Automatic, fast and robust characterization of noise distributions for diffusion MRI

Knowledge of the noise distribution in magnitude diffusion MRI images is the centerpiece to quantify uncertainties arising from the acquisition process. The use of parallel imaging methods, the number of receiver coils and imaging filters applied by the scanner, amongst other factors, dictate the resulting signal distribution. Accurate estimation beyond textbook Rician or noncentral chi distributions often requires information about the acquisition process (e.g. coils sensitivity maps or reconstruction coefficients), which is not usually available. We introduce a new method where a change of variable naturally gives rise to a particular form of the gamma distribution for background signals. The first moments and maximum likelihood estimators of this gamma distribution explicitly depend on the number of coils, making it possible to estimate all unknown parameters using only the magnitude data. A rejection step is used to make the method automatic and robust to artifacts. Experiments on synthetic datasets show that the proposed method can reliably estimate both the degrees of freedom and the standard deviation. The worst case errors range from below 2% (spatially uniform noise) to approximately 10% (spatially variable noise). Repeated acquisitions of in vivo datasets show that the estimated parameters are stable and have lower variances than compared methods.Comment: v2: added publisher DOI statement, fixed text typo in appendix A

Analyses of Use of Improved Beekeeping Equipment among Agricultural Development Programme Registered Bee Farmers in Imo State, Nigeria

The study examined improved beekeeping in Imo State, Nigeria. A sample of 30 registered bee farmers participated in the study. Data were elicited from the farmers using structured questionnaire and analysed using percentages and means. Results showed that the major sources of information on modern bee keeping equipment were farmers’ association (96%), extension agents (76%) and friends/relatives (70%). Available bee products in the area were honey (97%), bee wax (83%), bee venom (70%) and propolis (63%). Improved beekeeping equipment used in the area were foot wears (100%), gloves (100%), smokers (93%), bee veil (96%) and bee suits (87%). Constraints to improved beekeeping in the area include; lack of favourable agricultural policies (87%), lack of standard market for the products (77%), inadequate training and information on beekeeping (67%) and high cost of equipment (70%). The study therefore recommends the need for efforts aimed at promoting modern bee farming in the area, especially targeted at younger and educated farmers

The role of honey in the treatment of type 2 diabetes mellitus: a review of literature

The use of honey in the control of hyperglycemia in patients with type 2 diabetes mellitus is a current option being explored globally. Honey bees which are named in Latin as Apis, use the collected nectar from plants to produce honey after regurgitation and digestion of nectar. Carbohydrate constitutes about 80% of the components of honey. It includes monosaccharides [fructose (37.5%) and glucose (30.6%), disaccharides (sucrose (1.6%) and maltose (2.7%)] and oligosaccharides. Natural honey also contains water (17.2%), proteins, vitamins, minerals, enzymes, acids such as flavonoids, phenolic acids and other components. Honey is rich in antioxidant content and these antioxidant compounds function as endogenous cellular antioxidant defences against free radicals in diabetes mellitus. Antioxidants have also been shown to exert a beneficial effects on blood glucose. Fructose and other bioactive constituents of honey have also been linked with amelioration of hyperglycemia. Besides the beneficial effects of honey on blood glucose, honey is widely used in the management of diabetic foot ulcers, an important complication of diabetes mellitus. The wound-healing benefits of honey are attributed to its antioxidant constituents and broad-spectrum antimicrobial activity. Though additional studies are needed, the use of honey in the management of diabetes mellitus holds much promise

Analgesic, anti-inflammatory and antipyretic activities of ethanol extract of Annona senegalensis leaves in experimental animal models

Background: This study was carried out to establish the analgesic, anti-inflammatory and antipyretic effects of the ethanol extract of Anonna senegalensis leaves in experimental animals.Methods: The analgesic activity was measured using the abdominal constriction and tail flick tests. The anti-inflammatory activity was performed using xylene and egg-albumen paw induced tests, while the antipyretic activity was measured using brewer’s yeast and 2, 4 dinitrophenol induced pyrexia tests, respectively.Results: The leaf extract at all doses used exhibited significant (p<0.05) analgesic, anti-inflammatory and antipyretic activities.Conclusions: Results show that ethanol leaf extract of Anonna senegalensis possess therapeutic potential against pains and feverish conditions, supporting the claims of its this plant as remedy for similar ailments

Antiplasmodial activity of the ethanol extract of Dacryodes edulis leaf in Plasmodium berghei infected mice

Background: Malaria treatment in Africa is increasingly becoming difficult resulting from Plasmodium falciparum resistant to available antimalarial agents. Therefore, evaluating plants used in traditional medicines can lead to alternative treatment against malaria.Methods: This study evaluated the antiplasmodial activity of ethanol extract of Dacryodes edulis in chloroquine sensitive Plasmodium berghei NK65 strain in mice. The 4-day suppressive test, repository and curative effect against established rodent malaria infection models were assayed in this study. The oral acute toxicity test and phytochemical screening were also carried out on the ethanol leaf extract.Results: The ethanol leaf extract of Dacryodes edulis (D. edulis) at varying doses of 100 mg/kg, 200 mg/kg, 400 mg/kg significantly (p<0.05) exhibited dose-dependent decrease in parasitaemia at suppressive, repository and curative studies. Chloroquine 10 mg/kg significantly (p<0.05) decreased parasitaemia levels in the three models of malaria infections. The antiplasmodial activity of the leaf extract is comparable with the standard drug. The extract was found to be non-toxic acutely in mice.Conclusions: The findings show that D. edulis ethanol leaf extract demonstrated high antiplasmodial activity in a dose-dependent fashion. Thus, supporting claims of the plant traditional therapeutic importance for malaria treatment, and can be developed as an alternative therapy against the disease

