Quantum dynamics of localized excitations in a symmetric trimer molecule

We study the time evolution of localized (local bond) excitations in a symmetric quantum trimer molecule. We relate the dynamical properties of localized excitations such as their spectral intensity and their temporal evolution (survival probability and tunneling of bosons) to their degree of overlap with quantum tunneling pair states. We report on the existence of degeneracy points in the trimer eigenvalue spectrum for specific values of parameters due to avoided crossings between tunneling pair states and additional states. The tunneling of localized excitations which overlap with these degenerate states is suppressed on all times. As a result local bond excitations may be strongly localized forever, similar to their classical counterparts.Comment: 9 pages, 12 figures. Improved version with more discussions. Some figures were replaced for better understanding. Accepted in Phys. Rev.

Detection of a variable ultra-fast outflow in the Narrow Line Seyfert 1 galaxy PG 1448+273

Relativistically blueshifted absorption features of highly ionised ions, the so-called ultra-fast outflows (UFOs), have been detected in the X-ray spectra of a number of accreting supermassive black holes. If these features truly originate from accretion disc winds accelerated to more than 10 per cent of the speed of light, their energy budget is very significant and they can contribute to or even drive galaxy-scale feedback from active galactic nuclei (AGN). However, the UFO spectral features are often weak due to high ionisation of the outflowing material, and the inference of the wind physical properties can be complicated by other spectral features in AGN such as relativistic reflection. Here we study a highly accreting Narrow Line Seyfert 1 galaxy PG 1448+273. We apply an automated, systematic routine for detecting outflows in accreting systems and achieve an unambiguous detection of a UFO in this AGN. The UFO absorption is observed in both soft and hard X-ray bands with the XMM-Newton observatory. The velocity of the outflow is (26900 +- 600) km/s (~0.09c), with an ionisation parameter of log ({\xi} / erg cm s^-1)=4.03_{-0.08}^{+0.10} and a column density above 10^23 cm^-2. At the same time, we detect weak warm absorption features in the spectrum of the object. Our systematic outflow search suggests the presence of further multi-phase wind structure, but we cannot claim a significant detection considering the present data quality. The UFO is not detected in a second, shorter observation with XMM-Newton, indicating variability in time, observed also in other similar AGN.Comment: Accepted for publication in MNRAS. 14 pages, 11 figures, 1 tabl

HST Survey of Clusters in Nearby Galaxies. II. Statistical Analysis of Cluster Populations

We present a statistical system that can be used in the study of cluster populations. The basis of our approach is the construction of synthetic cluster color-magnitude-radius diagrams (CMRDs), which we compare with the observed data using a maximum likelihood calculation. This approach permits a relatively easy incorporation of incompleteness (a function of not only magnitude and color, but also radius), photometry errors and biases, and a variety of other complex effects into the calculation, instead of the more common procedure of attempting to correct for those effects. We then apply this procedure to our NGC 3627 data from Paper I. We find that we are able to successfully model the observed CMRD and constrain a number of parameters of the cluster population. We measure a power law mass function slope of alpha = -1.50 +/- 0.07, and a distribution of core radii centered at r_c = 1.53 +/- 0.15 pc. Although the extinction distribution is less constrained, we measured a value for the mean extinction consistent with that determined in Paper I from the Cepheids.Comment: 21 pages, 3 figures accepted for publication by A

Was the GLE on May 17, 2012 linked with the M5.1-class flare the first in the 24th solar cycle?

