Flavonoids from Sudanese Albizia zygia (Leguminosae, Subfamily Mimosoideae), a Plant with Antimalarial Potency

Three flavonoids were isolated for the first time from the Sudanese medicinal plants Albizia zygia. Compounds 1-3 were identified by interpretation of ESI mass data, 1H, 13C and 2D NMR as well as by comparison with published data as 4',7-dihydroxyflavanone (1) 3',4',7-trihydroxyflavone (2), 3-O-methylfisetin (3',4',7-trihydroxy-3-methoxyflavone, 3). All flavonoids were tested against Plasmodium falciparum, and only compound 2 showed high antimalarial activity (IC50 0.078 μg/ml).Keywords: Albizia zygia; Mimosoideae; flavonoids; antimalarial activit

Food safety knowledge and practices of street foodvendors in Atbara City (Naher Elneel State Sudan)

The study was conducted to evaluate the food safety knowledge and practices of street food vendors in Atbara city between March and April, 2008. The questionnaires respondents were 28% male and 72% were female, 48% of them had primary school education while 42% were illiterates. The most prevalent isolated bacteria from cooked meals, bottled drink and fresh juice were; Escherichia coli, Staphylococcus auerus and Bacillus sp. The viable bacterial counts were 4.6 CFU/ml, 3.7 CFU/ml and 4.1 CFU/ml for cooked meals, bottled drink and juice, respectively

Liver abscesses in dromedary camels: Pathological characteristics and aerobic bacterial aetiology

The study was carried out at Nyala abattoirs, South Darfur State, Sudan during a period from 2009 to 2011. Slaughtered camels (822) were examined for pathological changes of liver abscesses and identification of the involved aerobic bacteria. Grossly, a total of 111 (13.5%) liver abscesses were recorded in different camel ages; 90 (81.1%) were less than seven years old and 21 (18.9%) were more than seven years old. Histopathology of sectioned tissues revealed necrotic abscesses with infiltration of inflammatory cells, hydropic degeneration with swelling of hepatocytes comprising the sinusoid and different size of vacuoles in the hepatic cells. Proliferation of bile ducts with fibrous tissue and infiltration of inflammatory cells was also recorded. Investigation of bacteria revealed 90 aerobic isolates; they were identified to 52 (57.8%) gram positive cocci, 20 (22.2%) gram positive rods and 18 (20.0%) gram negative rods. Staphylococcus spp. (41.1%), Corynebacterium spp. (17.9%) and Streptococcus spp. (13.3%) were the most frequently identified bacteria involved in liver abscesses of camels in the region. Further studies are required to assess the pathogenicity of bacterial isolates from camel livers. This is particularly important from a public health perspective, since some people of Sudan are known to consume raw camel liver.Keywords: Aerobic bacterial, Dromedary camels, Liver abscesses, Pathology, Suda

Estimating the effect of nitrogen fertilizer on the greenhouse gas balance of soils in Wales under current and future climate

The Welsh Government is committed to reduce greenhouse gas (GHG) emissions from agricultural systems and combat the effects of future climate change. In this study, the ECOSSE model was applied spatially to estimate GHG and soil organic carbon (SOC) fluxes from three major land uses (grass, arable and forest) in Wales. The aims of the simulations were: (1) to estimate the annual net GHG balance for Wales; (2) to investigate the efficiency of the reduced nitrogen (N) fertilizer goal of the sustainable land management scheme (Glastir), through which the Welsh Government offers financial support to farmers and land managers on GHG flux reduction; and (3) to investigate the effects of future climate change on the emissions of GHG and plant net primary production (NPP). Three climate scenarios were studied: baseline (1961–1990) and low and high emission climate scenarios (2015–2050). Results reveal that grassland and cropland are the major nitrous oxide (N2O) emitters and consequently emit more GHG to the atmosphere than forests. The overall average simulated annual net GHG balance for Wales under baseline climate (1961–1990) is equivalent to 0.2 t CO2e ha-1 y-1 which gives an estimate of total annual net flux for Wales of 0.34 Mt CO2e y-1. Reducing N fertilizer by 20 and 40 % could reduce annual net GHG fluxes by 7 and 25 %, respectively. If the current N fertilizer application rate continues, predicted climate change by the year 2050 would not significantly affect GHG emissions or NPP from soils in Wales

Traditional Underground Grain Storage in Clay Soils in Sudan Improved by Recent Innovations

In the central clay plain of the Sudan, traditional subsistence farmers and small farmers that also produce for local markets want to keep the region near food self-sufficiency. They combine annual production of sorghum with underground pit storage of part of the harvest. With increasing climate variability this food security is coming more and more under pressure. Farmers recently experimented with pit innovations that would allow storage for more than one season. These innovations were quantified and further improvements were suggested. It was found that in the most abundantly occurring cracking clay soils, wide shallow pits, using thick chaff linings, with wider above ground soil caps, are most suitable for longer term storage

Contribution of Sudanese medical diaspora to the healthcare delivery system in Sudan: exploring options and barriers

