Transformations of Nitrogen and its Availability to Plants in Coal Mine Soils

The work of this thesis is concerned with the study of some aspects of nitrogen cycling in coal mine soils. A survey of sites in Central Scotland was made to assess which parts of the N cycle function in coal mine soils. 90 samples of widely varying properties were taken and various properties measured. The mineral N status of the waste material was low. Carbon dioxide evolution and nitrogen mineralization rates showed that a high level of carbon, but little nitrogen was turned over. Nitrification was measurable only on about half of the sites studied and was highly pH dependent, being inhibited below pH 5.0. However, even on sites above this pH, nitrification was not always measured which suggests that the introduction of nitrifying bacteria into the spoil was also an important factor. Some nitrogen was lost due to the fixation of ammonium by the clay minerals and much more was lost during incubation due to immobilization. The urease and amidase activities measured were similar to those in agricultural soils which suggests that the use of urea or amide-N fertilizers may be possible on these coal mine soils. Significant correlations of carbon turnover, urease activity, amidase activity and nitrification rate with each other, suggest the importance of organic matter for both microbial activity and enzyme stabilization. A laboratory incubation experiment was carried out to study the fate of nitrogen added as ammonium sulphate, urea or chicken manure in five selected samples of coal mine soils with different properties. Two samples showed no net mineralization of N at any stage in either the control, ammonium sulphate or urea treated samples. Two samples which were collected from the plots of an established organic manure trial, showed N mineralization rates comparable to agricultural soils suggesting the favourable effect of organic amendments in the long term on the establishment of N cycling. There were large losses of N in the first weeks of incubation, which were generally greater in the manure treated samples, where up to 69 % of added N was lost. These losses were attributed to a combination of ammonium fixation and immobilization. In the later stages of the incubations there was a clear contribution to mineralization from the chicken manure. Mineralization and nitrification rates were significantly improved by manure addition in all samples, especially in the acid soil where these processes did not occur with ammonium sulphate or urea addition. The manure not only increased the pH of the acid soil, but may have also added nitrifying bacteria to the soil. In general however, it would seem that these transformations of nitrogen species can occur in coal mine soils if other conditions, particularly pH, are suitable. A field experiment was set up to study nitrogen response on a reclaimed site for two years in 1986 and 1987. Seven rates of N fertilizer ranging between 0 and 150 kg N/ha as ammonium nitrate were added to triplicate plots. An attempt was also made to study the herbage response to N both in the presence and absence of added P and K, and to compare urea with ammonium nitrate. Nitrogen fertilizer significantly improved the herbage yield in both years, which was also reflected generally in higher N, P, and K contents in the herbage. In addition P and K tended to increase the yield of herbage when applied with N but their effect was not significant. Vegetation responded equally to both N fertilizers with no significant differences in herbage yield

Signal Path Loss Measurement for Future Terahertz Wireless Propagation Links

Terahertz Band (100GHz-10THz) offers larger bandwidth and ultra-higher data rates and is visualized as a key technology to alleviate the capacity limitation and spectrum scarcity of the currents wireless networks. There are some competent development and design challenges in the realization of wireless terahertz network. Signal high path loss is one of the major constraints for enabling wireless communication networks in the terahertz band. Thus for the consummation of wireless propagation links in the THz band an equivalent signal path loss model is designed incorporating the major peculiarities of the wireless channel that accounts for terahertz wave propagation in LoS propagation. The equivalent path loss model for terahertz LoS propagation is developed and simulated in matlabR. The simulation results are compared with the lognormal path loss model results

Physiology, Breast Milk

The production of breast milk initiates in larger amounts between 2 and 4 days after the birth of the baby and the breastmilk is said to have 'come in'. It is the sole best source of nutrition for an infant, providing an adequate amount of nutrients, growth factors, and antibodies required for the nourishment of the baby. Breast milk should be exclusively used for nutrition until 6 months of age after which breastmilk should be used in addition to complementary foods for at least 12 months of age. [1

