4,937 research outputs found
An Investigation of Inference of the Generalized Extreme Value Distribution Based on Record
In this article, the maximum likelihood and Bayes estimates of the generalized extreme value distribution based on record values are investigated. The asymptotic confidence intervals as well as bootstrap confidence are proposed. The Bayes estimators cannot be obtained in closed form so the MCMC method are used to calculate Bayes estimates as well as the credible intervals. A numerical example is provided to illustrate the proposed estimation methods developed here. Keywords: Generalized extreme value distribution, Record values, Maximum likelihood estimation, Bayesian estimation
Evaluation of multi-stress tolerant maize varieties for sustainable intensification in Northern Guinea Savanna of north eastern Nigeria
Maize productivity is limited by multiple stresses in the savannas of West and Central Africa. Field trials were conducted in northern Guinea savanna of Nigeria in 2011 and 2012 to evaluate the performance of multi-stress tolerant maize varieties. Thirteen varieties including Local Check replicated three times were tested in randomized complete block design. Plant and ear heights were significantly higher for LNTP x LNP-WC3 and 2004 TZE-W DT-STRC4 than POOL 18-SR, 2009 TZE-W POP-STR, EVDT 99-W STR; and EVDT 2000-Y STRQPM, respectively. Striga count was significantly lower for EVDT 99-W STR and LNTP x LNP-WC3 than all the other entries. Days to 50% tassel and 50% silk were each significantly earlier for EVDT 99STR W-STR QPM, DT-W STR SYN, EVDT-99W STR and 2009 TZEW DT STR than the Local Check. Anthesis Silk Interval (ASI) was significantly lower for TZE COMP3 DT-WC2, 2009 TZEW DT STR, and EVDT 99-W STR than Local Check. Number of ears plant-1 was sigÂŹnificantly higher for 2008 DTMA-Y STR than Local Check. Grain yield ha-1 was significantly superior for DT-Y STR SYN, 2008 DTMA-Y STR, 2004 TZE-W DTSTR C4, 2009 TZEW DT STR and EVDT 99-W STRQPM, respectively. Plant height was positively correlated with ASI and ear height, while ear height was positively associated with ears plant-1, days to 50% silk and 50% tassel. Grain yield ha-1 was positively correlated with ears plant-1, days to 50 % silk, days to 50% tassel and ear height, while ears plant-1 was negatively correlated with ear weight. Farmer selecÂŹtion criteria for acceptance of variety were in the order: Striga tolerance > nutrient value > drought tolerance > flour value > good taste > high yield > early maturity. The five varieties: DTY STR SYN, 2008 DTMA-Y STR, 2004 TZE-W DT STRC4, 2009 TZEW DT STR and EVDT 99-W STRQPM satisfied farmers criteria and were promising and thus nominated for on-farm demonstration and subsequent adoption in the region
Performance Evaluation of Three PID Controller Tuning Algorithm on a Process Plant
Accurate tuning of controller in industrial process operation is prerequisite to system smooth operation which directly reduce process variability, improved efficiency, reduced energy costs, and increased production rates. Performance evaluation of a model based PID controller tuning algorithm on a chemical process plant is presented in this paper. The control action of three different PID controller tuning algorithms namely; Hagglund-Astrom, Cohen and Coon, and Ziegler-Nichols on the process plant was examined in a closed loop control configuration under normal operating condition and in the face of disturbance. LabVIEW software was used to model a chemical process plant from open loop control test data. The time domain response analysis of the controllers shows that each tuning algorithm exhibit different time response. Ziegler-Nichols algorithm shows the best performance with fastest rise time, settling time and was able to restore the system back to normal operating condition in a short time when subjected to disturbance compare to Cohen & Coon controller and Hagglund-Astrom algorithm settings
On the EDM Cancellations in D-brane models
We analyze the possibility of simultaneous electron, neutron, and mercury
electric dipole moment (EDM) cancellations in the mSUGRA and D--brane models.
