571 research outputs found

    Synchrotron oscillation damping due to beam-beam collisions

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    In DA{\Phi}NE, the Frascati e+/e- collider, the crab waist collision scheme has been successfully implemented in 2008 and 2009. During the collision operations for Siddharta experiment, an unusual synchrotron damping effect has been observed. Indeed, with the longitudinal feedback switched off, the positron beam becomes unstable with beam currents in the order of 200-300 mA. The longitudinal instability is damped by bringing the positron beam in collision with a high current electron beam (~2A). Besides, we have observed a shift of \approx 600Hz in the residual synchrotron sidebands. Precise measurements have been performed by using both a commercial spectrum analyzer and the diagnostics capabilities of the DA{\Phi}NE longitudinal bunch-by-bunch feedback. This damping effect has been observed in DA{\Phi}NE for the first time during collisions with the crab waist scheme. Our explanation is that beam collisions with a large crossing angle produce a longitudinal tune shift and a longitudinal tune spread, providing Landau damping of synchrotron oscillations.Comment: 3 pages, 5 figures, talk presented to IPAC'10 - Kyoto - May 24-28 201

    Flow-cytometric quantification of microbial cells on sand from water biofilters

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    Rapid quantification of absolute microbial cell abundances is important for a comprehensive interpretation of microbiome surveys and crucial to support theoretical modelling and the design of engineered systems. In this paper, we propose a protocol specifically optimised for the quantification of microbial abundances in water biofilters using flow cytometry (FCM). We optimised cell detachment from sand biofilter particles for FCM quantification through the evaluation of five chemical dispersants (NaCl, Triton-X100, CaCl2, sodium pyrophosphate (PP), Tween 80 combined with PP), different mechanical pre-treatments (low and high energy sonication and shaking) and two fixation methods (glutaraldehyde and ethanol). The developed protocol was cross-compared using other established and commonly employed methods for biomass quantification in water filter samples (adenosine triphosphate (ATP) quantification, real-time quantitative PCR (qPCR) and volatile solids (VS)). The highest microbial count was obtained by detaching the biofilm from biofilter grains and dispersing clusters into singles cells using Tween 80 and sodium pyrophosphate combined with four steps of high energy sonication (27W, for 80 s each step); glutaraldehyde was shown to be the best fixative solution. The developed protocol was reliable and highly reproducible and produced results that are comparable to data from alternative quantification methods. Indeed, high correlations were found with trends obtained through ATP and qPCR (ρ = 0.98 and ρ = 0.91) measurements. The VS content was confirmed as an inaccurate method to express biomass in sand samples since it correlated poorly with all the other three methods (ρ = 0.005 with FCM, 0.002 with ATP and 0.177 with qPCR). FCM and ATP showed the strongest agreement between absolute counts with a slope of the correlation equal to 0.7, while qPCR seemed to overestimate cell counts by a factor of ten. The rapidity and reproducibility of the method developed make its application ideal for routine quantification of microbial cell abundances on sand from water biofilters and thus useful in revealing the ecological patterns and quantifying the metabolic kinetics involved in such systems

    Berry fruits-enriched pasta: effect of processing and in vitro digestion on phenolics and its antioxidant activity, bioaccessibility and potential bioavailability

