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Huchen or Danube salmon Hucho hucho(Linnaeus 1758) is one of the largest salmonid species in the world and the largest species native to the Danube basin in Europe. In Serbia, this species inhabits the Drina river system, as well as the upper reaches of the River Ibar. It has already been introduced into the rivers Moravica and Đetinja, which are part of the Zapadna Morava catchment area. Most recently, huchen was stocked from its native habitat into the rivers Jerma and Nišava in the Južna Morava river system, and into the River Mlava which flows into the Danube. Huchen is listed as an endangered (EN) species on the IUCN Red List of Threatened Species and is protected in Serbia, and a Conservation Action Plan has already been adopted. In this report, we present the first record of this species in the River Grza, which is a part of the Velika Morava river system, outside its native range. The ichthyofauna of this recipient river consists of brown trout Salmo truttaL. and Eurasian minnow Phoxinus phoxinusL. In a small river of a fragile ecosystem such as this, the introduction of huchen as an apex predator can seriously harm the species of the native fish community, which warns of the illegal stocking measures currently in process.

Early exposure to digital media has become an integral part of everyday life, which is frequently being reported as one of potential risk factors for a number of developmental disorders, including language development in infants and toddlers. The current article represents introduction to a research study which will be dealing with a potential link between the risk of language delay and excessive screen media time in children. With this in mind, we will present three case reports involving young children who experienced a language delay, but did not have any health problems diagnosed, nor did they have any of the physical high-risk factors for language and other developmental disorders detected. What these three children have in common is the fact that they were all excessively exposed to digital media during the first two years of life. The existing empirical findings suggest that different forms of digital content may be overstimulating for the developing brain, which is true both for active and background screen viewing. Moreover, screen time may be seen as a distraction from other more developmentally important activities. Keeping parents informed about a potential negative influence of prolonged media exposure can prompt parents to make informed decisions about whether and to what extent they will expose their children to digital media in the earliest period of their development.

Globally, marine bioinvasions threaten marine ecosystem structure and function, with the Mediterranean Sea being one of the most affected regions. Such invasions are expected to increase due to climate change. We conducted a risk screening of marine organisms (37 fishes, 38 invertebrates, and 9 plants), both extant and ‘horizon’ (i.e., not present in the area but likely to enter it). Based on expert knowledge for the Eastern Adriatic Sea coasts of Slovenia, Croatia, and Montenegro, screenings were conducted under both current and predicted climate conditions indicating with an increase in sea surface temperature and salinity of the Adriatic Sea together with changes in precipitation regime. Our aims were to: (1) identify non-native extant and horizon marine species that may pose threats to native biodiversity and (2) evaluate the risk of invasiveness of the selected species under current and predicted climate conditions. Of the 84 species screened, there was an increase in those ranked as ‘high risk’ from 33 (39.3%) under current climate conditions and to 47 (56.0%) under global warming scenarios. For those ranked as ‘very high’ risk, the increase was from 6 (7.1%) to 21 (25.0%). Amongst the screened species, the already established high-risk species Pacific oyster Magallana gigasand Atlantic blue crab Callinectes sapidusrepresent a threat to ecosystem services. Given the under-representation of marine species in the current European Union List, the species we have ranked as high to very high risk should be included.

AbstractThis study presents primary observations of the natural diet of two endemic fishes, Delminichthys ghetaldiiand Telestes dabar, along with an examination of their niche overlap. The feeding habits of these species were analyzed based on a dataset comprising 115 specimens collected from five karst poljes during the year 2018. Statistical analyses, including one-way ANOVA and Tukey’s HSD post-hoc testing, were employed to discern significant differences in body size and weight among the five populations of Delminichthys ghetaldii. Numeric indices such as numerical abundance, weight percentage of abundance, and frequency of occurrence, alongside a composite index (IRI - index of relative importance), were applied to elucidate the feeding strategy of these species. The diversity of diet and poljes utilization was assessed using Simpson’s diversity index, while predation selectivity was analyzed through the electivity index. Considerable overlap in the diet of Delminichthys ghetaldiiwas observed among the five poljes, as well as in the overlap between these two species. The findings of this study indicate that Delminichthys ghetaldiiexhibits a zoophagous planktivorous diet, i.e. carnivorous, while Telestes dabardemonstrates a phytofagous planktivorous diet, i.e. herbivorous.