We find that the mercury EDM constraint practically rules out the cancellation
scenario in D-brane models whereas in the context of mSUGRA it is still allowed
with some fine-tuning.Comment: 10 pages, to appear in Phys. Rev. Let
Determination of the rate of kill, mode of action, and the bioactive components from the ethyl acetate sub-fraction of methanol extract of Phyllanthus amarus.
The time-kill rate of methanol extract of Phyllanthus amarus was determined in this study which showed that the extract caused a reduction of the viable cells of all the test bacteria after a contact time of 30 mins and there were virtually no surviving cells of all the test bacteria after a contact time of 180 mins. The extract was also found to cause leakages of cellular materials such as potassium ions, sodium ions, protein and nucleic acids from the test bacteria which led to the loss of cell viability. The ethyl acetate sub-fraction of the extract was analyzed by GC-MS and FTIR analysis and the result revealed the presence of Phytochemicals such as 1, 2-Benzenedicarboxilic acid mono (2-Ethylhexyl) ester, Columbin, 2-(6-Methylpyridin-2-ylmethyl) cyclohexane, 2(1H) Naphthalenone,3,5,6,7,8,8a-hexahydro-4,8a-dimethyl-6-(1-methylethenyl) which have all been reported to possess antibacterial activity against both gram-positive and gram-negative bacteria. The result of this study will contribute to the baseline data on the pharmacodynamics of the extract if applied as herbal medicine for human treatment thereby reducing the dosage and period of treatment. The finding also revealed that the ethyl acetate sub-fraction of methanol extract of P. amarus contains antibacterial phytochemicals that may be used to develop more potent, safe and cheap antimicrobial agents using nanotechnology.
 
Epicardial fat thickness in patients with rheumatoid arthritis
Background: Epidemiologic data indicates that rheumatoid arthritis is an independent risk factor for cardiovascular disease. Epicardial adipose tissue is a novel cardio-metabolic risk factor. Our aim was to evaluate epicardial fat thickness (EFT) using echocardiography in patients with rheumatoid arthritis compared to healthy control subjects. Secondly, we investigated relationship between epicardial fat thickness and clinical and echocardiographic parameters in patients with rheumatoid arthritis.Method: The study population included 76 consecutive patients with rheumatoid arthritis (64 female; mean age, 53 ±11 years, median disease duration, 7.8 years) and 50 healthy subjects as controls (39 female; mean age, 52 ± 6 years). All patients underwent echocardiography to assess left ventricular diastolic dysfunction, left ventricular hypertrophy and EFT. All values were compared between groups.Results: EFT was higher in rheumatoid arthritis patients than in healthy controls (0.66±0.20 vs. 0.54±0.18; p= 0.003). Thickness of Intra Ventricular Septum (IVS) (1.1±0.06 and 9.8±0.08; p=0.001) and posterior wall (PW) (0.98±0.05 and 0.93±0.08; p=0.015) was higher in patients with rheumatoid arthritis compared to healthy controls. Early diastolic myocardiac peak velocity or late diastolic mitral peak velocity (E/A) ratio was lower in rheumatoid arthritis patients compared to healthy patients (1.1 ±0.8 and 1.24±0.1 p=0.001) as well as, E/eâ was higher in Rheumatoid arthritis (RA) patients than healthy patients. (E/eâ:8.7±1.6 and 8.0±1.4 p=0.020). In patients with rheumatoid arthritis, EFT was positively correlated with hypertension and duration of disease and E/eâ (r: 0.10, p: 0.010, r: 0.306, p: 0.004 and r: 0.465 p: 0.007 respectively) and EFT was negatively correlated with E/A (r: -.262 p:0.022 )Conclusion: To our knowledge, this is the first report about epicardial adipose tissue in rheumatoid arthritis patients. Epicardial fat thickness as an indicator of cardiovascular involvement was higher in rheumatoid arthritis patients.Keywords: Rheumatoid arthritis, epicardial fat thickness, cardiac involvemen
Retrospective Study on the Prevalence of Surgical Wound Infections in Specialist Hospital Sokoto â North West Nigeria
Introduction: Nosocomial surgical site infections remain a key drawback in health care facilities, resulting in extended length of stay, significant morbidity and mortality, elevated excess of cost, and less regular basis of death in the surgical patient.
