Endogenous Exchange Rate Regime Switches

In this paper we demonstrate that exchange rate regime switching is compatible with optimal government policies. Nominal exchange-rate regimes are formalized as equilibrium commitments on future seigniorage policies, and the collapse of an exchange-rate peg as an excusable default which allows the government to lump-sum tax private sector money holdings. We demonstrate that a regime in which the exchange-rate peg is allowed to collapse when government spending is unusually high is a trigger-strategy equilibrium. Such a regime can be superior to both fixed and flexible exchange rate because it combines some of the flexibility of the floating exchange rates with some of the benefits of precommitment afforded by fixed rates.

Frugivory and ornitochorous fruits removal in Chaco forest fragments of Córdoba (Argentina)

La pérdida de bosques naturales y su fragmentación en el paisaje por actividad agrícola pueden afectar procesos ecológicos como la dispersión biótica y también el mantenimiento de la diversidad de especies nativas y la invasión de plantas exóticas. En el contexto de la fragmentación del bosque chaqueño de la provincia de Córdoba se evaluó remoción y frugivoría de frutos carnosos en especies de dos fragmentos con superficie menor a 5 ha y dos de bosque continuo superior a 300 ha. Una vez por semana durante dos meses los frutos de cada individuo se contabilizaron tomándose como indicador de la dispersión biótica a la probabilidad de supervivencia de los frutos (PSF). Los elementos florísticos ornitócoros incluyen a 15 especies, principalmente leñosas. En todas las especies ornitócoras presentes en cada sitio se encontraron diferencias en la PSF, siendo mayor en los fragmentos pequeños respecto a los sitios de bosque continuo. Asimismo, la PSF fue menor en la especie arbustiva de origen exótico en relación con la nativa. Contrariamente, en las especies exóticas leñosas la PSF fue mayor que en las nativas. Estos resultados sugieren que la dispersión de frutos es afectada por la reducción del bosque chaqueño y que los fragmentos pequeños son aún utilizados por las aves como áreas de alimentación. Este comportamiento de las aves sería importante para la persistencia y colonización de nuevos sitios por las plantas con frutos carnosos, así como para la conservación de los pequeños fragmentos de bosque inmersos en los agroecosistemas del centro de Argentina.Forests loss and habitat fragmentation due to agricultural activity could be related to different ecological processes such as biotic dispersion, as well as the maintenance of native plant diversity and exotic plant invasions. The objective of this work was to analyze fruit removal and frugivory by animals in the Chaco forest of Córdoba, in the context of landscape fragmentation. The study was carried out in two continuous (> 300 ha) and two small forest fragments (< 5 ha). We randomly selected three to five individuals with ornitochorous fruits at the sampling time (March-June, 2006). We counted the fruits in focal plants once a week during two month. Fruit survival probability (FSP) was used as an indicator of fruit removal. Ornitochorous plants included 15 species, mainly woody. The FSP for the plant community showed statistically significant differences between small fragments and continuous sites. FSP was lower in continuous forests than in small fragments. FSP in the exotic bush was lower than in the native bush species. Contrary to bushes, FSP values in woody exotic species were higher than those for native species. Results suggest that the dispersion of the ornitochorous fruits would be related to the process of fragmentation, but small fragments are used by birds as feeding sites, which confers them a high conservation value. This behavior of bird species would be important for the persistence and colonization of new sites for plant species with ornitochorous fruits, as well as for the conservation of small forests fragments disseminated within agro-ecosystems of central Argentina.Fil: Ponce, Analía Melisa. Universidad Nacional de Córdoba; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Grilli, Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentina. Universidad Nacional de Córdoba; ArgentinaFil: Galetto, Leonardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentina. Universidad Nacional de Córdoba; Argentin

Trait-based approaches in arbuscular mycorrhizal fungi need to distinguish between response and effect traits

Mycologists usually borrow models or theoretical frameworks from other ecological disciplines to test them in fungal ecology. For example, using models from plant and animal ecology, some attempts intended to classify fungi according to life-history strategies, or functional groups and guilds. In this way, species composition in a community is simplified to a few groups or guilds of species sharing similar traits from which we can make some predictions about nature functioning. Importantly, theseclassifications could be based on “response” traits to environmental changes or “effect” traits on ecosystem processes, and classifications based on response traits could differ from those based on effect traits.Fil: Urcelay, Roberto Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Grilli, Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Marro, Nicolás Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentin

Trait-based approaches in arbuscular mycorrhizal fungi need to distinguish between response and effect traits

Mycologists usually borrow models or theoretical frameworks from other ecological disciplines to test them in fungal ecology. For example, using models from plant and animal ecology, some attempts intended to classify fungi according to life-history strategies, or functional groups and guilds. In this way, species composition in a community is simplified to a few groups or guilds of species sharing similar traits from which we can make some predictions about nature functioning. Importantly, theseclassifications could be based on “response” traits to environmental changes or “effect” traits on ecosystem processes, and classifications based on response traits could differ from those based on effect traits.Fil: Urcelay, Roberto Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Grilli, Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Marro, Nicolás Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentin

Arbuscular mycorrhizal fungal communities of high mountain ecosystems of South America: Relationship with microscale and macroscale factors