Abstract: The interesting property of coupling systems is the subsystems interaction and its representation. This paper presents the synchronization and resynchronization like one of that subsystems interaction possibility. The treated models of coupling system are models of coupled linear and nonlinear oscillators with elements of static and dynamic coupling and of two circular plates connected with rolling visco-elastic nonlinear layer. Mathematical models of such systems are built up using the D’Alamberts principle and Bernoulli’s method of particular integrals. Obtained systems of coupled differential nonlinear non homogeneous equations are the start points in numerical investigation of identical synchronization in modelled system. Depending of coefficient of coupling the effect of synchronization is less or more present. For complex coupling hybrid systems, such as the system of two plates coupled non-linear visco-elastic rolling layer, the occurrence of synchronization depends on a number of parameters and their relationships. In the presented hybrid systems the values of the coefficients of coupling : static, dynamic, nonlinearity, damping, which are needed and enough for identical synchronization were considered. Presented numerical way to analyze the appearance of synchronization provides an opportunity for verification of system parameters that are required for that, which is useful tool for shortening the time necessary for design of the system feature.

The paper presents phenomena of transient resonant jumps in the small, forced transversal oscillations of the coupled deformable bodies’ systems and the ways of their control. The representative system consists of the plates coupled with a layer of continuously distributed discrete elements with visco-elastic nonlinear rolling properties. However, the other deformable structures like coupled membranes, beams or belts also can be considered using mathematical phenomenology and structural analogies. The structural models consist of a set of two coupled non-homogenous partial non-linear differential equations. The problems to solve are divided into space and time domains by classical Bernoulli-Fourier method. In the time domains, the systems of coupled ordinary non-linear differential equations are completely analog for different systems of deformable bodies and are solved using the Krilov–Bogolyubov–Mitropolskiy asymptotic method. The first asymptotic approximation of the solutions for amplitude and phase difference of coupled time modes in every amplitude mode of small transversal oscillation of bodies was obtained. These solutions were further numerically solved in Mathematica ODE and Maple solver for analysis of amplitude and phase jumps in the resonant stationery and non-stationary transition regimes, the appearance of the newborn unstable branches and the main curve shifting after the transition. The result shows that the magnitude of the amplitude jumps decreases in the case of slower changes of the external excitation frequencies in the non-stationary regimes of oscillations. Thus, the parameter to control for stability in transient regimes is the rate of the external excitation frequency changes.

This paper presents an on-board multi-sensor system which is able to detect obstacles and estimate their distances in railway scenes in different illumination conditions. The system was developed within the H2020 Shift2Rail project SMART (Smart Automation of Rail Transport) and aims at increasing the safety of rail transport by detecting obstacles on the rail tracks ahead of a moving train in order to reduce the number of collisions. The system hardware consists of cameras of different types integrated into a specially designed housing, mounted on the front of the train. Multiple vision sensors complement each other in order to handle different illumination and environmental conditions. The system software uses a novel machine learning-based method that is suited to a particular challenge of railway operations, the need for long-range obstacle detection and distance estimation. The development of this method used a long-range railway dataset, which was specifically generated for this project. Evaluation results of reliable obstacle detection in various environmental conditions using the SMART RGB camera in day light illumination conditions and using the SMART Night Vision sensor in poor (night) illumination conditions are presented. The results demonstrate both the potential of the on-board SMART obstacle detection system in the operational railway environment and the benefit of the use of different cameras to be more independent of light and environmental conditions.

The paper presents a starting, but necessary comparative study between two diverse designs of single-seat tandem helicopter configuration, piston-propelled vs. electrically-driven. Both possibilities have their pros and cons, and need to be considered in detail, with respect to the initial requirements. In this investigation, the primary design objectives include 100 kg of payload as well as satisfactory performances in both hover and progressive flight. The comparison is conducted through the initial sizing procedures that enabled the estimation of takeoff mass (along with its main contributors), but also characteristic speeds, flight limits and basic helicopter performances. Used models and assumptions are explained in the paper. In the beginning, some essential advantages of tandem configuration helicopters are mentioned and accentuated. Also, future trends in electric aviation are considered. After that, total mass is decomposed into several main components and rotor dimensioning is performed. By assuming sufficient available power, it is possible to estimate the basic helicopter performances in both axisymmetric and progressive flight. Obtained results are presented graphically and numerically. In the end, some conclusions and recommendations for further research are given. For the time being, piston-propelled single-seat tandem helicopter can achieve better numerical results.

