7,762 research outputs found
Discrete breathers in polyethylene chain
The existence of discrete breathers (DBs), or intrinsic localized modes
(localized periodic oscillations of transzigzag) is shown. In the localization
region periodic contraction-extension of valence C-C bonds occurs which is
accompanied by decrease-increase of valence angles. It is shown that the
breathers present in thermalized chain and their contribution dependent on
temperature has been revealed.Comment: 5 pages, 6 figure
Elliptic operators in even subspaces
In the paper we consider the theory of elliptic operators acting in subspaces
defined by pseudodifferential projections. This theory on closed manifolds is
connected with the theory of boundary value problems for operators violating
Atiyah-Bott condition. We prove an index formula for elliptic operators in
subspaces defined by even projections on odd-dimensional manifolds and for
boundary value problems, generalizing the classical result of Atiyah-Bott.
Besides a topological contribution of Atiyah-Singer type, the index formulas
contain an invariant of subspaces defined by even projections. This homotopy
invariant can be expressed in terms of the eta-invariant. The results also shed
new light on P.Gilkey's work on eta-invariants of even-order operators.Comment: 39 pages, 2 figure
Hemoperfusive Removal of Specific Intoxicants: The Role of the Rabbit in Preclinical Trials
Fjemelse af specifikke giftsloffer ved hemoperfusion Haemoperfusion er den foretrukne metode til direkte detoksifikation af patienter med akutte forgiftninger. Som adsorbant anvendes saedvanligvis kul. Den nyeste forskning indenfor dette omrade beskmftiger Sig med udvikling af specifikke adsorbanter til fjernelse at specitikke antistoffer, immunkomplekser 0g giftstoffer. Der gives en beskrivelse af en dyreeksperimentel model til udvikling af specifik detoksifikation ved anvendelse af haemoperfusion. Som forsagsdyr anvendes kaniner med permanente katetre i v. jugularis og a. carotis. Haemoperfusionssystemet bestfir af en peristaltisk pumpe og en stajle med agaroseperler (0.5—1.0 mm i diameter) indeholdende tusinder af mikrosphaerer (0.2 p. i diameter) koblet til specifikke antigener. Det arterielle blod pumpes fra a. carotis gennem sajlen til V. jugularis. Systemet perfunderes med hepariniseret saltvand (1 enh/ml) far brug, og kaninen hepariniseres med 300 enh heparin pr. kg legemsvaegt. Perfusionshastigheden er 8—15 ml/min, svarende til en perfusionshastighed p5. 20—30 min. I fig. 5 og 6 Vises resultaterne af forsog pa fjernelse af kviksolv og anti bovint serum albumin
Asymptotic normalization coefficients of alpha-particle removal from O()
Asymptotic normalization coefficients (ANC) determine the overall
normalization of cross sections of peripheral radiative capture reactions. In a
recent paper [Blokhintsev et al., Eur. Phys. J. A 58, 257 (2022)], we
considered the ANC for the virtual decay O MeV)C(g.s.). In the present paper, which can be regarded as a
continuation of the previous, we treat the ANCs for the vertices
OC(g.s.) corresponding to the other three bound
excited states of O (, , , ). ANCs
() are found by analytic continuation in energy of the
C -wave partial scattering amplitudes, known from the
phase-shift analysis of experimental data, to the pole corresponding to the
O bound state and lying in the unphysical region of negative energies.
To determine , the scattering data are approximated by the sum of
polynomials in energy in the physical region and then extrapolated to the pole.
For a more reliable determination of the ANCs, various forms of functions
expressed in terms of phase shifts were used in analytical approximation and
subsequent extrapolation.Comment: arXiv admin note: substantial text overlap with arXiv:2208.0958
On the nonlinear dynamics of topological solitons in DNA
Dynamics of topological solitons describing open states in the DNA double
helix are studied in the frameworks of the model which takes into account
asymmetry of the helix. It is shown that three types of topological solitons
can occur in the DNA double chain. Interaction between the solitons, their
interactions with the chain inhomogeneities and stability of the solitons with
respect to thermal oscillations are investigated.Comment: 16 pages, 16 figure
Cryogenic micro-calorimeters for mass spectrometric identification of neutral molecules and molecular fragments
We have systematically investigated the energy resolution of a magnetic
micro-calorimeter (MMC) for atomic and molecular projectiles at impact energies
ranging from to 150 keV. For atoms we obtained absolute energy
resolutions down to eV and relative energy resolutions
down to . We also studied in detail the MMC
energy-response function to molecular projectiles of up to mass 56 u. We have
demonstrated the capability of identifying neutral fragmentation products of
these molecules by calorimetric mass spectrometry. We have modeled the MMC
energy-response function for molecular projectiles and conclude that
backscattering is the dominant source of the energy spread at the impact
energies investigated. We have successfully demonstrated the use of a detector
absorber coating to suppress such spreads. We briefly outline the use of MMC
detectors in experiments on gas-phase collision reactions with neutral
products. Our findings are of general interest for mass spectrometric
techniques, particularly for those desiring to make neutral-particle mass
measurements
Hemodynamic and ADH responses to central blood volume shifts in cardiac-denervated humans
Hemodynamic responses and antidiuretic hormone (ADH) were measured during body position changes designed to induce blood volume shifts in ten cardiac transplant recipients to assess the contribution of cardiac and vascular volume receptors in the control of ADH secretion. Each subject underwent 15 min of a control period in the seated posture, then assumed a lying posture for 30 min at 6 deg head down tilt (HDT) followed by 20 min of seated recovery. Venous blood samples and cardiac dimensions (echocardiography) were taken at 0 and 15 min before HDT, 5, 15, and 30 min of HDT, and 5, 15, and 30 min of seated recovery. Blood samples were analyzed for hematocrit, plasma osmolality, plasma renin activity (PRA), and ADH. Resting plasma volume (PV) was measured by Evans blue dye and percent changes in PV during posture changes were calculated from changes in hematocrit. Heart rate (HR) and blood pressure (BP) were recorded every 2 min. Results indicate that cardiac volume receptors are not the only mechanism for the control of ADH release during acute blood volume shifts in man
Learning at the Interstices; Locating Practical Philosophies for Understanding Physical/virtual Inter-spaces
Virtual worlds are relatively recent developments, and so it is tempting to believe that they need to be understood through newly developed theories and philosophies. However, humans have long thought about the nature of reality and what it means to be “real.” This paper examines the three persistent philosophical concepts of Metaxis, Liminality and Space that have evolved across more than 2000 years of meditation, contemplation and reflection. Our particular focus here is on the nature of the interface between the virtual and the physical: at the interstices, and how the nature of transactions and transitions across those interfaces may impact upon learning. This may, at first, appear to be an esoteric pursuit, but we ground our arguments in primary and secondary data from research studies in higher education
ИНТЕГРАЦИЯ НАУКИ, ОБРАЗОВАНИЯ И БИЗНЕСА – НОВАЯ ПАРАДИГМА БИЗНЕС-ОБРАЗОВАНИЯ
Improving the quality of (professional) labor force is given at the present time the whole progressive world of business education. The concept of creating a business of universities that can provide a completely new quality of training, reaching the learning process all the necessary highlyskilled specialist skills and knowledge through the integration of science, education and business.Повышение качества (профессионализма) трудовых ресурсов страны в настоящее время во всем прогрессивном мире зависит от бизнес-образования. Предлагается концепция создания бизнес-университетов, способных обеспечить совершенно новое качество профессиональной подготовки кадров, достигающих в процессе обучения всех необходимых для высококвалифицированного специалиста компетенций и знаний на основе интеграции науки, образования и бизнеса
- …