Numerical investigation of the Ostrogradsky number effect on natural convection and thermal radiation in an enclosure

Unsteady natural convection combined with surface thermal radiation in closed cavity with a local heat-generating source has been investigated. The heat source of triangular shape of internal volumetric heat generation is located on the bottom wall. The vertical side walls are supposed to be isothermal and cooled. The governing equations of conservation of momentum, mass and energy, described the fluid flow and heat transfer have been represented by dimensionless variable "stream function - vorticity - temperature". The effects of the heat source power and emissivity factor on fluid flow and heat transfer within the cavity have been analyzed. Streamlines and isotherms as well as fluid flow rate, the local Nusselt numbers, average convective and radiative Nusselt numbers have been obtained

Attention toward interpersonal stimuli in individuals with and without chronic daily headache

Attentional capture of threat is a normal and adaptive process, although facilitated processing of mildly threatening stimuli irrelevant to current goals may result in attentional interference and compromised performance. In the field of chronic pain, attentional biases towards pain-related information have been commonly found. Pain is inexorably connected with emotion however, and a transdiagnostic approach elucidating similar mechanisms underlying pain and mood disorders has been advocated. One such mechanism may be repetitive thinking on negative themes, including worry and rumination. Attentional biases for threatening (e.g., angry faces) and negative (e.g., sad faces) information have been observed in anxious and depressed populations, although to date it has not been fully established whether biases for such information are heightened in individuals with chronic pain relative to healthy individuals. In this study, attentional biases for angry, sad and also happy facial expressions, at 500 and 1250 ms presentation times, were assessed via visual-probe task in chronic daily headache (n = 20) and healthy control (n = 26) groups. Results showed participants to demonstrate significant bias towards angry and sad expressions at 500 and 1250 ms, and happy expressions at 1250 ms. No significant differences in attentional bias were found between chronic daily headache and healthy control groups. These results suggest that attentional biases towards interpersonal threat are not specifically heightened in individuals with chronic daily headache. While similar mechanisms such as rumination may underlie biases in different disorders, this does not translate to heightened biases for the same specific content

Ultrafast Dynamics of Carrier Multiplication in Quantum Dots

A quantum-kinetic approach to the ultrafast dynamics of carrier multiplication in semiconductor quantum dots is presented. We investigate the underlying dynamics in the electronic subband occupations and the time-resolved optical emission spectrum, focusing on the interplay between the light-matter and the Coulomb interaction. We find a transition between qualitatively differing behaviors of carrier multiplication, which is controlled by the ratio of the interaction induced time scale and the pulse duration of the exciting light pulse. On short time scales, i.e., before intra-band relaxation, this opens the possibility of detecting carrier multiplication without refering to measurements of (multi-)exciton lifetimes.Comment: 12 pages, 7 figures, submitte

Анализ отечественного и зарубежного опыта в разработке инновационной стратегии

The purpose of this study was to investigate if functional activity with spinal cord somatosensory stimulation can be visualized using BOLD fMRI. We investigated nine healthy volunteers using a somatosensory stimulus generator. The stimuli were applied in three different runs at the first, third, and fifth finger tip of the right hand, respectively, corresponding to dermatomes c6, c7, and c8. The stimuli gave an increase of BOLD signal (activation) in three different locations of the spinal cord and brain stem. First, activations could be seen in the spinal segment corresponding to the stimulated dermatome in seven out of nine volunteers for c6 stimulation, two out of eight for c7, and three out of eight for c8. These activations were located close to the posterior margin of the spinal cord, presumably reflecting synaptic transmission to dorsal horn interneurons. Second, activation in the medulla oblongata was evident in four subjects, most likely corresponding to the location of the nucleus cuneatus. The third location of activation, which was the strongest and most reliable observed was inside the spinal cord in the c3 and c4 segments. Activation at these spinal levels was almost invariably observed independently of the dermatome stimulated (9/9 for c6, 8/8 for c7, and 7/8 for c8 stimulation). These activations may pertain to an interneuronal system at this spinal level. The results are discussed in relation to neurophysiological studies on cervical spinal interneuronal pathways in animals and humans

Антиоксиданты в яблочном соке

We examined to what degree the visualization of anatomic structures in the human knee is improved using 3.0-T magnetic resonance imaging (MRI) and many element RF receive coils as compared to 1.5 T. We imaged 20 knees at 1.5 and 3.0 T using T2-weighted STIR, T2-weighted gradient echo, T1-weighted spin-echo, true-FISP and T2-weighted fast spin echo techniques in conjunction with 32-element RF coil arrays. The 3.0-T examination was considerably faster than its 1.5-T counterpart. A superior subjective visibility at 3.0 T vs 1.5 T was found in 27 of 50 evaluated structures (meniscus, ligaments) with the exception of true-FISP techniques. The 3.0-T examination provided a better visibility (evaluated by blinded consensus-reading by two radiologists) of small structures such as the ligamentum transversum genu. Also, cartilage was better delineated at 3.0 T. A 23% increased average signal-to-noise ratio as assessed using a temporal filter was observed at 3.0 T as compared to 1.5 T. At 3.0 T, imaging of the human knee is faster and results in a subjective visibility of anatomic structures that is superior to and competitive with 1.5 T

Measurement of polarization-transfer to bound protons in carbon and its virtuality dependence

We measured the ratio $P_{x}/P_{z}$ of the transverse to longitudinal components of polarization transferred from electrons to bound protons in $^{12}\mathrm{C}$ by the $^{12}\mathrm{C}(\vec{e},e'\vec{p})$ process at the Mainz Microtron (MAMI). We observed consistent deviations from unity of this ratio normalized to the free-proton ratio, $(P_{x}/P_{z})_{^{12}\mathrm{C}}/(P_{x}/P_{z})_{^{1}\mathrm{H}}$, for both $s$- and $p$-shell knocked out protons, even though they are embedded in averaged local densities that differ by about a factor of two. The dependence of the double ratio on proton virtuality is similar to the one for knocked out protons from $^{2}\mathrm{H}$ and $^{4}\mathrm{He}$, suggesting a universal behavior. It further implies no dependence on average local nuclear density