462 research outputs found
Сутність та особливості стратегічного планування в інтересах забезпечення політичної безпеки
У статті розкрито сутність та особливості стратегічного планування в інтересах забезпечення політичної безпеки. З’ясовано, що ефективність державно-управлінських стратегій щодо адекватного реагування на виклики та загрози політичній безпеці значною мірою визначається якістю вказаного планування. Встановлено, що головна увага суб’єктів стратегічного планування в інтересах забезпечення політичної безпеки має бути зосереджена на забезпеченні якості результатів стратегічного аналізу. Вони обов’язково мають враховувати наслідки реалізації тих чи інших управлінських рішень у перспективі, суспільну підтримку, ресурсні можливості, вирішення завдань суспільно-політичного розвитку, планування та здійснення відповідних зовнішньополітичних акцій. Акцентовано увагу на важливості наукового супроводження стратегічного планування у сфері політичної безпеки
Resonant ion-pair formation in electron recombination with HF^+
The cross section for resonant ion-pair formation in the collision of
low-energy electrons with HF^+ is calculated by the solution of the
time-dependent Schrodinger equation with multiple coupled states using a wave
packet method. A diabatization procedure is proposed to obtain the electronic
couplings between quasidiabatic potentials of ^1Sigma^+ symmetry for HF. By
including these couplings between the neutral states, the cross section for
ion-pair formation increases with about two orders of magnitude compared with
the cross section for direct dissociation. Qualitative agreement with the
measured cross section is obtained. The oscillations in the calculated cross
section are analyzed. The cross section for ion-pair formation in electron
recombination with DF^+ is calculated to determine the effect of isotopic
substitution.Comment: 12 pages, 12 figure
X-ray speed reading: enabling fast, low noise readout for next-generation CCDs
Current, state-of-the-art CCDs are close to being able to deliver all key
performance figures for future strategic X-ray missions except for the required
frame rates. Our Stanford group is seeking to close this technology gap through
a multi-pronged approach of microelectronics, signal processing and novel
detector devices, developed in collaboration with the Massachusetts Institute
of Technology (MIT) and MIT Lincoln Laboratory (MIT-LL). Here we report results
from our (integrated) readout electronics development, digital signal
processing and novel SiSeRO (Single electron Sensitive Read Out) device
characterization.Comment: To appear in SPIE Proceeding of Astronomical Telescopes +
Instrumentation, 202
Observations of H3+ in the Diffuse Interstellar Medium
Surprisingly large column densities of H3+ have been detected using infrared
absorption spectroscopy in seven diffuse cloud sightlines (Cygnus OB2 12,
Cygnus OB2 5, HD 183143, HD 20041, WR 104, WR 118, and WR 121), demonstrating
that H3+ is ubiquitous in the diffuse interstellar medium. Using the standard
model of diffuse cloud chemistry, our H3+ column densities imply unreasonably
long path lengths (~1 kpc) and low densities (~3 cm^-3). Complimentary
millimeter-wave, infrared, and visible observations of related species suggest
that the chemical model is incorrect and that the number density of H3+ must be
increased by one to two orders of magnitude. Possible solutions include a
reduced electron fraction, an enhanced rate of H2 ionization, and/or a smaller
value of the H3+ dissociative recombination rate constant than implied by
laboratory experiments.Comment: To be published in Astrophysical Journal, March 200
Enhanced cosmic-ray flux toward zeta Persei inferred from laboratory study of H3+ - e- recombination rate
The H3+ molecular ion plays a fundamental role in interstellar chemistry, as
it initiates a network of chemical reactions that produce many interstellar
molecules. In dense clouds, the H3+ abundance is understood using a simple
chemical model, from which observations of H3+ yield valuable estimates of
cloud path length, density, and temperature. On the other hand, observations of
diffuse clouds have suggested that H3+ is considerably more abundant than
expected from the chemical models. However, diffuse cloud models have been
hampered by the uncertain values of three key parameters: the rate of H3+
destruction by electrons, the electron fraction, and the cosmic-ray ionisation
rate. Here we report a direct experimental measurement of the H3+ destruction
rate under nearly interstellar conditions. We also report the observation of
H3+ in a diffuse cloud (towards zeta Persei) where the electron fraction is
already known. Taken together, these results allow us to derive the value of
the third uncertain model parameter: we find that the cosmic-ray ionisation
rate in this sightline is forty times faster than previously assumed. If such a
high cosmic-ray flux is indeed ubiquitous in diffuse clouds, the discrepancy
between chemical models and the previous observations of H3+ can be resolved.Comment: 6 pages, Nature, in pres
Overview of the use of the PCI bus in present and future high energy physics data acquisition systems
Foliations of Isonergy Surfaces and Singularities of Curves
It is well known that changes in the Liouville foliations of the isoenergy
surfaces of an integrable system imply that the bifurcation set has
singularities at the corresponding energy level. We formulate certain
genericity assumptions for two degrees of freedom integrable systems and we
prove the opposite statement: the essential critical points of the bifurcation
set appear only if the Liouville foliations of the isoenergy surfaces change at
the corresponding energy levels. Along the proof, we give full classification
of the structure of the isoenergy surfaces near the critical set under our
genericity assumptions and we give their complete list using Fomenko graphs.
