3,345 research outputs found
Diversity of yeasts involved in the fermentation of tchoukoutou, an opaque sorghum beer from Benin
Opaque sorghum beers are traditional alcoholic beverages in several African countries. Known as tchoukoutou in Benin, the beer is often obtained from an uncontrolled fermentation. It is consumed in an actively fermenting state and has a sour taste. The present study characterized and identified the yeasts involved in the fermentation process of this type of beer using the phenotypical approach. Of 12 beers from 4 different locations, the mean values of the pH, titratable acidity, dry matter content and refractive index were respectively 3.67, 0.70 (% as lactic acid) 18.08% and 7.00. Lactic acid bacteria and yeasts were the predominant microorganisms involved in the fermentation of tchoukoutou. Their counts were respectively 9.1 log cfu/ml and 9.1 logcfu/g. Enterobacteriaceae were not detectable in the beer. Based on the phenotypic characters and the assimilation profiles of 40 isolated yeasts, four genera with seven species of yeasts were identified. The yeast species predominant in the Benin opaque sorghum beer tchoukoutou was Saccharomyces cerevisa
Absorbing systematic effects to obtain a better background model in a search for new physics
This paper presents a novel approach to estimate the Standard Model
backgrounds based on modifying Monte Carlo predictions within their systematic
uncertainties. The improved background model is obtained by altering the
original predictions with successively more complex correction functions in
signal-free control selections. Statistical tests indicate when sufficient
compatibility with data is reached. In this way, systematic effects are
absorbed into the new background model. The same correction is then applied on
the Monte Carlo prediction in the signal region. Comparing this method to other
background estimation techniques shows improvements with respect to statistical
and systematical uncertainties. The proposed method can also be applied in
other fields beyond high energy physics
A simple one step process for enhancement of titanium foil dye sensitised solar cell anodes
The photo-conversion efficiency and stability of back-illuminated dye sensitised solar cells with titanium foil based photoanodes are enhanced by a simple nitric acid treatment through which the foil is passivated. This treatment changes the morphology of the titanium foil and increases its electrochemical double layer capacitance
Willingness to pay for market information received by mobile phone among smallholder pineapple farmers in Benin
Published online: 04 April 2016Access to up-to-date information on market prices and quality requirements remains a key issue for smallholder farmersâ access to high income markets. The aim of this chapter is to explore the problem of information asymmetry between farmers and buyers in the pineapple supply chain in Benin, and to assess strategies using mobile phones to overcome this problem. Data was collected from an exploratory case study in Ghana and a survey with 285 farmers in Benin. Results show that farmers face market information asymmetry leading to lower prices and income. In Ghana, market price alerts through mobile phones messaging allowed decreasing transaction costs for farmers. In Benin, farmers expressed a willingness to pay a premium of up to US$ 2.5 per month to get market price and quality information. Econometric analysis showed that decisive factors for the size of the premium include farm location, market channel, profit margin, contact with agricultural extension services, and technical support from buyers
A Transparent Reporting of a multivariable prediction model for Individual Prognosis Or Diagnosis analysis to evaluate the quality of reporting of postoperative pancreatic fistula prediction models after pancreatoduodenectomy:A systematic review
BACKGROUND: Postoperative pancreatic fistula is a frequent and potentially lethal complication after pancreatoduodenectomy. Several models have been developed to predict postoperative pancreatic fistula risk. This study was performed to evaluate the quality of reporting of postoperative pancreatic fistula prediction models after pancreatoduodenectomy using the Transparent Reporting of a multivariable prediction model for Individual Prognosis Or Diagnosis (TRIPOD) checklist that provides guidelines on reporting prediction models to enhance transparency and to help in the decision-making regarding the implementation of the appropriate risk models into clinical practice.METHODS: Studies that described prediction models to predict postoperative pancreatic fistula after pancreatoduodenectomy were searched according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The TRIPOD checklist was used to evaluate the adherence rate. The area under the curve and other performance measures were extracted if reported. A quadrant matrix chart is created to plot the area under the curve against TRIPOD adherence rate to find models with a combination of above-average TRIPOD adherence and area under the curve.RESULTS: In total, 52 predictive models were included (23 development, 15 external validation, 4 incremental value, and 10 development and external validation). No risk model achieved 100% adherence to the TRIPOD. The mean adherence rate was 65%. Most authors failed to report on missing data and actions to blind assessment of predictors. Thirteen models had an above-average performance for TRIPOD checklist adherence and area under the curve.CONCLUSION: Although the average TRIPOD adherence rate for postoperative pancreatic fistula models after pancreatoduodenectomy was 65%, higher compared to other published models, it does not meet TRIPOD standards for transparency. This study identified 13 models that performed above average in TRIPOD adherence and area under the curve, which could be the appropriate models to be used in clinical practice.</p
