How Does Liquidity Affect Government Bond Yields?

The paper explores the determinants of yield differentials between sovereign bonds in the Euro area. There is a common trend in yield differentials, which is correlated with a measure of aggregate risk. In contrast, liquidity differentials display sizeable heterogeneity and no common factor. We propose a simple model with endogenous liquidity demand, where a bond’s liquidity premium depends both on its transaction cost and on investment opportunities. The model predicts that yield differentials should increase in both liquidity and risk, with an interaction term of the opposite sign. Testing these predictions on daily data, we find that the aggregate risk factor is consistently priced, liquidity differentials are priced for a subset of countries, and their interaction with the risk factor is in line with the model’s prediction and crucial to detect their effect.

Diet of Olrog’s Gull (Larus atlanticus) in the Mar Chiquita coastal Lagoon (Buenos Aires, Argentina) during non-breeding period

La dieta de la Gaviota de Olrog (Larus atlanticus) fue monitoreada durante los períodos no reproductivos de 2004, 2005 y 2006 en la Laguna costera Mar Chiquita, (Provincia de Buenos Aires, Argentina). Los cangrejos Neohelice granulata y Cyrtograpsus angulatus fueron las presas más importantes durante los tres períodos de muestreo. En líneas generales la proporción de sexos consumidos estuvo desviada hacia los machos para N. granulata y hacia las hembras de C. angulatus. En el primer caso, el desvío hacia el consumo de machos podría vincularse a que estos individuos se encuentran más frecuentemente en la entrada de sus cuevas que las hembras y por lo tanto estarían más expuestos a la predación. Las mayores talla promedio de N. granulata fueron consumidas durante el otoño de 2005 y 2006, y durante el invierno de 2004. En los años 2005 y 2006 se observaron diferencias las tallas promedio de C. angulatus entre las estaciones invierno y primavera.We studied differences in the diet of this species in Mar Chiquita Lagoon during three consecutive non-breeding seasons. Diet was assessed by analysis of regurgitated pellets. The varunid crabs were the most important preys, with Neohelice granulata (70%) being dominant numerically over Cyrtograpsus angulatus (30%) throughout the non-breeding cycle. Other crab species, insects, and fish were occasionally present in the diet. The proportion of sexes consumed was biased to the males for N. granulata and to females of C. angulatus. In the first case, the bias to the consumption of males could be linked to these individuals are most often at the entrance of their burrows than females and thus be more exposed to predation. The largest average size of N. granulata was consumed during the autumn of 2005 and 2006 and in winter 2004. The average size of C. angulatus was significantly different between winter and spring seasons during 2005 and 2006.Fil: Beron, Maria Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina. Universidad Nacional de Mar del Plata. Facultad de Cs.exactas y Naturales. Departamento de Biología. Laboratorio de Vertebrados; ArgentinaFil: Favero, Marco. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina. Universidad Nacional de Mar del Plata. Facultad de Cs.exactas y Naturales. Departamento de Biología. Laboratorio de Vertebrados; Argentin

La gaviota cangrejera (larus atlanticus) asociada a arrastreros de altura durante la temporada reproductiva

En este trabajo se dan a conocer avistajes de la Gaviota Cangrejera (Larus atlanticus) obtenidos durante el desarrollo de un proyecto de evaluación de la interacción entre pesquerías de arrastre de altura y aves marinas en aguas argentinas. A fines de la primavera de 2009, ocho individuos (incluyendo aves adultas y subadultas) fueron registrados alimentándose del descarte pesquero de un buque arrastrero fresquero en aguas cercanas al área del frente costero de El Rincón, en el sudeste de la provincia de Buenos Aires. Este es el primer registro de la Gaviota Cangrejera haciendo uso del descarte proveniente de pesquerías de altura a una distancia de 120 millas náuticas de la línea de costa durante la etapa reproductiva.We report sightings of the Olrog´s Gull (Larus atlanticus) obtained during observations of the interaction between commercial high-seas trawl fisheries and seabirds off Argentina. In late spring 2009, up to eight individuals (both adult and sub-adult birds) were noted feeding on fishery discard of an ice-trawler operating in waters relative close to the El Rincón estuary. This is the first record of Olrog´s Gull exploiting discards from high-seas fisheries 120 nautical miles off the coastline during the breeding season.Fil: Seco Pon, Juan Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Favero, Marco. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentin

ACAP advice for reducing the impact of pelagic longline fishing operations on seabirds

