226 research outputs found
The place and role of intellectual property in education
Modern times place great emphasis on workscreated as a product of the intellectual work of individuals orgroups. At the same time, there is an increasing abuse of bothintellectual property rights and the degree of protection thatintellectual property offers. The educational process as well asthe scientific research work which is an integral part of theeducational process in many cases form the basis for theemergence of new intellectual works. The acts thus createdremain in most cases the intellectual property of the educationalinstitutions within which they were created. The degree ofprotection introduced in this way is also a restriction for thepeople who worked to develop the work in question. It is for thesereasons that the aim of this paper is to look at the position ofintellectual property created in the education system, as well asthe advantages and disadvantages of such works
Diversity, Distribution, Microhabitat Differentiation and Community Structure of Bryophytes of Fruška Gora Mountain
U radu je analizirana brioflora Fruške gore. Cilj istraživanja bio je utvrđivanje diverziteta, distribucije, uslova mikrostaništa i strukture zajednica mahovina na različitim tipovima staništa na Fruškoj gori. Takođe, jedan od ciljeva je bio i testiranje i optimizacija metode za kvantitativna uzorkovanja briofita na različitim tipovima staništa. Terenska istraživanja su vršena u periodu 2013-2017 godine. Za potrebe florističkih istraživanja terenska uzorkovanja su vršena metodom transekta na 120 lokaliteta na području Fruške gore. Za testiranje i optimizaciju metoda za kvantitativna briološka uzorkovanja korišćene su različite varijante metoda „kvadrata“ (metod ugneždenih kvadrata za prizemnu briofloru i metod postavljanja mikroplotova na različitoj udaljenosti za epifitsku briofloru). Odgovarajuće metode su odabrane na osnovu kriva minimum areala i kriva sličnosti (eng. species-area curve, similarity area curve). Odgovarajuće metode su primenjene za dalja uzorkovanja u ovom istraživanju. Na pojedinim lokalitetima (šumska i livadska staništa) vršeno je merenje nekoliko ekoloških parametara (pH zemljišta i kore drveta, vlažnost zemljišta, temperatura zemljišta, pokrovnost stelje, pokrovnost zeljastih vaskularnih biljaka, udaljenost od potoka u šumskim staništima i udaljenost šumskih ekosistema na livadskim staništima) u cilju utvrđivanja uticaja merenih ekoloških parametara na diverzitet i distribuciju briofita. Briofitske zajednice su utvrđene na različitim tipovima staništa i podloge uz pomoć „label propagating community detection“ analize.Rezultati ovog istraživanja su pokazali da je Fruška gora područje koje se odlikuje visokim diverzitetom briofita i ukupno je zabeleženo 235 briofitskih taksona (na osnovu literaturnih podataka i terenskih istraživanja). 73 taksona briofita je prvi put zabeleženo na području Fruške gore. Od ukupnog broja taksona, 11% je pod nekim stepenom ugroženosti ili zakonske zaštite. Metoda mikrocenoze se pokazala kao najadekvatniji metod za kvantitativna uzorkovanja prizemnih briofita (sa minimalnom adekvatnom veličinom kvadrata 0.5x0.5 m u šumskim odnosno 1x1 m na livadskim staništima). Za epifitske briofite, kao najadekvatnija se pokazale metoda postavljanja mikroplotova dimenzija 10x10 cm sa sve četiri strane stabla na međusobnoj udaljenosti od 20 cm. Struktura staništa ima značajno veći uticaj na diverzitet prizemnih briofita u šumskim staništima u odnosu na karakteristike zemljišta, dok je na livadskim staništima zabeležen obrnut slučaj. Najveći uticaj na diverzitet epifitskih briofita ima visina na stablu kao i tip forofite. Na istraživanom području je detektovano devet zajednica u prizemnoj brioflori šumskih staništa; šest epifitskih zajednica; pet zajednica na livadskim staništima; četiri zajednice na trulim deblima i panjevima; 10 zajednica na stenama i kamenju; četiri zajednice u potocima. Dobijeni rezultati predstavljaju građu za dalja briološka istraživanja, kako floristička tako i ekološka, i dopunu flore Srbije.In this research, the bryophyte flora of Fruška gora Mountain was analyzed. The aim of this research was to determine the diversity, distribution, microhabitat conditions and community structure of bryophytes on different types of habitats on Fruška Gora. Also, one of the goals was testing and optimization of the method for quantitative sampling of bryophytes on different types of habitats. Field research was carried out in the period 2013-2017. For the purposes of floristic research, field sampling was carried out using the transect method at 120 localities. Different variants of the "quadrat" method (method of nested quadrats for terrestrial bryophytes and the method of placing microplots at different distances for the epiphytic byphytes) were used for testing and optimization of methods for quantitative bryophyte sampling. Appropriate methods were selected on the basis species-area curve and similarity-area curve. Appropriate methods have been applied to further sampling in this study. On some localities (forest and meadow habitats) several environmental parameters (pH of soil and bark of wood, soil moisture, soil temperature, roof cover, coverage of herbaceous vascular plants, distance from the stream in forest habitats and distance of forest ecosystems in meadow habitats) were measured in order to determine their impact on the diversity and distribution of bryophytes. Bryophyte communities were identified on different substrates and habitat types using "label propagating community detection" analysis. The results of this study have shown that Fruška gora is an area characterized by a high diversity of bryophytes and a total number of 235 taxa were recorded (based on literature data and field research). 