484 research outputs found

    Elongated theropod tracks from the Cretaceous Apenninic Carbonate Platform of southern Latium (central Italy)

    Get PDF
    New dinosaur footprints were recently discovered in southern Latium (Italy). The tracks all appear slightly differently preserved and are characterized by elongated metatarsal impressions, recording the complex locomotor behaviour of a medium-sized theropod. The spatial distribution and the features of the footprints indicate that the trackmaker adopted a “crouched” position as part of an activity as well as a resting phase suggested by sub-parallel, calcigrade tracks. These new data once again highlight the great potential of ichnological evidence in the study of the biology and behaviour of extinct tetrapods

    An alternative 3D inversion method for magnetic anomalies with depth resolution

    Get PDF
    This paper presents a new method to invert magnetic anomaly data in a variety of non-complex contexts when a priori information about the sources is not available. The region containing magnetic sources is discretized into a set of homogeneously magnetized rectangular prisms, polarized along a common direction. The magnetization distribution is calculated by solving an underdetermined linear system, and is accomplished through the simultaneous minimization of the norm of the solution and the misfit between the observed and the calculated field. Our algorithm makes use of a dipolar approximation to compute the magnetic field of the rectangular blocks. We show how this approximation, in conjunction with other correction factors, presents numerous advantages in terms of computing speed and depth resolution, and does not affect significantly the success of the inversion. The algorithm is tested on both synthetic and real magnetic datasets

    A realistic inversion algorithm for magnetic anomaly data: the Mt. Amiata volcano test

    Get PDF
    The aim of this work is the formulation of a 3D model of the Mt. Amiata volcanic complex (Southern Tuscany) by means of geomagnetic data. This work is shown not only as a real test to check the validity of the inversion algorithm, but also to add information about the structure of the volcanic complex. First, we outline briefly the theory of geomagnetic data inversion and we introduce the approach adopted. Then we show the 3D model of the Amiata volcano built from the inversion, and we compare it with the available geological information. The most important consideration regards the surface distribution of the magnetization that is in good agreement with rock samples from this area. Moreover, the recovered model orientation recall the extension of the lava flows, and as a last proof of validity, the source appears to be contained inside of the topographic contour level. The credibility of the inversion procedure drives the interpretation even for the deepest part of the volcano. The geomagnetic signal appears suppressed at a depth of about 2 km, but the most striking consequence is that sub-vertical structures are found even in different positions from the conduits shown in the geologic sections. The results are thus in good agreement with the information obtained from other data, but showing features that had not been identified, stressing the informative power of the geomagnetic signal when a meaningful inversion algorithm is used

    Actinobacteria isolated from subterranean and cultural heritage: implications for biotechnology

    Get PDF
    Due to their extraordinary properties, Actinobacteria can thrive in extreme environments, such as limestone caves, lava tubes and stone monuments. They grow forming microbial mats and speleothems on the walls and ceilings of caves, ranging from extensive coatings to small colonies (Riquelme et al. 2015). Their colour includes yellow, tan, orange, grey, pink and white. Recently, we have found abundant yellow and white-coloured bacterial mats coating the cave walls and secondary mineral deposits (speleothems) of lava tubes from La Palma Island, Canary Islands, Spain (Gonzalez-Pimentel et al. 2018) and Mount Etna in Catania (Sicily, Italy). Field Emission Scanning Electron Microscopy (FESEM) of the coloured microbial mats revealed abundant Actinobacteria-like cells, including a variety of filaments and spore structures with smooth surface ornamentation or profuse surface appendages. The DNA-/RNA-based analyses confirmed that these microbial mats are mainly composed of metabolically active Actinobacteria (Gonzalez-Pimentel et al. 2018). It is well known that Actinobacteria, mainly isolated from marine and soil ecosystems, are an important source of bioactive compounds, with Streptomyces ranking first with a huge number of bioactive secondary metabolites (Guo et al. 2015). These compounds, not only produced by Streptomyces but also by Bacillus, are very important to the industrial sector, such as pharmacology, biofuel and food industries, as well as to the conservation of stone cultural heritage, due to their antimicrobial properties (Silva et al. 2017). In the last decades, these sectors have intensified demands for exploring novel eco-friendly bioactive compounds, which stresses the need to investigate new groups of Actinobacteria from underexplored habitats. Yet, Actinobacteria from caves have not been the target of intensive screening for bioactive secondary metabolites. Hence, Actinobacterial-like microbial mats were collected and isolated from lava tubes in La Palma and Mount Etna to investigate their biotechnological potential. The screening of antimicrobial activity was based both on culture-dependent techniques using the agar diffusion assay and on metagenomics. Our study has showed that the strain Streptomyces sp. MZ0467C isolated from La Palma lava tube has antimicrobial activity against Microbacterium, Rhodococcus, Arthrobacter, Kocuria, Sphingomonas and Paenibacillus due to its ingenious adaptations and metabolic strategies to survive under extreme environmental conditions. This demonstrates that Actinobacteria from subterranean environments are promising sources of antibacterial compounds with interest for cultural heritage conservation