The incidental mortality of seabirds, mostly albatrosses and petrels, in longline fisheries continues to be aserious global concern and was the major reason for the establishment of the Agreement on theConservation of Albatrosses and Petrels (ACAP). In longline fisheries seabirds are killed when theybecome hooked and drowned while foraging for baits on longline hooks as the gear is deployed. Theyalso can become hooked as the gear is hauled, although many of these seabirds can be released alive withcareful handling. ACAP routinely reviews the scientific literature regarding seabird bycatch mitigation infisheries, and on the basis of these reviews updates its best practice advice. The most recent review wasconducted in May 2016 at ACAP´s Seabird Bycatch Working Group and Advisory Committee meetings(ACAP 2016), and this document presents a distillation of that review for the consideration of theWCPFC Scientific Committee. A combination of weighted branch lines, bird scaring lines and nightsetting remains the best practice approach to mitigate seabird bycatch in pelagic longline fisheries.Changes in this regard only applied to the recommended minimum standards for line weighting regimes,now updated to the following configurations: (a) 40 g or greater attached within 0.5 m of the hook; or (b)60 g or greater attached within 1 m of the hook; or (c) 80 g or greater attached within 2 m of the hook. Inaddition, ACAP endorsed the inclusion in the list of best practice measures of two hook-shielding devicesas stand-alone mitigation measures. Such hook-shielding devices encase the point and barb of baitedhooks until a prescribed depth or time immersed to prevent seabird becoming hooked during line setting.The following performance requirements were used by ACAP to assess the efficacy of hook-shieldingdevices in reducing seabird bycatch: (a) the device shields the hook until a prescribed depth of 10 m orimmersion time of 10 minutes is reached; (b) the device meets current recommended minimum standardsfor branch line weighting; and (c) experimental research has been undertaken to allow assessment of theeffectiveness, efficiency and practicality of the technology against the ACAP best practice seabird bycatchmitigation criteria. ACAP recognizes that factors such as safety, practicality and the characteristics of thefishery should also be taken into account when considering the efficacy of seabird bycatch mitigationmeasures and consequently in the development of advice and guidelines on best practice.Fil: Favero, Marco. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Wolfaardt, Anton. No especifíca;Fil: Walker, Nathan. No especifíca;12th Regular Session of the Scientific CommitteePohnpeiMicronesiaWestern and Central Pacific Fisheries Commissio

Is it possible for a Procellariiform to raise two chicks? A case of chick adoption in Southern Giant petrels Macronectes giganteus in the South Shetland Islands, Antarctica

We report on the adoption of a Southern Giant Petrel Macronectes giganteus chick by a breeding pair on 25 de Mayo Island (King George Island), South Shetland Islands, Antarctica. Our observations showed both chicks received similar amounts of food, but there were differences in their growth rates that could be explained by their gender. After the third week of adoption, aggressive behaviors were common between chicks, usually expressed through regurgitation. This resulted in a low rate of growth in both chicks. Neither chick fledged, and both were found dead near the colony seven weeks after adoption. The constant fights between them could be one of the causes of their death, particularly if death resulted from excessive regurgitation. Although exclusion of unrelated chicks at nest sites has not been reported in M. giganteus, chick adoption seems to have no clear benefits and may contribute to brood failure.Fil: Archuby, Diego Ignacio. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Coria, Néstor Rubén. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; ArgentinaFil: Harrington, Ana. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Fusaro, Bruno. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo; ArgentinaFil: Montalti, Diego. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Favero, Marco. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentin

