9,201 research outputs found

    Burley tobacco clubs in Malawi : nonmarket institutions for exports

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    This paper studies nonmarket institutions that facilitate exports. In Malawi, as in many other developing countries, farmers face numerous constraints that disconnect them from export markets. The paper explores the role of a local institution, the burley tobacco clubs, in bridging smallholders to exports. Burley clubs potentially enable farmers to increase their tobacco farming productivity by providing services related to institutional access, collective action, economies of scale, and supporting network. Using matching methods and instrumental variable techniques, the authors find that tobacco club membership causes an increase of between 40-74 percent in output per acre and an increase of between 45-89 percent in tobacco sales per acre. Instead, neither the land share allocated to tobacco nor the unit value obtained by the producers is affected by club membership.Tobacco Use and Control,Alcohol and Substance Abuse,Crops&Crop Management Systems,Adolescent Health,Access to Finance

    Tunable, Functional Diblock Copolypeptide Hydrogels Based on Methionine Homologs.

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    The preparation of new diblock copolypeptide hydrogels derived from homologs of l-methionine, that is, l-homomethionine and l-6-(methylthio)-l-norleucine is described. Compared to l-methionine residues, use of l-methionine homologs allow improved copolymerization with l-leucine residues to give well-defined block copolypeptides. These copolypeptides are subsequently modified using robust thioether alkylation reactions employing a variety of functional epoxides, which yield samples capable of forming transparent, self-healing hydrogels in water. The facile variation of different functional epoxides for postpolymerization modification is found to allow predictable functionalization and tuning of hydrogel properties by the modification of simple precursors

    Cut-free Calculi and Relational Semantics for Temporal STIT Logics

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    We present cut-free labelled sequent calculi for a central formalism in logics of agency: STIT logics with temporal operators. These include sequent systems for Ldm , Tstit and Xstit. All calculi presented possess essential structural properties such as contraction- and cut-admissibility. The labelled calculi G3Ldm and G3Tstit are shown sound and complete relative to irreflexive temporal frames. Additionally, we extend current results by showing that also Xstit can be characterized through relational frames, omitting the use of BT+AC frames

    Biometric characterization of the Red-legged Partridges Alectoris rufa of northwestern Italy

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    The biometrics of the Red-legged Partridge Alectoris rufa has been relatively well studied in the western part of its distribution range (Iberian Peninsula and France), especially due to the available large hunting bag samples. Conversely, the Italian population is poorly characterized. We analysed a sample of 254 live birds trapped and ringed in the northern Apennines (province of Alessandria, northwestern Italy), by measuring body mass and the length of wing, eighth primary, tail, tarsus and bill. We found significant differences in some biometric measurements between sex and age classes. A subsample of birds (n = 112) was genetically tested for introgressive hybridization with A. chukar, an introduced species, showing that 16.1 % of free-living partridge are hybrid individuals. When we analysed separately "pure"and "introgressed"birds we found only small biometric differences in body mass of adult males. Finally, our results were compared with the biometry of other populations from the whole natural range of the species (France, Spain and Portugal) showing a negative biometric trend of wing length from westernmost to southeastern birds of the range. Introgressed birds found in the studied population were not easily distinguishable with biometric criteria from pure A. rufa rufa, so genetic analysis is highly recommended when planning reintroductions or restocking

    Idmb: a tool for navigating the Inspire data model and generating an Inspire SQL database and WFS Configuration

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    The Inspire Data Model Browser (IDMB) is a free tool that performs the following functions: (i) it presents the Inspire UML Data Model as a tree-based structure, which is complementary to the UML diagrams; (ii) it generates a Postgis SQL Script for creating an INSPIRE compliant SQL database (Inspire Database) and a configuration file for the Deegree tool that enables the access to the Inspire Database through a Web Feature Service (WFS) producing GML according to the Inspire XML Schemas