This may be viewed as a step towards completing the Smale program for relating
the energy surfaces foliation structure to singularities of the momentum
mappings for non-degenerate integrable two degrees of freedom systems.Comment: 30 pages, 19 figure
Single electron Sensitive Readout (SiSeRO) X-ray detectors: Technological progress and characterization
Single electron Sensitive Read Out (SiSeRO) is a novel on-chip charge
detector output stage for charge-coupled device (CCD) image sensors. Developed
at MIT Lincoln Laboratory, this technology uses a p-MOSFET transistor with a
depleted internal gate beneath the transistor channel. The transistor
source-drain current is modulated by the transfer of charge into the internal
gate. At Stanford, we have developed a readout module based on the drain
current of the on-chip transistor to characterize the device. Characterization
was performed for a number of prototype sensors with different device
architectures, e.g. location of the internal gate, MOSFET polysilicon gate
structure, and location of the trough in the internal gate with respect to the
source and drain of the MOSFET (the trough is introduced to confine the charge
in the internal gate). Using a buried-channel SiSeRO, we have achieved a
charge/current conversion gain of >700 pA per electron, an equivalent noise
charge (ENC) of around 6 electrons root mean square (RMS), and a full width
half maximum (FWHM) of approximately 140 eV at 5.9 keV at a readout speed of
625 Kpixel/s. In this paper, we discuss the SiSeRO working principle, the
readout module developed at Stanford, and the characterization test results of
the SiSeRO prototypes. We also discuss the potential to implement Repetitive
Non-Destructive Readout (RNDR) with these devices and the preliminary results
which can in principle yield sub-electron ENC performance. Additional
measurements and detailed device simulations will be essential to mature the
SiSeRO technology. However, this new device class presents an exciting
technology for next generation astronomical X-ray telescopes requiring fast,
low-noise, radiation hard megapixel imagers with moderate spectroscopic
resolution.Comment: To appear in SPIE Proceedings of Astronomical Telescopes +
Instrumentation, 202
The Use of Fecal Calprotectin Testing in Paediatric Disorders : A Position Paper of the European Society for Paediatric Gastroenterology and Nutrition Gastroenterology Committee
Objectives: The aim of the study was to review the evidence regarding the clinical use and value of fecal calprotectin (FC) measurements in different gastrointestinal disorders in children. Methods: A literature search was conducted in the PubMed, MEDLINE, EMBASE, and Cochrane databases until October 31, 2019. Subtopics were identified and each assigned to individual authors. Results: A total of 28 recommendations were voted on using the nominal voting technique. Recommendations are given related to sampling, measurement methods, and results interpretation. The 14 authors anonymously voted on each recommendation using a 9-point scale (1 strongly disagree to 9 fully agree). Consensus was considered achieved if at least 75% of the authors voted 6, 7, 8, or 9. Conclusions: Consensus was reached for all recommendations. Limitations for the use of FC in clinical practice include variability in extraction methodology, performance of test kits as well as the need to establish local reference ranges because of the influence of individual factors, such as age, diet, microbiota, and drugs. The main utility of FC measurement at present is in the diagnosis and monitoring of inflammatory bowel disease (IBD) as well as to differentiate it from functional gastrointestinal disorders (FAPDs). FC, however, has neither utility in the diagnosis of infantile colic nor to differentiate between functional and organic constipation. A rise in FC concentration, may alert to the risk of developing necrotizing enterocolitis and help identifying gastrointestinal involvement in children with Henoch-Schonlein purpura. FC measurement is of little value in Cow's Milk Protein Allergy, coeliac disease (CD), and cystic fibrosis. FC does neither help to distinguish bacterial from viral acute gastroenteritis (AGE), nor to diagnose Helicobacter Pylori infection, small intestinal bacterial overgrowth (SIBO), acute appendicitis (AA), or intestinal polyps.Peer reviewe
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