11,672 research outputs found

    Phonon arithmetic in a trapped ion system

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    Single-quantum level operations are important tools to manipulate a quantum state. Annihilation or creation of single particles translates a quantum state to another by adding or subtracting a particle, depending on how many are already in the given state. The operations are probabilistic and the success rate has yet been low in their experimental realization. Here we experimentally demonstrate (near) deterministic addition and subtraction of a bosonic particle, in particular a phonon of ionic motion in a harmonic potential. We realize the operations by coupling phonons to an auxiliary two-level system and applying transitionless adiabatic passage. We show handy repetition of the operations on various initial states and demonstrate by the reconstruction of the density matrices that the operations preserve coherences. We observe the transformation of a classical state to a highly non-classical one and a Gaussian state to a non-Gaussian one by applying a sequence of operations deterministically

    Comparative Study on The Potency of Antibiotic Discs With Commercially Sold Antibiotics on Clinical Isolates From Urinary Tract

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    A total of 250 urine samples were collected from patients attending Ahmadu Bello University Health Service Clinic (Sick bay), Salama Hospital and Major Ibrahim Abdullahi Memorial Hospital (Kaduna State Ministry of Health). The samples were screened for UTI and forty-three (43) were positive for Klebsiella and Escherichia coli. Of all the isolates, 24 were K. species and 19 were Escherichia coli. Their susceptibilities to Ampicillin, Ciprofloxacin and Gentamicin were examined using the antibiotics disc and the commercially sold antibiotics. The susceptibility of K. species to Ampicillin, Ciprofloxacin and Gentamicin for the antibiotics disc was 16.7%, 62.5% and 41.7% respectively. For the commercially sold antibiotics its susceptibility was 0%, 8.3% and 50.0% to Ampicillin, Ciprofloxacin and Gentamicin respectively. The susceptibility of Escherichia coli to Ampicillin, Ciprofloxacin and Gentamicin for the antibiotics disc was 31.6%, 52.6% and 57.9% respectively. For the commercially sold antibiotics its susceptibility was 0%, 36.8% and 31.6% to Ampicillin, Ciprofloxacin and Gentamicin respectively. Our results showed that antibiotics disc was more effective than the commercially sold antibiotics and that both organisms were resistant to Ampicillin but susceptible to Gentamicin and Ciprofloxacin.Keywords: Potency, Antibiotics, Disc Isolates, Urinary tractNigerian Journal of Basic and Applied Science (2011), 19(2):231- 23

    The Effect of Electrode Configuration on the Unipolar His-Bundle Electrogram

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75654/1/j.1540-8159.1989.tb06148.x.pd

    Human immunodeficiency virus rebound after suppression to < 400 copies/mL during initial highly active antiretroviral therapy regimens, according to prior nucleoside experience and duration of suppression

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    This study evaluated 1433 human immunodeficiency virus (HIV)-infected patients starting highly active antiretroviral therapy (HAART), 409 (28%) of whom had prior nucleoside experience and achieved an HIV load of <400 copies/mL by 24 weeks of therapy. Three hundred seven patients experienced virus rebound during a total of 2773.3 person-years of follow-up. There was a higher rate of virus rebound among the patients with pre-HAART nucleoside experience (relative hazard [RH], 2.86; 95% confidence interval, 2.22-3.84; P < .0001) and a decreasing rate of virus rebound with increasing duration of virus suppression (i.e., time since achieving a virus load of <400 HIV RNA copies/mL) among both the nucleoside-experienced and naive patients (P < .0001), but the difference between the groups persisted into the third year of follow-up (P = .0007). Even patients who had experienced <2 months of nucleoside therapy before beginning HAART had an increased risk of virus rebound (RH, 1.95; P = .009). It appears that only a small period of pre-HAART nucleoside therapy is sufficient to confer a disadvantage, in terms of risk of virus rebound, that persists for several years

    Treatment exhaustion of highly active antiretroviral therapy (HAART) among individuals infected with HIV in the United Kingdon: multicentre cohort study