A Versatile, Portable Intravital Microscopy Platform for Studying Beta-cell Biology In Vivo
The pancreatic islet is a complex micro-organ containing numerous cell types, including endocrine, immune, and endothelial cells. The communication of these systems is lost upon isolation of the islets, and therefore the pathogenesis of diabetes can only be fully understood by studying this organized, multicellular environment in vivo. We have developed several adaptable tools to create a versatile platform to interrogate ÎČ-cell function in vivo. Specifically, we developed ÎČ-cell-selective virally-encoded fluorescent protein biosensors that can be rapidly and easily introduced into any mouse. We then coupled the use of these biosensors with intravital microscopy, a powerful tool that can be used to collect cellular and subcellular data from living tissues. Together, these approaches allowed the observation of in vivo ÎČ-cell-specific ROS dynamics using the Grx1-roGFP2 biosensor and calcium signaling using the GcAMP6s biosensor. Next, we utilized abdominal imaging windows (AIW) to extend our in vivo observations beyond single-point terminal measurements to collect longitudinal physiological and biosensor data through repeated imaging of the same mice over time. This platform represents a significant advancement in our ability to study ÎČ-cell structure and signaling in vivo, and its portability for use in virtually any mouse model will enable meaningful studies of ÎČ-cell physiology in the endogenous islet niche
The missing Rheic Ocean magmatic arcs: Provenance analysis of Late Paleozoic
Early Carboniferous turbiditic sedimentary rocks in synorogenic basins located on both sides of the Rheic suture in
SW Iberiawere studied for provenance analysis. An enigmatic feature of this suture, which resulted from closure
of the Rheic Ocean with the amalgamation of Pangea in the Late Carboniferous, is that there are no recognizable
mid- to Late Devonian subduction-related magmatic rocks,which should have been generated during the process
of subduction, on either side of it. UâPb LAâICP-MS geochronology of detrital zircons from Early Carboniferous
turbidites in the vicinity of the Rheic suture in SW Iberia, where it separates the OssaâMorena Zone (with
Gondwana continental basement) to the north from the South Portuguese Zone (with unknown/Meguma?
continental basement) to the south, reveals the abundance of mid- to Late Devonian (51â81%) and Early
Carboniferous (13â25%) ages. The Cabrela andMĂ©rtola turbidites of the OssaâMorena and South Portuguese
zones, respectively, are largely devoid of older zircons, differing from the age spectra of detrital zircons in
the oldest (Late Devonian) strata in the underlying South Portuguese Zone, which contain abundant Cambrian
and Neoproterozoic ages. Mid- to Late Devonian zircons in the Cabrela Formation (age cluster at c. 391 Ma,
EifelianâGivetian transition) and MĂ©rtola Formation (age clusters at c. 369 Ma and at c. 387 Ma, Famennian
and Givetian respectively) are attributable to a source terrane made up of magmatic rocks with a simple
geological history lacking both multiple tectonic events and older continental basement. The terrane capa-
ble of sourcing sediments dispersed on both sides of the suture is interpreted to have been completely re-
moved by erosion in SW Iberia. Given that closure of the Rheic Ocean required subduction of its oceanic
lithosphere and the absence of significant arc magmatism on either side of the Rheic suture, we suggest:
1) the source of the zircons in the SW Iberia basins was a short-lived Rheic ocean magmatic arc, and
2) given the lack of older zircons in the SW Iberia basins, this short-lived arc was probably developed
in an intra-oceanic environment
Allergen immunotherapy on the way to product-based evaluation - a WAO statement
Allergen immunotherapy (AIT) is widely used in clinical practice for patients with moderate to severe allergic rhinitis due to inhalant allergens and may be delivered via subcutaneous (SCIT) and sublingual routes (SLIT). However, the quality of evidence for individual AIT products is very heterogeneous, and extensions of overall conclusions ("class effects") on the efficacy and disease-modifying effects to all AIT products are unjustified. In contrast, each product needs to be evaluated individually, based on available study results, to justify efficacy and specific claims on sustained and disease modifying effects per allergen and targeted patient group (children vs. adults, allergic rhinitis vs. asthma). WAO intends to support the current development to evidence-based AIT, which ultimately will lead to a more efficacious treatment of allergic patients and the appropriate recognition of AIT
Currency Unions and Trade: A PPML Re-Assessment with High-Dimensional Fixed Effects
Recent work on the effects of currency unions (CUs) on trade stresses the importance of using many countries and years in order to obtain reliable estimates. However, for large samples, computational issues associated with the three-way (exporter-time, importer-time, and country-pair) fixed effects currently recommended in the gravity literature have heretofore limited the choice of estimator, leaving an important methodological gap. To address this gap, we introduce an iterative Poisson Pseudo-Maximum Likelihood (PPML) estimation procedure that facilitates the inclusion of these fixed effects for large data sets and also allows for correlated errors across countries and time. When applied to a comprehensive sample with more than 200 countries trading over 65 years, these innovations flip the conclusions of an otherwise rigorously-specified linear model. Most importantly, our estimates for both the overall CU effect and the Euro effect specifically are economically small and statistically insignificant. We also document that linear and PPML estimates of the Euro effect increasingly diverge as the sample size grows
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