23 research outputs found
Metallic water: transient state under ultrafast electronic excitation
The modern means of controlled irradiation by femtosecond lasers or swift
heavy ion beams can transiently produce such energy densities in samples that
reach collective electronic excitation levels of the warm dense matter state
where the potential energy of interaction of the particles is comparable to
their kinetic energies (temperatures of a few eV). Such massive electronic
excitation severely alters the interatomic potentials, producing unusual
nonequilibrium states of matter and different chemistry. We employ density
functional theory and tight binding molecular dynamics formalisms to study the
response of bulk water to ultrafast excitation of its electrons. After a
certain threshold electronic temperature, the water becomes electronically
conducting via the collapse of its band gap. At high doses, it is accompanied
by nonthermal acceleration of ions to a temperature of a few thousand Kelvins
within sub-100 fs timescales. We identify the interplay of this nonthermal
mechanism with the electron-ion coupling, enhancing the electron-to-ions energy
transfer. Various chemically active fragments are formed from the
disintegrating water molecules, depending on the deposited dose.Comment: to be submitte
The H2O southern Galactic Plane Survey(HOPS): NH3 (1,1) and (2,2) catalogues
The H2O Southern Galactic Plane Survey (HOPS) has mapped a 100 degree strip
of the Galactic plane (-70deg > l > 30deg, |b| < 0.5deg) using the 22-m Mopra
antenna at 12-mm wavelengths. Observations were conducted in on-the-fly mode
using the Mopra spectrometer (MOPS), targeting water masers, thermal molecular
emission and radio-recombination lines. Foremost among the thermal lines are
the 23 GHz transitions of NH3 J,K = (1,1) and (2,2), which trace the densest
parts of molecular clouds (n > 10^4 cm^{-3}). In this paper we present the NH3
(1,1) and (2,2) data, which have a resolution of 2 arcmin and cover a velocity
range of +/-200 km/s. The median sensitivity of the NH3 data-cubes is sigma_Tmb
= 0.20 +/1 0.06 K. For the (1,1) transition this sensitivity equates to a 3.2
kpc distance limit for detecting a 20 K, 400 Msun cloud at the 5-sigma level.
Similar clouds of mass 5,000 Msun would be detected as far as the Galactic
centre, while 30,000 Msun clouds would be seen across the Galaxy. We have
developed an automatic emission finding procedure based on the ATNF DUCHAMP
software and have used it to create a new catalogue of 669 dense molecular
clouds. The catalogue is 100 percent complete at the 5-sigma detection limit
(Tmb = 1.0 K). A preliminary analysis of the ensemble cloud properties suggest
that the near kinematic distances are favoured. The cloud positions are
consistent with current models of the Galaxy containing a long bar. Combined
with other Galactic plane surveys this new molecular-line dataset constitutes a
key tool for examining Galactic structure and evolution. Data-cubes, spectra
and catalogues are available to the community via the HOPS website.Comment: 22 pages, 19 figures. Accepted for publication in MNRAS
(25-July-2012
Omecamtiv mecarbil in chronic heart failure with reduced ejection fraction, GALACTICâHF: baseline characteristics and comparison with contemporary clinical trials
Aims:
The safety and efficacy of the novel selective cardiac myosin activator, omecamtiv mecarbil, in patients with heart failure with reduced ejection fraction (HFrEF) is tested in the Global Approach to Lowering Adverse Cardiac outcomes Through Improving Contractility in Heart Failure (GALACTICâHF) trial. Here we describe the baseline characteristics of participants in GALACTICâHF and how these compare with other contemporary trials.
Methods and Results:
Adults with established HFrEF, New York Heart Association functional class (NYHA)ââ„âII, EF â€35%, elevated natriuretic peptides and either current hospitalization for HF or history of hospitalization/ emergency department visit for HF within a year were randomized to either placebo or omecamtiv mecarbil (pharmacokineticâguided dosing: 25, 37.5 or 50âmg bid). 8256 patients [male (79%), nonâwhite (22%), mean age 65âyears] were enrolled with a mean EF 27%, ischemic etiology in 54%, NYHA II 53% and III/IV 47%, and median NTâproBNP 1971âpg/mL. HF therapies at baseline were among the most effectively employed in contemporary HF trials. GALACTICâHF randomized patients representative of recent HF registries and trials with substantial numbers of patients also having characteristics understudied in previous trials including more from North America (n = 1386), enrolled as inpatients (n = 2084), systolic blood pressureâ<â100âmmHg (n = 1127), estimated glomerular filtration rate <â30âmL/min/1.73 m2 (n = 528), and treated with sacubitrilâvalsartan at baseline (n = 1594).