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    Objectives: To investigate whether there is evidence that an increasing proportion of HIV infected patients is starting to experience increases in viral load and decreases in CD4 cell count that are consistent with exhaustion of available treatment options. Design: Multicentre cohort study. Setting: Six large HIV treatment centres in southeast England. Participants: All individuals seen for care between 1 January 1996 and 31 December 2002. Main outcome measures: Exposure to individual antiretroviral drugs and drug classes, CD4 count, plasma HIV RNA burden. Results: Information is available on 16 593 individuals (13 378 (80.6%) male patients, 10 340 (62.3%) infected via homosexual or bisexual sex, 4426 (26.7%) infected via heterosexual sex, median age 34 years). Overall, 10 207 of the 16 593 patients (61.5%) have been exposed to any antiretroviral therapy. This proportion increased from 41.2% of patients under follow up at the end of 1996 to 71.3% of those under follow up in 2002. The median CD4 count and HIV RNA burden of patients under follow up in each year changed from 270 cells/mm3 and 4.34 log10 copies/ml in 1996 to 408 cells/mm3 and 1.89 log10 copies/ml, respectively, in 2002. By 2002, 3060 (38%) of patients who had ever been treated with antiretroviral therapy had experienced all three main classes. Of these, around one quarter had evidence of “viral load failure” with all these three classes. Patients with three class failure were more likely to have an HIV RNA burden > 2.7 log10 copies/ml and a CD4 count < 200 cells/mm3. Conclusions: The proportion of individuals with HIV infection in the United Kingdom who have been treated has increased gradually over time. A substantial proportion of these patients seem to be in danger of exhausting their options for antiretroviral treatment. New drugs with low toxicity, which are not associated with cross resistance to existing drugs, are urgently needed for such patients

    Mutual information rate and bounds for it

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    The amount of information exchanged per unit of time between two nodes in a dynamical network or between two data sets is a powerful concept for analysing complex systems. This quantity, known as the mutual information rate (MIR), is calculated from the mutual information, which is rigorously defined only for random systems. Moreover, the definition of mutual information is based on probabilities of significant events. This work offers a simple alternative way to calculate the MIR in dynamical (deterministic) networks or between two data sets (not fully deterministic), and to calculate its upper and lower bounds without having to calculate probabilities, but rather in terms of well known and well defined quantities in dynamical systems. As possible applications of our bounds, we study the relationship between synchronisation and the exchange of information in a system of two coupled maps and in experimental networks of coupled oscillators

    Atomic-scale combination of germanium-zinc nanofibers for structural and electrochemical evolution

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    Alloys are recently receiving considerable attention in the community of rechargeable batteries as possible alternatives to carbonaceous negative electrodes; however, challenges remain for the practical utilization of these materials. Herein, we report the synthesis of germanium-zinc alloy nanofibers through electrospinning and a subsequent calcination step. Evidenced by in situ transmission electron microscopy and electrochemical impedance spectroscopy characterizations, this one-dimensional design possesses unique structures. Both germanium and zinc atoms are homogenously distributed allowing for outstanding electronic conductivity and high available capacity for lithium storage. The as-prepared materials present high rate capability (capacity of similar to 50% at 20 C compared to that at 0.2 C-rate) and cycle retention (73% at 3.0 C-rate) with a retaining capacity of 546 mAh g(-1) even after 1000 cycles. When assembled in a full cell, high energy density can be maintained during 400 cycles, which indicates that the current material has the potential to be used in a large-scale energy storage system

    Participatory evaluation of drought tolerant maize varieties in the Guinea Savanna of Ghana using mother and baby trial design