The high mountain ecosystems of South America represent one of the main hotspots of biodiversity. There is an increasing interest in disentangling global patterns of arbuscular mycorrhizal fungi (AMF). Recently studies postulated that the majority of AMF taxa are cosmopolitan, although community composition changes depend on microscale and macroscale factors. In this Chapter we reviewed the studies performed at high mountain ecosystems of South America analyzing the richness of morphospecies and structure of AMF communties in relation to microscale (host species, pH, N, P) and macroscale factors (latitude, temperature, precipitation). AMF communities differed in both scales being associated with sampling site, vegetation type or host identity. Glomeraceae and Gigasporaceae families were related to micro- and macro-scale factors, while Acaulosporaceae did not show significant relationships with neither micro- nor with macro-scale factors. At higher scales, AMF community composition of tropical and temperate ecosystems differed due to latitude, precipitation and temperature. Meanwhile, at lower scales soil characteristics and host species became the most relevant factors in differentiating AMF composition of sites. AMF communities of high mountain forests of South America are differentially affected by the particular characteristics of these environments instead of showing a cosmopolitan pattern.Fil: Soteras, María Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Menoyo, Eugenia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis. Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; ArgentinaFil: Grilli, Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Becerra, Alejandra Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentin

Flower trade-offs derived from nectar investment in female reproduction of two nicotiana species (Solanaceae)

Animal-pollinated flowers may orient resources for competing activities, such as nectar production for attracting flower visitors but then saving nectar (through inhibiting nectar production or by final resorption) for the subsequent maturation of fruits and seeds. Nectar production is continuous in Nicotiana longiflora and N. alata after flower opening, but early nectar removal reduces total secreted nectar. Resource trade-off between nectar investment and seed production were experimentally assessed in manually pollinated flowers experiencing different numbers of repeated nectar removals, while controlling for maternal effects. We expected that flowers with less nectar secretion produce larger seed sets. The results showed that for both species the earlier the nectar removal during flower anthesis, the lower the total nectar secreted and the higher the mass of seeds produced. This general pattern was clearer for N. longiflora. The link between decreased nectar production and the subsequent increase in the seed set implies that resources are limited. Consequently, nectar savings during the pollination process through early nectar removal by pollinators can be interpreted as a trade-off between resources secreted by flowers for pollinator attraction and those utilized during fruit and seed maturation.Fil: Galetto, Leonardo. Universidad Nacional de Córdoba; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Araujo, Francielle Paulina. Universidade Estadual do Rio Grande do Sul; BrasilFil: Grilli, Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Amarilla, Leonardo. Universidad Nacional de Córdoba; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Torres, Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentina. Universidad Nacional de Córdoba; ArgentinaFil: Sazima, Marlies. Universidade Estadual de Campinas; Brasi

Taxonomic and Functional Response of Arbuscular Mycorrhizal Fungi to Land Use Change in Central Argentina

It has been predicted that land use change will pose the main threattobiodiversity worldwide (Sala et al. 2000). A recent meta-analysis showsthat,at local scale, conversion and degradation of habitats promote onaverageglobal decline of 8.1 % of species richness and 10.1 % of abundance(Newbold et al. 2015). These human-mediated changes in biodiversitystrongly affect ecosystem stability (Hautier et al. 2015). Given theimportance of biodiversity on ecosystem functions and services, studies onthe effects of land use on species assemblages are highly relevant incurrent global context.Fil: Longo, Maria Silvana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Cofré, María Noelia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Soteras, María Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Grilli, Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Lugo, Mónica Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis. Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; ArgentinaFil: Urcelay, Roberto Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis. Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; Argentin

Magnetic bearings with double crossed loops modelled with T-A formulation and electric circuits

The application of High-Temperature Superconductor (HTS) coils made of coated conductors has been investigated for many years. A possible configuration for such coils is the jointless loop, also known as the ring coil. The double crossed loop coil (DCLC) has been successfully applied in superconducting magnetic bearings (SMBs). The design of SMBs with DCLCs requires flexible modelling to allow all parts of the device to be represented. This work proposes the T-A formulation with a thin-film approximation for modelling SMB with DCLCs in the finite element analysis framework. A 2D representation of the system is coupled with an external electric circuit to model the continuity of the lines that represent the parts of each jointless loop. To couple the T-A formulation and the circuit, an average of the total electric field, with both resistive and inductive components, is applied to the circuit. The total current computed by the circuit is applied to the T-A formulation. The proposed methodology was validated by comparison with levitation force experimental data. Two types of tests were simulated: five levitation force tests and three guidance force tests. It is shown that there is a limit to the behaviour of the levitation force related to the high-loss state. Below this limit, the stack of DCLCs behaves as an equivalent bulk. Beyond this limit, a high-loss state appears as a linear growth of the levitation force. It is also shown that this high-loss state in vertical displacement influences the lateral force

2D Modeling of HTS Coils with T-A Formulation: How to Handle Different Coupling Scenarios

Numerical models based on the finite-element method (FEM) are popular tools for investigating the macroscopic electromagnetic behavior of high-temperature superconductor (HTS) applications. This article explains how to use the T-A formulation for modeling HTS coils in 2D with different coupling scenarios between the turns. First we consider a racetrack coil wound from one piece of superconducting tape. Then we consider a coil obtained by winding a cable composed of different HTS tapes. In the latter case, the tape turns are either electrically connected along their entire length or just at the two ends of the coil: in the model, these two different types of electrical connection are implemented with the help of the electrical circuit module. The current density distributions and the AC losses of the coils in the different coupling scenarios are compared and discussed. The limits of applicability of the presented approach are pointed out. The model is developed for the straight section of racetrack coils, but can be easily adapted to axisymmetric geometries