Aim: The objective of the study is to determine the rate of occurrence of surgical site nosocomial infections in surgical patients in Specialist Hospital Sokoto, Nigeria.
Study Design: Retrospective study.
Place and Duration of Study: A 2-year retrospective study of nosocomial surgical site infections (June 2011 to May 2013) was carried out in Specialist Hospital Sokoto, Nigeria.
Methodology: Patients' folders and microbiology laboratory records were used for the determination of prevalence of nosocomial infections in. Data was analyzed using SPSS version 20.
Results: Result of the retrospective study of surgical site infection in the hospital showed that surgical site nosocomial infections are frequent in the hospital, with a prevalence rate of 4.7% (2011/2012) and 7.6% (2012/2013).
Conclusion: Despite the fact that this study is limited to nosocomial surgical site infections in three surgical wards only, surgical site infection exists as a major problem hospital. The results of this study are consistent with reports of similar studies in Nigeria and other parts of the world
Physicians and AIDS Care: Does Knowledge Influence Their Attitude and Comfort in Rendering Care?
Adequate knowledge, positive attitude, and feeling of comfort are
important factors in providing compassionate care to patients. The
purpose of this study was to assess physicians\u2019 knowledge,
attitude and global comfort in caring for patients with AIDS (PWA), to
determine the sociodemographic variables that could influence
physicians\u2019 attitude and global comfort, and to identify any
relationship between their knowledge, attitude and comfort. Consultants
and residents (N=211) in two Nigerian teaching hospitals were surveyed
using a two-part questionnaire. Part I elicited sociodemographic and
previous AIDS encounter information, and Part II assessed knowledge,
attitude and global comfort with AIDS patients care. Nigerian
physicians showed satisfactory knowledge, but they harbored negative
attitude and low level of comfort in caring for PWA. Previous AIDS care
experience, age and being a consultant or a senior resident influenced
attitude, while male gender and knowing someone with AIDS influenced
global comfort. Knowledge is weakly but positively associated with
attitude, while attitude is modestly associated with comfort. The study
reinforced the need for an ongoing education focused on experiential
learning, and professional socialization in order to influence
physicians\u2019 attitude and enhance their feeling of comfort when
caring for PWA
Design and Construction of an Arduino - Based Solar Power Parameter-Measuring System with Data Logger
Accurate monitoring and measurement of solar photovoltaic panel parameters are important for solar power plant analysis to evaluate the performance and predict the future energy generation. There are always challenges of getting such data readily available due to huge amount of money to be spent on state of the art equipment or the purchase of reliable satellite weather data. This study aimed at the development of a cost-effective parameter-measuring system for a solar photovoltaic panel using Arduino microprocessor board. The systems measure five parameters, including voltage, current, light intensity, temperature, and pressure. The hardware circuit was designed to link different sensors with the Arduino board and the measured data were in turn were documented into a computer for further analysis. The accuracy of the constructed device was ascertained by comparing the measured parameters with that of conventional standard measuring instruments which shows good agreement. The measured parameters show that the output energy generation from solar photovoltaic panel largely depends on the solar irradiance and temperatur
Probing CP Violation with and without Momentum Reconstruction at the LHC
We study the potential to observe CP-violating effects in SUSY cascade decay
chains at the LHC. We consider squark and gluino production followed by
subsequent decays into neutralinos with a three-body leptonic decay in the
final step. Asymmetries composed by triple products of momenta of the final
state particles are sensitive to CP-violating effects. Due to large boosts
these asymmetries can be difficult to observe at a hadron collider. We show
that using all available kinematic information one can reconstruct the decay
chains on an event-by-event basis even in the case of 3-body decays, neutrinos
and LSPs in the final state. We also discuss the most important experimental
effects like major backgrounds and momentum smearing due to finite detector
resolution. We show that with 300 fb of collected data, CP violation may
be discovered at the LHC for a wide range of the phase of the bino mass
parameter .Comment: Version accepted for publication in JHEP. Clarifications added on the
assumptions used for plots. New references adde
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