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    Pasta samples were made by substituting wheat flour (2.5% and 7.5%) for lyophilised raspberry, boysenberry, and redcurrant and blackcurrant. Total polyphenol content showed minimum variation during processing while anthocyanins presented high degradation. In general, the first minutes of cooking showed the major detrimental effect on antioxidant activity. In vitro starch hydrolysis showed the lowest value with the addition of raspberries and boysenberries. During simulated digestion, polyphenols were released from pasta matrix reaching a 2.3- to 4.3-fold increase in bioaccessible polyphenols. Likewise, values observed for reducing power and free radical scavenging activity ranged from a 0.7- to 2.0-fold and 1.6- to 6.8-fold increase in relation to cooked pasta, respectively. In addition, ≈40% of dialysability was observed for scavenging activity. In conclusion, enrichment of pasta with fine fruits is an effective tool to obtain a product with enhanced antioxidant potential.Fil: Bustos, Mariela C.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Ciencia y Tecnología de Alimentos Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Ciencia y Tecnología de Alimentos Córdoba; ArgentinaFil: Vignola, María Belén. Universidad Tecnológica Nacional. Facultad Reg.san Francisco. Departamento de Química; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Ciencia y Tecnología de Alimentos Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Ciencia y Tecnología de Alimentos Córdoba; ArgentinaFil: Paesani, Candela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Ciencia y Tecnología de Alimentos Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Ciencia y Tecnología de Alimentos Córdoba; ArgentinaFil: Leon, Alberto Edel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Ciencia y Tecnología de Alimentos Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Ciencia y Tecnología de Alimentos Córdoba; Argentin

    At the origins of Pompeii: the plant landscape of the Sarno River floodplain from the first millennium bc to the ad 79 eruption

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    The ad 79 eruption of the Vesuvius severely affected the floodplain surrounding the ancient city of Pompeii, i.e. the Sarno River floodplain. The landscape was covered with volcaniclastic materials that destroyed the ecosystem but, at the same time, preserved the traces of former environmental conditions. This study provides—for the first time—a pollen sequence reconstructing the environmental evolution and the plant landscape of the Sarno floodplain between 900 and 750 cal bc and ad 79, i.e. before and during the foundation of the city, and during its life phases. Previous geomorphological studies revealed that the portion of the Sarno floodplain under the “Pompeii hill” was a freshwater backswamp with patchy inundated and dry areas. Palynology depicts a thin forest cover since the Early Iron Age, suggesting an open environment with a mosaic of vegetation types. The local presence of Mediterranean coastal shrubland, hygrophilous riverine forest and mesophilous plain forest is combined with the regional contribution of mountain vegetation through the sequence. Oscillations between inundated and wet ground characterized the studied area until the ad 79 eruption. Such a natural environment shows anthropogenic traits since pre-Roman times: pasturelands, cultivated fields and olive groves, which probably occupied drier soils. The most important change in the land use system was the introduction of cabbage cultivation in the fourth century bc and its intensification from the second century bc, when Roman influence grew. The presence of tree crops and of ornamental trees reveals the opulence of the Imperial age until the catastrophic eruption

    Impact of the Wiggler Coherent Synchrotron Radiation Impedance on the Beam Instability

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    Coherent Synchrotron Radiation (CSR) can play an important role by not only increasing the energy spread and emittance of a beam, but also leading to a potential instability. Previous studies of the CSR induced longitudinal instability were carried out for the CSR impedance due to dipole magnets. However, many storage rings include long wigglers where a large fraction of the synchrotron radiation is emitted. This includes high-luminosity factories such as DAPHNE, PEP-II, KEK-B, and CESR-C as well as the damping rings of future linear colliders. In this paper, the instability due to the CSR impedance from a wiggler is studied assuming a large wiggler parameter KK. The primary consideration is a low frequency microwave-like instability, which arises near the pipe cut-off frequency. Detailed results are presented on the growth rate and threshold for the damping rings of several linear collider designs. Finally, the optimization of the relative fraction of damping due to the wiggler systems is discussed for the damping rings.Comment: 10 pages, 7 figure

    Cerebral cortex activity in freely moving sheep using a wireless CW fNIRS system: preliminary results