    Native state of natural proteins optimizes local entropy

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    The differing ability of polypeptide conformations to act as the native state of proteins has long been rationalized in terms of differing kinetic accessibility or thermodynamic stability. Building on the successful applications of physical concepts and sampling algorithms recently introduced in the study of disordered systems, in particular artificial neural networks, we quantitatively explore how well a quantity known as the local entropy describes the native state of model proteins. In lattice models and all-atom representations of proteins, we are able to efficiently sample high local entropy states and to provide a proof of concept of enhanced stability and folding rate. Our methods are based on simple and general statistical-mechanics arguments, and thus we expect that they are of very general use

    Progress in cancer epidemiology: Avoided deaths in Europe over the last three decades

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    Progress in cancer epidemiology and prevention has been a key determinant of the fall in cancer mortality in Europe. Using mortality and population figures from the WHO and Eurostat databases, we estimated the number of averted cancer deaths in the EU27 over the period 1989-2021, for both sexes, for all cancers, and nine major cancer sites. We also computed the avoided deaths for all cancers in five major European countries and the UK. We estimated a total of 4 958 000 (3 339 000 men and 1 619 000 women) avoided deaths for all neoplasms over the period 1989-2021 and 348 000 (246 000 men and 102 000 women) in 2021 alone in the EU27. For both sexes, we estimated 1 679 000 avoided deaths for stomach cancer, 747 000 for colorectum, 227 000 for bladder, 102 000 for leukemias. Avoided deaths for lung cancer accounted for 1 156 000 in men, while no reduction was estimated for women. For breast and uterine cancer, avoided deaths were about 300 000, for ovary 105 000 and for prostate 352 000. In the UK, a total of 1 061 000 (721 000 men and 340 000 women) deaths was avoided. Elimination of tobacco may avoid a further 20% of cancer mortality by 2050. Control of alcohol, overweight and obesity, and occupational and environmental carcinogens may avoid an additional 10% of cancer deaths. A similar reduction may be due to optimal adoption of cervical, colorectal, breast, and probably, lung and prostate cancer screening. Thus, primary and secondary cancer prevention can avoid an additional third of cancer deaths in Europe up to 2050

    A Voltage Unbalance Mitigation Technique for Low-voltage Applications with Large Single-phase Loads

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    In this paper a voltage unbalance mitigation technique for low-voltage microgrids or feeders in presence of large single-phase loads is introduced. In order to take maximum advantage of the existing hardware, the proposed solution consists of a sequence-based decentralized voltage control to be embedded in three-phase VSC connecting distributed generation to the considered system. Furthermore, a centralized controller is proposed to define optimal negative and zero sequence voltage reference. Control effectiveness is numerically verified considering a low-voltage feeder case study

    Application of the GeoUML Tools for the Production and Validation of Inspire Datasets

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    The structure of INSPIRE datasets is oriented to the exchange of data, not to its storage and manipulation in a database. Therefore data transformation is required. This paper analyses the possibility of using in this context the tools developed by SpatialDBGroup at Politecnico di Milano in order to create and validate spatial databases. The considered scenario is the following one: - an organisation (data provider) is willing to provide WFS and GML conformant to INSPIRE specifications (services and data); - this organisation is hosting geodata related to one or more INSPIRE themes on a spatial relational database, called here Source Database - in order to facilitate the implementation of INSPIRE compliant GML data, the organisation implements a new "INSPIRE-structured" spatial database, called here INSPIRE Database - a Transformation Procedure is created which extracts the data from the Source Database and loads it into the INSPIRE Database - the INSPIRE Database is "validated" also using topological operators, in order to identify also topological constraints gaps. We assume that both the Source Database and the INSPIRE Database are SQL based and that their physical schemas have been generated by the GeoUML Catalogue tool from the corresponding conceptual schemas, called SCSOURCE and SCINSPIRE. In this scenario the availability of the conceptual schemas suggests different areas where the tools can provide a great benefit: 1. Creation of the GeoUML specification SCINSPIRE, automatic generation of the corresponding physical SQL structure and Validation of the INSPIRE Database with respect to the specification 2. (Semi)automatic generation of the Transformation Procedure using a set of correspondence rules between elements of SCSOURCE and SCINSPIRE 3. Automatic generation of the WFS configuration from the SCINSPIRE In this paper we describe the work which has already been done and the research directions which we are following in order to deal with these points
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