Strategic assessment of research priorities for sweetpotato.

The following report presents an ex‐ante evaluation of priority research options for sweetpotato carried out in the scope of the strategic assessment of research priorities for the CGIAR Research Program on Roots, Tubers, and Bananas (RTB). It contains the results from the economic surplus model used for the assessment, which are extended to include estimations of the number of beneficiaries and poverty reduction effects. The report identifies and describes the sweetpotato research options taken into consideration for and included into the assessment. The socioeconomic and technological parameters used as input data for the analysis are described and information on the elicitation process and data sources is provided. Results are presented so as to explain the outputs obtained and interpreted with respect to the relevant differences between research option

Faster linearizability checking via PP-compositionality

Linearizability is a well-established consistency and correctness criterion for concurrent data types. An important feature of linearizability is Herlihy and Wing's locality principle, which says that a concurrent system is linearizable if and only if all of its constituent parts (so-called objects) are linearizable. This paper presents $P$-compositionality, which generalizes the idea behind the locality principle to operations on the same concurrent data type. We implement $P$-compositionality in a novel linearizability checker. Our experiments with over nine implementations of concurrent sets, including Intel's TBB library, show that our linearizability checker is one order of magnitude faster and/or more space efficient than the state-of-the-art algorithm.Comment: 15 pages, 2 figure

Technology challenges for space interferometry: the option of mid-infrared integrated optics

Nulling interferometry is a technique providing high angular resolution which is the core of the space missions Darwin and the Terrestrail Planet Finder. The first objective is to reach a deep degree of starlight cancelation in the range 6 -- 20 microns, in order to observe and to characterize the signal from an Earth-like planet. Among the numerous technological challenges involved in these missions, the question of the beam combination and wavefront filtering has an important place. A single-mode integrated optics (IO) beam combiner could support both the functions of filtering and the interferometric combination, simplifying the instrumental design. Such a perspective has been explored in this work within the project Integrated Optics for Darwin (IODA), which aims at developing a first IO combiner in the mid-infrared. The solutions reviewed here to manufacture the combiner are based on infrared dielectric materials on one side, and on metallic conductive waveguides on the other side. With this work, additional inputs are offered to pursue the investigation on mid-infrared photonics devices.Comment: Accepted in Adv. in Space Researc

Release and adoption of improved sweetpotato varieties in Southeast and South Asia

In this study we close the identified gaps in the existing literature and databases by documenting release and adoption of improved sweetpotato varieties in eight major sweetpotato producing countries in Southeast, South, and East Asia. Methodologically, this study adopts a refined expert elicitation (EE) approach applied in previous projects. EE workshops were used as an inexpensive alternative to the collection of national representative adoption data. An average of 12.67 experts working in the sweetpotato value chain participated in a one-day event to elicit perceived adoption rates and to update release databases. In total, 228 experts attended in 18 workshops held during 2014-2016

Release and adoption of improved potato varieties in Southeast and South Asia

In this study, we close the identified gaps in the existing literature and databases by documenting release and adoption of improved potato varieties in seven major potato producing countries in Southeast, South, and East Asia. Methodologically, this study adopts a refined expert elicitation (EE) approach applied in previous projects. EE workshops were used as an inexpensive alternative to the collection of national representative adoption data. An average of 15 experts working in the potato value chain participated in a one-day event to elicit perceived adoption rates and to update release databases. In total, 347 experts attended 23 workshops which were held during 2014-2016

Driving factors of agrobiodiversity: which characteristics influence intra-household potato diversity in the peruvian Andes?.

