Nutrition-sensitive value chains from a smallholder perspective: A framework for project design

"The Alliance of Bioversity International and the International Center for Tropical Agriculture (CIAT) gratefully acknowledges permission from IFAD to re-publish that work as an Alliance Working Paper, with updated acknowledgements, author information and information on additional resources.

Convolutive superposition for multicarrier cognitive radio systems

Recently, we proposed a spectrum-sharing paradigm for single-carrier cognitive radio (CR) networks, where a secondary user (SU) is able to maintain or even improve the performance of a primary user (PU) transmission, while also obtaining a low-data rate channel for its own communication. According to such a scheme, a simple multiplication is used to superimpose one SU symbol on a block of multiple PU symbols.The scope of this paper is to extend such a paradigm to a multicarrier CR network, where the PU employs an orthogonal frequency-division multiplexing (OFDM) modulation scheme. To improve its achievable data rate, besides transmitting over the subcarriers unused by the PU, the SU is also allowed to transmit multiple block-precoded symbols in parallel over the OFDM subcarriers used by the primary system. Specifically, the SU convolves its block-precoded symbols with the received PU data in the time-domain, which gives rise to the term convolutive superposition. An information-theoretic analysis of the proposed scheme is developed, which considers different amounts of network state information at the secondary transmitter, as well as different precoding strategies for the SU. Extensive simulations illustrate the merits of our analysis and designs, in comparison with conventional CR schemes, by considering as performance indicators the ergodic capacity of the considered systems.Comment: 29 pages, 8 figure

Ruolo dell'etanolo nella trasduzione del segnale in anossia

La carenza di ossigeno è un fenomeno assai frequente in natura e le piante ne risultano fortemente influenzate. Tra le colture d’interesse agrario il riso è una specie modello per lo studio dell’anossia. Le sue cariossidi infatti sono le uniche capaci di germinare in assenza di ossigeno. L’etanolo è il principale prodotto della fermentazione e per molto tempo si riteneva che il suo accumulo fosse il maggior responsabile degli effetti negativi della carenza di ossigeno, fino a quando Alpi e Beevers smentirono questa teoria nel 1985. Escluso dunque il ruolo dell’etanolo come agente fitotossico, in questo lavoro si è cercato di valutare una possibile funzione di questa molecola nella percezione del segnale, ambito in cui ad oggi poco è noto a livello molecolare. Il segnale che porta all’alterazione del metabolismo cellulare, non è necessariamente legato ad una percezione diretta della concentrazione di ossigeno, ma è probabilmente dovuta ad una compartecipazione di diversi fattori tra i quali l’etanolo è risultato influente. Il comportamento di cariossidi di riso poste in anossia è stato comparato con quello di cariossidi mantenute in aerobiosi ma con concentrazioni crescenti di etanolo nel mezzo di coltura. E’ stato valutato lo sviluppo delle plantule, la presenza dei carboidrati solubili, ma anche la sintesi di proteine coinvolte nella via metabolica fermentativa. Per questa seconda parte si sono utilizzati come parametri, due enzimi chiave della glicolisi, le fruttochinasi, in particolare FK1 e FK2. Mediante analisi molecolari si è potuto confermare che la FK1 è tipicamente espressa in aria, mentre la FK2 risulta espressa in organi sottoposti a condizioni anossiche. Inoltre si è osservato che in coleoptile e ancor più in embrione, concentrazioni crescenti di alcool etilico stimolano la produzione di queste proteine. Dai risultati ottenuti appare quindi chiaro che l’etanolo riveste un ruolo nella modulazione di alcuni geni tipicamente attivati in carenza di ossigeno

Blasco Giurato. Un grande direttore della fotografia.

Blasco Giurato rappresenta una figura di spicco ed eccellenza nella professione di operatore di macchina e di direttore della fotografia cinematografica e televisiva. Anche semplicemente a scorrere la sua vastissima filmografia e a consultare gli elenchi delle pellicole e degli sceneggiati televisivi a cui ha partecipato in veste di protagonista in un'attività preziosa e incessante che dura da quasi mezzo secolo, si resta ammirati e conquistati. Non c'è film e non c'è fiction che non si segnali per la qualità della luce, per gli specifici cromatismi, per i movimenti di macchina e, spesso, per i suoi interventi innovativi, sia di illuminotecnica sia di messa in quadro. Quella di Blasco Giurato è una lezione di stile e di cromatismo cinematografico che ha fatto e continua a fare scuola: un esempio di professionalità ed alto artigianato che fa parte a pieno titolo della migliore tradizione della Storia del Cinema italiano

Value chains to improve diets: Diagnostics to support intervention design in Malawi

Governments and development partners looking to accelerate progress in addressing malnutrition have been examining how to use interventions in value-chains to improve diets. However, the links between interventions in value chains and diets involve a range of direct and indirect effects that are not yet well understood. We apply a mixed-method multisectoral diagnostic to examine potential interventions in food systems to improve diets of smallholder farmers in Malawi. We examine entry points for interventions involving public and private-sectors, and explore the methodological requirements for undertaking this type of multisectoral analysis. We find that although food consumption is dominated by maize, a range of nutritious foods are also being consumed; including leafy greens, fruits, chicken, dried fish, dried beans and peas, and groundnuts. Yet important deficits in nutrient intake remain prevalent in low-income households due to inadequate quantity of consumption. While increasing consumption through own-production is one potentially important channel to increase quantity of nutritious foods available (particularly fruits and leafy green vegetables), markets also play a potentially important role. Nutritious foods are available on markets year-round, although strong seasonality impacts the availability and price of perishable products. For beans, peas and groundnuts, supply appears to be available throughout the year, with price fluctuations relatively controlled due to storage capacity and imports. The capacity of markets to supply safe and nutritious food is limited by a number of issues, including poor hygiene; lack of infrastructure for storage and selling; limited information on nutrition, and weak coordination among sellers and producers. Other bottlenecks include: on-farm constraints for expanded production, consumers with limited purchasing capacity, intense competition among sellers and few services for sellers to increase volume of product sold during peak demand. The diagnostics identify the role of information-related interventions to optimize decisions related to food choices, involving a range of different foods and value-chains, that could potentially lead to short- and medium-term improvements in diets. Longer-term and more resource-intensive interventions are also identified, such as improving capacity for product differentiation, processing, storage, and market infrastructure across a different range of food chains, so as to maximise coherence between short- and long-term planning. The findings highlight the benefits of applying a strategic, food systems-based approach of identifying specific and complementary actions for both the public and private sectors that can improve the diets of low-income populations

Putting it all together: Aggregating impacts of school-feeding programmes on education, health and nutrition: two proposed methodologies

School-feeding is an important intervention to attract children to school and augment their learning. The benefits of school-feeding cover several domains. Key to the overall assessment of these benefits is understanding how different implementation models compare to each other and to other interventions with similar aims and objectives. Herein, we outline two approaches to aggregating outcomes for school-feeding. One involves a discreet choice experiment to derive utility scores combining outcomes into one measure. The other focuses on quality-adjusted school days as a measure that encompasses the varied benefits from school-feeding. The discrete choice experiment offers a robust method to integrate utility for different benefits. However, it necessitates a complex design. The quality-adjusted school days method has greater simplicity. When developed, different interventions that aim to foster learning could be meaningfully compared