Objective.The aim of the study was to determine the association of family violence with the functioning of the family system, psychological functioning and development of specific characteristics of the adolescents who grew up in a violent families.

Claude V. Palisca (1921–2001) was a prominent American musicologist and music educator. He authored books and articles about Renaissance and Baroque music theory and developments in musicology, but is most widely known as the founder and first editor of the Norton Anthology of Western Music(NAWM) and coauthor of A History of Western Music, the two music history textbooks that are still in use in classrooms worldwide. In this article, we trace Palisca’s first idea of the NAWM’s structure, content, and purpose through his writings and activities between the 1950s and late 1970s. The central part among Palisca’s activities in music education belongs to his organization of the Yale Seminar on Music Education, his seminar report, and the listening curriculum designed to instill more balance between performance and academic study in largely performance-oriented public school music programs. In his listening curriculum, Palisca argued for emphasis on understanding music through listening within the historical and theoretical context of the music work, an approach he would later pursue in the NAWM. Palisca hinted that a similar teaching “package” is needed for the undergraduate level, thus identifying the listening curriculum from his Yale Seminar report as the first glimmer of the future NAWM.

ABSTRACTChicory (Cichorium intybusL.) is a medicinal and industrial plant from the Asteraceae family that produces a variety of sesquiterpene lactones (STLs), most importantly bitter guaianolides: lactucin, lactucopicrin and 8-deoxylactucin as well as their modified forms such as oxalates. These compounds have medicinal properties; however, they also hamper the extraction of inulin – a very important food industry product from chicory roots. The first step in guaianolide biosynthesis is catalyzed by germacrene A synthase (GAS) which in chicory exists in two isoforms – GAS long (encoded by CiGASlo) and GAS short (encoded by CiGASsh). AmiRNA silencing was used to obtain plants with reduced GASgene expression and level of downstream metabolites, guaianolide-15-oxalates, as the major STLs in chicory. This approach could be beneficial for engineering new chicory varieties with varying STL content, and especially varieties with reduced bitter compounds more suitable for inulin production.

The RNA-guided Cas9 endonuclease from Streptococcus pyogenesis a single-turnover enzyme that displays a stable product state after double-stranded-DNA cleavage. Here, we present cryo-EM structures of precatalytic, postcatalytic and product states of the active Cas9–sgRNA–DNA complex in the presence of Mg2+. In the precatalytic state, Cas9 adopts the ‘checkpoint’ conformation with the HNH nuclease domain positioned far away from the DNA. Transition to the postcatalytic state involves a dramatic ~34-Å swing of the HNH domain and disorder of the REC2 recognition domain. The postcatalytic state captures the cleaved substrate bound to the catalytically competent HNH active site. In the product state, the HNH domain is disordered, REC2 returns to the precatalytic conformation, and additional interactions of REC3 and RuvC with nucleic acids are formed. The coupled domain motions and interactions between the enzyme and the RNA-DNA hybrid provide new insights into the mechanism of genome editing by Cas9. Cryo-EM structures of the active Cas9–sgRNA–DNA complex in the presence of Mg2+capture Cas9 in the pre- and postcatalytic states as well as in the product-bound state, and reveal coupled domain motions and interactions between the enzyme and nucleic acids.

The major objective of this study was to investigate the impact of wastewaters on the level of genotoxicity and the possible reflection of genotoxicity on the genetic variability in chub (Squalius cephalus) collected from the sites under different pollution pressures along the Sava River. To emphasize the impact of wastewaters, this study was carried out in a season with low water discharge. The level of genotoxic potential at the sites was studied by alkaline and Fpg-modified comet assay in fish blood, while RAPD technique was employed on the fish muscle tissue. The variations in the genotoxic potential were observed along the Sava River based on the level of DNA damage in blood of the specimens collected at the selected sites. Clustering of the impacted sites was also observed based on RAPD fingerprints. Comparison of the data obtained in RAPD and the data from the comet assay indicated the possible reflection of genotoxicity on the genetic variability in chub collected from the sites with different pollution pressure. This is a preliminary study which reports the differentiation of the population of chub along the Sava River based on RAPD analysis.

