Minimizing ammonia loss from urea through mixing with zeolite and acid sulphate soil.

Ammonia volatilization is a major cause of nitrogen loss from surface applied urea. While all top dressed ammonia and ammonium-based fertilizers can be volatized, the potential is greatest with urea and fluid containing urea. This laboratory study compared the effect of four different urea-zeolite-acid sulphate soil mixtures on NH3 volatilization and, soil exchangeable NH4 and available NO3 contents of an acid soil with surface-applied urea without additives. The soil used in the study was a sandy loam Typic Paleudults (Nyalau Series). The mixtures significantly minimized NH3 loss by 6 to 15% compared to urea alone. These treatments also significantly increased soil exchangeable NH4 and available NO3 contents compared to urea without additives. The increase in the formation of NH4+ over NH3 and the temporary decrease in soil pH retarded urea hydrolysis at the microsite immediately around the fertilizer. Surface applied urea fertilizer efficiency could be increased by mixing it with zeolite and acid sulphate soil

Optimal strategies to protect a sub-population at risk due to an established epidemic.

Epidemics can particularly threaten certain sub-populations. For example, for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the elderly are often preferentially protected. For diseases of plants and animals, certain sub-populations can drive mitigation because they are intrinsically more valuable for ecological, economic, socio-cultural or political reasons. Here, we use optimal control theory to identify strategies to optimally protect a 'high-value' sub-population when there is a limited budget and epidemiological uncertainty. We use protection of the Redwood National Park in California in the face of the large ongoing state-wide epidemic of sudden oak death (caused by Phytophthora ramorum) as a case study. We concentrate on whether control should be focused entirely within the National Park itself, or whether treatment of the growing epidemic in the surrounding 'buffer region' can instead be more profitable. We find that, depending on rates of infection and the size of the ongoing epidemic, focusing control on the high-value region is often optimal. However, priority should sometimes switch from the buffer region to the high-value region only as the local outbreak grows. We characterize how the timing of any switch depends on epidemiological and logistic parameters, and test robustness to systematic misspecification of these factors due to imperfect prior knowledge

Distance Properties of Short LDPC Codes and their Impact on the BP, ML and Near-ML Decoding Performance

Parameters of LDPC codes, such as minimum distance, stopping distance, stopping redundancy, girth of the Tanner graph, and their influence on the frame error rate performance of the BP, ML and near-ML decoding over a BEC and an AWGN channel are studied. Both random and structured LDPC codes are considered. In particular, the BP decoding is applied to the code parity-check matrices with an increasing number of redundant rows, and the convergence of the performance to that of the ML decoding is analyzed. A comparison of the simulated BP, ML, and near-ML performance with the improved theoretical bounds on the error probability based on the exact weight spectrum coefficients and the exact stopping size spectrum coefficients is presented. It is observed that decoding performance very close to the ML decoding performance can be achieved with a relatively small number of redundant rows for some codes, for both the BEC and the AWGN channels

The effect of talent management factors on teacher's leadership at the secondary school

Talent management is one of the roles in human resources management and there has been a long debate about talent management for years. This study aims to identify the relationship between talent management and teacher leadership development. In addition, the study also analyzes the talent management and teacher leadership levels. The data are analyzed using descriptive and inferential statistics. Statistical Package for the Social Sciences Software (SPSS) version 23 and Partial Least Squares Structural (Smart PLS) version 3 are also applied to analyze the data. The survey study involves 473 teachers in Malaysia residential school. The findings reveal that talent management and teacher leadership practices were at high levels. There is a significant positive relationship between talent management and teacher leadership development. The results of the study promote the role of talent management that can lead to positive changes in teacher leadership at schools. It is hoped that through this study various stakeholders such as schools, district education offices and the ministry of education of Malaysia will be able to assist in planning and organizing efforts in order to produce good leaders in future. It is hoped that through this study, various stakeholders such as school, district education offices as well as the Ministry of Education will be able to assist in planning and organizing efforts to address the role of teacher leadership to produce highly talented future leaders at schools

A Method for Producing Site-Specific TEM Specimens from Low Contrast Materials with Nanometer Precision

A method that enables high precision extraction of transmission electron microscope (TEM) specimens in low contrast materials has been developed. The main idea behind this work is to produce high contrast markers on both sides of and close to the area of interest. The markers are filled during the depositing of the protective layer. The marker material can be of either Pt or C depending on which one gives the highest contrast. It is thereby possible to distinguish the location of the area of interest during focused ion beam (FIB) milling and ensure that the TEM sample is extracted precisely at the desired position. This method is generally applicable and enables FIB/scanning electron microscope users to make high quality TEM specimens from small features and low contrast materials without a need for special holders. We explain the details of this method and illustrate its potential by examples from three different types of materials

Comparing sterofundin to 0.9% sodium chloride infusion in managing diabetic ketoacidosis: a pilot study

Fluid replacement is the mainstay treatment for diabetic ketoacidosis (DKA). Currently, the best choice of fluids is still debatable. An amount of 0.9% sodium chloride is commonly used. Sterofundin® is an alternative crystalloid that is assumed to expedite resolution of acidosis. Advantages in sterofundin content being smaller significant ion difference (SID) to plasma and lower chloride content. The main objective of the study was to compare rate of acidosis resolution in DKA patients between treatment with 0.9% normal saline and Sterofundin over 12 hrs. Other objectives were to compare significant ion difference (SID), 12-hr blood ketone clearance and electrolyte balance between the two groups. The study was a prospective open labelled randomized control trial. This study was conducted over 6 months. Sample size of 18 was obtained with 9 for each arm. Main difference between two groups was initial median 2-hr pH level improvement (NS = +0.006 vs. Sterofundin = +0.05, P=0.063), however not being significant. Ketone, anion gap reduction, bicarbonate normalisation, sodium, chloride, urea and creatinine levels failed to show any significant differences between both groups. Twelve-hour median chloride levels increments were higher in the NS group (+11) compared to the sterofundin group (+6). There was no difference between mortality and morbidity. Comparing the two fluid groups, there was no significant biochemical differences during treatment of DKA. This was a pilot study that can initiate further clinical trials

A New Piecewise-Spectral Homotopy Analysis Method for Solving Chaotic Systems of Initial Value Problems

An accurate algorithm for solving initial value problems (IVPs) which are highly oscillatory is proposed. The proposed method is based on a novel technique of extending the standard spectral homotopy analysis method (SHAM) and adapting it to a sequence of multiple intervals. In this new application the method is referred to as the piecewise spectral homotopy analysis method (PSHAM). The applicability of the proposed method is examined on the differential equation system modeling HIV infection of CD4+ T cells and the Genesio-Tesi system which is known to be chaotic and highly oscillatory. Also, for the first time, we present here a convergence proof for SHAM. We treat in detail Legendre collocation and Chebyshev collocation. The method is compared to MATLAB’s ode45 inbuilt solver as a measure of accuracy and efficiency