73 taxa were recorded for the first time on this area. Of the total number of taxa, 11% is threatened or under legislative protection. The microcenose method proved to be the most adequate for quantitative sampling of terrestrial bryophytes (with a minimum quadrat size of 0.5x0.5 m in forests and 1x1 m in meadow habitats). For the epiphytic bryophytes, the method of placing the microplots (10x10 cm) on all four sides of the tree at a distance of 20 cm is most suitable. The stand structure has a significantly greater influence on the diversity of terrestrial bryophytes in forest habitats compared to soil haracteristics, while in the meadow habitats there is a reverse case. The greatest influence on the diversity of epiphytic bryophytes has height on the tree as well as the type of phorphyte. In the investigated area, nine bryophyte communities were detected in ground bryopyhte flora of forest habitats; six epiphytic communities; five communities in meadow habitats; four communities on rotten trunks and horns; 10 communities on the rocks and stones; four communities in streams. The obtained results represent the base for further bryological research, both floristic and ecological, and the addition to the flora of Serbia
Analytical determination of the availability of a rotary excavator as a part of coal mining system: Case study: Rotary excavator SchRs 800.15/1.5 of the Drmno open pit
Rotary excavators as the basic machines at the open pits of lignite operate in very difficult working conditions, where they are constantly expected to be highly productive, reliable, available and safe as the production carriers. Determining the availability as well as the duration and number of failures using the analytical methods allows to analyze the key influencing factors on their occurrence and values of these parameters and to determine the essential elements of system maintenance and management in order to optimize them
Analytical determination of the availability of a rotary excavator as a part of coal mining system: Case study: Rotary excavator SchRs 800.15/1.5 of the Drmno open pit
Rotary excavators as the basic machines at the open pits of lignite operate in very difficult working conditions, where they are constantly expected to be highly productive, reliable, available and safe as the production carriers. Determining the availability as well as the duration and number of failures using the analytical methods allows to analyze the key influencing factors on their occurrence and values of these parameters and to determine the essential elements of system maintenance and management in order to optimize them
Model-based stagnation pressure control in a supersonic wind tunnel
Upravljanje parametrima strujanja u aerotunelima je oblast intenzivnog istraživanja poslednjih godina, sa ciljem poboljšanja kvaliteta i efikasnosti rada aerotunelskih instalacija. Ovaj rad predstavlja pokušaj da se doprinese boljem razumevanju upravljanja zaustavnim pritiskom u supersoničnim instalacijama prekidnog dejstva. Razmotrena je strategija upravljanja zaustavnim pritiskom u aerotunelu T-38 Vojnotehničkog instituta u Beogradu. Poboljšani matematički model supersoničnih aerotunelskih instalacija je predložen i primenjen na aerotunel T-38. Tačnost sa kojom matematički model predviđa odziv instalacije u uslovima supersoničnog strujanja demonstrirana je poređenjem podataka iz simulacija i eksperimenata. Matematički model je upotrebljen za uvođenje izmenjenog algoritma upravljanja u polazni upravljački sistem aerotunela T-38. Aerotunelski eksperimenti su potvrdili predviđanja modela u pogledu smanjenja vremena uspostavljanja strujanja i povećanja raspoloživog vremena za merenje, čime je postignuto značajno poboljšanje efikasnosti rada aerotunela.The flow parameters control in wind tunnels is an area of intense research in recent years, with the aim of improving quality and efficiency of the wind tunnel operation. In this paper, an attempt is made to contribute to a better understanding of the stagnation pressure control in supersonic blowdown-type facilities. The stagnation pressure control strategy in the VTI Belgrade T-38 wind tunnel is discussed. An improved mathematical model for a supersonic wind tunnel is suggested and applied to the T-38 facility. Comparisons of simulation and experimental data are made to demonstrate accurate prediction of the facility response in supersonic flow conditions by the mathematical model. The model is used to incorporate a modified feedforward control in the original T-38 wind tunnel control system. The actual wind tunnel tests confirm model-predicted decrease of flow stabilization time and increase of available measurement time, bringing significant improvement in the wind tunnel operation efficiency
Model-based stagnation pressure control in a supersonic wind tunnel
