1,397 research outputs found

    Meaurement of Cosmic Ray elemental composition from the CAKE balloon experiment

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    CAKE (Cosmic Abundances below Knee Energies) was a prototype balloon experiment for the determination of the charge spectra and of abundances of the primary cosmic-rays (CR) with Z>>10. It was a passive instrument made of layers of CR39 and Lexan nuclear track detectors; it had a geometric acceptance of ∌\sim0.7 m2^2sr for Fe nuclei. Here, the scanning and analysis strategies, the algorithms used for the off-line filtering and for the tracking in automated mode of the primary cosmic rays are presented, together with the resulting CR charge distribution and their abundances.Comment: 5 pages, 8 figure

    \u3cem\u3eArabidopsis\u3c/em\u3e AZI1 Family Proteins Mediate Signal Mobilization for Systemic Defence Priming

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    Priming is a major mechanism behind the immunological \u27memory\u27 observed during two key plant systemic defences: systemic acquired resistance (SAR) and induced systemic resistance (ISR). Lipid-derived azelaic acid (AZA) is a mobile priming signal. Here, we show that the lipid transfer protein (LTP)-like AZI1 and its closest paralog EARLI1 are necessary for SAR, ISR and the systemic movement and uptake of AZA in Arabidopsis. Imaging and fractionation studies indicate that AZI1 and EARLI1 localize to expected places for lipid exchange/movement to occur. These are the ER/plasmodesmata, chloroplast outer envelopes and membrane contact sites between them. Furthermore, these LTP-like proteins form complexes and act at the site of SAR establishment. The plastid targeting of AZI1 and AZI1 paralogs occurs through a mechanism that may enable/facilitate their roles in signal mobilization

    Cosmic rays 10Be biennal data and their relationship to aurorae and sunspots

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    The galactic cosmic ray (C.R.) variations which should give information on three dimensional aspects of the heliospheric magnetic fields and on the solar wind, which modulate their influx into the Solar System were studied. In order to decode the information from the C.R. series it is necessary to know the mechanisms through which the modulation is produced. It it clear that a balance of effects with sources at different heliospheric latitudes results in the modulated C.R. intensity. It is found that the modulation of 10Be in polar ice may be due to at least two main contributions: (1) negative and in phase with the Solar flare activity modulating the cosmic ray flux in Forbush-type decreases, and (2) positive in phase with the appearance of large wind streams situated at both polar coronal holes. It is found that the high heliolatitude activity is related to a stable periodicity of 11.1y whereas the low heliolatitude activity contributes to the wondering of the solar cycles

    Fluorescence Spectroscopy for the Diagnosis of Endometritis in the Mare

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    By exploiting the PMN property to produce high quantities of oxygen peroxide to neutralize pathogens, the oxygen peroxide content of uterine cells was measured to diagnose endometritis. After preliminary in vitro studies in which endometrial cells from slaughtered mares were mixed with leukocytes from peripheral blood, endometrial samples were collected by uterine flushing from mares before insemination. Staining endometrial cells with H2DCF-DA was combined with hydroethidine to normalize the fluorescence intensity with the cellular content of the sample. Stained cell smears were assumed as the gold standard of endometritis, and based on this assay, the samples were considered positive (C+) and negative (C-) for endometritis. The amount and the turbidity of fluid recovered by uterine flushing were significantly (p < 0.01) higher in C+ than in C-. Moreover, the oxygen peroxide content of the endometrial cells was significantly higher in the C+ than in the C- group (6.31 ± 1.92 vs. 3.12 ± 1.26, p = 0.001). Using the value of 4.4 as the cutoff level of this fluorescence cytology assay, it was found that only one C- sample exceeded the cutoff level (false positives = 7.7%) while three C+ samples showed values below the cutoff level (false negative = 11.5%)

    High frequency mechanical excitation of a silicon nanostring with piezoelectric aluminum nitride layers

