Predicting biological invasions in marine habitats through eco-physiological mechanistic models: a case study with the bivalve Brachidontes pharaonis

Aim We used a coupled biophysical ecology (BE)-physiological mechanistic modelling approach based on the Dynamic Energy Budget theory (DEB, Dynamic energy budget theory for metabolic organisation, 2010, Cambridge University Press, Cambridge; DEB) to generate spatially explicit predictions of physiological performance (maximal size and reproductive output) for the invasive mussel, Brachidontes pharaonis. Location We examined 26 sites throughout the central Mediterranean Sea. Methods We ran models under subtidal and intertidal conditions; hourly weather and water temperature data were obtained from the Italian Buoy Network, and monthly CHL-a data were obtained from satellite imagery. Results Mechanistic analysis of the B. pharaonis fundamental niche shows that subtidal sites in the Central Mediterranean are generally suitable for this invasive bivalve but that intertidal habitats appear to serve as genetic sinks. Main conclusions A BE-DEB approach enabled an assessment of how the physical environment affects the potential distribution of B. pharaonis. Combined with models of larval dispersal, this approach can provide estimates of the likelihood that an invasive species will become established

Eco-physiological response of two marine bivalves to acute exposition to commercial Bt-based pesticide

Microbial products based on the entomopathogenic bacterium Bacillus thuringiensis (Bt) are among the most common biopesticides used worldwide to suppress insect pests in forests, horticulture and agricultural crops. Some of the effects of commercial Bt have been recorded for terrestrial and freshwater non-target organisms but little research is available on marine fauna. Nevertheless, due to the contiguity of agro-ecosystems and coastal habitats, marine fauna may be highly influenced by this control method. We studied the effect of a commercial Bt product on the physiological and ecological responses and the energy budget of two of the most frequent marine intertidal bivalves in the Mediterranean, the native Mytilaster minimus and the invasive Brachidontes pharaonis. To test the effects experimentally, we simulated the worst scenarios possible using the average dose applied to fields and a hypothetical accumulation dose. The results showed the feeding rates of both species were affected detrimentally by the different experimental conditions; higher concentrations led to higher respiration rates, however neither species showed any significant difference in excretion rates. The biopesticide had a significant effect on the energy budget, the values decreasing with doses. In addition, it led to high mortality for the worst treatments and, in both species, induced significantly higher cardiac activity than in the controls. These results indicate a measurable effect of Bt commercial products on marine organisms, and great attention should be paid to biopesticides composed by entomopathogenic bacteria and addictive compounds. In addition, the results highlight the urgent need to study not only the effects of anthropogenic pressures on target organisms but also to extend our view to other ecosystems not expected to be influenced. Gaining data at the organismal level should help increase the sustainability of pest control and reduce the consequences of side-effects

Dynamic Energy Budget model parameter estimation for the bivalve Mytilus californianus: Application of the covariation method

Dynamic Energy Budget (DEB) models serve as a powerful tool for describing the flow of energy through organ- ismsfrom assimilation offoodtoutilization for maintenance,growth andreproduction.The DEB theoryhas been successfully applied to several bivalve species to compare bioenergetic and physiological strategies for the utili- zation of energy. In particular, mussels within the Mytilus edulis complex (M. edulis,M. galloprovincialis , and M. trossulus) have been the focus of many studies due to their economic and ecological importance, and their worldwide distribution. However, DEB parameter values have never been estimated for Mytilus californianus ,a species that is an ecological dominant on rocky intertidal shores on the west coast of North America and which likely varies considerably from mussels in the M. edulis complex in its physiology. We estimated a set of DEB parameters for M. californianus using the covariation method estimation procedure and compared these to parameter values from other bivalve species. Model parameters were used to compare sensitivity to environ- mental variability among species, as a first examination of how strategies for physiologically contending with environmental change by M. californianus may differ from those of other bivalves. Results suggest that based on the parameter set obtained, M. californianus has favorable energetic strategies enabling it to contend with a range of environmental conditions. For instance, the allocation fraction of reserve to soma ( \u3ba ) is among the highest of any bivalves, which is consistent with the observation that this species can survive over a wide range of environmental conditions, including prolonged periods of starvatio