Modern in-situ XRD investigations on C3S-C3A-GY systems

The origin of cement, employed as a binding material, can be attributed to Romans who found that a mixture of lime and crushed volcanic ashes was able to set under water, the resistance being increased along the time, in a way completely different to any other material. Since that age, a huge amount of different kind of cements have been produced to satisfy the request of different mechanical behaviors. To deeply understand the mechanisms that lead to the development of mechanical strength, reaction kinetics that occur during the hydration process must be known. Nowadays we can affirm that cement research has set many important results but despite of this “long-time story”, a lot of improvements are required to better understand the mechanisms of kinetics. Cements mixed with water are complex systems undergoing critical chemical and physical changes during the hydration process. A unique hydration model able to explain the controlling mechanisms is the main purpose of cement research, but the physical-chemical parameters involved are actually too many. To partly overcome the chemical complexity of common cement materials, simplified cement systems are often used for research purposes. A project has been set to investigate the fundamental reactions occurring during the hydration process and has been divided within 3 different partners: NIST (National Institute of Standards and Technology), W.R. GRACE and University of Padua. Our part of the project was to collect x-ray powder diffraction patterns on the hydrating suspensions, using Rietveld refinement for quantitative phase analysis. Three simplified cement systems formed by the synthetic phases tricalcium silicate Ca3SiO5 (C3S), tricalcium aluminate Ca3Al2O6 (C3A) and a varying amount of gypsum CaSO4∙2H2O (CŠH2) were investigated by means of in-situ x-ray powder diffraction (XRPD) and isothermal calorimetry (IC) in order to evaluate dissolution-precipitation kinetics. The main hydration products detected by means of XRPD were ettringite, hemicarboaluminate, portlandite, Ca-Si hydrates (C-S-H): the same occurring in real cements. The Avrami nucleation and growth model successfully fits the degree of hydration data, confirming that C-S-H should have a layered structure as well as the phases resulting from the decomposition of ettringite. The mass balance method was used to calculate the exact amount of C-S-H formed during hydration, which is not directly accessible from Rietveld refinement. The comparison between the degree of hydration calculated from isothermal calorimetry data and the degrees of hydration calculated from x-ray diffraction has revealed how much the reactant phases are responsible for heat release. In particular, it was seen that the study of C3S-C3A-Gy systems is not a simple sum of the investigations of C3S-Gy and C3A-Gy systems, which are two further simplified model cements. The synthetic materials suffered a loss on reactivity despite of the under-vacuum sealing, leading to a continuous and unpredictable change of the materials features (particle size, degree of reactivity) during time. The obtained experimental data should be necessary to proof the effectiveness of software modelling (HydratiCA). The software has been tested and returned satisfactory results for further simplified systems, such C3S-Gy. Nevertheless, the software is still under a development stage and improvements has to be planned for C3A-Gy systems before testing more complex blend

Poesia e metrica di Niccolò Tommaseo

Niccolò Tommaseo riconosce di avere conseguito i migliori risultati poetici della sua gioventù tra il 1833 e il 1838, pervenendo in questo periodo alla piena maturità non solo di poeta ma anche di uomo. Il presente lavoro si concentra su questo arco temporale, dall’ultimo anno del suo soggiorno a Firenze fino all’esilio in Francia, dapprima a Parigi dal febbraio 1834 al novembre del 1837, quindi a Nantes e infine in Corsica. In Francia nel giro di pochi anni, tra il 1836 e il 1838, Tommaseo allestisce ben due raccolte poetiche, costituite in gran parte dalle poesie scritte in esilio: le Confessioni, uscite anonime a Parigi nel gennaio 1836, e l’appendice di Poesie delle Memorie poetiche, stampate a Venezia nel 1838 ma composte in Corsica. Sempre a Parigi, nel marzo del 1837, egli pubblica un opuscolo destinato a una vendita di beneficenza, i Versi facili per la gente difficile, formato da sette poesie. Va ricordato, tuttavia, che molte delle poesie delle Confessioni e dei Versi facili vengono riproposte nell’appendice di Poesie delle Memorie poetiche. Nella prima parte della tesi lo studio delle poesie è integrato con le notizie ricavate dai carteggi di Tommaseo, in particolare quelli con Gino Capponi, Giovan Pietro Vieusseux, Cesare Cantù, Alessandro Poerio e Giovita Scalvini, e con le annotazioni private dell’autore nel Diario intimo. Delle Confessioni, dei Versi facili e dell’appendice di Poesie delle Memorie poetiche si descrive inoltre l’organizzazione interna, prestando particolare attenzione al rapporto che i testi intrattengono con la macro-struttura. Vi si dimostra che nelle sezioni dedicate all’espressione privata di Tommaseo è presente uno svolgimento narrativo, che coincide con la sua “confessione”: dall’ammissione delle sue colpe fino al pentimento e alla volontà di espiare gli errori commessi. Infine si raccolgono i giudizi degli amici sulle poesie di Tommaseo, da lui richiesti con insistenza. Nella seconda parte della tesi si offre un Repertorio metrico, fondato sull’edizione definitiva delle Poesie di Tommaseo (1872), ma valido anche per le raccolte poetiche precedenti, poiché nell’opera vengono riproposte quasi tutte le poesie già edite. Segue il Commento di tutti gli schemi impiegati nei 213 testi delle Poesie. Con questa scelta si è inteso mettere in rilievo la grandissima varietà dei metri adottati da Tommaseo, sperimentatore instancabile di forme. Nel Commento si segnalano, quando possibile, anche i possibili modelli degli schemi di Tommaseo, al fine di misurare il suo rapporto con la tradizione metrica italiana antica e recente. Nell’appendice della tesi è collocata una Tavola sinottica, che consente di seguire più facilmente le poesie di Tommaseo nel transito di raccolta in raccolta, nelle quali in molti casi ricompaiono con titoli diversi