Background: Medical diaspora options, including the engagement of expatriate physicians in development efforts within their home country, are being called for to reverse the effects of brain drain from developing countries. This paper presents the results of a study exploring the potential contributions for the Sudanese Medial Diaspora Options to the healthcare delivery system (HCDS) in Sudan, focusing on the options of temporal and permanent returns and the likely obstacles faced in their implementation. Methods: This was a cross-sectional study using a mixed methods design including quantitative and qualitative approaches. For the quantitative approach, the study, which focused on the possible contribution of the diaspora to healthcare delivery in Sudan, was based on an online survey using random purposive and snowballing sampling techniques involving 153 Sudanese physicians working in Saudi Arabia and other Gulf States, the United Kingdom, the Republic of Ireland, and the United States of America. The qualitative approach involved in-depth interviews with returnee physicians and key informants in Sudan, focusing on the return experiences, the barriers for return, and the options to improve future contributions. Results: Despite contributions of the Sudanese medical diaspora being of a small scale considering the size of the phenomenon, as well as infrequent and not appropriately organized, their inputs to academia and the links built with overseas institutions and specialist clinical services were nevertheless remarkable. The main barrier to temporal return was inappropriate organization by the local counterparts, while those for permanent return of physicians were poor work environment, insufficient financial payment, unsecured accommodation, and offspring education. The study identified short-term return as a feasible option considering the country’s current conditions. Proper coordination mechanisms for short-term returns and facilitation of permanent return through stakeholders’ collaboration were proposed to improve diaspora contributions. Conclusions: The potentials of Sudanese medial diaspora contributions to the HCDS in Sudan are promising. Short-term contributions were observed as the best option for the current country situation. Creation of a coordinating body from within the healthcare sector in Sudan to effectively coordinate diaspora contributions is recommended

Photo-z Performance for Precision Cosmology

Current and future weak lensing surveys will rely on photometrically estimated redshifts of very large numbers of galaxies. In this paper, we address several different aspects of the demanding photo-z performance that will be required for future experiments, such as the proposed ESA Euclid mission. It is first shown that the proposed all-sky near-infrared photometry from Euclid, in combination with anticipated ground-based photometry (e.g. PanStarrs-2 or DES) should yield the required precision in individual photo-z of sigma(z) < 0.05(1+z) at I_AB < 24.5. Simple a priori rejection schemes based on the photometry alone can be tuned to recognise objects with wildly discrepant photo-z and to reduce the outlier fraction to < 0.25% with only modest loss of otherwise usable objects. Turning to the more challenging problem of determining the mean redshift of a set of galaxies to a precision of 0.002(1+z) we argue that, for many different reasons, this is best accomplished by relying on the photo-z themselves rather than on the direct measurement of from spectroscopic redshifts of a representative subset of the galaxies. A simple adaptive scheme based on the statistical properties of the photo-z likelihood functions is shown to meet this stringent systematic requirement. We also examine the effect of an imprecise correction for Galactic extinction and the effects of contamination by fainter over-lapping objects in photo-z determination. The overall conclusion of this work is that the acquisition of photometrically estimated redshifts with the precision required for Euclid, or other similar experiments, will be challenging but possible. (abridged)Comment: 16 pages, 11 figures; submitted to MNRA

Constraining the interacting dark energy models from weak gravity conjecture and recent observations

We examine the effectiveness of the weak gravity conjecture in constraining the dark energy by comparing with observations. For general dark energy models with plausible phenomenological interactions between dark sectors, we find that although the weak gravity conjecture can constrain the dark energy, the constraint is looser than that from the observations.Comment: 14 pages, 12 figures, revtex4, v2: minor corrections, accepted for publication in PL

Catastrophic photometric redshift errors: weak lensing survey requirements

We study the sensitivity of weak lensing surveys to the effects of catastrophic redshift errors - cases where the true redshift is misestimated by a significant amount. To compute the biases in cosmological parameters, we adopt an efficient linearized analysis where the redshift errors are directly related to shifts in the weak lensing convergence power spectra. We estimate the number Nspec of unbiased spectroscopic redshifts needed to determine the catastrophic error rate well enough that biases in cosmological parameters are below statistical errors of weak lensing tomography. While the straightforward estimate of Nspec is ~10^6 we find that using only the photometric redshifts with z<=2.5 leads to a drastic reduction in Nspec to ~30,000 while negligibly increasing statistical errors in dark energy parameters. Therefore, the size of spectroscopic survey needed to control catastrophic errors is similar to that previously deemed necessary to constrain the core of the z_s-z_p distribution. We also study the efficacy of the recent proposal to measure redshift errors by cross-correlation between the photo-z and spectroscopic samples. We find that this method requires ~10% a priori knowledge of the bias and stochasticity of the outlier population, and is also easily confounded by lensing magnification bias. The cross-correlation method is therefore unlikely to supplant the need for a complete spectroscopic redshift survey of the source population.Comment: 14 pages, 3 figure

Modelling methane emissions and grain yields for a double-rice system in Southern China with DAYCENT and DNDC models

Acknowledgements This work contributed to the following projects: EU Horizon 2020 programme (SuperG) and The Scientific and Technological Innovation Special Fund Project of Carbon Peak and Carbon Neutrality in Jiangsu Province (No. BE2022311). The first author (Yang Guo) gratefully acknowledges financial support from China Scholarship Council (CSC).Peer reviewedPublisher PD