IMPACT OF FAMILY OWNERSHIP ON FINANCING DECISIONS: A COMPARATIVE ANALYSIS OF COMPANIES LISTED AT THE KSE

The current study attempts to investigate debt and dividendpolicies under the umbrella of capital structure’s theories in bothorganizational types i.e. family owned business (FOB) and non-familyowned business (NFOB). Two threshold points of ownership structure(25% & 50%) were used to distinguishing FOB from NFOB. A sampleof 280 listed firms at the KSE was collected for the period 2002-13.Generalized Method of Moments (GMM) was applied on paneldata to estimate the coefficients of variables. The empirical resultsindicated the weak application of pecking order theory and higherpayout ratio in family firms comparatively. The study providedexplanation regarding speedier rebalancing the target capitalstructure of family firms due to easier access to debt and long termpresence of the family in the firm. However, FOBs smooth dividends tolesser extent than their counterpart NFOBs indicate lower agencyand information asymmetry problems in them. SECP as well as stockexchanges are advised to bring required changes in corporate lawsto ensure lucid and verifiable disclosure regarding dividend policyin their reports, prospectus and websites et

Impact of CSR, Quality of Work Life and Organizational Structure on Employee’s Performance in Pakistan

The trends of organizations are changing and demanding satisfied employees rather than dissatisfied employees. This paper provides factors through which employee’s performance can be increased to achieve organizational goals and objectives. To attract the motivated employees and building relations, CSR can perform for society which will change the thoughts of stakeholders. Quality of work life has impact on organization’s effectiveness which is essential for firms to be healthy and productive. Firms should adopt employee oriented policies which satisfies them to achieve organizational objectives. This study also indicates that effective organizational structure is necessary for improving the performance of employees and the organization. The structure is a source of success or failure because it empowers the employee which will increase the sense of responsibility. For the improvement in the organization and removing stress of the employees management must consider the hygiene factors to motivate the employees. The conceptualized work is conducted which is proved through evidence. For further study statistical analysis can be done for confirmation of the hypothesis

A NOVEL CELL BY CELL ARTIFICIAL NEURAL NETWORKS APPROACH FOR PREDICTING THE TEMPERATURE OF STEADY STATE, INCOMPRESSIBLE, LAMINAR FLOWS

A cell-by-cell artificial neural network approach is used to predict the temperature field of steady-state, incompressible, laminar flows in a two-dimensional computational domain. The temperature field is characterized by the initial flow velocity, fluid temperature and the temperature of the wall boundaries. Two types of neural network architectures are developed in this research, namely cascade-forward and feedforward models. Both models are trained using Levenberg-Marquardt and Bayesian regularization backpropagation algorithms. The training data for the models are obtained by solving the Navier-Stokes equations for steady-state, incompressible, heat conducting laminar flow in two-dimensional domain using commercial ANSYS Fluent software. The results show that the predicted values produced by the ANN models are in good agreement with the CFD simulation data. Even though the introduction of artificial neural networks at the cell level increases the complexity of the training process, this drawback is compensated by the increase in flexibility (generality) of the models. More importantly, the results show that the cell-by-cell artificial neural network approach is capable of providing an accurate prediction of the temperature field for the fluid flow investigated in this research, as indicated by the statistical indices used to evaluate the performance of prediction models. The feedforward ANN model trained using the Bayesian regularization backpropagation algorithm gives the most accurate predictions among all models

Protocol optimization for deoxyribonucleic acid (DNA) extraction from dried, fresh leaves, and seeds of groundnut (Arachis hypogaea L.)

Consistent isolation of best quality deoxyribonucleic acid (DNA) from peanut (Arachis hypogaea L.) is particularly problematic due to the presence of phenolic compounds and polysaccharides. Inconsistencies in extraction results can be attributed to the age and growth stages of the plant material analyzed. Mature leaves have higher quantities of polyphenols, tannins and polysaccharides that can contaminate DNA during isolation. In this study, we used fresh and dried leaves as well as seeds for optimization of high quality DNA isolation protocols from A. hypogaea. The DNA extracted with three different methods cetyltrimethylammonium bromide (CTAB), sodium dodecyl sulfate (SDS), and cesium chloride (CsCl) density gradient) were comparatively studied by polymerase chain reaction (PCR) analysis in terms of quantity and quality. High quality genomic DNA was obtained from fresh leaves by modified CTAB methods. The DNA obtained ranged from 1 to 2.5 ng/μl. DNA obtained by this method was strong and reliable showing its compatibility for simple sequence repeat (SSR) analyses. The SDS based methodology give large quantities of DNA contaminated with polysaccharides. Fresh leaves also gave best result in SDS method. The quantity and quality of DNA obtained was very poor in all the tested methods in case of dried leaf tissues. The current protocol will probably be useful for the extraction of high-molecular weight DNA from other plant materials containing large amounts of secondary metabolites and essential oils.Key words: Polysaccharides, polyphenols, tannins, cetyltrimethylammonium bromide (CTAB), sodium dodecyl sulfate (SDS), cesium chloride (CsCl), secondary metabolites, SSR

