Census-based typological usability fragility curves for Italian unreinforced masonry buildings

The main vulnerability models available in the literature aim to develop damage fragility curves to estimate the damage level suffered by a building after a seismic event. However, recent earthquakes have highlighted the great importance of predicting the usability of residential buildings, i.e. the condition of a building being habitable or occupiable after a seismic event. The building usability performance can be used as an indicator for allocating economic funding after a seismic event because recent researches have demonstrated a stronger correlation between repair costs and usability assessment rather than between repair costs and structural damage. Therefore, this work focused on the development of census-based fragility curves for the preventive forecast of the usability of Italian unreinforced-masonry buildings. The proposed usability model was calibrated based on the 2009 L'Aquila earthquake database, including almost 60,000 unreinforced-masonry buildings, and this database was increased by adding data from the Italian census to account for uninspected constructions. Six typological classes were defined considering two parameters available both in the post-earthquake and Italian census databases: construction timespan and state of repair. Additionally, it was highlighted in which cases the number of stories was also relevant. The usability fragility curves were defined as a function of peak ground acceleration for two building usability states: partially unusable and unusable. The results confirmed that older buildings are more vulnerable and clearly pointed out the crucial role of the state of repair as a parameter influencing the building usability

In vitro propagation of isoëtes sabatina (Isoetaceae): A key conservation challenge for a critically endangered quillwort

Isoëtes sabatina is an aquatic quillwort endemic to Italy. It is one of the rarest quillworts in Europe, and is critically endangered due to restricted range and to the continuous decline of both population and habitat quality. This study aims to develop an optimized protocol to reproduce and grow I. sabatina sporelings. Mature and immature megaspores were mixed with mature microspores to evaluate the influence of the developmental stage on germination and sporeling development. Two substrates, distilled water and water-agar medium, were tested for germination and sporeling emergence, and three substrates, sand, lake sediment and water-agar, were tested for transplants. A high percentage of megaspore germination (a total of 79.1%) was obtained in both substrates, higher for mature than immature spores. A total of 351 sporelings were produced in distilled water and water-agar cultures, with similar percentages (64.5% and 69.6%, respectively). The development stage of the megaspores affected both germination and sporeling development. Sporeling emergence showed significantly higher percentages in mature megaspores than immature ones (69.6% vs. 11.6%, respectively), with 85% of germinated spores developing sporelings. Only transplants over water-agar medium were successful. This protocol could be useful for the propagation of sporelings as the key step towards the planning of in situ actions to save this Mediterranean quillwort from extinction

The CN Isotopic Ratios In Comets

Our aim is to determine the isotopic ratios (12)C/(13)C and (14)N/(15)N in a variety of comets and link these measurements to the formation and evolution of the solar system. The (12)C/(13)C and (14)N/(15)N isotopic ratios are measured for the CN radical by means of high-resolution optical spectra of the R branch of the B-X (0, 0) violet band. 23 comets from different dynamical classes have been observed, sometimes at various heliocentric and nucleocentric distances, in order to estimate possible variations of the isotopic ratios in parent molecules. The (12)C/(13)C and (14)N/(15)N isotopic ratios in CN are remarkably constant (average values of, respectively, 91.0 +/- 3.6 and 147.8 +/- 5.7) within our measurement errors, for all comets whatever their origin or heliocentric distance. While the carbon isotopic ratio does agree with the terrestrial value (89), the nitrogen ratio is a factor of two lower than the terrestrial value (272), indicating a fractionation in the early solar system, or in the protosolar nebula, common to all the comets of our sample. This points towards a common origin of the comets independently of their birthplaces, and a relationship between HCN and CN.NSFAstronom

Molecular ions in L1544. I. Kinematics

We have mapped the dense dark core L1544 in H13CO+(1-0), DCO+(2-1), DCO+(3-2), N2H+(1-0), NTH+(3-2), N2D+(2-1), N2D+(3-2), C18O(1-0), and C17O(1-0) using the IRAM 30-m telescope. We have obtained supplementary observations of HC18O+(1-0), HC17O+(1-0), and D13CO+(2-1). Many of the observed maps show a general correlation with the distribution of dust continuum emission in contrast to C18O(1-0) and C17O(1-0) which give clear evidence for depletion of CO at positions close to the continuum peak. In particular N2D+(2-1) and (3-2) and to a lesser extent N2H+(1-0) appear to be excellent tracers of the dust continuum. We find that the tracers of high density gas (in particular N2D+) show a velocity gradient along the minor axis of the L1544 core and that there is evidence for larger linewidths close to the dust emission peak. We interpret this using the model of the L1544 proposed by Ciolek & Basu (2000) and by comparing the observed velocities with those expected on the basis of their model. The results show reasonable agreement between observations and model in that the velocity gradient along the minor axis and the line broadening toward the center of L1544 are predicted by the model. This is evidence in favour of the idea that amipolar diffusion across field lines is one of the basic processes leading to gravitational collapse. However, line widths are significantly narrower than observed and are better reproduced by the Myers & Zweibel (2001) model which considers the quasistatic vertical contraction of a layer due to dissipation of its Alfvenic turbulence, indicating the importance of this process for cores in the verge of forming a star.Comment: 24 pages, 9 figures, to be published in Ap

