Does cannibalism of larvae by adults affect settlement and connectivity of mussel populations?     

Francesca Porri  Tembisa Jordaan  Christopher D. McQuaid   《Estuarine, Coastal and Shelf Science》2008,79(4):687-693

Intertidal population dynamics are driven by a complex series of processes, including larval supply and the possibility of larval predation by benthic animals such as filter-feeders. We hypothesised that cannibalism by adults could play a major role in the population connectivity of mussel populations by removing larvae as they attempt to settle in the adult habitat. Specifically, we tested hypotheses that consumption of mussel larvae by adults removes a significant proportion of potential settlers and is influenced by both settlement intensity and tidal state (flooding or ebbing). Predation of mussel larvae by adult mussels was investigated on incoming and ebbing tides during four spring tides by analysing the gut contents of adult Perna perna and Mytilus galloprovincialis collected from the low intertidal mussel zone between October 2005 and January 2006. Consumption rates were then compared with estimates of successful settler densities on natural beds. The results showed that mortality of competent mussel larvae through adult ingestion removes up to 77% a of potential settlers. Rates of larval consumption were highest during months of intense settlement, suggesting that mussels feed opportunistically, filtering a relatively fixed volume of water and removing particles, including larvae, in proportion to their densities in the water. Rates of larviphagy were also higher during receding than incoming tides. We suggest that this is due to changes in larval density or, more probably, in adult filtration efficiency that are related to the state of the tide. Despite significant effects of both tidal state and settlement intensity on rates of larval ingestion, neither had a significant effect on the proportion of potential settlers removed. During settlement more than half of all potential settlers are lost through cannibalism, with potentially serious consequences for population maintenance. The results highlight the paradoxical nature of the evolution of settlement mechanisms in mussels, which must balance the advantages of settlement in habitats favourable to adults against the consumption of larvae by adults.  相似文献   

The apsidal motion of V 380 Cygni     

P. Battistini  A. Bonifazi  A. Guarnieri 《Astrophysics and Space Science》1974,28(1):163-171

Measurements have been made with an electronographic image tube spectrograph of two helium and three hydrogen lines at twenty nine positions in the dense core of the Orion Nebula. Values for the helium abundance derived show that a large amount of the helium is neutral. This must be caused by large optical depth variations in the core near partially ionised globules (PIG's). The total abundance of helium is shown to be in the range $$0.0104< N(He)/N(H)< 0.132$$ .  相似文献   

Fourteen years of multifrequency-coordinated observations of the X-ray/Be system A 0535+26/HDE 245770     

F. Giovannelli  C. Bartolini  A. Guarnieri  A. Piccioni  M. Burger  E. L. Van Dessel  V. G. Kurt  E. K. Sheffer  D. De Martino  R. Waters  I. Gonzalez Martinez-Pais  Yu. N. Gnedin  V. M. Larionov  N. I. Shakovskaya 《Astrophysics and Space Science》1990,169(1-2):139-145

Within the framework of a very long multifrequency campaign of coordinated, and very often simultaneous, observations of the transient X-ray/Be system A 0535+26/HDE 245770, we present a summary of this large collection of data taken with IUE and ASTRON satellites as well as with many ground-based telescopes in optical and IR regions.In this paper we emphasize the study of the physics and dynamics of the mass transfer at periastron and subsequent X-ray flaring, which is a typical problem of the X-ray/Be binary system class.Paper presented at the 11th European Regional Astronomical Meetings of the IAU on New Windows to the Universe, held 3–8 July, 1989, Tenerife, Canary Islands, Spain.  相似文献   

Comparisons among the five ground-motion models developed using RESORCE for the prediction of response spectral accelerations due to earthquakes in Europe and the Middle East   总被引：5，自引：5，他引：0  

John Douglas  Sinan Akkar  Gabriele Ameri  Pierre-Yves Bard  Dino Bindi  Julian J. Bommer  Sanjay Singh Bora  Fabrice Cotton  Boumédiène Derras  Marcel Hermkes  Nicolas Martin Kuehn  Lucia Luzi  Marco Massa  Francesca Pacor  Carsten Riggelsen  M. Abdullah Sandıkkaya  Frank Scherbaum  Peter J. Stafford  Paola Traversa 《Bulletin of Earthquake Engineering》2014,12(1):341-358

This article presents comparisons among the five ground-motion models described in other articles within this special issue, in terms of data selection criteria, characteristics of the models and predicted peak ground and response spectral accelerations. Comparisons are also made with predictions from the Next Generation Attenuation (NGA) models to which the models presented here have similarities (e.g. a common master database has been used) but also differences (e.g. some models in this issue are nonparametric). As a result of the differing data selection criteria and derivation techniques the predicted median ground motions show considerable differences (up to a factor of two for certain scenarios), particularly for magnitudes and distances close to or beyond the range of the available observations. The predicted influence of style-of-faulting shows much variation among models whereas site amplification factors are more similar, with peak amplification at around 1s. These differences are greater than those among predictions from the NGA models. The models for aleatory variability (sigma), however, are similar and suggest that ground-motion variability from this region is slightly higher than that predicted by the NGA models, based primarily on data from California and Taiwan.  相似文献   

Users’ perception analysis for sustainable beach management in Italy     

Valentina Marin  Francesca Palmisani  Roberta Ivaldi  Rosanna Dursi  Mauro Fabiano 《Ocean & Coastal Management》2009,52(5):268-277

