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VARIABILITY OF VESSELS AND WOOD RAYS DENSITY BY CONTAINER SEEDLINGS OF DIFFERENT SPECIES FROM QUERCUS GENERA
No full textThe anatomical traits of one-year old container seedlings of three species from Quercus
genera – Quercus robur, Quercus petraea and Quercus frainetto were analyzed. Seedlings
were planted in the same type of container. The scope of the paper was to establish density of
vessels and wood rays per 1 mm2. These two anatomical elements play a very significant role
– vessels are conductive elements responsible for water and minerals moving from the root to
the upper parts of the tree, while wood rays are in charge of nutrients storage. The obtained
results showed that the greatest density of both anatomical elements was recorded by Q.
petraea (110.07 vessels, and 34.07 wood rays per mm2) which means that this species had the
narrowest vessels and wood rays. On the other hand, in Q. robur we found presence of 102.1
vessels, and 24.93 wood rays per mm2, while Q. frainetto had the lowest vessels density
(97.03), but came to the second place in terms of wood rays density (33.07). As for the
possibility of using of investigated oaks container seedlings for reforestation purposes, Q.
petraea would be more suitable for arid sites, according to the greatest density of vessels and
wood rays, which should be related to the lowest width of these elements. Bearing in mind
this fact, we can deduce that narrower vessels are more efficient for conducting, while smaller
wood rays can store enough nutrients for a short time. However, in order to obtain reliable
conclusions, in addition to analyzed parameters, it is needed to investigate some
morphological (height and root collar diameter) and anatomical (vessels width, wood rays
width and height) traits
Sacred geography and cultural heritage – the case of mountains
Get PDFU radu se proučavaju planine, brda i gore u kontekstu sakralnog geokulturnog nasleđa. Neki od ključnih događaja u istoriji judeohrišćanstva odigrali su se na planinama, zbog čega se sakralna geografija proučava objedinjeno sa kulturnom istorijom. Istorija jevrejskog naroda opisana u Starom zavetu neodvojiva je od planina, posebno od visoke Sinajske gore, dok reljefna uzvišenja iz Novog zaveta (Maslinska gora, Tavor, Golgota) spadaju u niske planine. Visoke planine i teško pristupačni predeli brdsko-planinskog reljefa lokacije su mnogobrojnih pravoslavnih svetinja koje su na listi Uneskove kulturne baštine, poput manastira Svete Katarine, Svete gore Atonske, Meteora, srednjovekovnog grada Lalibela u Etiopiji i Rilskog manastira.In this paper, mountains and hills are being studied in the context of sacred geocultural heritage. Some of the key events in the history of Judeo-Christianity took place in mountains, which is why sacred geography is studied jointly with cultural history. History of the Jewish people described in the Old Testament is inseparable from the mountains, especially from the high Mount Sinai, while the relief elevations from the New Testament (the Mount of Olives, Tabor, Golgotha) belong to low mountains. In high mountains and hard-to-reach mountainous relief areas there are numerous Orthodox holy sites listed as the UNESCO cultural heritage, such as St. Catherine's Monastery, Mount Athos, Meteora, the medieval city of Lalibela in Ethiopia, and the Rila Monastery
Laboratory Experimental Setup for High Voltage Corona Polarization of Thin PVDF Films
No full textFerroelectric thin films based on the polymer material
polyvinylidene fluoride (PVDF) can potentially have a wide range
of applications, due to the strong connection between their
electrical, mechanical and thermal properties. PVDF thin films
can be applied in memory devices. The most widespread
application of these elements is in piezoelectric sensors, actuators
and energy harvesters from mechanical vibrations and
mechanical impacts (the so-called "energy harvesting"). A very
important operation in the production and testing of thin PVDF
films is the polarization of the ferroelectric domains in the
material. Similar to the case of ferromagnetic materials, after the
production of the polymer material, the polarization domains in
it are oriented stochastically, so it is necessary to perform their
orientation by direction and course. For this reason, the
ferroelectric sample is exposed to relatively high electric field
strengths of (30÷100) kV/cm in order to orient and direct the
domains. The paper presents the practical realization of the
laboratory experimental setup of the system for high-voltage
polarization of ultra-thin PVDF films by means of a high-voltage
corona. Controlled corona is achieved in a hermetically sealed,
temperature controlled and electrically isolated chamber. Finally,
some key experimental results concerning high-voltage
polarization are given
Selection of the optimal lettuce cultivar to agronomic traits in summer production using multicriteria decision-making MABAC method- Abstract
Get PDFFive lettuce cultivars ('Kiribati', 'Tourbillon', 'Carmesi', 'Lianabel', and 'Biondonna') were grown
in the open-field experiment during the summer of 2018. The aim was to find the optimal summer
lettuce cultivar according to morphological and production parameters, suitable for the fresh
market and food industry processing by applying the MABAC (Multi-Attributive Border Approximation Area Comparison) method. The correlation analysis was carried out to reduce the
number of criteria that have high coefficient values and a double influence on the ranking results.
