Internal anatomy of an erg sequence from the aeolian-fluvial system of the De La Cuesta Formation (Paganzo Basin, northwestern Argentina)

Permian red beds of the De La Cuesta Formation in the Sierra de Narváez (Paganzo Basin, northwestern Argentina) are essentially composed of sandstones associated with mudstones and subordinate conglomerates. Facies distributions and stacking patterns indicate that these sediments resulted from the interaction between aeolian and ephemeral fluvial systems, and are represented by aeolian dune, dry aeolian interdune and Aeolian sand sheet, mudflat, wet aeolian interdune, and fluvial deposits. The De La Cuesta Formation is characterized by aeolian (erg) sequences alternating with non-aeolian (terminal alluvial fan - mudflat) sequences. Each erg sequence is bounded at its base by a regionally extensive sand-drift surface and at the top by an extinction surface. A number of architectural elements, including aeolian dunes limited by interdunes, grouped crescentic Aeolian dunes, longitudinal dunes, and draa with superimposed crescentic dunes are recognised in the erg sequences. The sand sea developed during phases of increasing aridity, whereas non-aeolian deposition might have occurred during more humid phases. Thus, the styles of aeolian-fluvial interaction are considered to result from cyclical climatic changes. Within the drier hemicycles, the rhythmic alternation between draa deposits and aeolian dune and interdune deposits indicates higher frequency cycles that could be attributed to subtle climatic oscillations and/ or changes in sand supply and availability. The development of the Permian sand sea in the inland Paganzo Basin seems to be related to the growth of a volcanic chain to the west. This topographic barrier separated the Paganzo Basin from the Chilean Basin, located along the western margin of Gondwana and characterised by shallow marine carbonate sedimentation. The correlation between the Permian erg and the shallow marine carbonates suggests a regional warming period during the Middle Permian in western Gondwana

Celiotomía en una tortuga mora

En el presente trabajo se describe la técnica quirúrgica empleada para resolver una obstrucción de oviducto en una tortuga mora debido a una alteración ovulatoria.In this work it is described the surgical technique used to resolve an oviduct obstruction in a Greek tortoise (Testudo graeca) caused by the retention of eggs

Retranslocament de nutrients en les fulles senescents de faig (Fagus sylvatica L.)

Nutrient (P. K. Ca and Mg) contents of leaves prior to senescence, nutrient return in leaf litterfall, and nutrient lcaching in throughfall were measured during October and November in a beech forest experimental plot in the Montseny Mountains (NE Spain). Only K was leached in significant amounts. Rctranslocation of P and K amounted to 46% and 13%. respectively. of the foliar nutrient contents before senescence. Calcium accumulated in the leaves during this period. while Mg showed no net retranslocation or accumulation. Retranslocated P can supply a large fraction of the annual P requirements of the trees. and contributes to keep a tight P cycle. However. the percentagc of P retranslocated in this forest lies in the lower range of literature values for forest ecosystems.Es mesuraren les mineralomasses foliars de P, K, Ca i Mg abans de la senescencia i el retorn de nutrients per la caiguda de fulles i per la lixiviació en el trascol durant octubre i novembre en una parcel4a experimental de la fageda de Santa Fe (Montseny, Barcelona). Només el K es lixivia en quantitats significatives. El retranslocament de P i K representi, respectivament, el 46% i el 13% de la mineralomassa foliar abans de la senescbncia. Les fulles acumularen Ca durant aquest període. mentre que el Mg no manifesta retranslocament ni acumulació nets. La quantitat de P retranslocada (1.4 kg ha-') pot subministrar una part important dels requeriments anuals de P del faig, i contribueix a mantenir un cicle tancat de P. No obstant, el percentatge de P retranslocat en aquest bosc es dels més baixos dels trobats a la bibliografia sobre ecosistemes forestals

Experimental and numerical characterization of metallic studs

In this paper, the characterization of metallic studs used to mount lightweight double wall systems is studied both experimentally and numerically. The metallic studs are usually considered by introducing translational and rotational springs to couple the plasterboards composing the double wall. Therefore, the characterization involves determining these spring characteristics. The performance of this type of lightweight double wall in terms of sound transmission is presented in a companion paper. Different experimental setups have been investigated to determine the equivalent translational and rotational spring values. These experimental setups are described and involve the measurement of an input mobility. A finite element model of the laboratory tests has been developed. Shell and massive finite elements are employed in order to reproduce the experimental setups. A comparison of the measured and numerical results is shown. The FEM modelling is intended to help in developing new type of studs for double walls in order to obtain better sound transmission performance.Peer ReviewedPostprint (published version

Supply and demand chain management: The effect of adding services to product offerings

Purpose: The purpose of this paper is to understand how firms manage their product and service offerings, integrating supply chain management (SCM) and demand chain management (DCM) strategies. Adding services to the product portfolio of a firm may bring benefits to an organisation, but requires a reconsideration of the supply chain management approach. Design/methodology/approach: A survey is used to collect data, with valid questionnaires obtained for 4,227 UK-based respondents. Empirical analysis utilises structural equation modelling (SEM). Findings: The paper proposes that a combination of management approaches is required by firms which add services to their portfolio of traditional product offerings. A supply chain management approach may be suitable for traditional product offerings. The management of the services value chain, where the customers' role as value creator is a central feature of the construct, is better served by integration of the market orientation of DCM. Originality/value: The paper addresses a research gap related to the shift in traditional activities carried out by a firm moving from purely product to a product service offer and reconsiders the supply and demand chain management approach. The paper is from a Business to Consumer (B2C) perspective. In this context, the work pioneers analysis into a particular case where a firm's product and service offerings may be substitutes for each other in the eyes of the customer. © Emerald Group Publishing Limited