Conclusions:
GALACTICâHF enrolled a wellâtreated, highârisk population from both inpatient and outpatient settings, which will provide a definitive evaluation of the efficacy and safety of this novel therapy, as well as informing its potential future implementation
Structure of realised risks of projects for construction nuclear power plant by Rosatom State Corporation in 2010-2020
Rosatom State Corporation is one of the world leaders in the construction of nuclear power plant (NPP), keeping a ten-year portfolio of foreign orders at the level of 140 billion $. Taking into account the long period of construction nuclear power plant, significant amount of capital investment, significant number of participants investment-construction project, critically important for constructer organizer to identify and consider possible risks of project implementation in time, developing and improving its management mechanisms. As a part of research risk analysis and systematization was performed, realized in the construction of nuclear power plants by domestic specialist in 2008-2020 (Novovoronezh NPP-2, Rostov NPP, Kursk NPP-2, Belarussian NPP, NPP Kudankulm, NPP El-Dabaa, NPP Akkuyu, NPP Rooppur, NPP Paksh-2). Based on the analysis formed 8 risk families, determined shares of these groups in general registry. The revealed structure of realized risks demonstrates, that the largest share in general registry is made up of technical and organizational risks, which are systematically given insufficient attention by researches and construction organizers. Conducted research also allows us to draw a conclusion about the most common risk concerning late detection of complex conditions of the object placement site, which was implemented in five projects out of nine considered. The results of the accomplished research can be used in the development of modern nuclear power plant construction projects in Russia and abroad, which will have a positive impact on the competitiveness of domestic projects in the global nuclear power plant market and increase their profitability. The experience of nuclear power in terms of risk management can become a driver for full-scale improvement of organizational and technological approaches in the construction of unique buildings and structures in the future
Modeling Time-Resolved Kinetics in Solids Induced by Extreme Electronic Excitation
The authors present a concurrent Monte Carlo (MC)âmolecular dynamics (MD) approach to modeling matter response to excitation of its electronic system at nanometric scales. The two methods are combined on-the-fly at each time step in one code, TREKIS-4. The MC model describes the arrival of irradiation (a photon, an electron, or a fast ion). It traces induced cascades of secondary electrons and holes, and their energy exchange with atoms due to scattering. The excited atomic system is simulated with an MD model. An efficient way is proposed to account for nonthermal effects in the electron-atom energy transfer in covalent materials via the conversion of the potential energy of the electronic ensemble into the kinetic energy of atoms. Such a combined MCâMD approach enables a time-resolved tracing of the excitation kinetics of both, the electronic and atomic systems, and their simultaneous response to a deposited dose. As a proof-of-principle, it is shown that the proposed method describes atomic dynamics after X-ray irradiation in good agreement with tight-binding MD. The model also allows gaining insights into the atomic system behavior during the energy deposition from a nonequilibrium electronic system excited by an ion impact
Reaction of bis(trimethylsilyl) sulfate with hydrogen halides and with phosphorus and sulfur halides and oxyhalides
The 6-GHz methanol multibeam maser catalogue â II. Galactic longitudes 6° to 20°
The definitive version is available at: http://onlinelibrary.wiley.com Copyright Royal Astronomical Society.We present the second portion of an unbiased survey of the Galactic plane for 6668-MHz methanol masers. This section of the survey spans the longitude range 6° to 20°. We report the detection of 119 maser sources, of which 42 are new discoveries. The masers are tightly constrained to the Galactic plane, with only four outside a latitude range of ±1°. This longitude region includes the brightest known 6668-MHz methanol maser, 9.621+0.196, as well as the two brightest newly discovered sources in the southern survey as a whole. We list all the sources associated with the 3-kpc arms within ±15° longitude and consider further candidates beyond 15° longitude. We identify three new sources associated with the Galactic bar and comment on the density of masers in relation to the bar orientation.Peer reviewe