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    A strong trend for quantum based technologies and applications follows the avenue of combining different platforms to exploit their complementary technological and functional advantages. Micro and nano-mechanical devices are particularly suitable for hybrid integration due to the easiness of fabrication at multi-scales and their pervasive coupling with electrons and photons. Here, we report on a nanomechanical technological platform where a silicon chip is combined with an aluminum nitride layer. Exploiting the AlN piezoelectricity, Surface Acoustic Waves are injected in the Si layer where the material has been localy patterned and etched to form a suspended nanostring. Characterizing the nanostring vertical displacement induced by the SAW, we found an external excitation peak efficiency in excess of 500 pm/V at 1 GHz mechanical frequency. Exploiting the long term expertise in silicon photonic and electronic devices as well as the SAW robustness and versatility, our technological platform represents a strong candidate for hybrid quantum systems

    Search for nuclearites with the SLIM detector

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    We discuss the properties of cosmic ray nuclearites, from the point of view of their search with large nuclear track detector arrays exposed at different altitudes, in particular with the SLIM experiment at the Chacaltaya high altitude lab (5290 m a.s.l.). We present calculations concerning their propagation in the Earth atmosphere and discuss their possible detection with CR39 and Makrofol nuclear track detectors.Comment: 11 pages, 6 figure

    Early fluoride intake and Molar Incisor Hypomineralisation (MIH) defects: A systematic review and dose-response meta-analysis

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    Background: Excessive intake of fluoride has been implicated in the complex multifactorial etiology of hypomineralisation (MIH) defects. Objective: To study the possible effect of early exposure to fluoride on the risk of molar incisor hypomineralisation, also through a dose-response approach. Methods: Observational and clinical studies investigating the relation between fluoride exposure from any source or evaluating exposure biomarkers and MIH defects. PubMed MEDLINE, Embase and Web of Science databases were con-sulted up to December 1, 2023, using terms related to “fluoride”, “enamel defects” and “demarcated opacities”. We performed a meta-analysis comparing the highest versus lowest fluoride exposure using a random-effects model, and we quantitively assessed this relation using piece-wise linear meta-regression. Results: Thirteen studies were included in the meta-analysis, 12 of which were eligible for the dose-response analysis, all regarding exposure from fluoride in drinking water. Three of them specifically addressed MIH, while the remaining concerned “demarcated opacities”, yet with features attributable to MIH. Comparing the highest versus lowest water fluoride exposure categories, virtually no evidence of a fluoride effect was identified, with an overall odds ratio of 0.93 [95% confidence interval 0.60; 1.45]. The dose-response meta-regression showed a decreasing risk for MIH defects exposure up to 1 mg/L, whereas an increase in risk emerged at higher exposure levels. Conclusions: This meta-analysis suggests that early systemic exposure to fluoride may affect the occurrence of MIH defects differently depending on fluoride concentration. However, these results need to be evaluated with caution due to potential methodological limitations of the studies included. (www.actabiomedica.it)

    Fragmentation cross sections of Fe^{26+}, Si^{14+} and C^{6+} ions of 0.3-10 A GeV on CR39, polyethylene and aluminum targets

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    New measurements of the total and partial fragmentation cross sections in the energy range 0.3-10 A GeV of Fe^{26+}, Si^{14+} and C^{6+} beams on polyethylene, CR39 and aluminum targets are presented. The exposures were made at Brookhaven National Laboratory (BNL), USA, and Heavy Ion Medical Accelerator in Chiba (HIMAC), Japan. The CR39 nuclear track detectors were used to identify the incident and survived beams and their fragments. The total fragmentation cross sections for all targets are almost energy independent while they depend on the target mass. The measured partial fragmentation cross sections are also discussed.Comment: 4 pages, 5 eps figures. Talk given at the 24th International Conference on Nuclear Tracks in Solids, Bologna, Italy, 1-5 September 200
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