398 research outputs found

    Lateral stress evolution in chromium sulfide cermets with varying excess chromium

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    The shock response of chromium sulfide-chromium, a cermet of potential interest as a matrix material for ballistic applications, has been investigated at two molar ratios. Using a combustion synthesis technique allowed for control of the molar ratio of the material, which was investigated under near-stoichiometric (cermet) and excess chromium (interpenetrating composite) conditions, representing chromium:sulfur molar ratios of 1.15:1 and 4:1, respectively. The compacts were investigated via the plate-impact technique, which allowed the material to be loaded under a onedimensional state of strain. Embedded manganin stress gauges were employed to monitor the temporal evolution of longitudinal and lateral components of stress in both materials. Comparison of these two components has allowed assessment of the variation of material shear strength both with impact pressure/strain-rate and time for the two molar ratio conditions. The two materials exhibited identical material strength despite variations in their excess chromium content

    A comprehensive molecular cytogenetic analysis of chromosome rearrangements in gibbons.

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    Chromosome rearrangements in small apes are up to 20 times more frequent than in most mammals. Because of their complexity, the full extent of chromosome evolution in these hominoids is not yet fully documented. However, previous work with array painting, BAC-FISH, and selective sequencing in two of the four karyomorphs has shown that high-resolution methods can precisely define chromosome breakpoints and map the complex flow of evolutionary chromosome rearrangements. Here we use these tools to precisely define the rearrangements that have occurred in the remaining two karyomorphs, genera Symphalangus (2n = 50) and Hoolock (2n = 38). This research provides the most comprehensive insight into the evolutionary origins of chromosome rearrangements involved in transforming small apes genome. Bioinformatics analyses of the human–gibbon synteny breakpoints revealed association with transposable elements and segmental duplications, providing some insight into the mechanisms that might have promoted rearrangements in small apes. In the near future, the comparison of gibbon genome sequences will provide novel insights to test hypotheses concerning the mechanisms of chromosome evolution. The precise definition of synteny block boundaries and orientation, chromosomal fusions, and centromere repositioning events presented here will facilitate genome sequence assembly for these close relatives of humans

    Retrospective analysis for detecting seismic precursors in groundwater argon content

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    We examined the groundwater Argon content data sampled from 1988 to 2001 at two wells in Kamchatka (Russia) and anomalous increases appeared clearly during June-July&nbsp;1996. On 21&nbsp;June, a shallow (1km) earthquake with <i>M</i>=7.1 occurred at a distance less than 250km from the wells and so the previous increases could be related to this earthquake and, in particular, could be considered premonitory anomalies. In order to support this raw interpretation, we analysed the data collected in details. At first we smoothed out the high frequency fluctuations arising from the errors in a single measurement. Next we considered the known external effects on the water of a well that are the slow tectonic re-adjustment processes, the meteorology and the gravity tides and we separated these effects applying band-pass filters to the Argon content raw trends. Then we identified the largest fluctuations in these trends applying the 3 σ criterion and we found three anomalies in a case and two anomalies in other case. Comparing the time occurrence of the anomalies at the two wells we found out that a coincidence exists only in the case of the premonitory anomalies we are studying. The simultaneous appearance of well definite anomalies in the residual trends of the same parameter at two different sites supports their meaning and the possibility that they are related to some large scale effect, as the occurrence of a strong earthquake. But, other earthquakes similar to the June&nbsp;1996 event took place during the Argon content measurements time and no anomaly appeared in this content. In the past, some of the authors of this paper studied the Helium content data collected in three natural springs of the Caucasus during seven years. A very similar result, that is the simultaneous appearance of clear premonitory anomalies only on the occasion of a strong (<i>M</i>=7.0) but shallow (2–4km) earthquake, was obtained. The correspondence with the case of the Caucasus validates the interpretation of the Kamchatkian anomalies as precursors

    A thin layer angiogenesis assay: a modified basement matrix assay for assessment of endothelial cell differentiation

