Linking Geometry, Algebra and Calculus with GeoGebra

GeoGebra is a free, open-source, and multi-platform software that combines dynamic geometry, algebra and calculus in one easy-to-use package. Students from middle-school to university can use it in classrooms and at home. In this workshop, we will introduce the features of GeoGebra with a special focus on not very common applications of a dynamic geometry program. We will inform about plans for developing training and research networks connected to GeoGebra. We can expect that at the time of the conference a spreadsheet will be integrated into GeoGebra which offers new ways teaching mathematics using the interplay between the features of a spreadsheet and the objects of dynamic geometry

Intestinal Structure and Function of Broiler Chickens on Diets Supplemented with a Synbiotic Containing Enterococcus faecium and Oligosaccharides

A feeding trial was conducted on broiler chickens to study the effects of the synbiotic BIOMIN IMBO [a combination of Enterococcus faecium, a prebiotic (derived from chicory) and immune modulating substances (derived from sea algae)], with a dose of 1 kg/ton of the starter diets and 0.5 kg/ton of the grower diets on the intestinal morphometry and nutrient absorption. The general performance was improved (P < 0.05) by the dietary inclusion of synbiotic compared with the controls. Furthermore, the addition of synbiotic increased (P < 0.001) the villus height/crypt depth ratio and villus height in ileum. However, the ileal crypt depth was decreased by dietary supplementation of synbiotic compared with control. The addition of glucose in Ussing chamber produced a significant increase (P ≤ 0.001) in short-circuit current (Isc) in jejunum and colon relative to the basal values in both synbiotic and control groups. However, in jejunum the percentage of Isc increase after glucose addition was higher for synbiotic group (333 %) than control group (45 %). In conclusion, dietary inclusion of synbiotic BIOMIN IMBO increased the growth performance and improved intestinal morphology and nutrient absorption

Ultrasonographic Identification of Fibromuscular Bands Associated with Neurogenic Thoracic Outlet Syndrome: The "Wedge-Sickle" Sign.

Thoracic outlet syndrome (TOS) is a disorder characterized by compression of the lower trunk of the brachial plexus, most often in association with anomalous congenital fibromuscular bands in the scalenic region. Early diagnosis is important, because the neurologic deficit associated with TOS may be irreversible. Using high-resolution ultrasound, we investigated 20 consecutive patients with clinical signs suggestive of TOS (all females, average age: 40.4 +/- 14.9 y) and 25 control patients. In 19 patients, we identified a hyper-echoic fibromuscular structure at the medial edge of the middle scalene muscle, which indented the lower trunk of the brachial plexus ("wedge-sickle sign"). It was associated with the significant enlargement (p < 0.0001) and hypo-echogenicity of the lower trunk. This novel and distinctive ultrasonographic sign allows pre-surgical identification of anomalous fibromuscular bands causing TOS. It is especially useful in patients without neurologic deficit, in whom the diagnosis may not be as straightforward

The Toxicological Impacts of the Fusarium Mycotoxin, Deoxynivalenol, in Poultry Flocks with Special Reference to Immunotoxicity

Deoxynivalenol (DON) is a common Fusarium toxin in poultry feed. Chickens are more resistant to the adverse impacts of deoxynivalenol (DON) compared to other species. In general, the acute form of DON mycotoxicosis rarely occurs in poultry flocks under normal conditions. However, if diets contain low levels of DON (less than 5 mg DON/kg diet), lower productivity, impaired immunity and higher susceptibility to infectious diseases can occur. The molecular mechanism of action of DON has not been completely understood. A significant influence of DON in chickens is the impairment of immunological functions. It was known that low doses of DON elevated the serum IgA levels and affected both cell-mediated and humoral immunity in animals. DON is shown to suppress the antibody response to infectious bronchitis vaccine (IBV) and to Newcastle disease virus (NDV) in broilers (10 mg DON/kg feed) and laying hens (3.5 to 14 mg of DON/kg feed), respectively. Moreover, DON (10 mg DON/kg feed) decreased tumor necrosis factor alpha (TNF-α) in the plasma of broilers. DON can severely affect the immune system and, due to its negative impact on performance and productivity, can eventually result in high economic losses to poultry producers. The present review highlights the impacts of DON intoxication on cell mediated immunity, humoral immunity, gut immunity, immune organs and pro-inflammatory cytokines in chickens

Comparison of Pandemics and Epidemics of the 20th and 21st Centuries

Od 12. března 2020 až po současnost jsou v České republice zavedeny v určité míře protiepidemická opatření z důvodu omezení šíření SARS-CoV-2. Šíření tvz. „nového“ druhu lidského koronaviru je velmi podrobně sledováno a vyhodnocováno na celé planetě. Jsou zaváděna opatření proti jeho šíření a dopadům na společnost dle aktuálního stavu v daném státu. Kroky ke snížení šíření nákazy byly zaváděny i při minulých epidemiích a pandemiích. Článek se zabývá porovnáním proběhlých a probíhajících epidemií a pandemií 20. a 21. století. Cílem je komparace epidemií a pandemií 20. a 21. století s probíhající pandemií COVID-19. V rámci vlastního šetření jsou vybrány významné pandemie podle počtu mrtvých, ke kterým byly vytvořeny přehledové grafy. Z šetření vyplývá, že viry jsou původci všech porovnávaných pandemií a dominuje jim přenos kapénkami. Dále vyplývá vysoká podobnost mezi pandemií španělské chřipky a pandemií COVID-19.From 12 March 2020 to the present day, certain antiepidemic measures have been introduced in the Czech Republic to limit the spread of SARS-CoV-2. The spread of the so-called. The spread of the "new" type of human coronavirus is being monitored and evaluated very closely across the planet. Measures against its spread and its impact on society are being implemented according to the current situation in the country concerned. Steps to reduce the spread of the disease have also been implemented in past epidemics and pandemics. The article deals with a comparison of past and ongoing epidemics and pandemics of the 20th and 21st centuries. The aim is to compare the epidemics and pandemics of the 20th and 21st centuries with the ongoing pandemic COVID-19. In the actual investigation, major pandemics are selected according to the number of casualties for which overview graphs have been produced. The investigation shows that viruses are the causative agents of the pandemics compared and are dominated by droplet transmission. It also shows a high similarity between the Spanish influenza pandemic and the COVID-19 pandemic