On May 17, 2012 an M5.1-class flare exploded from the sun. An O-type coronal mass ejection (CME) was also associated with this flare. There was an instant increase in proton flux with peak at $\geq 100$ MeV, leading to S2 solar radiation storm level. In about 20 minutes after the X-ray emission, the solar particles reached the Earth.It was the source of the first (since December 2006) ground level enhancement (GLE) of the current solar cycle 24. The GLE was detected by neutron monitors (NM) and other ground based detectors. Here we present an observation by the Tupi muon telescopes (Niteroi, Brazil, $22^{0}.9 S$, $43^{0}.2 W$, 3 m above sea level) of the enhancement of muons at ground level associated with this M5.1-class solar flare. The Tupi telescopes registered a muon excess over background $\sim 20\%$ in the 5-min binning time profile. The Tupi signal is studied in correlation with data obtained by space-borne detectors (GOES, ACE), ground based neutron monitors (Oulu) and air shower detectors (the IceTop surface component of the IceCube neutrino observatory). We also report the observation of the muon signal possibly associated with the CME/sheath striking the Earth magnetosphere on May 20, 2012. We show that the observed temporal correlation of the muon excess observed by the Tupi muon telescopes with solar transient events suggests a real physical connection between them. Our observation indicates that combination of two factors, the low energy threshold of the Tupi muon telescopes and the location of the Tupi experiment in the South Atlantic Anomaly region, can be favorable in the study and detection of the solar transient events. Our experiment provides new data complementary to other techniques (space and ground based) in the study of solar physics.Comment: 9 pages, 10 figure

Evidence for entanglement at high temperatures in an engineered molecular magnet

The molecular compound [Fe$_{2}$($\mu_{2}$-oxo)(C$_{3}$H$_{4}$N$_{2}$)$_{6}$(C$_{2}$O$_{4}$)$_{2}$] was designed and synthesized for the first time and its structure was determined using single-crystal X-ray diffraction. The magnetic susceptibility of this compound was measured from 2 to 300 K. The analysis of the susceptibility data using protocols developed for other spin singlet ground-state systems indicates that the quantum entanglement would remain at temperatures up to 732 K, significantly above the highest entanglement temperature reported to date. The large gap between the ground state and the first-excited state (282 K) suggests that the spin system may be somewhat immune to decohering mechanisms. Our measurements strongly suggest that molecular magnets are promising candidate platforms for quantum information processing

Monitoring the phenolics compounds of the 2G ethanol process.

Made available in DSpace on 2018-01-24T22:13:42Z (GMT). No. of bitstreams: 1 PMonitoringthePhenolicsCompounds....pdf: 681535 bytes, checksum: 7ab63cb1e84bf72f8e2fd6ddd0ff40da (MD5) Previous issue date: 2018-01-23bitstream/item/171587/1/P-Monitoring-the-Phenolics-Compounds-....pd

Prevention of ventilator-associated pneumonia: guideline adherence and outcomes

Introduction: Ventilator-Associated Pneumonia (VAP) is one of the leading causes of morbidity and mortality in Intensive Care Units (ICU). VAP has a high incidence rate that can be reduced through the use of bundles, thus ensuring better outcomes. However, its effectiveness is closely related to implementation and dissemination strategies. Objectives: To assess adherence to a VAP prevention bundle; to assess the impact of adherence on outcomes (VAP, mortality rate, hospital length of stay (LOS), and duration of invasive ventilation (IV)). Methods: A quasi-experimental study was conducted, pre-and post-intervention, with historical control in three ICU over 6 months. The bundle was implemented and disseminated based on a multimodal approach, targeting physicians and nurses. The sample comprised patients hospitalized in the ICU aged≥18 years and submitted to endotracheal intubation for more than 48 h. Adherence to the bundle was assessed through auditing by observation. Outcome data were collected daily and entered into an intern database. Results were processed by the Statistical Package for the Social Sciences. The study was approved by the Ethics Committee and the hospital’s Board of Directors following the ethical principles for health research. Results: The sample comprised 828 patients aged between 18 and 95 years (M=61.85; SD=15.8 years). Increasing adherence to most of the recommendations over the course of the study was found, with two being statistically significant (p = 0.014), (p = 0.002). Also, adherence to all interventions simultaneously increased from 83.4% to 88.2% (p = 0.015). These results showed the effectiveness of a multimodal strategy approach. In addition, the statistical analysis confirmed that greater adherence to maintaining endotracheal tube cuff pressure was associated with shorter IV (p<0.001), ICU LOS (p<0.001) and lower mortality rate (p=0.002). On the other hand, results showed that greater adherence to all interventions simultaneously was directly related to fewer in ICU LOS (p=0.004) and fewer IV (p=0.016, p=0.005). Conclusion: From the data obtained on the association between adherence to each recommendation and health outcomes, this study provided a valuable contribution to better understanding the effectiveness of each intervention individually concerning VAP prevention.info:eu-repo/semantics/publishedVersio