Scalar products of spinors and an extension of Brauer-Wall groups

1981 ◽  
Vol 11 (9-10) ◽  
pp. 721-740 ◽  
Author(s):  
Pertti Lounesto
Keyword(s):  
Scalar Products ◽  
Wall Groups

scholarly journals Aspirin treatment prevents inflammation in experimental bifurcation aneurysms in New Zealand White rabbits

2021 ◽  
pp. neurintsurg-2020-017261
Author(s):  
Stefan Wanderer ◽  
Basil Erwin Grüter ◽  
Fabio Strange ◽  
Gwendoline Boillat ◽  
Sivani Sivanrupan ◽  
...  
Keyword(s):  
New Zealand ◽  
Clinical Situation ◽  
Fluorescence Angiography ◽  
Preventive Effect ◽  
Aneurysm Formation ◽  
Aneurysm Wall ◽  
New Zealand White Rabbits ◽  
Aneurysm Thrombosis ◽  
Wall Groups

BackgroundAneurysm wall degeneration is linked to growth and rupture. To address the effect of aspirin (ASA) on aneurysm formation under various wall conditions, this issue was analyzed in a novel rabbit bifurcation model.MethodsBifurcation aneurysms created in 45 New Zealand White rabbits were randomized to vital (n=15), decellularized (n=13), or elastase-degraded (n=17) wall groups; each group was assigned to a study arm with or without ASA. At follow-up 28 days later, aneurysms were evaluated for patency, growth, and wall inflammation at macroscopic and histological levels.Results36 rabbits survived to follow-up at the end of the trial. None of the aneurysms had ruptured. Patency was visualized in all aneurysms by intraoperative fluorescence angiography and confirmed in 33 (92%) of 36 aneurysms by MRI/MRA. Aneurysm size was significantly increased in the vital (without ASA) and elastase-degraded (with and without ASA) groups. Aneurysm thrombosis was considered complete in three (50%) of six decellularized aneurysms without ASA by MRI/MRA. Locoregional inflammation of the aneurysm complex was significantly reduced in histological analysis among all groups treated with ASA.ConclusionASA intake prevented inflammation of both the periadventitial tissue and aneurysm wall, irrespective of initial wall condition. Although ASA prevented significant growth in aneurysms with vital walls, this preventive effect did not have an important role in elastase-degraded pouches. In possible translation to the clinical situation, ASA might exert a potential preventive effect during early phases of aneurysm formation in patients with healthy vessels but not in those with highly degenerative aneurysm walls.

Features of determining the deformed state of a particle material during hot stamping of porous moldings

2021 ◽  
pp. 21-30
Author(s):  
B. G. Gasanov ◽  
A. A. Aganov ◽  
P. V. Sirotin
Keyword(s):  
Displacement Vector ◽  
Hot Stamping ◽  
Strain Tensor ◽  
Particle Material ◽  
Software Algorithms ◽  
Deformed State ◽  
Metal Strain ◽  
Scalar Products ◽  
Analytical Expressions ◽  
Kinetics Of

The paper describes main methods for assessing the deformed state of porous body metal frames developed by different authors based on the analysis of yield conditions and governing equations, using the principle of equivalent strains and stresses, and studying the kinetics of metal strain during pressing. Formulas were derived to determine the components of the powder particle material strain tensor through dyads, as scalar products of the basis vectors of the convected coordinate system at each moment of porous molding strain. The expediency of using the analytical expressions developed to determine the deformed state of the particle material was experimentally substantiated subject to the known displacement vector parameters of representative elements (macrostrains) of porous billets. The applications of well-known analytical expressions were established, and the proposed formulas proved applicable for the deformed state assessment of particle metal during the pressure processing of powder products of different configurations and designing billets with a defined porosity and geometric parameters as a basis for compiling software algorithms for the computer simulation of porous molding hot stamping.