The study involved five alternatives (cultivars) and five different criteria regarding morphological
parameters (rosette height, rosette diameter, rosette fresh weight, number of leaves, and stem
height). Weight coefficients were determined using the AHP (Analytic Hierarchy Process) method
while the stability of the obtained ranking list was determined by applying sensitive analysis
through six scenarios. According to the selected criteria, the obtained results showed that the green cultivar 'Tourbillon' has the best results, while the least favorable results were obtained by the red cultivar 'Carmesi'. Furthermore, this study tends to facilitate cultivar selection by farmers to avoid economic losses and sustain the required quantity and quality standard demands for the fresh product and food industry market
HAEMOSPORIDIAN PARASITES IN LONG-EARED OWLS WINTERING IN BANAT, SERBIA
Get PDFParasites from the Phylum Apicomplexa (genera Haemoproteus, Plasmodium and Leucocytozoon) are the vector-born blood parasites distributed worldwide. This group of parasites has been the subject of extensive study in passerines, but less so in other groups of birds, such as owls. Four haemosporidian species have been discovered in the Long-eared Owl Asio otus so far. As there are only a few records of haemosporidian infection in wintering Long-eared Owls, in our pilot project we studied the prevalence, parasitemia, and diversity of the blood parasites of owl mentioned above in Banat, Serbia. We found the presence of all three genera, of which Leucocytozoon was the most abundant. The total prevalence was 52.2%, while the average parasitemia in winter was low, only 0.16%. We also observed two cases of co-infection. Interestingly, the presence of parasites did not affect the SMI (scaled mass index) and the health status of the birds
The antioxidant activity of the Calluna vulgaris (L.) Hull. extracts obtained by supercritical CO2 extraction
Get PDFCalluna vulgaris (L.) Hull. is an evergreen perennial plant of the Ericaceae family possesses noteworthy pharmacological properties and has long been used in traditional medicine for
addressing many medical conditions [1]. A plethora of bioactive compounds have been
discovered in C. vulgaris, with phenolics being the primary source of its diverse health benefits,
including antioxidant, anti-inflammatory, and antimicrobial properties, among others [2, 3]. However, a detailed study of its antiradical activity has not been conducted before. Herein, the supercritical CO2 extraction of C. vulgaris branches has been employed to obtain an extract rich in polyphenolic compounds. Supercritical CO2 extraction, a green technology method, replaces classical solvent-based extraction, enabling the isolation of plant compounds in their purest form without degradation of the sample [4]. Owing to its high sensitivity and specificity,
Electron paramagnetic resonance (EPR) spectroscopy has been utilized to access the extract's scavenging activity against free radical species (DPPH and hydroxyl radicals). The spin-trapping technique was employed to detect activity against short-lived hydroxyl radicals.