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    Functional near-infrared spectroscopy (fNIRS) was recently applied in studies involving animals, showing great potential as, to date, this is the only technique that can be used to non-invasively measure hemodynamic brain responses in freely moving animals [1\u20133]. The aim of this study was to evaluate the cerebral activity of freely moving sheep undergoing different tasks (motor and somatosensory). Four one-year-old Sarda ewes were exposed to two different stimuli: a motor task (walking), and a sudden noise. To measure the changes of oxyhemoglobin ([\u394O2Hb]) and deoxyhemoglobin ([\u394HHb]) concentration, a mobile and miniaturized wireless CW fNIRS system (Octamon, Artinis Medical Systems, The Netherlands) was used. Sensors were applied on the forehead of the sheep depilated head and held in place with a customized head cap (Fig.1(a)). Four transmitters and two receivers (four channels in total), with pairs of transmitter-receiver at short (10 mm) and long (30 mm) distance, were used to cover the left and right hemisphere of the sheep head. The intensity of the light after transmission through tissue was recorded. The optical density was converted into [\u394O2Hb] and [\u394HHb] by the modified Lambert-Beer law. Our result of the motor task showed a decrease of [\u394O2Hb] and increase of [\u394HHb] in both hemispheres when sheep were walking (Fig.1(b)). For the sudden noise test, both hemispheres showed a transient decrease when the stimulus began, followed by a gradual increase in [\u394O2Hb] concentration (Fig.1(c)). Our preliminary results suggest that fNIRS has the potential to non-invasively measure cerebral cortex activity in free moving sheep undergoing different tasks. Combining behavioral indicators with these innovative measurements will strengthen knowledge on animal cognition and perception of different environmental situations, thus enhancing their welfare. This work was supported by MIUR-PRIN2015 (Grant 2015Y5W9YP)

    High luminosity interaction region design for collisions inside high field detector solenoid

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    An innovatory interaction region has been recently conceived and realized on the Frascati DA{\Phi}NE lepton collider. The concept of tight focusing and small crossing angle adopted to achieve high luminosity in multibunch collisions has evolved towards enhanced beam focusing at the interaction point with large horizontal crossing angle, thanks to a new compensation mechanism for the beam-beam resonances. The novel configuration has been tested with a small detector without solenoidal field yielding a remarkable improvement in terms of peak as well as integrated luminosity. The high luminosity interaction region has now been modified to host a large detector with a strong solenoidal field which significantly perturbs the beam optics introducing new design challenges in terms of interaction region optics design, beam transverse coupling control and beam stay clear requirements. Interaction region design criteria as well as the luminosity results relevant to the structure test are presented and discussed.Comment: 12 pages, 9 figures, submitted to JINS

    How different husbandry conditions influence hind-gut microbiome, cortisol level and behaviour in lambs?

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    The gut microbiota\u2013brain axis is a bidirectional pathway through which the brain regulates the activity of the gut and vice versa. The intestinal microbiota was proven to influence and be influenced by stressrelated responses caused by management conditions. The aim of this work was to evaluate whether different husbandry conditions in lambs influenced gut microbiome (composition and diversity), cortisol level and behaviour. Fifteen Sarda breed lambs, aged 6 months, were randomly assigned to three groups of 5 animals each: Isolation (tactile and visual isolation; 3 h/day for 8 weeks); Enriched (in group in a outdoor grassy pen with a new enrichment each week; 3 h/day for 8 weeks); Control (habitual farm environment). Every week, 2 video-recordings of 1-hour each were collected respectively during and after each treatment, and analysed using a scan sampling technique (60 scans per video). Every two weeks hair was collected from the right shoulder using a shave and re-shave method. Cortisol concentration was measured by means of an ELISA test conducted on hair samples and expressed as pg/ml. At week 8 faecal material was collected directly from the rectal ampulla and immediately frozen at 1220\ub0C until DNA extraction was performed using a QIAmp DNA Stool kit (Qiagen, Hilden, Germany). DNA quality and quantity were assessed using a NanoDrop ND-1000 spectrophotometer (NanoDrop Technologies, Wilmington, DE, USA). The microbiota of enriched animals was clearly different from the other two groups and showed lower within group variability. During treatment, only isolated sheep showed escape attempts (23% of scans during the first week) and freezing (58% of scans during the first week). In the home pen, after treatment, lambs did not show any stress-related behaviour. After one month of treatment, hair cortisol increased only in the isolated group. In conclusion, differences in microbiome could be related to the different stimulating enrichment and addition of grass on the diet. Although, from a behavioural point of view, sheep apparently habituated to the isolation, increase in cortisol levels could be related to experiencing a stressful situation
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