Use of Non-commercial Software in Mathematics

This work describes the use of non-commercial software in terms of innovation oftraditional educational process in mathematics in higher education in Serbia whichis largely based on the concepts in the last century, with a very low teachingadjustment which follows individual characteristics and abilities of students, sotoday it gives very limited results in efficiency and in study duration. The ideabehind the non-commercial software is to simplify the understanding of basic termsand concepts for students, which are studied in subjects related to mathematics, andalso to reduce the cost of higher education institutions. High price of commercialsoftware can often make them inaccessible to many of our institutions andindividuals. Non-commercial educational mathematical software are designed forinnovative, interactive and dynamic teaching in various areas of mathematics that isthe basis for development of logical thinking necessary for further education. Theiruse would have a significant role in distance education that involves the physicaldistance between teachers and students as well as benefits for students using it in theprocess of visual mastering of mathematical material. This work suggests a simpleand free model in mathematics that includes information technology. Such modelcan be a good recommendation for mathematics in universities and other highereducation institutions that have a similar curriculum in mathematical subjects. Inthis work the emphasis is on GeoGebra Octave and Maxim non-commercialprograms which in mathematical sense join geometry, algebra and analysis. There isalso an explanation how to use this software in mathematics. The work is writtenwith the purpose of popularizing free software GeoGebra, Octave and Maxima, andall with the idea of improving the quality of mathematics in the higher educationinstitutions

Parametri kvaliteta plodova kod različitih genotipova paradajza u organskoj proizvodnji

The aim of this study was to examine the content of total soluble solids, organic acids and lycopene in fruits of different tomato genotypes grown in organic production. Four different genotypes (Volovsko heart Red cherry, Tigrella and Viva) were used during this experiment. The quality of tomato fruits was analyzed based on the measurement of total soluble solids, organic acids and lycopene in fresh weight of the fruit. The values obtained for the analyzed parameters of fruit quality were as follows: total soluble solids 4.98, 5.26, 5.28 and 4.70 (° Brix), organic acids 160.67, 110.34, 132.77 and 116 (citric acid µmol g-1 FW), lycopene, 8.22, 5.70, 7.61, 9.21 (mg kg-1 FW) in genotypes Volovsko srce, Red cherry, Tigrella and Viva. Oscillations in the obtained parameters, especially in the content of lycopene in different genotypes were probably the result of genetic resources, but also the influence of abiotic factors.Cilj ovog istraživanja je bio da se ispita sadržaj ukupnih rastvorljivih suvih materija, organskih kiselina i likopena u plodovima različitih genotipova paradajza gajenog u organskoj proizvodnji. Četiri različita genotipa (Volovsko srce, Red cherry, Tigrella i Viva) su korišćeni tokom ovog eksperimenta. Kvalitet plodova paradajza analiziran je na osnovu merenja ukupnih rastvorljivih suvih materija, organskih kiselina i likopena u svežoj masi plodova. Dobijene vrednosti za analizirane parametre kvaliteta plodova su iznosile: ukupne rastvorljive materije 4.98, 5.26, 5.28 i 4.70 (oBrix), organske kiseline 160.67, 110.34, 116 i 132.77 (citric acid µmol g-1 FW), likopen 8.22, 5.70, 7.61, 9.21 (mg kg-1 FW) kod analiziranih genotipova Volovsko srce, Red cherry, Tigrella i Viva. Variranje u dobijenim parametrima, a naročito u sadržaju likopena kod različitih genotipova su bile posledica genetskog potencijala, ali i uticaja abiotičkih faktora

Broadband phonon scattering in PbTe-based materials driven near ferroelectric phase transition by strain or alloying

The major obstacle in the design of materials with low lattice thermal conductivity is the difficulty in efficiently scattering phonons across the entire frequency spectrum. Using first-principles calculations, we show that driving PbTe materials to the brink of the ferroelectric phase transition could be a powerful strategy to solve this problem. We illustrate this concept by applying biaxial tensile (001) strain to PbTe and its alloys with another rocksalt IV-VI material, PbSe; and by alloying PbTe with a rhombohedral IV-VI material, GeTe. This induces extremely soft optical modes at the zone center, which increase anharmonic acoustic-optical coupling and decrease phonon lifetimes at all frequencies. We predict that PbTe, Pb(Se,Te), and (Pb,Ge)Te alloys driven close to the phase transition in the described manner will have considerably lower lattice thermal conductivity than that of PbTe (by a factor of 2–3). The proposed concept may open new opportunities for the development of more efficient thermoelectric materials

NEUROCOGNITIVE PROFILES OF PATIENTS WITH THE FIRST EPISODE OF PSYCHOSIS AND SCHIZOPHRENIA DO NOT DIFFER QUALITATIVELY: A NESTED CROSS-SECTIONAL STUDY