    A NEW BRANCH of the ANIO NOVUS AQUEDUCT (ROME, ITALY) REVEALED by ARCHAEOLOGY and GEOPHYSICS

    Get PDF
    The area south-east of Rome is characterised by the presence of several roman aqueducts which brought water to the eternal city from the Apennine and Alban Hills springs. In the last 40 years, several pieces of evidence about these aqueducts were acquired during the realisation of archaeological test trenches before building activities. In 2019, a small branch of a subterranean aqueduct unknown to the Latin sources was unearthed in Via dei Sette Metri. Here we show that this aqueduct is a lateral branch of the Anio Novus, a major imperial aqueduct built between 38 and 52 CE. To achieve this result, we employed detailed photogrammetric restitution of the new aqueduct and an integrated geophysical survey focused in the area where the Anio Novus was supposed to pass. Electrical Resistivity Tomography (ERT) and Ground Penetrating Radar (GPR) methods were used to reconstruct aqueduct paths and their relative heights. Different light conditions were tested during the picture acquisition step to determine the best practice in the photogrammetric restitution. The results obtained in this study confirmed the great effectiveness of the integration between geophysical investigation methods and the modern archaeology approach in detecting buried ancient structures

    On the Absorption of X-rays in the Interstellar Medium

    Full text link
    We present an improved model for the absorption of X-rays in the ISM intended for use with data from future X-ray missions with larger effective areas and increased energy resolution such as Chandra and XMM, in the energy range above 100eV. Compared to previous work, our formalism includes recent updates to the photoionization cross section and revised abundances of the interstellar medium, as well as a treatment of interstellar grains and the H2molecule. We review the theoretical and observational motivations behind these updates and provide a subroutine for the X-ray spectral analysis program XSPEC that incorporates our model.Comment: ApJ, in press, for associated software see http://astro.uni-tuebingen.de/nh

    Imaging the structural style of an active normal fault through multidisciplinary geophysical investigation: a case study from the Mw 6.1, 2009 L'Aquila earthquake region (central Italy)

