Revisiting the Solid Flux Theory

Several variations of the basic activated sludge process and of the related design procedures for final clarifiers have been developed, which are frequently based on the well-known solid flux theory (SFT). In this paper, by using the Lambert W function and a “virtual” solid flux corresponding to the Vesilind parameters’ ratio, the SFT is reformulated, and dimensionless groups are detected, which highly reduce the number of parameters that are involved in the final clarifiers’ design procedure. The derived dimensionless relationships and the corresponding plots have general validity since they can be applied to all the possible design/verification parameter combinations. Moreover, it is shown that for any input dataset, the suitable domains of the SS concentration and of the solid flux can be simply expressed by the two branches of the Lambert W function. By using data retrieved from the literature, several numerical applications and validations of the dimensionless relationships are performed. Finally, it is shown that by introducing in the SFT a new reduction hydrodynamic factor, rhoR, to be applied to the modified return flow formula rather than to the limiting solid flux as in the past, a significant improvement in the comparison between the results by theory and by experiments can be obtained

Developmental ethanol exposure and its impact on behaviour and HPI axis activity of zebrafish

Ethanol exposure during pregnancy is one of the leading causes of preventable birth defects, leading to a range of symptoms collectively known as fetal alcohol spectrum disorder (FASD). More moderate levels of prenatal ethanol exposure (PNE) lead to a range of behavioural deficits including aggression, poor social interaction, poor cognitive performance and increased likelihood of addiction in later life. Current theories suggest that adaptation in the hypothalamic-pituitaryadrenal (HPA) axis and neuroendocrine systems contributes to mood alterations underlying behavioural deficits and vulnerability to addiction. This has led to the suggestion that corticotrophin-releasing factor (CRF) antagonists and glucocorticoid (steroid) inhibitors may be potential therapeutics to address the deficits of PNE and for the treatment of addiction. The zebrafish (Danio rerio) has several advantages over mammalian models, such as low cost of maintenance, short life cycle, easy embryological manipulation and the possibility of large-scale genetic screening. By using this model, our aim is to determine whether developmental ethanol exposure provokes changes in the HPA axis (HPI axis in fish), as it does in mammalian models, therefore opening the possibilities of using zebrafish to elucidate the mechanisms involved, and to test novel therapeutics to alleviate deleterious symptoms. Thus this thesis focuses solely on the effect of developmental ethanol exposure on the functioning of the HPI axis in zebrafish. Stress-reactivity in zebrafish larvae ethanol-treated 1-9 days post 4 fertilisation (dpf) was assessed using thigmotaxis and thigmotaxis following airstress. In both tests, lower stress-related responses were obtained with ethanol treated animals, in that they spent less time at the edges of the apparatus (P<0.01, n=3). They also showed lower total body cortisol (P=0.04, n=14). Larvae also showed the same behaviour pattern two weeks after ethanol exposure, (23dpf) (P=0.04, n=3), again with reduced total cortisol (P=0.03, n=4). HPI-related gene transcription was also assessed in 9dpf ethanol treated zebrafish larvae, by qRT-PCR. Revealing up-regulation of CRH, CRHBP and CRHR2, normalized against β-Actin, Elav1 and Gap43 housekeeping genes. In situ hybridization revealed no spatial changes in CRH, CRH-BP and POMC with animals at the same stage. Behavioural stress-reactivity differences in 6-months old adults that had been exposed developmentally to ethanol were assessed using novel tank diving and thigmotaxis. Both assays indicated a decrease in stress-like behaviour due to early ethanol exposure compared to controls (P<0.05, n=5 both). Finally, cortisol levels were assayed from 9dpf larvae and 6-month-old adults that had been treated with ethanol during early development showed a significant reduction in cortisol output when air-exposed stressed compared to controls (P=0.04, n=5). Conclusion: Early ethanol exposure produced significant changes in cortisol, HPI gene mRNA expression and stress-reactive behaviour in 9dpf animals. Changes in cortisol and behaviour were still detected in 6-months old adults, developmentally treated with ethanol, indicating that early ethanol exposure has permanent effects on the HPI axis. 5 As our data contradicts the findings in mammalian literature where early ethanol exposure increases stress-like behaviour in later life, it is also possible that more permanent effects of PNE in mammals may arise through maternal-offspring interactions, during and post gestation, such as breastfeeding and maternal grooming of the offspring, which are absent in the zebrafish model.BBSRC (grant: BB/F016913/1