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    BACKGROUND: Basement matrices such as Matrigel™ and Geltrex™ are used in a variety of cell culture assays of anchorage-dependent differentiation including endothelial cell tube formation assays. The volumes of matrix recommended for these assays (approximately 150 μl/cm(2)) are costly, limit working distances for microscopy, and require cell detachment for subsequent molecular analysis. Here we describe the development and validation of a thin-layer angiogenesis (TLA) assay for assessing the angiogenic potential of endothelial cells that overcomes these limitations. RESULTS: Geltrex™ basement matrix at 5 μl/cm(2) in 24-well (10 μl) or 96-well (2 μl) plates supports endothelial cell differentiation into tube-like structures in a comparable manner to the standard larger volumes of matrix. Since working distances are reduced, high-resolution single cell microscopy, including DIC and confocal imaging, can be used readily. Using MitoTracker dye we now demonstrate, for the first time, live mitochondrial dynamics and visualise the 3-dimensional network of mitochondria present in differentiated endothelial cells. Using a standard commercial total RNA extraction kit (Qiagen) we also show direct RNA extraction and RT-qPCR from differentiated endothelial cells without the need to initially detach cells from their supporting matrix. CONCLUSIONS: We present here a new thin-layer assay (TLA) for measuring the anchorage-dependent differentiation of endothelial cells into tube-like structures which retains all the characteristics of the traditional approach but with the added benefit of a greatly lowered cost and better compatibility with other techniques, including RT-qPCR and high-resolution microscopy. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12860-014-0041-5) contains supplementary material, which is available to authorized users

    LF radio anomalies revealed in Italy by the wavelet analysis: possible preseismic effects during 1997-1998

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    Since 1996, the electric field strength of the broadcasting station CZE (Czech Republic, f = 270 kHz) has been sampled each ten minutes, by a receiver (AS) located in central Italy, 818 km far from the transmitter. Here, we present the results obtained by a detailed analysis applied on the data recorded from February 1996 up to September 2004. At first, we separated the day time data and the night time data in the radio signals; then, in the day time data we separated the data collected in winter from the data collected in summer. Finally, we applied the wavelet analysis on the previous trends. The first result was the appearance of a very clear anomaly during February– March 1998, at winter day time and at night time. This result confirms an anomaly revealed previously in the same data but analysed with a different approach. The anomaly was related to a strong (M = 5.1–6.0) seismic sequence occurred in a zone (Slovenia) lying in the middle of the transmitter–receiver path. The present result reinforces the hypothesis of the occurrence of some disturbances in the ionosphere during the preparatory phase of the Slovenia seismic sequence. The second result came from the wavelet analysis applied to the summer day time data and it was the appearance of a very clear anomaly during August–September 1997. On September 26 the Umbria– Marche (central Italy) seismic sequence started with two earthquakes with magnitude M = 5.6 and M = 5.9 and the seismic activity lasted for more than six months. We consider the August–September 1997 radio anomaly as a precursor of the previous earthquakes and a possible explanation model is proposed

    A possible preseismic anomaly in the ground wave of a radio broadcasting (216 kHz) during July-August 1998 (Italy)

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    International audienceOn February 1996, a receiver able to measure the electric field strength of LF radio broadcastings, with a sampling frequency of ten minutes, was put into operation in a site (AS) located in central Italy. One of the broadcasting stations selected is MCO (f=216 kHz), located in southeast France, 518 km far from the receiver. The MCO data collected since February 1996 up to September 2004 were examined and, at first, the night time data and the day time data (in winter and summer) were separated. Then, the wavelet analysis on the night and day time data was applied. The main result of the analysis was the appearance of a very clear anomaly during summer (July?August) 1998, at day time and at night time. The anomaly is a strong exaltation of the signal components with period in the 25?40 days range. Theoretical calculations of electric field strength were made and the only way to justify this anomaly seems to be the occurrence of an increase of the ground wave propagation mode of the radio signal. Such an increase could have been produced by an increase of the ground conductivity and by modifications of some parameter of the troposphere, mainly the refractive index. On 15 August 1998 a seismic sequence started with 17 earthquakes (M=2.2?4.6) on the Reatini mountains, a seismogenic zone located 30 km far from the AS receiver along the path MCO-AS. In this paper, the possibility that the previous radio anomaly can be a precursor of this seismic sequence is proposed. </p

    Disturbances in a VLF radio signal prior the M =4.7 offshore Anzio (central Italy) earthquake on 22 August 2005

