Gaussian block algorithms for solving path problems

Path problems are a family of optimization and enumeration problems that reduce to determination or evaluation of paths in a directed graph. In this paper we give a convenient algebraic description of block algorithms for solving path problems. We also develop block versions of two Gaussian algorithms, which are counterparts of the conventional Jordan and escalator method respectively. The correctness of the two considered block algorithms is discussed, and their complexity is analyzed. A parallel implementation of the block Jordan algorithm on a transputer network is presented, and the obtained experimental results are listed

Holographic neural networks

Holographic neural networks are a new and promising type of artificial neural networks. This article gives an overview of the holographic neural technology and its possibilities. The theoretical principles of holographic networks are first reviewed. Then, some other papers are presented, where holographic networks have been applied or experimentally evaluated. A case study dealing with currency exchange rate prediction is described in more detail

Angular Motion of the Spin Axis of the Tiros 1 Meteorological Satellite due to Magnetic and Gravitational Torques

No abstract availabl

Neurospora crassa qa-2 gene fragment.

Neurospora crassa qa-2 gene fragment

COVID-19 revisiting inflammatory pathways of arthritis

Coronavirus disease 2019 (COVID-19) is an infectious disease, caused by severe acute respiratory syndrome coronavirus 2, which predominantly affects the lungs and, under certain circumstances, leads to an excessive or uncontrolled immune activation and cytokine response in alveolar structures. The pattern of pro-inflammatory cytokines induced in COVID-19 has similarities to those targeted in the treatment of rheumatoid arthritis. Several clinical studies are underway that test the effects of inhibiting IL-6, IL-1\u3b2 or TNF or targeting cytokine signalling via Janus kinase inhibition in the treatment of COVID-19. Despite these similarities, COVID-19 and other zoonotic coronavirus-mediated diseases do not induce clinical arthritis, suggesting that a local inflammatory niche develops in alveolar structures and drives the disease process. COVID-19 constitutes a challenge for patients with inflammatory arthritis for several reasons, in particular, the safety of immune interventions during the pandemic. Preliminary data, however, do not suggest that patients with inflammatory arthritis are at increased risk of COVID-19

Sociality Affects REM Sleep Episode Duration Under Controlled Laboratory Conditions in the Rock Hyrax, Procavia capensis.

The rock hyrax, Procavia capensis, is a highly social, diurnal mammal. In the current study several physiologically measurable parameters of sleep, as well as the accompanying behavior, were recorded continuously from five rock hyraxes, for 72 h under solitary (experimental animal alone in the recording chamber), and social conditions (experimental animal with 1 or 2 additional, non-implanted animals in the recording chamber). The results revealed no significant differences between solitary and social conditions for total sleep times, number of episodes, episode duration or slow wave activity (SWA) for all states examined. The only significant difference observed between social and solitary conditions was the average duration of rapid eye movement (REM) sleep episodes. REM sleep episode duration was on average 20 s and 40 s longer under social conditions daily and during the dark period, respectively. It is hypothesized that the increase in REM sleep episode duration under social conditions could possibly be attributed to improved thermoregulation strategies, however considering the limited sample size and design of the current study further investigations are needed to confirm this finding. Whether the conclusions and the observations made in this study can be generalized to all naturally socially sleeping mammals remains an open question

Synthetic Studies in the Chloramphenicol Series. III. Synthesis of threo-DL-Chloramphenicol from DL-Serine Ethyl Ether

A synthesis of threo-DL-chloramphenicol (I) from a-phthalimido-~-ethoxy-DL-propiophenone (II) is described. The crude ketone II obtained from a-phthalimido-~-ethoxy-DL-propionyl chloride via Friedel-Crafts reaction was reduced with aluminium isopropoxide to give a yield of 17.2 % of the corresponding carbinol III. This carbinol gave in a series of reactions threo -DL-chloramphenicol in an overall yield of 2.4 %