The results demonstrate that the C. vulgaris branch extract is a significant free-radical scavenger. It exhibited remarkable selectivity in eliminating hydroxyl radicals (68.5% compared to 21.7% for DPPH), which is particularly noteworthy as hydroxyl radicals are considered the most reactive oxygen radical species, biologically relevant, and responsible for a number of pathologies. These findings underscore the therapeutic potential of C. vulgaris branch extract in combating oxidative stress-related medical conditions but also suggest possibilities for further investigation into its mechanism of action and formulation into pharmaceutical or nutraceutical products
New record of the topmouth gudgeon (Pseudorasbora parva) in Rača River – an invasion of National park ″Tara″ waters (Serbia)
Get PDFThe topmouth gudgeon expanded its range invading the Rača River which is within the boundaries of the National Park "Tara". In September of 2018, eight individuals of this species was registered in the part of the stream downstream from the Rača monastery, which flows next to the monastery's carp pond. We believe that the main reason for the appearance of the topmouth gudgeon in Rača is associated with the escape of individuals from this pond. The average length of individuals was 5.8 ± 1.6 cm (range 3.6 – 8.1 cm) and weight 3.3 ± 2.1 g (range 1 –7 g). The topmouth gudgeon prefers warmer lowland waters, but it seems that it is also well acclimatized to colder small salmonid streams. The topmouth gudgeon should not have a significant impact on brown trout, but further monitoring will show whether its appearance requires taking some measures or if it is a temporary phenomenon
An Assessment of the Climate Change Impacts on the Distribution of the Glacial Relict Woodpecker Three-Toed Woodpecker Picoides tridactylus
No full textThe Three-Toed Woodpecker Picoides tridactylus is a rare and endangered woodpecker
on the Balkan Peninsula. Despite being widely distributed in Northern Europe, its distribution on
the Balkan Peninsula is limited to high-altitude forest habitats, where it represents a glacial relict.
Assessing the climate change impacts on its distribution can be crucial for improving the conservation and future survival of this specialist species on the Balkan Peninsula. We used species distribution modelling (SDM) to identify its potential distribution in the past (last interglacial and last glacial maximum), present, and future (2050 and 2070). Our results indicate that this species had the greatest distribution during the last glacial maximum, after which its distribution contracted to areas where suitable environment persisted (high altitudes). The largest territory of the Balkan Peninsula has an unsuitable environment for the species to inhabit, while highly suitable habitats have the smallest share in the total area of suitable habitats. All future models show a decrease in the area of suitable habitats compared with the current period, indicating that global warming has a negative effect on the distribution of the species. We recommend that conservation activities must be of greater extent to ensure the species’ survival in the Balkans
High-temperature water vapor sensors based on rare-earth-doped barium cerate
No full textIn this novel study, BaCe0.9Y0.1O3–δ, BaCe0.9Eu0.1O3–δ, BaCe0.9Nd0.1O3–δ, and BaCe0.9Dy0.1O3–δ powders were synthesized by the self-combustion method and processed into thick porous films (60–70 % porosity) to investigate the water vapor sensing properties in the 400–700 °C temperature range. All samples showed a stable response value to water vapor in the whole temperature range, expressed as impedance ratio in dry and wet argon (ZdryAr/ZwetAr), and were able to detect 0.03 vol% of water vapor at 550 °C within the impedance range of 103 Ω at 100 Hz. The response values increased with the partial pressure of water and decreased with the temperature, whereas the maximal value of 3.41 reached the BaCe0.9Eu0.1O3–δ sample at 550 °C and p(H2O) = 4.28 kPa. The average response time was several seconds and only slightly changed with the material type and experimental conditions. The recovery time depended on temperature and the ZdryAr/ZwetAr ratio, whereas the increase in the gas flow rate from 100 cm3/min to 200 cm3/min significantly reduced the recovery time for the BaCe0.9Eu0.1O3–δ sample from 230 s to 55 s at 550 °C and p(H2O) = 2.14 kPa. All the samples exhibited stability and a high degree of reversibility after multiple exchanges of wet and dry atmospheres at different temperatures. Yet, their tendency to deteriorate in the presence of CO2 might challenge a potential application in aggressive environments
PHENOL REMOVAL FROM WASTEWATER WITH HORSERADISH PEROXIDASE IMMOBILIZED BY PERIODATE METHOD ONTO NOVEL MACROPOROUS POLY(GMA-CO-EGDMA) CARRIERS
No full textOne of the most important environmental problems that need to be adressed is wastewater
contamination. Numerous reserarches have focused on solving the aforementioned problem by
applying immobilized enzymes. When horseradish peroxidase, the most commonly used enzyme, is
immobilized by one of many available methods on a suitable support, a biocatalyst with improved
properties in terms of increased stability and reusability, is obtained. Dispersion polymerization was
used for the synthesis of macroporous poly(GMA-co-EGDMA) copolymers with different pore size
diameters. Prior to immobilization of HRP onto these carriers, their amination with ethylenediamine
was performed. Periodate method was applied for the formation of covalent bond between the enzyme
and used copolymer. Increase in specific activity of immobilized peroxidase was noticed. The
copolymer with the pore size diameter of 297 nm showed the highest activity