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    Abstract. On 22 August 2005 an earthquake with magnitude M=4.7 occurred in the Anzio (central Italy) offshore area. From 2002, a VLF-LF radio receiver is into operation in Bari (southern Italy). The intensity and the phase of the signals transmitted by GB (f=16 kHz, United Kingdom), FR (f=20.9 kHz, France), GE (f=23.4 kHz, Germany), IC (f=37.5 kHz, Island) and IT (f=54 kHz, Sicily, Italy) has been monitored with a 5 s sampling rate. The previous epicenter is near enough to some of the radio paths and the data collected were studied in order to reveal possible seismic effects. The raw analysis revealed a clear drop in the intensity of the FR radio signal on 19 August. Then the wavelet analysis was applied to the intensity and the phase data of the different radio signals. In the mentioned day an increase in the band 60–120 min was revealed in the spectra of the FR signal. Then the principal component analysis was applied and again the 19 August stood up as an anomalous day for the FR radio signal. The path of this signal, among the paths of the five radio signals collected by the Bari receiver, is the nearest to the mentioned epicentre and the anomaly revealed on 19 August appears as a precursor of the earthquake. This result confirms the possible precursor revealed by other researchers in the air Rn content in a site located 5 miles far from the epicenter

    The Microcalorimeter Arrays for a Rhenium Experiment (MARE): a next-generation calorimetric neutrino mass experiment

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    Neutrino oscillation experiments have proved that neutrinos are massive particles, but can't determine their absolute mass scale. Therefore the neutrino mass is still an open question in elementary particle physics. An international collaboration is growing around the project of Microcalorimeter Arrays for a Rhenium Experiment (MARE) for directly measuring the neutrino mass with a sensitivity of about 0.2eV/c2. Many groups are joining their experiences and technical expertise in a common effort towards this challenging experiment. We discuss the different scenarios and the impact of MARE as a complement of KATRIN.Comment: 3 pages, 1 figure Nucl. Instr. Meth. A, proceedings of LTD11 workshop, Tokyo 200

    DNA content of a functioning chicken kinetochore

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    © The Author(s) 2014. In order to understand the three-dimensional structure of the functional kinetochore in vertebrates, we require a complete list and stoichiometry for the protein components of the kinetochore, which can be provided by genetic and proteomic experiments. We also need to know how the chromatin-containing CENP-A, which makes up the structural foundation for the kinetochore, is folded, and how much of that DNA is involved in assembling the kinetochore. In this MS, we demonstrate that functioning metaphase kinetochores in chicken DT40 cells contain roughly 50 kb of DNA, an amount that corresponds extremely closely to the length of chromosomal DNA associated with CENP-A in ChIP-seq experiments. Thus, during kinetochore assembly, CENP-A chromatin is compacted into the inner kinetochore plate without including significant amounts of flanking pericentromeric heterochromatin. © 2014 The Author(s).Wellcome Trust [grant number 073915]; Wellcome Trust Centre for Cell Biology (core grant numbers 077707 and 092076); Darwin Trust of Edinburg

    Database of the Italian disdrometer network

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    In 2021, a group of seven Italian institutions decided to bring together their know-how, experience, and instruments for measuring the drop size distribution (DSD) of atmospheric precipitation, giving birth to the Italian Group of Disdrometry (in Italian named Gruppo Italiano Disdrometria, GID, https://www.gid-net.it/, last access: 16 May 2023). GID has made freely available a database of 1 min records of DSD collected by the disdrometer network along the Italian peninsula. At the time of writing, the disdrometer network was composed of eight laser disdrometers belonging to six different Italian institutions (including research centres, universities, and environmental regional agencies). This work aims to document the technical aspects of the Italian DSD database consisting of 1 min sampling data from 2012 to 2021 in a uniform standard format defined within GID. Although not all the disdrometers have the same data record length, the DSD data collection effort is the first of its kind in Italy, and from here onwards, it opens up new opportunities in the surface characterization of microphysical properties of precipitation in the perspective of climate records and beyond. The Version 01 GID database can be downloaded at https://doi.org/10.5281/zenodo.6875801 (Adirosi et al., 2022), while Version 02 can be downloaded at https://doi.org/10.5281/zenodo.7708563 (Adirosi et al., 2023). The difference among the two versions is the diameter–fall velocity relation used for the DSD computation
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