2,353 research outputs found
Longitudinal beam dynamics in the Frascati DAΦNE e^{+}e^{-} collider with a passive third harmonic cavity in the lengthening regime
A high-harmonic rf system is going to be installed in both rings of the DAΦNE Φ-Factory collider to improve the Touschek lifetime. The main goal of this paper is to study the impact of the 3rd harmonic cavity on beam dynamics making a special emphasis on the dynamics of a bunch train with a gap. The shift of the coherent synchrotron frequencies of the coupled-bunch modes has been estimated. In the following we investigated the effect of magnification of the synchrotron phase spread and beam spectrum variation due to the gap. Besides we simulated the bunch lengthening for different bunches along the unevenly filled train and evaluated the Touschek lifetime enhancement taking into account the obtained bunch distributions. Finally, the "cavity parking" option is discussed. It can be considered as a reliable backup procedure consisting of tuning the cavity away from the 3rd harmonic frequency and in between two revolution harmonics. It allows recovering, approximately, the same operating conditions as were before the harmonic cavity installation
Design and Test of the Off-Detector Electronics for the CMS Barrel Muon Trigger
Drift Tubes chambers are used in the CMS barrel for tagging the passage of high Pt muons generated in a LHC event and for triggering the CMS data read out. The Sector Collector (SC) system synchronizes the track segments built by trigger modules on the chambers and deliver them to reconstruction processors (Track Finder, TF) that assemble full muon tracks. Then, the Muon Sorter (MS) has to select the best four candidates in the barrel and to filter fake muons generated by the TF system redundancy. The hardware implementations of the Sector Collector and Muon Sorter systems satisfy radiation, I/O and fast timing constraints using several FPGA technologies. The hardware was tested with custom facilities, integrated with other trigger subsystems, and operated in a beam test. A test beam on a 40 MHz bunched beam validated the local trigger electronics and off-detector prototype cards and the synchronization tools. The CMS Magnet Test and Cosmic challenge in 2006 proved stable and reliable operation of the Drift Tubes trigger and its integration with other trigger systems and with the readout system. Constraints, design, test and operation of the modules are presented
Balloon aortic valvuloplasty as a palliative treatment in patients with severe aortic stenosis and limited life expectancy : a single center experience
Whether balloon aortic valvuloplasty (BAV) may provide an effective palliation in symptomatic high-risk patients is uncertain. Therefore, we aimed to evaluate outcomes in symptomatic high-risk patients with severe aortic stenosis (AS), who underwent BAV. All-cause mortality and length of hospitalization for heart failure (HF) up to death or to 1-year follow up were collected after BAV. One hundred thirty-two (132) patients (62% women), mean age 85±7 years, underwent BAV with a substantial reduction of the peak-to-peak aortic gradient from 53±21 to 29±15 mmHg (p<0.001). The median of days of HF hospitalization prior to BAV was 9 (0-19), and decreased after BAV to 0 (0-9), p<0.001. During 1-year follow-up patients with untreated CAD (85, 64%) had a higher mortality compared to patients with insignificant/treated CAD (47, 36%): 1-year survival: 45±7% vs. 66± 7%; p=0.02. After adjustment for STS risk score and severity of residual AS, patients with untreated CAD remained at higher risk of mortality (adjusted HR 1.74 [1.01-2.91]; p=0.04). Thus, in this series of symptomatic high-risk patients, BAV was associated with a significant reduction in aortic valve gradient and hospitalization time for HF post-BAV. In patients with significant CAD, percutaneous intervention might be considered in order to improve survival
Moringa oleifera Leaf Powder as Functional Additive in Cookies to Protect SH-SY5Y Cells
The aim of this work is the evaluation of the addition of Moringa leaf powder (MLP)
in cookies in terms of antioxidant properties, dough processability and sensorial properties of the
cookies. The total content of biophenols and flavonoids in MLP was detected and the identification of
the bioactive molecules was performed by HPLC-ESI-TOF-MS measurements, before and after oven
treatment at 180 â—¦C for 20 min. After a preliminary evaluation of the MLP water soluble fraction
(MLPsf) cytotoxicity, its protective effect against an oxidative injury induced in the SH-SY5Y cells
was assessed. Data evidence that the bioactive molecules present in MLPsf are effective in preventing
ROS production and in protecting neuronal cells against oxidative stress. Prototypes of cookies
containing MLP in different concentrations were then produced and evaluated by a consumer panel.
Selected doughs containing MLP were analysed to determine the total content of biophenols in the
cookies after baking and their enrichment in terms of valuable chemical elements. The influence of
MLP on the viscoelastic behaviour and morphology of the doughs was also assessed. Finally, the
potential role in counteracting the insurgence of not treatable neurodegenerative pathologies of two
main MLP components, glucomoringin and kaempferol derivatives, present also after the thermal
treatment, was discussed
The CMS Drift Tube Trigger Track Finder
Muons are among the decay products of many new particles that may be discovered at the CERN Large Hadron Collider. At the first trigger level the identification of muons and the determination of their transverse momenta and location is performed by the Drift Tube Trigger Track Finder in the central region of the Compact Muon Solenoid experiment, using track segments detected in the Drift Tube muon chambers. Track finding is performed both in pseudorapidity and azimuth. Track candidates are ranked and sorted, and the best four are delivered to the subsequent high level trigger stage. The concept, design, control and simulation software as well as the expected performance of the system are described. Prototyping, production and tests are also summarized
Nitrogen Concentration Estimation in Tomato Leaves by VIS-NIR Non-Destructive Spectroscopy
Nitrogen concentration in plants is normally determined by expensive and time consuming chemical analyses. As an alternative, chlorophyll meter readings and N-NO3 concentration determination in petiole sap were proposed, but these assays are not always satisfactory. Spectral reflectance values of tomato leaves obtained by visible-near infrared spectrophotometry are reported to be a powerful tool for the diagnosis of plant nutritional status. The aim of the study was to evaluate the possibility and the accuracy of the estimation of tomato leaf nitrogen concentration performed through a rapid, portable and non-destructive system, in comparison with chemical standard analyses, chlorophyll meter readings and N-NO3 concentration in petiole sap. Mean reflectance leaf values were compared to each reference chemical value by partial least squares chemometric multivariate methods. The correlation between predicted values from spectral reflectance analysis and the observed chemical values showed in the independent test highly significant correlation coefficient (r = 0.94). The utilization of the proposed system, increasing efficiency, allows better knowledge of nutritional status of tomato plants, with more detailed and sharp information and on wider areas. More detailed information both in space and time is an essential tool to increase and stabilize crop quality levels and to optimize the nutrient use efficiency
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