Indigenous Preparation Methods of Medicinal plants Used for the Treatment of Small Ruminant Diseases in Imo State, Nigeria

The study examined the indigenous preparation methods of herbal medicines used for the treatment of small ruminant diseases in Imo State, Nigeria. A total of 120 small ruminant farmers participated in the study. Data were collected using interview schedule and analyzed using mean and percentages. Results identified retained placenta (82%), pneumonia (82%), foot rot (82%) and helminthosis (81%) as the most prevalent small ruminant diseases in the area. Available medicinal plants included Garcinia kola (93%), Ageratum conyzoides (92%), Costus afer (91%) and Vernonia amygdalina (80%).The result further indicated that many medicinal plants were used in the treatment of more than one small ruminant disease by the farmers. Roots (98%), leaves (98%), juice (93%) and stem (91%) were the commonly used plant parts for the preparation of the medicines. Popular preparation methods among the farmers included squeezing (98%), mixing with palm oil (97%) and pounding (91%). It was concluded that medicinal plants still support rural livestock industry in the state and should therefore be encouraged

Indigenous Preparation Methods of Medicinal plants Used for the Treatment of Small Ruminant Diseases in Imo State, Nigeria

The study examined the indigenous preparation methods of herbal medicines used for the treatment of small ruminant diseases in Imo State, Nigeria. A total of 120 small ruminant farmers participated in the study. Data were collected using interview schedule and analyzed using mean and percentages. Results identified retained placenta (82%), pneumonia (82%), foot rot (82%) and helminthosis (81%) as the most prevalent small ruminant diseases in the area. Available medicinal plants included Garcinia kola (93%), Ageratum conyzoides (92%), Costus afer (91%) and Vernonia amygdalina (80%).The result further indicated that many medicinal plants were used in the treatment of more than one small ruminant disease by the farmers. Roots (98%), leaves (98%), juice (93%) and stem (91%) were the commonly used plant parts for the preparation of the medicines. Popular preparation methods among the farmers included squeezing (98%), mixing with palm oil (97%) and pounding (91%). It was concluded that medicinal plants still support rural livestock industry in the state and should therefore be encouraged

Design, development and verification of the 30 and 44 GHz front-end modules for the Planck Low Frequency Instrument

We give a description of the design, construction and testing of the 30 and 44 GHz Front End Modules (FEMs) for the Low Frequency Instrument (LFI) of the Planck mission to be launched in 2009. The scientific requirements of the mission determine the performance parameters to be met by the FEMs, including their linear polarization characteristics. The FEM design is that of a differential pseudo-correlation radiometer in which the signal from the sky is compared with a 4-K blackbody load. The Low Noise Amplifier (LNA) at the heart of the FEM is based on indium phosphide High Electron Mobility Transistors (HEMTs). The radiometer incorporates a novel phase-switch design which gives excellent amplitude and phase match across the band. The noise temperature requirements are met within the measurement errors at the two frequencies. For the most sensitive LNAs, the noise temperature at the band centre is 3 and 5 times the quantum limit at 30 and 44 GHz respectively. For some of the FEMs, the noise temperature is still falling as the ambient temperature is reduced to 20 K. Stability tests of the FEMs, including a measurement of the 1/f knee frequency, also meet mission requirements. The 30 and 44 GHz FEMs have met or bettered the mission requirements in all critical aspects. The most sensitive LNAs have reached new limits of noise temperature for HEMTs at their band centres. The FEMs have well-defined linear polarization characteristcs.Comment: 39 pages, 33 figures (33 EPS files), 12 tables. Planck LFI technical papers published by JINST: http://www.iop.org/EJ/journal/-page=extra.proc5/1748-022

Planck pre-launch status: calibration of the Low Frequency Instrument flight model radiometers

The Low Frequency Instrument (LFI) on-board the ESA Planck satellite carries eleven radiometer subsystems, called Radiometer Chain Assemblies (RCAs), each composed of a pair of pseudo-correlation receivers. We describe the on-ground calibration campaign performed to qualify the flight model RCAs and to measure their pre-launch performances. Each RCA was calibrated in a dedicated flight-like cryogenic environment with the radiometer front-end cooled to 20K and the back-end at 300K, and with an external input load cooled to 4K. A matched load simulating a blackbody at different temperatures was placed in front of the sky horn to derive basic radiometer properties such as noise temperature, gain, and noise performance, e.g. 1/f noise. The spectral response of each detector was measured as was their susceptibility to thermal variation. All eleven LFI RCAs were calibrated. Instrumental parameters measured in these tests, such as noise temperature, bandwidth, radiometer isolation, and linearity, provide essential inputs to the Planck-LFI data analysis.Comment: 15 pages, 18 figures. Accepted for publication in Astronomy and Astrophysic