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    Maize (Zea mays) is a major food crop in Ghana but grain yields are low as a result of drought and low soil fertility. This study evaluated drought tolerant maize varieties in 2008 and 2009 in the Guinea savanna of Ghana using researcher-managed mother and farmer-managed baby trial design. Mean grain yields ranged between 2574 and 3462 kg/ha for the mother trials and 1460 and 2328 kg/ha for baby trials. Several improved varieties performed better than the best local varieties, but two preferred varieties, TZEE Y POP STR QPM C0 and EVDT W 99 STR QPM CO which produced 35-52% more grain than the best local varieties of similar maturity rating were released in 2010. Farmers have multiple criteria for evaluating maize varieties apart from yield, though yield, larger cob and grain size were the three key criteria used by farmers to select and rank varieties. Researchers should incorporate farmers’ preferences in selecting varieties in the breeding process in order to increase likelihood of adoption of the varieties.Keywords: Drought-tolerant maize, farmer preference, mother and baby, participator

    Soil salinity, household wealth and food insecurity in tropical deltas: evidence from south-west coast of Bangladesh

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    As a creeping process, salinisation represents a significant long-term environmental risk in coastal and deltaic environments. Excess soil salinity may exacerbate existing risks of food insecurity in densely populated tropical deltas, which is likely to have a negative effect on human and ecological sustainability of these regions and beyond. This study focuses on the coastal regions of the Ganges–Brahmaputra delta in Bangladesh, and uses data from the 2010 Household Income and Expenditure Survey and the Soil Resource Development Institute to investigate the effect of soil salinity and wealth on household food security. The outcome variables are two widely used measures of food security: calorie availability and household expenditure on food items. The main explanatory variables tested include indicators of soil salinity and household-level socio-economic characteristics. The results of logistic regression show that in unadjusted models, soil salinisation has a significant negative effect on household food security. However, this impact becomes statistically insignificant when households’ wealth is taken into account. The results further suggest that education and remittance flows, but not gender or working status of the household head, are significant predictors of food insecurity in the study area. The findings indicate the need to focus scholarly and policy attention on reducing wealth inequalities in tropical deltas in the context of the global sustainable deltas initiative and the proposed Sustainable Development Goals.ESPA Deltas projectBelmont Forum DELTAS projectESPA – DFIDESRCNER

    The relationship between intraocular pressure and estimated intracranial pressure in patients with normal tension glaucoma

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    This study aims to determine the relationship between intracranial pressure (ICP) and intraocular pressure (IOP) in patients with normal-tension glaucoma (NTG) who were already on anti-glaucoma treatment using an estimated ICP (estICP) and translaminar pressure difference (estTPD) formula. A cross-sectional comparative study consisted of 66 subjects (66 eyes) who were divided into NTG (n=33) and normal (n=33) group was conducted from 1st November 2017 until 31st May 2020 at a tertiary hospital in Malaysia. After obtaining consent from subjects, ocular and systemic data including IOP, visual field testing, axial length, central corneal thickness (CCT), peripapillary and macular retinal nerve fibre layer evaluation as well as blood pressure (BP) and body mass index (BMI) were collected. The estICP (mm Hg) was calculated as 0.44 x BMI (kg/m2) + 0.16 x diastolic blood pressure (mmHg) – 0.18 x age (years) – 1.91. The estTPD was derived from this calculated value, where estTPD (mm Hg) = IOP – estICP. Analysis showed there was no significant difference in estimated ICP between NTG and normal subjects [mean difference (95% CI): 0.37 (-1.39, 2.12), p=0.679]. The difference in estTPD between NTG and normal subjects were found to be statistically insignificant too [mean difference (95% CI): -1.24 (-2.95, 0.47), p=0.149]. The variables significant in multivariate model included best corrected visual acuity (p=0.028), retinal nerve fiber layer (RNFL) (p=0.003), average macular (p=0.002) and estTPD (p=0.008). The EstTPD was found to be protective towards NTG, which the unit increased in estTPD will decreased the odds of having NTG by 26.5% [Adj. OR (95% CI): 0.735 (0.586, 0.922), p=0.008]. In conclusion, ICP was correlated in increased in IOP. A higher TPD may be associated with a lower chance of developing NTG
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