Contextual analysis in two villages of the Niger River Inner Delta

The Community-based Fish Culture in Seasonal Floodplains and Irrigation Systems (CBFC) project is a five year research project supported by the Challenge Program on Water and Food (CPWF), with the aim of increasing productivity of seasonally occurring water bodies through aquaculture. The project has been implemented in Bangladesh, Cambodia, China, Mali and Vietnam, where technical and institutional options for community based aquaculture have been tested. The project began in 2005 and was completed in March 2010. The objective of the study was to improve our knowledge of mare management and the livelihoods of two villages of the Niger Inner Delta, Severi and Komio. We wanted to understand mare access and fishery management and to highlight the different stakeholders involved in mare management as well as the different rules regulating access to the various mare resources. We implemented a series of Focus Group Discussion with the different socio-economic groups of the villages (fisherfolk, farmer-fishers, and herders) and a series of semi-structured interviews with key informants and stakeholders involved in mare management took place in July 2008.Fishing rights, River fisheries, Livelihoods

Systematic study of Oxygen vacancy tunable transport properties of few-layer MoO3- x enabled by vapor-based synthesis

Bulk and nanoscale molybdenum trioxide (MoO3) has shown impressive technologically relevant properties, but deeper investigation into 2D MoO3 has been prevented by the lack of reliable vapor-based synthesis and doping techniques. Herein, the successful synthesis of high-quality, few-layer MoO3 down to bilayer thickness via physical vapor deposition is reported. The electronic structure of MoO3 can be strongly modified by introducing oxygen substoichiometry (MoO3- x), which introduces gap states and increases conductivity. A dose-controlled electron irradiation technique to introduce oxygen vacancies into the few-layer MoO3 structure is presented, thereby adding n-type doping. By combining in situ transport with core-loss and monochromated low-loss scanning transmission electron microscopy–electron energy-loss spectroscopy studies, a detailed structure–property relationship is developed between Mo-oxidation state and resistance. Transport properties are reported for MoO3- x down to three layers thick, the most 2D-like MoO3- x transport hitherto reported. Combining these results with density functional theory calculations, a radiolysis-based mechanism for the irradiation-induced oxygen vacancy introduction is developed, including insights into favorable configurations of oxygen defects. These systematic studies represent an important step forward in bringing few-layer MoO3 and MoO3- x into the 2D family, as well as highlight the promise of MoO3- x as a functional, tunable electronic material

An accurate and interpretable model for siRNA efficacy prediction

BACKGROUND: The use of exogenous small interfering RNAs (siRNAs) for gene silencing has quickly become a widespread molecular tool providing a powerful means for gene functional study and new drug target identification. Although considerable progress has been made recently in understanding how the RNAi pathway mediates gene silencing, the design of potent siRNAs remains challenging. RESULTS: We propose a simple linear model combining basic features of siRNA sequences for siRNA efficacy prediction. Trained and tested on a large dataset of siRNA sequences made recently available, it performs as well as more complex state-of-the-art models in terms of potency prediction accuracy, with the advantage of being directly interpretable. The analysis of this linear model allows us to detect and quantify the effect of nucleotide preferences at particular positions, including previously known and new observations. We also detect and quantify a strong propensity of potent siRNAs to contain short asymmetric motifs in their sequence, and show that, surprisingly, these motifs alone contain at least as much relevant information for potency prediction as the nucleotide preferences for particular positions. CONCLUSION: The model proposed for prediction of siRNA potency is as accurate as a state-of-the-art nonlinear model and is easily interpretable in terms of biological features. It is freely available on the web a

A 'small-world-like' model for comparing interventions aimed at preventing and controlling influenza pandemics

BACKGROUND: With an influenza pandemic seemingly imminent, we constructed a model simulating the spread of influenza within the community, in order to test the impact of various interventions. METHODS: The model includes an individual level, in which the risk of influenza virus infection and the dynamics of viral shedding are simulated according to age, treatment, and vaccination status; and a community level, in which meetings between individuals are simulated on randomly generated graphs. We used data on real pandemics to calibrate some parameters of the model. The reference scenario assumes no vaccination, no use of antiviral drugs, and no preexisting herd immunity. We explored the impact of interventions such as vaccination, treatment/prophylaxis with neuraminidase inhibitors, quarantine, and closure of schools or workplaces. RESULTS: In the reference scenario, 57% of realizations lead to an explosive outbreak, lasting a mean of 82 days (standard deviation (SD) 12 days) and affecting 46.8% of the population on average. Interventions aimed at reducing the number of meetings, combined with measures reducing individual transmissibility, would be partly effective: coverage of 70% of affected households, with treatment of the index patient, prophylaxis of household contacts, and confinement to home of all household members, would reduce the probability of an outbreak by 52%, and the remaining outbreaks would be limited to 17% of the population (range 0.8%–25%). Reactive vaccination of 70% of the susceptible population would significantly reduce the frequency, size, and mean duration of outbreaks, but the benefit would depend markedly on the interval between identification of the first case and the beginning of mass vaccination. The epidemic would affect 4% of the population if vaccination started immediately, 17% if there was a 14-day delay, and 36% if there was a 28-day delay. Closing schools when the number of infections in the community exceeded 50 would be very effective, limiting the size of outbreaks to 10% of the population (range 0.9%–22%). CONCLUSION: This flexible tool can help to determine the interventions most likely to contain an influenza pandemic. These results support the stockpiling of antiviral drugs and accelerated vaccine development

Non-Standard Errors

In statistics, samples are drawn from a population in a data-generating process (DGP). Standard errors measure the uncertainty in estimates of population parameters. In science, evidence is generated to test hypotheses in an evidence-generating process (EGP). We claim that EGP variation across researchers adds uncertainty: Non-standard errors (NSEs). We study NSEs by letting 164 teams test the same hypotheses on the same data. NSEs turn out to be sizable, but smaller for better reproducible or higher rated research. Adding peer-review stages reduces NSEs. We further find that this type of uncertainty is underestimated by participants

Non-standard errors

In statistics, samples are drawn from a population in a data-generating process (DGP). Standard errors measure the uncertainty in estimates of population parameters. In science, evidence is generated to test hypotheses in an evidence generating process (EGP). We claim that EGP variation across researchers adds uncertainty: Non-standard errors (NSEs). We study NSEs by letting 164 teams test the same hypotheses on the same data. NSEs turn out to be sizable, but smaller for better reproducible or higher rated research. Adding peer-review stages reduces NSEs. We further find that this type of uncertainty is underestimated by participants

Geostatistical Approaches to Change of Support Problems - Theoretical Framework

This report is a deliverable of the EC funded "IMPACT" IST project on "Estimation of Human Impact in Presence of Natural Fluctuations . Chapter 1 gives a general introduction. Chapter 2 presents the geostatistical change of support model. Chapter 3 discusses the importance of support effect models in data assimilation. Chapter 4 presents a Monte Carlo simulation approach as an alternative to conventional change of support models. Chapter 5 discusses first ideas in connection with the Paris area air pollution case study being set up within the IMPACT project. Chapter 6 summarizes the conclusions of the report. In the appendix Chapter A is giving details about the Hermitian change of support model and Chapter B is dwelling about recent work by Wolpert and Ickstadt in the framework of a Gamma mode