A portrait of trade in value added over four decades

We combine data on trade, production, and input use to document changes in the value added content of trade between 1970 and 2009. The ratio of value-added to gross exports fell by roughly 10 percentage points worldwide. The ratio declined 20 percentage points in manufacturing, but rose in non-manufacturing sectors. Declines also differ across countries and trade partners: they are larger for fast growing countries, for nearby trade partners, and among partners that adopt regional trade agreements. Using a multi-sector structural gravity model with input-output linkages, we show that changes in trade frictions play a dominant role in explaining all these facts

Frame definability in finitely-valued modal logics

In this paper we study frame definability in finitely valued modal logics and establish two main results via suitable translations: (1) in finitely valued modal logics one cannot define more classes of frames than are already definable in classical modal logic (cf. [27, Thm. 8]), and (2) a large family of finitely valued modal logics define exactly the same classes of frames as classical modal logic (including modal logics based on finite Heyting and MV-algebras, or even BL-algebras). In this way one may observe, for example, that the celebrated Goldblatt–Thomason theorem applies immediately to these logics. In particular, we obtain the central result from [26] with a much simpler proof and answer one of the open questions left in that paper. Moreover, the proposed translations allow us to determine the computational complexity of a big class of finitely valued modal logics

Buyers' sourcing strategies and suppliers' markups in Bangladeshi garments

We study differences in markups earned by Bangladeshi garment exporters across buyers with different sourcing strategies and make three contributions. First, we distinguish buyers with a relational versus a spot sourcing strategy and show that a buyer's sourcing strategy is correlated across products and origins. Buyer fixed effects explain most of the variation in sourcing strategies, suggesting that these depend on organizational capabilities. Second, we use novel data that match quantities and prices of the two main variable inputs in the production of garments (fabric and labor on sewing lines) to specific export orders. We derive conditions under which these data allow measurement of within exporter-product-time differences in markups across orders produced for different buyers. Third, we show that exporters earn higher markups on otherwise identical orders produced for relational, as opposed to spot, buyers. A sourcing model with imperfect contract enforcement, idiosyncratic shocks to exporters, and buyers that adopt different sourcing strategies trading off higher prices and reliable supply rationalizes this and other observed facts in the industry. We discuss alternative explanations and policy implications

Syntactic characterizations of classes of first-order structures in mathematical fuzzy logic

This paper is a contribution to graded model theory, in the context of mathematical fuzzy logic. We study characterizations of classes of graded structures in terms of the syntactic form of their first-order axiomatization. We focus on classes given by universal and universal-existential sentences. In particular, we prove two amalgamation results using the technique of diagrams in the setting of structures valued on a finite MTL-algebra, from which analogues of the Los--Tarski and the Chang--Los--Suszko preservation theorems follow

Zonificación del riesgo por inundación como aporte a la prevención, en el puerto - Laguna de la Cocha- Colombia.