Numerical modelling of blood cells distribution in flow through cerebral artery aneurysm

Recent aneurysm studies have focused on the correlation between different parameters and rupture risk; however, there have been conflicting findings. Computational fluid dynamics (CFD) allows for better visualization but idealized aneurysm models may neglect important variables such as aneurysm shape and blood flow conditions. In this paper, one case of an aneurysm was studied with CFD using a non-Newtonian Power Law Model to investigate the correlation between wall shear stress and blood cells distribution. Results show that velocity of blood flow decreased as it entered the aneurysm and the neck of the aneurysm experienced a greater magnitude of wall shear stress than the remainder of the cerebral artery. Besides, the blood cells generally begin at low velocities and increase after the first curve of the artery. Findings and further studies with larger cases of patients will improve treatment and prevention of aneurysm ruptures

p62-Keap1-NRF2-ARE Pathway: A Contentious Player for Selective Targeting of Autophagy, Oxidative Stress and Mitochondrial Dysfunction in Prion Diseases

Prion diseases are a group of fatal and debilitating neurodegenerative diseases affecting humans and animal species. The conversion of a non-pathogenic normal cellular protein (PrPc) into an abnormal infectious, protease-resistant, pathogenic form prion protein scrapie (PrPSc), is considered the etiology of these diseases. PrPSc accumulates in the affected individual’s brain in the form of extracellular plaques. The molecular pathways leading to neuronal cell death in prion diseases are still unclear. The free radical damage, oxidative stress and mitochondrial dysfunction play a key role in the pathogenesis of the various neurodegenerative disorders including prion diseases. The brain is very sensitive to changes in the redox status. It has been demonstrated that PrPc behaves as an antioxidant, while the neurotoxic prion peptide PrPSc increases hydrogen peroxide toxicity in the neuronal cultures leading to mitochondrial dysfunction and cell death. The nuclear factor erythroid 2-related factor 2 (NRF2) is an oxidative responsive pathway and a guardian of lifespan, which protect the cells from free radical stress-mediated cell death. The reduced glutathione, a major small molecule antioxidant present in all mammalian cells, and produced by several downstream target genes of NRF2, counterbalances the mitochondrial reactive oxygen species (ROS) production. In recent years, it has emerged that the ubiquitin-binding protein, p62-mediated induction of autophagy, is crucial for NRF2 activation and elimination of mitochondrial dysfunction and oxidative stress. The current review article, focuses on the role of NRF2 pathway in prion diseases to mitigate the disease progression

Reinventing Undergraduate Clinical Placements with a Switch to Delivery by Clinical Teaching Fellows

Purpose: Undergraduate clinical placements have the potential for significant improvement. Previous research has shown the growing value of clinical teaching fellows (CTFs) within medical education. Changing traditional placements to a model whereby CTFs have defined roles and lead the majority of teaching can positively reinvent undergraduate clinical teaching. We wanted to see how a structured teaching programme delivered by CTFs could affect student experience and personal development within a large associate teaching hospital. We consider how such a model could be implemented and explore the opportunities for CTFs to develop in personal and professional capacities. Methods: A mixed methods study was organised to assess student experience of a CTF-led placement. A novel structured teaching programme was delivered by 14 CTFs, who provided or were involved with the majority of teaching for all medical students. Thematic analysis was conducted on focus groups with 48 final year medical students from Queen Mary University of London following completion of their clinical placements. The same students were asked to complete an anonymous survey from which results were analysed using modified 5-point Likert scales. Results: Eight themes were identified from the focus groups. Students appreciated the increased individualisation, relevance and variety of teaching and the ability to record progress. Other perceived effects were higher teacher to student ratios, more learning opportunities and increased familiarity and reliability with CTFs. Of the students surveyed, 96% felt their overall placement experience was very good in comparison to previous placements elsewhere. Survey results supported focus group themes and demonstrated perceived growth in students’ personal development. Conclusion: Placement models where CTFs lead most teaching can improve medical undergraduate experience and training. A move towards CTF-delivered teaching can be of financial benefit to hospital trusts whilst allowing time for junior doctors to explore different clinical specialities and hone their teaching skills