New approaches to the study of periodic leg movements during sleep in restless legs syndrome

Study Objectives: To describe a new approach for the analysis of quantity, type, and periodicity of the leg motor activity during sleep in patients with restless legs syndrome (RLS) and periodic leg movements (PLM). Methods: The following parameters were taken into account for LM: duration, amplitude, area under the curve, sleep stage, side, interval, and bilaterality. The analysis of inter-LM intervals was carried out by drawing their distribution graphs. A new index evaluated their periodicity and was validated by means of a Markovian analysis. The differences in inter-LM intervals, LM duration, and area under the curve between normal controls and patients and between the 3 patient subgroups identified on the basis of their periodicity were statistically analyzed. Setting: N/A Participants: Sixty-five patients with RLS and periodic LM and 22 young healthy controls. Measurements and Results: The RLS patients' inter-LM interval distribution graph showed a wide peak with a maximum located at around 15 to 30 seconds and extending from 10 to 90 seconds, not present in controls, and another peak for intervals less than 8 seconds, higher than that of controls. Three patient subgroups were identified with different proportions of these 2 peaks, periodicity, and Markovian parameters. Periodicity was not dependent on the periodic leg movement index. Patients showing the peak mainly at around 15 to 30 seconds tended to show slightly longer and higher area under the curve LM than did the other 2 subgroups. Conclusions: Our new approach seems to be useful in a new qualitative differentiation among patients with PLM, which is not possible by using the simple PLM index

Deep Impact : High Resolution Optical Spectroscopy with the ESO VLT and the Keck 1 telescope

We report on observations of comet 9P/Tempel 1 carried out before, during, and after the NASA DEEP IMPACT event (UT July 4), with the optical spectrometers UVES and HIRES mounted on the telescopes Kueyen of the ESO VLT (Chile) and Keck 1 on Mauna Kea (Hawaii), respectively. A total observing time of about 60 hours, distributed over 15 nights around the impact date, allowed us (i) to find a periodic variation of 1.709 +/- 0.009 day in the CN and NH flux, explained by the presence of two major active regions; (ii) to derive a lifetime > ~ 5 x 10^4 s for the parent of the CN radical from a simple modeling of the CN light curve after the impact; (iii) to follow the gas and dust spatial profiles evolution during the 4 hours following the impact and derive the projected velocities (400 m/s and 150 m/s respectively); (iv) to show that the material released by the impact has the same carbon and nitrogen isotopic composition as the surface material (12C/13C = 95 +/- 15 and 14N/15N = 145 +/- 20).Comment: Accepted for publication in ApJ Letter

The 16OH/18OH and OD/OH isotope ratios in comet C/2002 T7 (LINEAR)

The 16OH/18OH and OD/OH isotope ratios are measured in the Oort-Cloud comet C/2002 T7 (LINEAR) through ground-based observations of the OH ultraviolet bands at 3063 A (0,0) and 3121 A (1,1) secured with the Very Large Telescope (VLT) feeding the Ultraviolet-Visual Echelle Spectrograph (UVES). From the 16OH/18OH ratio, we find 16O/18O = 425 +/- 55, equal within the uncertainties to the terrestrial value and to the ratio measured in other comets, although marginally smaller. We also estimate OD/OH from which we derive D/H = 2.5 +/- 0.7 10-4 in water. This value is compatible with the water D/H ratios evaluated in other comets and marginally higher than the terrestrial value.Comment: Accepted for publication in A&A Letter

Molecular ions in L1544. II. The ionization degree

The maps presented in Paper I are here used to infer the variation of the column densities of HCO+, DCO+, N2H+, and N2D+ as a function of distance from the dust peak. These results are interpreted with the aid of a crude chemical model which predicts the abundances of these species as a function of radius in a spherically symmetric model with radial density distribution inferred from the observations of dust emission at millimeter wavelengths and dust absorption in the infrared. Our main observational finding is that the N(N2D+)/N(N2H+) column density ratio is of order 0.2 towards the L1544 dust peak as compared to N(DCO+)/N(HCO+) = 0.04. We conclude that this result as well as the general finding that N2H+ and N2D+ correlate well with the dust is caused by CO being depleted to a much higher degree than molecular nitrogen in the high density core of L1544. Depletion also favors deuterium enhancement and thus N2D+, which traces the dense and highly CO-depleted core nucleus, is much more enhanced than DCO+. Our models do not uniquely define the chemistry in the high density depleted nucleus of L1544 but they do suggest that the ionization degree is a few times 10^{-9} and that the ambipolar diffusion time scale is locally similar to the free fall time. It seems likely that the lower limit which one obtains to ionization degree by summing all observable molecular ions is not a great underestimate of the true ionization degree. We predict that atomic oxygen is abundant in the dense core and, if so, H3O+ may be the main ion in the central highly depleted region of the core

Fermat hypersurfaces and Subcanonical curves

We extend the classical Enriques-Petri Theorem to $s$-subcanonical projectively normal curves, proving that such a curve is $(s+2)$-gonal if and only if it is contained in a surface of minimal degree. Moreover, we show that any Fermat hypersurface of degree $s+2$ is apolar to an $s$-subcanonical $(s+2)$-gonal projectively normal curve, and vice versa.Comment: 18 pages; AMS-LaTe