification cost on the verifier.

Psychopathology in police custody: The role of importation, deprivation and interaction models

People experiencing mental illness are over-represented among police cell detainees, however limited work has sought to investigate the occurrence of psychopathology in police custody. The present study sought to examine the predictive power of personal factors (e.g., history of psychiatric hospitalisation), situational factors (e.g., police cell conditions), and their interactive effects to explain the occurrence of psychopathology in police custody. A total of 150 detainees were recruited from two metropolitan police stations in Melbourne, Australia. Personal factors were significantly associated with psychiatric symptomatology, with situational factors and interaction terms yielding no association. Detainees with preexisting vulnerabilities and those unsatisfied with police cell conditions demonstrated the highest levels of psychopathology. While all detainees experience some difficulties in police cells, it is those with pre-existing vulnerabilities that suffer the most. This may be due to the exacerbation of vulnerabilities by police cell conditions. The implications of these findings for provision of health care services in police cells are discussed.

Should we save or should we consume? Linking growth theories and the Keynesian models

In major economic growth theories, high saving rate gives rise to high level of output per capita. But in Keynesian economics, high saving rate causes low consumption and will lead the economy into recession. Students may ask, "For the well-being of an economy, should we save or should we consume?" In most of the intermediate macroeconomics textbooks, economic growth and Keynesian economics are taught in separate chapters; and in many cases, these chapters are not even successive to each other. There lacks a continuity between the long run and short run models. This paper builds a bridge between growth theories and Keynesian models. It links the Solow diagram and the IS-LM curves and depicts the short run and long run implications of a change in the saving rate.

Association between obesity and diabetes using nested linear models

A data source with 7260 cases from the prospective observational study was used. Cases included both sexes and age ranging between 20yr and 7Oyr. Chi-squared tests and linear models were used to examine the effects of age (linear and quadratic), sex, smoking habit (currently a smoker or non-smoker), presence or absence of type 2 diabetes on obesity as measured by body mass index (BMI) and waist to hip ratio (WHR). Both these measures of
obesity were significantly affected by age, sex and the presence of diabetes. Cases with diabetes were significantly more obese (10%) between the ages 40yr to 59yr compared to patients without diabetes. These results accentuate the need to further examine the association between age, diabetes and obesity and other risk factors with cardiovascular diseases.