Variable stars in the open cluster NGC 6791 and its surrounding field

Aims: This work presents a high--precision variability survey in the field of the old, super metal-rich open cluster NGC 6791. Methods: The data sample consists of more than 75,000 high-precision CCD time series measurements in the V band obtained mainly at the Canada-France-Hawaii Telescope, with additional data from S. Pedro Martir and Loiano observatories, over a time span of ten nights. The field covers an area of 42x28 arcmin^2. Results: We have discovered 260 new variables and re-determined periods and amplitudes of 70 known variable stars. By means of a photometric evaluation of the membership in NGC 6791, and a preliminary membership based on the proper motions, we give a full description of the variable content of the cluster and surrounding field in the range 16<V<23.5. Accurate periods can be given for the variables with P<4.0 d, while for ones with longer periods the limited time-baseline hampered precise determinations. We categorized the entire sample as follows: 6 pulsating, 3 irregular, 3 cataclysmic, 89 rotational variables and 61 eclipsing systems; moreover, we detected 168 candidate variables for which we cannot give a variability class since their periods are much longer than our time baseline. Conclusions: On the basis of photometric considerations, and of the positions of the stars with respect to the center of the cluster, we inferred that 11 new variable stars are likely members of the cluster, for 22 stars the membership is doubtful and 137 are likely non-members. We also detected an outburst of about 3 mag in the light curve of a very faint blue star belonging to the cluster and we suggest that this star could be a new U Gem (dwarf nova) cataclysmic variable.Comment: 24 pages, 19 Figures, A&A accepte

A proper motion study of the globular cluster M55

We have derived the absolute proper motion (PM) of the globular cluster M55 using a large set of CCD images collected with the du Pont telescope between 1997 and 2008. We find (PM_RA*cos(DEC), PM_DEC) = (-3.31 +/- 0.10, -9.14 +/- 0.15) mas/yr relative to background galaxies. Membership status was determined for 16 945 stars with 14<V<21 from the central part of the cluster. The PM catalogue includes 52 variables of which 43 are probable members of M55. This sample is dominated by pulsating blue straggler stars but also includes 5 eclipsing binaries, three of which are main sequence objects. The survey also identified several candidate blue, yellow and red straggler stars belonging to the cluster. We detected 15 likely members of the Sgr dSph galaxy located behind M55. The average PM for these stars was measured to be (PM_RA*cos(DEC), PM_DEC)=(-2.23 +/- 0.14, -1.83 +/- 0.24) mas/yr.Comment: 12 figures and 4 tables, accepted for publication in MNRAS Main Journal; full PM catalogue (Table 3) at http://case.camk.edu.p

Algunos desajustes en la regulación de la persona jurídica consorcio

El art. 148 del CCyCN, que enumera las personas jurídicas privadas, incorpora al consorcio de propietarios (inc. h), consideración que es reafirmada por el art. 2044 del CCyCN. Ello implica que éste tiene una personalidad diferenciada de los miembros que lo integran –los propietarios-, por lo cual estos no responden por las obligaciones del consorcio (art. 143 CCyCN), salvo que expresamente lo prevea el Título respectivo o bien la ley especial. Sin perjuicio de ello, perduran numerosos interrogantes respecto de la responsabilidad de los propietarios frente a las deudas del consorcio y fundamentalmente se reaviva la controversia respecto de la posibilidad o no de que el Consorcio pueda estar contemplado dentro de los sujetos concursables que determina el art. 2° de la ley 24.522, exhibiéndose dos posturas: a) la que considera que con las modificaciones del CCyCN el consorcio deviene en sujeto concursable; b) la que sostiene que si bien son personas jurídicas privadas con estructura y funciones no son concursables. A fin de resolver la cuestión, debemos analizar si la aplicación de las normas generales sobre personas jurídicas y de la Ley de Concursos y Quiebras a la persona jurídica consorcio es compatible y armónica con el instituto de la Propiedad Horizontal y con el derecho real creado por el nuevo Código, lo que eventualmente nos pondría frente a un conflicto de normas que deberá ser resuelto conforme lo prevén los arts. 1 y 2 del CCyCN.Facultad de Ciencias Jurídicas y Sociales (JURSOC

Gender, Disaster, and Resilience: Assessing Women\u27s Water and Sanitation Needs in Leogane, Haiti, before and after the 201 O Earthquake

This study investigates differences in men\u27s and women\u27s access to water and sanitation in Leogane, Haiti (population -300,000), a town situated at the epicenter of the January 2010 earthquake. While research suggests that women\u27s water and sanitation access is crucial to health, security, and equity in post-disaster situations, there are a number of limitations to current participa­tory approaches in post-disaster reconstruction. Underlining the social impor­tance of water access in Haiti were reports citing a Jack of potable water and sanitation as one factor contributing to the spread of cholera, which was intro­duced by UN peacekeepers aher the earthquake. Limited access to water and sanitation facilities was also reported as a factor in the lack of security for women and children in the internally displaced persons camps. The results of this NSF-RAPID study are presented pertaining to gender issues in the context of post-disaster infrastructure reconstruction efforts in Haiti. We ask specifically how gender dimensions can be integrated into community-based participatory processes of water and sanitation planning, which face many challenges in post-disaster situations. We conclude that more robust participatory processes that include women and other marginalized groups in planning and decision ­making can be used to elicit and support local knowledge, practices and preferences, ultimately leading to more appropriate infrastructure systems that will be more socially, economically, and ecologically sustainable