    Get PDF
    The normal fault-system responsible of the 2009 Mw 6.1 L'Aquila earthquake (Paganica-San Demetrio fault-system) comprises several narrow, fault-parallel valleys of controversial origin. We investigated a key section of the southeastern portion of this fault network along the small Verupola Valley. In order to characterize its nature and possible tectonic activity, we applied multiple-geosciences techniques able to image at depth the structure associated to this peculiar landform. We integrated magnetometry, 2-D P wave and resistivity tomography, surface waves and seismic noise analysis coupled with field mapping, shallow boreholes and trenching. According to our results, the Verupola Valley is a ∼30–40-m-deep graben controlled by a SW-dipping master fault and synthetic splays paired with an antithetic NE-dipping fault. The SW-dipping splays are active and cut very shallow (<2 m deep) Late Pleistocene sediments. The small amount of cumulated vertical offset (∼15 m) across the conjugated system may indicate a young fault inception or very low Quaternary slip-rates. Due to its structural continuity with the adjacent mapped strands of the Paganica–San Demetrio fault network, we relate the Verupola Valley to the recent activity of the southeastern segment of this fault system. We also suggest that other fault-parallel valleys can have the same tectonic origin and setting of the Verupola Valley. This latter represents a scale-independent analogue from metric scale (exposed in the palaeoseismological trenches) to the Middle Aterno Basin scale (seen from seismic profiles and fault mapping). Overall, the imaged structural style is coherent with the regional tectonic setting due to Quaternary crustal extension

    Three‐Dimensional Magnetic Models of La Gomera (Canary Islands): Insights Into the Early Evolution of an Ocean Island Volcano

    Get PDF
    An aeromagnetic data set from the island of La Gomera was studied through two inverse modeling approaches that produced complementary views of the inner structure of this volcanic island: (1) a variable magnetization model that identified the main lateral magnetization contrasts and (2) a constant magnetization model that imaged the main magnetic source by assuming that it was a uniformly magnetized body. The modeling reveals intense magnetizations beneath the northern part of La Gomera, which occupy an important portion of the northern submarine edifice, correspond well with outcrops of the submarine volcano (Basal Complex), and confirm that most of the magnetic signal revealed by aeromagnetic mapping in the Canary Islands is due to the intense magnetizations of the intrusive complexes (plutonic bodies and dike complexes) emplaced during the initial stages of growth of the volcanic edifices. The consistency of our models with the results of a previous gravimetric study suggests that these intrusive complexes are denser and more magnetic than the surrounding rocks. The location of the main magnetic source reinforces the interpretation, first suggested by geological evidence, that the submarine and early subaerial growth of La Gomera started to the north of the present island. The elongated shape of these intrusive complexes with a nearly E-W strike agrees with the orientation of analogous structures on Tenerife and Gran Canaria, suggesting that the initial formation of the central islands of the Canary Archipelago was controlled by a set of regional fractures in a strike-slip tectonic framework.Spanish Ministry of Science, Innovation and Universities (Project CGL2015-63799-P) and by the Junta de Castilla y León and the European Regional Development Fund (ERD) (Project BU235P18)

    Help-seeking behaviour for pelvic floor dysfunction in women over 55: drivers and barriers

    Get PDF
    Objective: Our aim was to identify drivers of and barriers to help-seeking behaviour of older women with pelvic floor dysfunction (PFD) living independently in Australia . Methods: Women aged =55 years were recruited to this cross-sectional study during July and August 2016. Bladder, bowel, pelvic organ prolapse (POP) and sexual dysfunction were assessed with the Australian Pelvic Floor Questionnaire (APFQ). Drivers and barriers were based on the Barriers to Incontinence Care Seeking Questionnaire. Univariate analyses were used to assess any significant relationships between PFD, age, education level, self-reported PFD, barriers and drivers. Results: Of the 376 study participants [mean, standard deviation (SD) age 68.6 (10.5) years], 67% reported symptoms of PFD and 98.7% scored &gt; 0 on the APFQ. Women were more likely to seek help if they scored higher on the APFQ (p &lt; 0.001). The main barrier to seeking help was the perception that PFD was a normal part of ageing (22.4%). Of those who did seek help (50%), the main factor was increased level of symptom bother (51.4%). There was no difference in age or education level between women who did and did not seek help. Conclusion: Women are more likely to seek help for PFD if scoring higher on the APFQ or symptoms are becoming more bothersome. They are less likely to seek help if they view their symptoms as normal. Future direction should be taken to raise awareness of normal pelvic floor function as well as the availability of help for PFD
    corecore