Ecología de forrajeo del macá grande Podicephorus major en la laguna Mar Chiquita (Buenos Aires, Argentina)

We studied the foraging ecology of the great grebe Podicephorus major through diet, prey energy return and foraging behaviour across three increasingly marine sites in the coastal lagoon of Mar Chiquita, Argentina. Grebes were followed by focal observations; we recorded dive duration, number of apparent successful and unsuccessful dives, size and type of captured prey and handling time above water.We analysed foraging effort as capture rate (i.e. number of prey eaten per minute) and capture success (i.e. number of successful dives per total dives made); and foraging efficiency as the number of captured prey per foraging time, the total biomass consumed and the energy intake obtained per time. We expected a piscivorous diet, but the most frequent prey were crabs, represented by Cyrtograpsus angulatus and Neohelice granulate, followed by diverse fish species. Diving time for different prey types and foraging sites did not differ. Handling time was higher for crabs. Foraging effort and foraging efficiency were higher for grebes that preyed on crabs, but in terms of biomass and energy return no differences were found, not even between sites. This suggests an opportunistic foraging behaviour for the great grebe in response to the possible higher availability of crabs in this and possibly other estuaries.Se estudió la ecología de forrajeo del macá grande Podicephorus major a través de la dieta, el rendimiento calórico de las presas y el esfuerzo y eficiencia de forrajeo en una laguna costera del sudeste de Argentina. El comportamiento de forrajeo fue cuantificado utilizando observaciones focales, donde se registró la duración del buceo, número de buceos aparentemente exitosos y no exitosos, tamaño y tipo de presa capturada, y tiempo de manipulación sobre el agua. Se analizó el esfuerzo de forrajeo medido como tasa de captura (número de presas ingeridas por minuto); éxito de captura (número de buceos exitosos sobre el número de buceos totales); eficiencia de forrajeo como el número de presas capturadas por tiempo de forrajeo, la biomasa total consumida y por el retorno energético (tiempo de forrajeo por unidad temporal). Se esperaba una dieta piscívora, pero las presas más frecuentes fueron los cangrejos, representados por Cyrtograpsus angulatus y Neohelice granulata, seguido por diversas especies de peces. El tiempo de buceo para diferentes tipos de presa y los diferentes lugares de forrajeo no varió. El tiempo de manipulación fue mayor para los cangrejos. El esfuerzo y la eficiencia de forrajeo fue mayor para los individuos que se alimentaron de cangrejos, pero en términos de biomasa consumida y retorno energético no hubo diferencias, tampoco para las áreas de forrajeo. Esto sugiere un comportamiento trófico oportunista para el macá grande en respuesta a la posible alta disponibilidad de cangrejos en el área de estudio y posiblemente en otros estuarios.Fil: Josens, Maria Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Favero, Marco. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Bo, Maria Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentin

A comparison of melatonin and α-lipoic acid in the induction of antioxidant defences in L6 rat skeletal muscle cells.

Aging is characterized by a progressive deterioration in physiological functions and metabolic processes. The loss of cells during aging in vital tissues and organs is related to several factors including oxidative stress and inflammation. Skeletal muscle degeneration is common in elderly people; in fact, this tissue is particularly vulnerable to oxidative stress since it requires large amounts of oxygen, and thus, oxidative damage is abundant and accumulates with increasing age. Melatonin (N-acetyl-5-methoxytryptamine) is a highly efficient scavenger of reactive oxygen species and it also exhibits beneficial anti-inflammatory and anti-aging effects. This study investigated the susceptibility of rat L6 skeletal muscle cells to an induced oxidative stress following their exposure to hydrogen peroxide (50 μM) and evaluating the potential protective effects of pre-treatment with melatonin (10 nM) compared to the known beneficial effect of alpha-lipoic acid (300 μM). Hydrogen peroxide-induced obvious oxidative stress; it increased the expression of tumour necrosis factor-alpha and in turn promoted nuclear factor kappa-B and overrode the endogenous defence mechanisms. Conversely, pre-treatment of the hydrogen peroxide-exposed cells to melatonin or alpha-lipoic acid increased endogenous antioxidant enzymes, including superoxide dismutase-2 and heme oxygenase-1; moreover, they ameliorated significantly oxidative stress damage and partially reduced alterations in the muscle cells, which are typical of aging. In conclusion, melatonin was equally effective as alpha-lipoic acid; it exhibited marked antioxidant and anti-aging effects at the level of skeletal muscle in vitro even when it was given in a much lower dose than alpha-lipoic acid