True polar wander driven by late-stage volcanism and the distribution of paleopolar deposits on Mars

The areal centroids of the youngest polar deposits on Mars are offset from those of adjacent paleopolar deposits by 5-10 degrees. We test the hypothesis that the offset is the result of true polar wander (TPW), the motion of the solid surface with respect to the spin axis, caused by a mass redistribution within or on the surface of Mars. In particular, we consider TPW driven by late-stage volcanism during the late Hesperian to Amazonian. There is observational and qualitative support for this hypothesis: in both North and South, observed offsets lie close to a great circle 90 degrees from Tharsis, as expected for polar wander after Tharsis formed. We calculate the magnitude and direction of TPW produced by mapped late-stage lavas for a range of lithospheric thicknesses, lava thicknesses, eruption histories, and prior polar wander events. If Tharsis formed close to the equator, the stabilizing effect of a fossil rotational bulge located close to the equator leads to predicted TPW of <2 degrees, too small to account for observed offsets. If, however, Tharsis formed far from the equator, late-stage TPW driven by low-latitude, late-stage volcanism would be 6-33 degrees, similar to that inferred from the location of paleopolar deposits. 4.4+/-1.3x10^19 kg of young erupted lava can account for the offset of the Dorsa Argentea Formation from the present-day south rotation pole. This mass is consistent with prior mapping-based estimates and would imply a mass release of CO2 by volcanic degassing similar to that in the atmosphere at the present time. The South Polar Layered Deposits are offset from the spin axis in the opposite sense to the other paleopolar deposits. This can be explained by an additional contribution from a plume beneath Elysium. We conclude with a list of observational tests of the TPW hypothesis.Comment: Accepted by Earth and Planetary Science Letters. 3 tables, 8 figure

Sensitivity Analysis of a Mathematical Modeling of Ebola Virus Population Dynamics in the Presence of Vaccine

The virus (Ebola virus) (EBV) belongs to the Filoviri-dae family which is a filovirus and is a serious disease which&nbsp; leads to hemorrhagic disease in human and non human such as chimpanzee, gorilla, porcupine, fruit bats etc. In&nbsp; this paper, a mathematical modeling for the population dynamics of EBV diseases in the presence of vaccination&nbsp; was developed. The research shows that, using the human control reproduction number ( Rc )as response and&nbsp; infectious individual as response function, that the sensitive parameters in the formulated system (1) are the&nbsp; personal hygiene (ε ), humans to human contact rate ( β1 ), modification parameter (η ), human vaccination rate ( ρ ), proper burial (φ ) and humans natural mortality rate (μh ). The study shows that personal hygiene rate, effective&nbsp; contact rate of humans, natural mortality of humans’ rate, vaccination rate and proper burial rate are very sensitive&nbsp; to both reproduction number and infectious humans.&nbsp

Optimal control of mathematical modelling for Ebola virus population dynamics in the presence of vaccination

Ebola virus is a severe often fatal illness in human, which is known to be very dangerous and highly infectious disease that seized many lives in west African countries. In this paper, a mathematical model for the population dynamics of Ebola virus diseases incorporating bats compartment, recovery due to immune response and vaccination was constructed. Pontryagin’s maximum principle has been applied on the model to determine the necessary conditions for the optimal control of the Ebola virus in the presence of vaccination and fruit bats population, the optimality of most of the controls have been analyzed to use a small resources available in other to maximize the performance of the controls. The numerical simulation shows that with small resources if 0.1 percent of the people in a society can be vaccinated daily, Ebola can be mitigated in the environment

Atomic absorbers for controlling pulse propagation in resonators

We consider pulse propagation through a Fabry-Perot cavity with silver mirrors that contain macroscopic samples of resonant absorbers. We show that the pulse velocity can be tuned from subluminal to superluminal in a strongly coupled atom-cavity system. We delineate the effects of the interplay of cavity and absorbers. We demonstrate the saturation effects of pulse advancement with increasing mirror thickness and atomic damping

Chloroquine-resistant Plasmodium falciparum in Sokoto, North Western Nigeria

Three patients, 30, 2 and one and a half years, were diagnosed as having falciparum malaria and were placed on chloroquine therapy which failed. They were then placed on quinine therapy that then cleared the parasitaemia. This case report seeks to draw the attention of the presence of possible chloroquine-resistant falciparum malaria in Sokoto, North Western Nigeria. (African Journal of Biotechnology: 2003 2(8): 244-245

Control of superluminal transit through a heterogeneous medium

We consider pulse propagation through a two component composite medium (metal inclusions in a dielectric host) with or without cavity mirrors. We show that a very thin slab of such a medium, under conditions of localized plasmon resonance, can lead to significant superluminality with detectable levels of transmitted pulse. A cavity containing the heterogeneous medium is shown to lead to subluminal-to-superluminal transmission depending on the volume fraction of the metal inclusions. The predictions of phase time calculations are verified by explicit calculations of the transmitted pulse shapes. We also demonstrate the independence of the phase time on system width and the volume fraction under specific conditions.Comment: 21 Pages,5 Figures (Published in Journal of Modern Optics

Detection of Multidrug-Resistant Acinetobacter baumannii among Gram-Negative Bacteria Isolated from Clinical Samples

Acinetobacter baumannii is an aerobic, Gram -negative cocco-bacilli, non-fermentative, non-motile, and non-fastidious organism belonging to the genus Acinetobacter. The A. baumannii has emerged as a worldwide nosocomial pathogen causing about 80%25 of nosocomial infections comprising ventilator-acquired pneumonia, bacteremia, meningitis, urinary tract infections, skin and soft tissues infections associated with high mortality rate of approximately 63.3%25. Although literature shows sufficient information about the drug resistant A. baumannii, there has been inadequate reports on the antibiotic resistance level of this bacterium in the study area. The aim of this research was to detect Multidrug-resistant A. baumannii isolates among Gram-negative bacteria isolated from Federal Teaching Hospital, Gombe, Nigeria. A total of 1008 clinical samples were collected and cultured on MacConkey agar and Blood agar plates at 37o C for 18-24 hours. Following the incubation period, discrete colonies obtained were subjected to Gram staining. The Gram-negative isolates were identified based on conventional biochemical tests with further use of VITEK 2 COMPACT (BioMérieux, France) for confirmation of A. baumannii amongst the Gram-negative organisms. The results obtained showed that 263 Gram-negative organisms were isolated. A. baumannii accounted for 8.5%25 prevalence. Most of the A. baumannii isolated were from the male patients (75%25) within the age range of 33-48 years. Antibiotic susceptibility test using Kirby Bauer method in accordance with CLSI guidelines was done on 20 A. baumannii isolates. The isolates were more sensitive to levofloxacin (60%25), followed by Gentamicin (55%25), then Ciprofloxacin and Tetracycline (50%25) respectively. High level of resistance to Ceftriaxone (80%25), Cefepime (75%25), Ceftazidime (65%25), Piperacillin-Tazobactam (55%25), Ampicillin%252FSulbactam (60%25), Tigecycline (60%25), Meropenem (55%25) and Amikacin (60%25). This study revealed that 15 (75%25) of the A. baumannii were found to be multidrug-resistant. Therefore, antibiotic stewardship is necessary to combat further dissemination of this organism