Background: The aim of study was to analyze neurocognitive profiles in patients with first-episode psychosis (FEP) and patients with schizophrenia (SCH), and their correlations with other clinical features. Subjects and methods: We performed a multicentric cross sectional study including 100 FEP and 100 SCH recruited from three Croatian hospitals during 2015-2017. Assessment included a set of neurocognitive tests, psychiatric scales and self-reporting questionnaires. The main analysis was done by multigroup latent profile analysis. Results: Multigroup latent profile analysis resulted in three structurally equivalent neurocognitive profiles ("Best", "Medium", "Worst"), with differences in the severity of neurocognitive deficits measured with successfulness in solving domain specific tasks. The "Best" profile was statistically significantly more prevalent in FEP and "Worst" profile in the SCH. Negative symptom score was the highest in patients with the "Worst" profile and the lowest among those with the "Best" profiles. Conclusions: Differences in neurocognitive profiles between FEP and SCH appear to be quantitative rather than qualitative nature, possibly reflecting a specific trait of illness that may progress over time. Defining neurocognitive profiles from the first episode of psychosis could help in tailoring individualized treatment options with focus on neurocognitive and negative symptoms and possible influence on patients\u27 overall clinical outcome

Electron-phonon scattering and thermoelectric transport in p-type PbTe from first principles

We present a first-principles-based model of electron-phonon scattering mechanisms and thermoelectric transport at the L and Σ valleys in p-type PbTe, accounting for their thermally induced shifts. Our calculated values of all thermoelectric transport parameters at room temperature are in very good agreement with experiments for a wide range of doping concentrations. Scattering due to longitudinal optical phonons is the main scattering mechanism in p-type PbTe, while scattering due to transverse optical modes is the weakest. The L valleys contribute most to thermoelectric transport at 300 K due to the sizable energy difference between the L and Σ valleys. We show that both scattering between the L and Σ valleys and additional transport channels of the Σ valleys are beneficial for the overall thermoelectric performance of p-type PbTe at 300 K. Our findings thus support the idea that materials with high valley degeneracy may be good thermoelectrics

Optimization of technological procedure for amygdalin isolation from plum seeds (Pruni domesticae semen)

The process of amygdalin extraction from plum seeds was optimized using central composite design (CCD) and multilayer perceptron (MLP). The effect of time, ethanol concentration, solid-to-liquid ratio, and temperature on the amygdalin content in the extracts was estimated using both mathematical models. The MLP 4-3-1 with exponential function in hidden layer and linear function in output layer was used for describing the extraction process. MLP model was more superior compared with CCD model due to better prediction ability. According to MLP model, the suggested optimal conditions are: time of 120 min, 100% (v/v) ethanol, solid-to liquid ratio of 1:25 (m/v) and temperature of 34.4 degrees C. The predicted value of amygdalin content in the dried extract (25.42 g per 100 g) at these conditions was experimentally confirmed (25.30 g per 100 g of dried extract). Amygdalin (>90%) was isolated from the complex extraction mixture and structurally characterized by FT-IR, UV, and MS methods

online condition monitoring of bearings for improved reliability in packaging materials industry

The production processes in the packaging materials industry has to be very efficient and cost-effective. These processes usually take place under extreme conditions and high speeds that requires a high level of reliability and efficiency. Rollers including their supporting bearings and motors are the most common components of production machines in the packaging materials industry. Bearing faults, which often occur gradually, represent one of the foremost causes of failures in the industry. Therefore it is very important to take care of bearings during maintenance and detect their faults in an early stage in order to assure safe and efficient operation. We present a new automated technique for early fault detection and diagnosis in rolling-element bearings based on vibration signal analysis. After normalization and the wavelet transform of vibration signals, the standard deviation as a measure of average energy level and the logarithmic energy entropy as a measure of the degree of order/disorder are extracted in a few sub-bands of interest as representative features. Then the feature space dimension is optimally reduced to two using scatter matrices. In the reduced two-dimensional feature space the fault detection is performed by a quadratic classifier and the fault diagnosis by another two quadratic classifiers. Accuracy of the new technique was tested on the ball bearing data recorded at the Case Western Reserve University Bearing Data Center. In total four classes of the vibrations signals were studied, i.e. normal, with the fault of inner race, outer race and balls operation. An overall accuracy of 100% was achieved. The new technique can be used to increase reliability and efficiency by preventing unexpected faulty operation of machinery bearings

The effect of different genotypes and growing seasons on the content of nitrate and vitamin C in lettuce leaves