It is generally accepted that end-users’ perception is likely to play a pivotal role for planning and policy consideration. Beach user analysis is thus an important component defining beach management policies. In the framework of a wider project on beaches management, an investigation on residents and tourists was conducted. A survey conducted through questionnaires and interviews was carried out in six coastal municipalities. Results allowed obtaining a clear picture about user profile, perception of the beaches, awareness and attitude about themes related to beach management (i.e. Blue Flag award and beach nourishment practices). Their integration with the “expert knowledge” based analysis allowed to support the definition of beach management interventions.  相似文献   

Environmental impacts of household appliances in Europe and scenarios for their impact reduction     

Roland Hischier  Francesca Reale  Valentina Castellani  Serenella Sala 《Chemie der Erde / Geochemistry》2012

Assessing the environmental impact due to consumption of goods and services is a pivotal step towards achieving the sustainable development goal related to responsible production and consumption (i.e. SDG 12). Household appliances plays a crucial role and should be assessed in a systemic manner, namely considering all life cycle stages, technological efficiency, and affluence aspects. The present study assess the impact of such household appliances used in Europe, and tests scenarios of potential impact reduction at various scales. Life cycle assessment is applied to 14 different household appliances (ranging from dishwashers to television devices) selected to build a set of representative products, based on their economic value and diffusion in households in Europe. Related impacts are calculated with the Environmental Footprint method for calculating a Consumer Footprint “appliances” for the baseline year 2010. A number of scenarios encompassing eco-solutions on a technical level, changes in consumption pattern, behavioral changes, as well as the combination of all these aspects are run to estimate the Consumer Footprint related to household appliances for the year 2030, compared against this baseline scenario. The baseline Consumer Footprint is confirming the importance of the use phase in leading the impacts in almost all impact categories. Testing different scenarios concludes that there is a reduction of the impact for most of the categories (with up to 67% for the ozone depletion potential, and still around 35% for the global warming potential), while two of the here examined impact categories (i.e. land-use and mineral resource depletion) show an overall potential that is even negative – i.e. the results of all scenarios are higher than the ones of the 2010 baseline scenario. The increase in purchase and use of such appliances may offset energy efficiency benefits in some of the examined categories. Hence, the assessment of sustainability of appliances consumption should always include several scales, from the efficiency of the products (micro scale), to the improvement of the energy mix (meso scale), up to accounting for socio-economic drivers and patterns of consumption affecting the overall appliances stock (macro scale).  相似文献   

A spectral comparison of (379) Huenna and its satellite     

Francesca E. DeMeo  Benoît Carry  Franck Marchis  Richard P. Binzel  Schelte J. Bus  Alin Nedelcu  Michael Busch 《Icarus》2011,212(2):677-681

We present near-infrared spectral measurements of Themis family Asteroid (379) Huenna (D ∼ 98 km) and its 6 km satellite using SpeX on the NASA IRTF. The companion was farther than 1.5″ from the primary at the time of observations and was approximately 5 magnitudes dimmer. We describe a method for separating and extracting the signal of a companion asteroid when the signal is not entirely resolved from the primary. The spectrum of (379) Huenna has a broad, shallow feature near 1 μm and a low slope, characteristic of C-type asteroids. The secondary’s spectrum is consistent with the taxonomic classification of C-complex or X-complex. The quality of the data was not sufficient to identify any subtle feature in the secondary’s spectrum.  相似文献   

Imposex and accumulation of organotin compounds in populations of Hexaplex trunculus (Gastropoda, Muricidae) from the Lagoon of Venice (Italy) and Istrian Coast (Croatia)     

Garaventa F  Centanni E  Pellizzato F  Faimali M  Terlizzi A  Pavoni B 《Marine pollution bulletin》2007,54(5):615-622

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Laboratory studies of the HNCO molecular spectrum for precise spectroscopy of dark clouds     

A. V. Lapinov  G. Yu. Golubiatnikov  V. N. Markov  A. Guarnieri 《Astronomy Letters》2007,33(2):121-129

Detailed studies of the internal motions of dark clouds using spectral lines of many molecules require a laboratory frequency accuracy of the order of a few m s^?1. Based on our laboratory studies of the HNCO rotational spectrum in the ground vibrational state, we have increased significantly the accuracy of frequency calculation in a wide range of quantum numbers. We have achieved an (1σ) uncertainty for rotational transitions in the K _a = 0, 1 states recalculated to the Doppler velocity scale ≤2 m s^?1 for all frequencies <1.1 THz. This value allows radio-astronomical measurements with an accuracy comparable to that of the highest-precision observations based on spectral lines of other molecules.  相似文献   

Research and development of advanced technologies for landslide hazard analysis in Italy   总被引：2，自引：0，他引：2  

Francesca Bozzano  Paolo Mazzanti  Alberto Prestininzi  Gabriele Scarascia Mugnozza 《Landslides》2010,7(3):381-385

The Research Centre on Prediction, Prevention and Control of Georisks, "Sapienza Università di Roma" (CERI) was selected as one of the World Centres of Excellence on Landslide Risk Reduction (WCoE) under the title of “Research and development of advanced technologies for landslide hazard analysis in Italy” in the period 2008–2011. The present paper provides background information on the activities carried out by the CERI, in the frame of the WCoE network. Pre-defined purposes have been achieved by the implementation of integrated monitoring systems and early warning systems for landslides movements. The application of GBInSAR technique for monitoring landslides interacting with infrastructures is discussed, and two case histories are presented. It is shown that this technique is particularly suitable for the displacements monitoring of landslides interacting with infrastructures, thanks to its peculiar features (i.e. areal mapping, operability under every weather and lighting conditions and continuous and completely remote monitoring). Hence, it can be considered a very important tool for the reduction of risks connected to the realisation and activity of large infrastructures.  相似文献