Sunbeam vectors and scalar products

1997 ◽  
Vol 35 (5) ◽  
pp. 310-311
Author(s):  
Ernest Zebrowski
Keyword(s):  
Scalar Products

A WAVE APPROACH TO PATTERN RECOGNITION (WITH APPLICATION TO OPTICAL CHARACTER RECOGNITION)

1994 ◽  
Vol 04 (01) ◽  
pp. 193-207 ◽  
Author(s):  
VADIM BIKTASHEV ◽  
VALENTIN KRINSKY ◽  
HERMANN HAKEN
Keyword(s):  
Pattern Recognition ◽  
Character Recognition ◽  
Optical Character Recognition ◽  
Dissipative Structures ◽  
Binary Images ◽  
Optical Character ◽  
Nonlinear Version ◽  
Medium Quality ◽  
Scalar Products ◽  
Machine Reading

The possibility of using nonlinear media as a highly parallel computation tool is discussed, specifically for image classification and recognition. Some approaches of this type are known, that are based on stationary dissipative structures which can “measure” scalar products of images. In this paper, we exploit the analogy between binary images and point sets, and use the Hausdorff metrics for comparing the images. It does not require the measure at all, and is based only on the metrics of the space whose subsets we consider. In addition to Hausdorff distance, we suggest a new “nonlinear” version of this distance for comparison of images, called “autowave” distance. This distance can be calculated very easily and yields some additional advantages for pattern recognition (e.g. noise tolerance). The method was illustrated for the problem of machine reading (Optical Character Recognition). It was compared with some famous OCR programs for PC. On a medium quality xerocopy of a journal page, in the same conditions of learning and recognition, the autowave approach resulted in much fewer mistakes. The method can be realized using only one chip with simple uniform connection of the elements. In this case, it yields an increase in computation speed of several orders of magnitude.

scholarly journals Is fibroid location associated with hemorrhage and complication rates following laparoscopic myomectomy?

2020 ◽  
Author(s):  
Kiper Aslan ◽  
Adnan Orhan ◽  
Engin Turkgeldi ◽  
Ebru Suer ◽  
Nergis Duzok ◽  
...  
Keyword(s):  
Posterior Wall ◽  
Anterior Wall ◽  
Uterine Wall ◽  
Laparoscopic Myomectomy ◽  
Complication Rates ◽  
Analgesic Requirement ◽  
Hospitalization Period ◽  
Before And After ◽  
Wall Groups ◽  
Type 3

Abstract Objective To determine whether hemorrhage and complication rates vary according location of the dominant fibroid following laparoscopic myomectomy. Background Laparoscopic myomectomy is associated with less postoperative pain, analgesic requirement, shorter hospitalization period, and less febrile complications when compared to conventional laparotomy. Despite the advantages, complications like hemorrhage, blood transfusion, bowel and urinary tract injury and conversion to laparotomy may be seen in laparoscopic myomectomy. We don’t know whether fibroid location effect these complications. Materials & Methods Women, who underwent laparoscopic myomectomy at two different tertiary academic hospitals, were analyzed retrospectively. Only women with at least one intramural fibroid (Monroe type 3, 4 or 5) were included. Patients were categorized according to localization of the dominant fibroid, i.e. anterior uterine wall, posterior uterine wall, and fundus. Change in hemoglobin levels before and after surgery, and complication rates were compared across categories. Results 219 women with mean age of 35.7 +/-6 years were included. There were 81 women with fundal fibroid, 56 with anterior wall, and 72 with posterior wall fibroid. Other 10 women with intraligamentary and isthmic fibroid were excluded. The mean fibroid diameter was 6.7 ± 2.6, 6.6 ± 2.3, and 6.7 ± 2.3 cm in the fundal, anterior and posterior groups, respectively (p=0.9). The median (25 th – 75 th percentile) changes in hemoglobin levels were 1.5 (0.8 – 2.2), 1.3 (0.6 – 2.1), and 1.3 (0.9 – 2) g/dl in fundal, anterior and posterior wall groups, respectively (p = 0.55). There were 5 (6.2%), 5 (8.9%), and 2 (2.8%) complications in fundal, anterior, and posterior wall groups, respectively (p = 0.33). Conclusion Incidence of hemorrhage or complication does not seem to vary depending on fibroid location. However, the sample size was limited, the observed values suggest that fibroid location does not affect hemorrhage and complication rates.

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