Lettuce is a cool season crop, grown worldwide and important vegetable usually used as a sal- ad. It is rich in vitamin C, which has significant role as antioxidant, but lettuce can also accumulate toxic compounds like nitrates. The purpose of this study was to examine the effect of different lettuce genotypes and growing seasons on the content of nitrate and vitamin C in the outer and inner leaves. Six cultivars (‘Kiribati’ RZ, ‘Murai’ RZ, ‘Aquino’ RZ, ‘Gaugin’ RZ, ‘Aleppo’ RZ, ‘Carmesi’ RZ) were grown in the greenhouse experiment during autumn, winter and spring. Vitamin C was determined spectrophotometrically at 550 nm and nitrate colorimetrically at 420 nm. Vitamin C ranged between 3.64-12.41 mg per 100 g FW in autumn, 3.68-7.34 mg per 100 g FW in winter and 3.05-7.72 mg per 100 g FW in spring. Cultivar ‘Carmesi’ had the highest level of vitamin C in the outer leaves (9.15 mg per 100 g FW) and ‘Gaugin’ in the inner leaves (12.41 mg per 100 g FW), both in autumn. Nitrate content ranged between 258.77-908.2 mg kg-1 FW in autumn, 296.62-977.64 mg kg-1 FW in winter and 42.74-450.74 mg kg-1 FW in spring. Cultivar ‘Carmesi’ had the highest level of nitrate in the outer leaves (977.64 mg kg -1 FW) and ‘Aleppo’ in the inner leaves (701.45 mg kg -1 FW), both in winter. Nitrate content in all seasons and genotypes stayed within the limit of EC regulation for protected lettuce. Generally, vitamin C was allocated to the inner and nitrate to the outer leaves. Results showed that genotype and growing season can affect the content of vitamin C and nitrate in lettuce leaves

Seasonal variation of total phenolic content in six lettuce cultivars grown with microbiological fertilizer

Lettuce (Lactuca sativa, L.) is an annual, cool season crop belonging to Asteraceae family and to a group of leafy vegetables. It is rich in minerals, vitamins and antioxidative compounds which are essential for human nutrition. The advantage of lettuce, as eaten raw, is that maintains more nutrients than other cooked vegetables. Lettuce is low in calories and it is suggested to diabetics, people with sleep problems and disturbed metabolism. Growers are interested in cultivating lettuce because of their short vegetation period and opportunity to cultivate in all seasons. The purpose of this study was to examine the effect of microbiological fertilizer Em Aktiv (Candor) on the total phenolic content (TPC) in six lettuce cultivars. Cultivars (′Kiribati′, ′Murai′, ′Aquino′, ′Gaugin′, ′Aleppo′, ′Carmesi′- Rijk Zwaan) were grown in the fertile soil in a greenhouse experiment during three successive seasons (autumn, winter and spring). Total phenolic content ranged between 175.85-372.73 μg GAE/g FW in autumn, 104.12-522.74 μg GAE/g FW in winter and 88.88-340.93 μg GAE/g FW in spring. Our results indicated that red cultivars mainly had higher total phenolic content compared to green cultivars with the exception in autumn experiment. Among all seasons, control treatment of cultivar ′Carmesi′ showed the highest total phenolic content (522.74 μg GAE/g FW) in winter. The effect of fertilizer Em Aktiv on TPC in different cultivars was to some extent positive in spring and autumn, but even negative during winter season. Such a complex response indicates the need for careful selection of varieties and fertilizers in relation to the season. To conclude, red cultivars were pointed out with higher total phenolic content and they could be recommended as a great source of bioactive compounds for healthy human diet.Salata (Lactuca sativa, L.) je jednogodišnja vrsta, prohladne klime koja pripada familiji Asteraceae i grupi lisnatog povrća. Bogata je mineralima, vitaminima, antioksidantima koji su neophodni u ljudskoj ishrani. Prednost salate, kao sirovog povrća, je da sadrži više hranljivih materija u odnosu na drugo termički obrađeno povrće. Salata ima nisku kalorijsku vrednost i preporučuje se u ishrani dijabetičara, ljudi sa poremećenim ritmom spavanja i metabolizma. Proizvođači su zainteresovani za gajenje salate zbog kratkog vegetacionog perioda i mogućnosti gajenja tokom cele godine. Cilj ovog istraživanja bio je da se utvrdi uticaj mikrobiološkog đubriva Em Aktiv (Candor) na sadržaj ukupnih fenola (TPC) kod šest sorti salate. Sorte (′Kiribati′, ′Murai′, ′Aquino′, ′Gaugin′, ′Aleppo′, ′Carmesi′- Rijk Zwaan) su gajene na plodnom zemljištu u plasteniku tokom tri uzastopne sezone (jesen, zima i proleće). Sadržaj ukupnih fenola kretao se u jesen između 175.85-372.73 μg GAE/g FW, u zimu 104.12-522.74 μg GAE/g FW i u proleće 88.88-340.93 μg GAE/g FW. Rezultati ukazuju da su crvene sorte uglavnom pokazale veći sadržaj ukupnih fenola u odnosu na zelene sorte sa izuzetkom jesenjeg ogleda. Među svim sezonama, najveći sadržaj ukupnih fenola određen je u kontroli kod sorte ′Carmesi′ (522.74 μg GAE/g FW) u zimskom ogledu. Uticaj đubriva Em Aktiv na sadržaj ukupnih fenola, kod različitih sorti salate, u određenom opsegu bio je pozitivan u proleće i jesen pa čak i negativan tokom zime. Ovako složen odgovor ukazuje na potrebu za pažljivim odabirom varijeteta salate i đubriva u odnosu na sezonu. Na osnovu dobijenih rezultata može se zaključiti da su crvene sorte salate pokazale veći sadržaj ukupnih fenola i mogu se preporučiti kao izvor bioaktivnih supstanci u zdravoj ishrani