Algunos desajustes en la regulación de la persona jurídica consorcio

El art. 148 del CCyCN, que enumera las personas jurídicas privadas, incorpora al consorcio de propietarios (inc. h), consideración que es reafirmada por el art. 2044 del CCyCN. Ello implica que éste tiene una personalidad diferenciada de los miembros que lo integran –los propietarios-, por lo cual estos no responden por las obligaciones del consorcio (art. 143 CCyCN), salvo que expresamente lo prevea el Título respectivo o bien la ley especial. Sin perjuicio de ello, perduran numerosos interrogantes respecto de la responsabilidad de los propietarios frente a las deudas del consorcio y fundamentalmente se reaviva la controversia respecto de la posibilidad o no de que el Consorcio pueda estar contemplado dentro de los sujetos concursables que determina el art. 2° de la ley 24.522, exhibiéndose dos posturas: a) la que considera que con las modificaciones del CCyCN el consorcio deviene en sujeto concursable; b) la que sostiene que si bien son personas jurídicas privadas con estructura y funciones no son concursables. A fin de resolver la cuestión, debemos analizar si la aplicación de las normas generales sobre personas jurídicas y de la Ley de Concursos y Quiebras a la persona jurídica consorcio es compatible y armónica con el instituto de la Propiedad Horizontal y con el derecho real creado por el nuevo Código, lo que eventualmente nos pondría frente a un conflicto de normas que deberá ser resuelto conforme lo prevén los arts. 1 y 2 del CCyCN.Facultad de Ciencias Jurídicas y Sociales (JURSOC

A new search for planet transits in NGC 6791

Context. Searching for planets in open clusters allows us to study the effects of dynamical environment on planet formation and evolution. Aims. Considering the strong dependence of planet frequency on stellar metallicity, we studied the metal rich old open cluster NGC 6791 and searched for close-in planets using the transit technique. Methods. A ten-night observational campaign was performed using the Canada-France-Hawaii Telescope (3.6m), the San Pedro M\'artir telescope (2.1m), and the Loiano telescope (1.5m). To increase the transit detection probability we also made use of the Bruntt et al. (2003) eight-nights observational campaign. Adequate photometric precision for the detection of planetary transits was achieved. Results. Should the frequency and properties of close-in planets in NGC 6791 be similar to those orbiting field stars of similar metallicity, then detailed simulations foresee the presence of 2-3 transiting planets. Instead, we do not confirm the transit candidates proposed by Bruntt et al. (2003). The probability that the null detection is simply due to chance coincidence is estimated to be 3%-10%, depending on the metallicity assumed for the cluster. Conclusions. Possible explanations of the null-detection of transits include: (i) a lower frequency of close-in planets in star clusters; (ii) a smaller planetary radius for planets orbiting super metal rich stars; or (iii) limitations in the basic assumptions. More extensive photometry with 3-4m class telescopes is required to allow conclusive inferences about the frequency of planets in NGC 6791.Comment: 23 pages, 23 figures, A&A accepte

Searching for transits in the Wide Field Camera Transit Survey with difference-imaging light curves

The Wide Field Camera Transit Survey is a pioneer program aiming at for searching extra-solar planets in the near-infrared. The images from the survey are processed by a data reduction pipeline, which uses aperture photometry to construct the light curves. We produce an alternative set of light curves using the difference-imaging method for the most complete field in the survey and carry out a quantitative comparison between the photometric precision achieved with both methods. The results show that differencephotometry light curves present an important improvement for stars with J > 16. We report an implementation on the box-fitting transit detection algorithm, which performs a trapezoid-fit to the folded light curve, providing more accurate results than the boxfitting model. We describe and optimize a set of selection criteria to search for transit candidates, including the V-shape parameter calculated by our detection algorithm. The optimized selection criteria are applied to the aperture photometry and difference-imaging light curves, resulting in the automatic detection of the best 200 transit candidates from a sample of ~475 000 sources. We carry out a detailed analysis in the 18 best detections and classify them as transiting planet and eclipsing binary candidates. We present one planet candidate orbiting a late G-type star. No planet candidate around M-stars has been found, confirming the null detection hypothesis and upper limits on the occurrence rate of short-period giant planets around M-dwarfs presented in a prior study. We extend the search for transiting planets to stars with J ≤ 18, which enables us to set a stricter upper limit of 1.1%. Furthermore, we present the detection of five faint extremely-short period eclipsing binaries and three M-dwarf/M-dwarf binary candidates. The detections demonstrate the benefits of using the difference-imaging light curves, especially when going to fainter magnitudes.Peer reviewe