Upravljanje parametrima strujanja u aerotunelima je oblast intenzivnog istraživanja poslednjih godina, sa ciljem poboljšanja kvaliteta i efikasnosti rada aerotunelskih instalacija. Ovaj rad predstavlja pokušaj da se doprinese boljem razumevanju upravljanja zaustavnim pritiskom u supersoničnim instalacijama prekidnog dejstva. Razmotrena je strategija upravljanja zaustavnim pritiskom u aerotunelu T-38 Vojnotehničkog instituta u Beogradu. Poboljšani matematički model supersoničnih aerotunelskih instalacija je predložen i primenjen na aerotunel T-38. Tačnost sa kojom matematički model predviđa odziv instalacije u uslovima supersoničnog strujanja demonstrirana je poređenjem podataka iz simulacija i eksperimenata. Matematički model je upotrebljen za uvođenje izmenjenog algoritma upravljanja u polazni upravljački sistem aerotunela T-38. Aerotunelski eksperimenti su potvrdili predviđanja modela u pogledu smanjenja vremena uspostavljanja strujanja i povećanja raspoloživog vremena za merenje, čime je postignuto značajno poboljšanje efikasnosti rada aerotunela.The flow parameters control in wind tunnels is an area of intense research in recent years, with the aim of improving quality and efficiency of the wind tunnel operation. In this paper, an attempt is made to contribute to a better understanding of the stagnation pressure control in supersonic blowdown-type facilities. The stagnation pressure control strategy in the VTI Belgrade T-38 wind tunnel is discussed. An improved mathematical model for a supersonic wind tunnel is suggested and applied to the T-38 facility. Comparisons of simulation and experimental data are made to demonstrate accurate prediction of the facility response in supersonic flow conditions by the mathematical model. The model is used to incorporate a modified feedforward control in the original T-38 wind tunnel control system. The actual wind tunnel tests confirm model-predicted decrease of flow stabilization time and increase of available measurement time, bringing significant improvement in the wind tunnel operation efficiency
Iridium anomaly in the cretaceous-paleogene boundary at Højerup (Stevns Klint, Denmark) and Woodside Creek (New Zealand): The question of an enormous proportion of extraterrestrial component
The Cretaceous-Paleogene boundary clays at Højerup and Woodside Creek show anomalous enrichments of iridium compared with the marine sedimentary rocks. For the average iridium content of 465 ppb in CI chondrite the estimate of the carbonaceous chondritic proportions in the decarbonated iridium-rich boundary layers, based on the integrated iridium fluencies, is about 26% at Højerup and 65% at Woodside Creek. These proportions are most likely too high due to a significant Ir influx from the nearby marine or continental site to these sections
Appearance of high submerged cavitating jet: The cavitation phenomenon and sono-luminescence
In order to study jet structure and behaviour of cloud cavitation within time and space, visualization of highly submerged cavitating water jet has been done using Stanford Optics 4 Quick 05 equipment, through endoscopes and other lenses with Drello3244 and Strobex Flash Chadwick as flashlight stroboscope. This included obligatory synchronization with several types of techniques and lenses. Images of the flow regime have been taken, allowing calculation of the non-dimensional cavitation cloud length under working conditions. Consequently a certain correlation has been proposed. The influencing parameters, such as; injection pressure, downstream pressure and cavitation number were experimentally proved to be very significant. The recordings of sono-luminescence phenomenon proved the collapsing of bubbles everywhere along the jet trajectory. In addition, the effect of temperature on sono-luminescence recordings was also a point of investigation
Role of β2 Integrins in the Binding of Thymocytes to Rat Thymic Macrophages
A role of β2 integrins and one of their ligands, ICAM-1, in thymic macrophage
(TMF)/thymocyte interactions was studied. TMF were isolated as adherent cells from 4-day
old culture of thymic-cell suspensions either from normal or hydrocortisone-treated rats.
Adherent cells were 94-98% positive with ED1 (a pan-macrophage marker). The majority
of them (75-95%) expressed the CD11b and CD18 molecules, and 60-70% expressed CD54
(ICAM-1). A low proportion of TMF (10-20%) expressed CDlla (LFA-1). The expression
of all these antigens was upregulated by IFN-α and TNF-α. The effect of these mAbs on
TMF/thymocyte binding was studied using a simple rosette assay by incubating unstimulated
or IFN-γ or TNF-α stimulated TMF, grown on microscopic slides with resting or
ConA +IL-2 activated thymocytes. It was found that LFA-1/CD18 and ICAM-1 play a
significant role in the TMF/thymocyte adhesion. In addition, a LFA-l-dependent/ICAM-
1-independent adhesion pathway was observed, suggesting that LFA-1 might use another
ligand. The inhibitory effect of anti-CD18 mAb (WT-3) was higher than the effect of
anti-LFA-1 mAb (WT-1) and was a consequence of blocking the CD18 chain both on
thymocytes and TMF. No significant difference in the expression and function of adhesion
molecules was found between TMF obtained from normal or hydrocortisone-treated rats.
The involvement of CD1 1b in these processes was of lesser importance than the role of the
CD11a molecule. By using mAbs to different epitopes of the CD11b molecule, such as
OX-42 (anti-CD11b/CD11c), ED7, and ED8 (anti-CD11b), it was found that they were
either slightly or moderately inhibitory under certain experimental conditions or did not
significantly modulate TMF/thymocyte binding. Oχ-42 was slightly stimulatory in some
experiments. Cumulatively, these results show that 2 integrins play a significant role in
TMF/thymocyte interactions and probably contribute to T-cell development in vivo
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