In the planning and planning of the territory of flood-prone areas, risk management must be an integral part and the basis for decision-making, which harmonize prevention and well-being in the context of sustainable development. The present study allowed determining the zoning of the risk of flood disaster in the hamlet of the Port - Laguna de La Cocha, Colombia, in order to generate guidelines for land use planning. For this, an analysis of the historical behavior of the hydrological variable was carried out, a statistical distribution was adjusted and levels were estimated for different return periods adopted. These become levels to take them to topographic planes, and thus based on hydrological and geomorphological criteria, define different areas under threat. Based on the identification of infrastructure and critical facilities present in the area, vulnerability was assessed, and from the combination of threat and vulnerability zones, three flood risk zones were established: high, medium and low. Determined risk categories were generated measures of prevention and territorial planning, for high and medium risk areas with high probability of occurrence of floods, it is advisable to prohibit housing settlements, in these sectors potentially harmful effects may occur, given the exposure of people, infrastructure and critical facilities. For the low risk area, supported by the principle of prevention and sustainability, it is suggested to avoid being populated, and thus prevent increasing the degree of risk.En el ordenamiento y planificación del territorio de zonas propensas a inundaciones, la gestión del riesgo debe ser parte integral y la base para la toma de decisiones, que armonicen la prevención y el bienestar en el contexto de un desarrollo sostenible. El presente estudio permitió determinar la zonificación del riesgo de desastre por inundaciones en el caserío del Puerto - Laguna de La Cocha, Colombia, con el objeto de generar pautas para el ordenamiento territorial. Para ello se llevó a cabo un análisis del comportamiento histórico de la variable hidrológica, se ajustó una distribución estadística y estimaron niveles para diferentes periodos de retorno adoptados. Estos se convierten en cotas para llevarlos a planos topográficos, y así con base en criterios hidrológicos y geomorfológicos, definir distintas zonas bajo amenaza. Con base en la identificación de infraestructura e instalaciones críticas presentes en el área, se evaluó la vulnerabilidad, y a partir de la combinación de zonas de amenaza y vulnerabilidad se establecieron tres zonas del riesgo por inundación: alto, medio y bajo. Determinadas las categorías de riesgo, se generaron medidas de prevención y ordenamiento territorial, para zonas de alto y mediano riesgo con probabilidad alta de ocurrencia de inundaciones, se aconseja prohibir los asentamientos de viviendas, en estos sectores, pues pueden ocurrir efectos potencialmente dañinos, dada la exposición de personas, infraestructura e instalaciones críticas. Para la zona de bajo riesgo, apoyados en el principio de prevención y sostenibilidad, se sugiere evitar que sea poblado, y así impedir aumentar el grado de riesgo

Dynamic modelling of ammonia biofiltration from waste gases

A dynamic model to describe ammonia removal in a gas-phase biofilter was developed. The math-ematical model is based on discretized mass balances and detailed nitrification kinetics that includeinhibitory effects caused by free ammonia (FA) and free nitrous acid (FNA). The model was able to pre-dict experimental results operation under different loading rates (from 3.2 to 13.2 g NH3h-1m-3). In par-ticular the model was capable of reproducing inhibition caused by high inlet ammonia concentrations. Alsoelimination capacity was accurately predicted. Experimental data was also used to optimize certain modelparameters such as the concentration of ammonia- and nitrite-oxidizing biomass.Peer ReviewedPostprint (published version

International buyers' sourcing and suppliers markups in Bangladeshi garments

Large international buyers play a key role in global value chains. We exploit detailed transaction-level data on the usage of material inputs to study how Bangladeshi garment suppliers' markups vary across international buyers. We find substantial dispersion in markups across export orders of a given seller for the same product. Buyer effects explain a significant share of this variation, while destination effects do not. Buyers adopting relational sourcing strategies pay higher markups than non-relational buyers. This pattern holds within seller-product-year combinations, is robust to controlling for the buyer's size, traded volumes, and quality, and, together with larger volumes, implies higher profits for suppliers dealing with relational buyers

Teatros romanos de Hispania: introducción a su estado de conservación y criterios de restauración

Actualmente hay más de veinte Teatros Romanos de la Antigüedad descubiertos en el territorio de la antigua Hispania, y muchos de ellos en el último tercio del siglo XX. La restauración de los mismos, aunque se inició en el primer tercio del siglo XX con Mérida, Sagunto y Segóbriga, corresponde íntegramente a nuestra época contemporánea, siendo muy diferentes en cuanto a criterios y resultados, por lo que resulta necesario una puesta en común. El objetivo de este artículo es iniciar esta tarea partiendo del estado actual de los mismos y del conocimiento de sus restauraciones, como introducción a un estudio posterior que establezca una metodología que ponga en común los criterios con los que abordar su restauración y sus posibles usos, de cara a su explotación cultural y turística.Noguera Giménez, JF.; Guimaraens Igual, G.; Lara Ortega, S.; Noguera Mayen, M. (2011). Teatros romanos de Hispania: introducción a su estado de conservación y criterios de restauración. Arché. (6):383-390. http://hdl.handle.net/10251/34465383390