Exhaust Gas Temperature Pulsations of a Gasoline Engine and Its Stabilization Using Thermal Energy Storage System to Reduce Emissions

Modern automotive gasoline engines have highly efficient after-treatment systems that reduce exhaust gas emissions. However, this efficiency greatly depends on the conditions of the exhaust gas, mainly the temperature and air-fuel ratio. The temperature instability during transient conditions may cause a reduction in the efficiency of the three-way catalyst (TWC). By using a thermal energy storage system before TWC, this negative effect can be suppressed. In this paper, the effects of the temperature stabilization on the efficiency of the three-way catalyst were investigated on a 1-D turbocharged gasoline engine model, with a focus on fuel consumption and emissions. The thermal energy storage system (TESS) was based on PCM materials and was built in the exhaust between the turbine and TWC to use the energy of the exhaust gas. Three different materials were picked up as possible mediums in the storage system. Based on the results, the usage of a TESS in a gasoline after-treatment system has shown great potential in improving TWC efficiency. This approach can assist the catalyst to operate under optimal conditions during the drive. In this study, it was found that facilitating the heat transfer between the PCM and the catalyst can significantly improve the emissions' reduction performance by avoiding the catalyst to light out after the cold start. The TESS with PCM H430 proved to reduce the cumulative CO and HC emissions by 8.2% and 10.6%, respectively, during the drive. Although a TES system increases the after-treatment cost, it can result in emission reductions and fuel consumption over the vehicle's operating life

Towards Massively Parallel Computations in Algebraic Geometry

Introducing parallelism and exploring its use is still a fundamental challenge for the computer algebra community. In high-performance numerical simulation, on the other hand, transparent environments for distributed computing which follow the principle of separating coordination and computation have been a success story for many years. In this paper, we explore the potential of using this principle in the context of computer algebra. More precisely, we combine two well-established systems: The mathematics we are interested in is implemented in the computer algebra system Singular, whose focus is on polynomial computations, while the coordination is left to the workflow management system GPI-Space, which relies on Petri nets as its mathematical modeling language and has been successfully used for coordinating the parallel execution (autoparallelization) of academic codes as well as for commercial software in application areas such as seismic data processing. The result of our efforts is a major step towards a framework for massively parallel computations in the application areas of Singular, specifically in commutative algebra and algebraic geometry. As a first test case for this framework, we have modeled and implemented a hybrid smoothness test for algebraic varieties which combines ideas from Hironaka’s celebrated desingularization proof with the classical Jacobian criterion. Applying our implementation to two examples originating from current research in algebraic geometry, one of which cannot be handled by other means, we illustrate the behavior of the smoothness test within our framework and investigate how the computations scale up to 256 cores

Nutritional Value of the Duckweed Species of the Genus Wolffia (Lemnaceae) as Human Food

Species of the genus Wolffia are traditionally used as human food in some of the Asian countries. Therefore, all 11 species of this genus, identified by molecular barcoding, were investigated for ingredients relevant to human nutrition. The total protein content varied between 20 and 30% of the freeze-dry weight, the starch content between 10 and 20%, the fat content between 1 and 5%, and the fiber content was ~25%. The essential amino acid content was higher or close to the requirements of preschool-aged children according to standards of the World Health Organization. The fat content was low, but the fraction of polyunsaturated fatty acids was above 60% of total fat and the content of n-3 polyunsaturated fatty acids was higher than that of n-6 polyunsaturated fatty acids in most species. The content of macro- and microelements (minerals) not only depended on the cultivation conditions but also on the genetic background of the species. This holds true also for the content of tocopherols, several carotenoids and phytosterols in different species and even intraspecific, clonal differences were detected in Wolffia globosa and Wolffia arrhiza. Thus, the selection of suitable clones for further applications is important. Due to the very fast growth and the highest yield in most of the nutrients, Wolffia microscopica has a high potential for practical applications in human nutrition

Ultrasonographic identification of nerve pathology in neuralgic amyotrophy: Enlargement, constriction, fascicular entwinement and torsion.

Objective: To characterize the ultrasonographic findings on nerves in neuralgic amyotrophy. Methods: Fourteen patients with neuralgic amyotrophy were examined using high resolution ultrasound. Results: Four types of abnormalities were found: 1. Focal or diffuse nerve / fascicle enlargement (57%), 2. incomplete nerve constriction (36%), 3. complete nerve constriction with torsion (50%) (hourglass-like appearance), and 4. fascicular entwinement (28%). Torsions were confirmed intraoperatively and occurred on the radial nerve in 85% of the patients. A significant correlation was found between no spontaneous recovery of nerve function and constriction / torsion / fascicular entwinement (p=0.007). Conclusion: Ultrasonographic nerve pathology in neuralgic amyotrophy varies in order of severity from nerve enlargement to constriction to nerve torsion, with treatment moving from conservative to surgical. We postulate that the constriction caused by inflammation is the precursor of torsion and that the development of nerve torsion is facilitated by rotational movements of limbs. This article is protected by copyright. All rights reserved