Domesticated potatoes (Solanum spp.) originated in the Andes. Genetic hotspots of this important staple food exist throughout the mountain range. The conservation of potato diversity (and agrobiodiversity in general) is necessary to ensure functioning ecosystems and food security. Sufficient genetic material is the backbone of evolution and breeding. Despite agricultural modernisation (by e.g. introducing improved potato varieties), smallholder farmers continue to cultivate a large number of potato landraces. The initiative Chirapaq Nan promotes in-situ conservation of such potato landraces and monitors some of their hotspots across the Andes. So far, the initiative’s focus was cataloguing cultivated landraces and their genetic resources. Now, the better understanding of farmers’ varietal choice is an additional aim. That is crucial to efficiently design and carry out in-situ projects. This study contributes to these efforts by assessing socioeconomic and environmental characteristics, which influence farming households’ potato diversity. After literature review and expert interviews, eleven independent variables of the domains location, household assets, potato production and cultural factors were chosen. A binary dependent variable assigning farmers with up to three landrace varieties to the low potato diversity group and the spare to the high diversity group was created. Subsequently we ran a binary logistic regression model with household data from two Central Andean Peruvian provinces. The International Potato Center (CIP) collected these data in production year 2011/12. Results showed that four variables have a significant impact on intra-household potato diversity. These are the province in which farmers reside, their wealth (measured by cows per household), their level of technology adoption (number of improved varieties per household), and their participation in potato fairs. This study provides an overview of possible incentives and disincentives of potato diversity. Future research should apply a mix of quantitative and qualitative methods to better capture and analyse farmers’ intrinsic value systems regarding agrobiodiversity and changing varietal preferences

Driving factors of agrobiodiversity: which characteristics influence intra-household potato diversity in the peruvian Andes?.

Domesticated potatoes (Solanum spp.) originated in the Andes. Genetic hotspots of this important staple food exist throughout the mountain range. The conservation of potato diversity (and agrobiodiversity in general) is necessary to ensure functioning ecosystems and food security. Sufficient genetic material is the backbone of evolution and breeding. Despite agricultural modernisation (by e.g. introducing improved potato varieties), smallholder farmers continue to cultivate a large number of potato landraces. The initiative Chirapaq Nan promotes in-situ conservation of such potato landraces and monitors some of their hotspots across the Andes. So far, the initiative’s focus was cataloguing cultivated landraces and their genetic resources. Now, the better understanding of farmers’ varietal choice is an additional aim. That is crucial to efficiently design and carry out in-situ projects. This study contributes to these efforts by assessing socioeconomic and environmental characteristics, which influence farming households’ potato diversity. After literature review and expert interviews, eleven independent variables of the domains location, household assets, potato production and cultural factors were chosen. A binary dependent variable assigning farmers with up to three landrace varieties to the low potato diversity group and the spare to the high diversity group was created. Subsequently we ran a binary logistic regression model with household data from two Central Andean Peruvian provinces. The International Potato Center (CIP) collected these data in production year 2011/12. Results showed that four variables have a significant impact on intra-household potato diversity. These are the province in which farmers reside, their wealth (measured by cows per household), their level of technology adoption (number of improved varieties per household), and their participation in potato fairs. This study provides an overview of possible incentives and disincentives of potato diversity. Future research should apply a mix of quantitative and qualitative methods to better capture and analyse farmers’ intrinsic value systems regarding agrobiodiversity and changing varietal preferences

A weak compact jet in a soft state of Cygnus X-1

We present evidence for the presence of a weak compact jet during a soft X-ray state of Cygnus X-1. Very-high-resolution radio observations were taken with the VLBA, EVN and MERLIN during a hard-to-soft spectral state change, showing the hard state jet to be suppressed by a factor of about 3-5 in radio flux and unresolved to direct imaging observations (i.e. < 1 mas at 4 cm). High time-resolution X-ray observations with the RXTE-PCA were also taken during the radio monitoring period, showing the source to make the transition from the hard state to a softer state (via an intermediate state), although the source may never have reached the canonical soft state. Using astrometric VLBI analysis and removing proper motion, parallax and orbital motion signatures, the residual positions show a scatter of ~0.2 mas (at 4 cm) and ~3 mas (at 13 cm) along the position angle of the known jet axis; these residuals suggest there is a weak unresolved outflow, with varying size or opacity, during intermediate and soft X-ray states. Furthermore, no evidence was found for extended knots or shocks forming within the jet during the state transition, suggesting the change in outflow rate may not be sufficiently high to produce superluminal knots.Comment: Accepted in MNRAS; 4 figures and 1 tabl