Simplified Interception/Evaporation Model

It is known that at the event scale, evaporation losses of rainfall intercepted by canopy are a few millimeters, which is often not much in comparison to other stocks in the water balance. Nevertheless, at yearly scale, the number of times that the canopy is filled by rainfall and then depleted can be so large that the interception flux may become an important fraction of rainfall. Many accurate interception models and models that describe evaporation by wet canopy have been proposed. However, they often require parameters that are difficult to obtain, especially for large-scale applications. In this paper, a simplified interception/evaporation model is proposed, which considers a modified Merrian model to compute interception during wet spells, and a simple power-law equation to model evaporation by wet canopy during dry spells. Thus, the model can be applied for continuous simulation, according to the sub hourly rainfall data that is appropriate to study both processes. It is shown that the Merrian model can be derived according to a simple linear storage model, also accounting for the antecedent intercepted stored volume, which is useful to consider for the suggested simplified approach. For faba bean cover crop, an application of the suggested procedure, providing reasonable results, is performed and discussed

The Interaction of Pain and Morphine on Analgesia, Locomotion, and Cognitive Functioning

Opioid medications are medicine\u27s best weapon against severe intractable pain, but prolonged use of these medications can be complicated by side effects like tolerance and mental clouding which, themselves, can be disabling. The present study examined the independent and combined effects of inflammatory pain and opioid medication on spatial memory for a well learned task in Sprague-Dawley rats. The Hargreaves method was used to verify the pain state of the animals after complete Freund\u27s adjuvant injection and morphine treatment. Whereas pain had little effect on spatial memory, morphine had profound detrimental effects that persisted beyond the analgesic effectiveness of the drug. However, morphine-induced cognitive deficits were absent when morphine was provided to animals in chronic pain. Also, analgesic tolerance was significantly attenuated in these animals. Taken together, these results suggest that chronic pain activates a neural mechanism that antagonizes the unwanted effects of opioids

New Orleans, the New South, and the Fight for the Panama Exposition

For various reasons, the city of New Orleans has often been ignored in discussions of the New South movement. New Orleans politicians joined the movement during the Progressive Era, much later than other Southern municipal leaders. In becoming a New South city, the Crescent City was launched onto the international trade scene. By an examination of city leaders\u27 efforts to gain federal rights to host an exposition in celebration of the Panama Canal, this study argues New Orleans not only became a New South city, but an international trade entrepôt. Though the exposition efforts failed, the efforts of the city to cultivate its business and hospitality potential served the city well

New Orleans, the New South, and the Fight for the Panama Exposition

For various reasons, the city of New Orleans has often been ignored in discussions of the New South movement. New Orleans politicians joined the movement during the Progressive Era, much later than other Southern municipal leaders. In becoming a New South city, the Crescent City was launched onto the international trade scene. By an examination of city leaders\u27 efforts to gain federal rights to host an exposition in celebration of the Panama Canal, this study argues New Orleans not only became a New South city, but an international trade entrepôt. Though the exposition efforts failed, the efforts of the city to cultivate its business and hospitality potential served the city well

Bacteriogenic Origin of Secondary Minerals in Ohio Based on Carbon and Sulfur Isotope Compositions

The origin of secondary minerals in northwestern Ohio has been attributed to a variety of causes including magmatic and bacterial activity. This research was conducted to determine whether secondary calcite, pyrite, sphalerite, galena, and celestite in Ohio result from bacterial processes. This combination of minerals is similar to those of Mississippi Valley type deposits, which have yielded economic wealth in other areas. The carbon isotope composition in secondary calcite establishes a link with petroleum by exhibiting S13C values of -21.5o/oo to -27.6o/oo. The δ34S values of sulfide minerals (-24.2o/oo to +7.0o/oo) demonstrate consistent depletion in the heavy sulfur isotope compared to coexisting sulfate minerals whose δ34S values range from +28.4%o/oo to +66.4o/oo. The isotope fractionation of carbon and sulfur minerals confirms that sulfurreducing bacteria metabolized hydrocarbons by means of oxygen derived by reduction of sulfate to sulfide. The CO2 and H2S released by bacteria resulted in the deposition of secondary carbonate and sulfide minerals in the rocks of northwestern Ohio.No embarg

The effects of Rhes, a striatal specific protein, on the expression of behavioral and neuropathological symptoms in a transgenic mouse model of Huntington\u27s disease

Huntington\u27s disease (HD) is a neuropsychiatric disorder characterized by choreiform movement of the limbs, cognitive disability, psychosis and dementia. It is untreatable, incurable, and ultimately fatal. HD is invariably associated with an abnormally long CAG expansion within the IT15 gene on human chromosome 4. Although the mutant huntingtin protein (mHtt) is ubiquitously expressed in HD patients, cellular degeneration occurs only in neurons within the striatum and cerebral cortex. The Ras homolog Rhes is expressed very selectively in the precise brain areas affected by HD. Recent work using cultured cells suggests that Rhes may be a co-factor with mHtt in cell death. However, there is controversy as to whether cell death underlies the symptoms of HD. We used a validated transgenic mouse model of HD crossed with Rhes knockout mice to show that the behavioral symptoms of HD are regulated by Rhes. HD/Rhes-/- mice showed greatly delayed expression of HD-like symptoms in this in vivo model. Drugs that block or inhibit the actions of Rhes may be useful as the first treatments for HD