The investigation of fish parasites in Bosnia and Herzegovina in recent years became significant, and therefore new records of parasitic trematodes and their hosts are important for better understanding of fish parasitology and pathology. In this study 41 parasitic specimens were collected and the basic taxonomical characters were measured (body length and width, diameter of oral and ventral sucker, length and width of pharynx, ovary length and width, testes length and width and eggs length and width). After the sampling of the parasites, they were collected and conserved in 70% ethanol. After that procedure the aforementioned characters were measured using Digimizer Image Analyzer Version 4.1. After all measurements, the trematode parasite Azygia robustawas confirmed for the first time on brown trout Salmo trutta. This first record was found in the Vrbas River near Banja Luka, Bosnia and Herzegovina (Sava River Basin). Former records of this parasite in Europe were observed on other salmonid fish species, as huchen Hucho hucho. This new record should be very important part of data of fish parasitology in Bosnia and Herzegovina.

ABSTRACTAminoacyl-tRNA synthetases (AaRSs) are ubiquitously expressed enzymes that ensure accurate translation of the genetic information into functional proteins. These enzymes also execute a variety of non-canonical functions that are significant for regulation of diverse cellular processes and that reside outside the realm of protein synthesis. Associations between faults in AaRS-mediated processes and human diseases have been long recognized. Most recent research findings strongly argue that 10 cytosolic and 14 mitochondrial AaRSs are implicated in some form of pathology of the human nervous system. The advent of modern whole-exome sequencing makes it all but certain that similar associations between the remaining 15 ARSgenes and neurologic illnesses will be defined in future. It is not surprising that an intense scientific debate about the role of translational machinery, in general, and AaRSs, in particular, in the development and maintenance of the healthy human neural cell types and the brain is sparked. Herein, we summarize the current knowledge about causative links between mutations in human AaRSs and diseases of the nervous system and briefly discuss future directions.

Seryl-tRNA synthetase (SerRS) attaches L-serine to the cognate serine tRNA (tRNASer) and the noncognate selenocysteine tRNA (tRNASec). The latter activity initiates the anabolic cycle of selenocysteine (Sec), proper decoding of an in-frame Sec UGA codon, and synthesis of selenoproteins across all domains of life. While the accuracy of SerRS is important for overall proteome integrity, it is its substrate promiscuity that is vital for the integrity of the selenoproteome. This raises a question as to what elements in the two tRNA species, harboring different anticodon sequences and adopting distinct folds, facilitate aminoacylation by a common aminoacyl-tRNA synthetase. We sought to answer this question by analyzing the ability of human cytosolic SerRS to bind and act on tRNASer, tRNASec, and 10 mutant and chimeric constructs in which elements of tRNASerwere transposed onto tRNASec. We show that human SerRS only subtly prefers tRNASerto tRNASec, and that discrimination occurs at the level of the serylation reaction. Surprisingly, the tRNA mutants predicted to adopt either the 7/5 or 8/5 fold are poor SerRS substrates. In contrast, shortening of the acceptor arm of tRNASecby a single base pair yields an improved SerRS substrate that adopts an 8/4 fold. We suggest that an optimal tertiary arrangement of structural elements within tRNASecand tRNASerdictate their utility for serylation. We also speculate that the extended acceptor-TΨC arm of tRNASecevolved as a compromise for productive binding to SerRS while remaining the major recognition element for other enzymes involved in Sec and selenoprotein synthesis.

Staphylococcus aureus is known worldwide as a frequent cause of mastitis in dairy cattle. Due to the production of heath resistant enterotoxins, this pathogen is also a major cause of food poisoning among humans, with symptoms of often severe vomiting and diarrhea. The aim of our study was to determine the prevalence of enterotoxinproducing strains of S. aureus originating from samples of cows with subclinical and clinical mastitis in the Republic of Serbia. Furthermore, we analyzed the type of staphylococcal enterotoxin they produce and phylogenetic relatedness among the S. aureus isolates recovered from milk in this study. Production of staphylococcal enterotoxins A, B, C, D and E was determined by commercial immunoenzyme assay VIDAS® SET2, and presence of corresponding genes encoding enterotoxin synthesis in positive isolates confi rmed by Polymerase Chain Reaction. Enterotoxin production was determined in 5 out of 75 (6.67%) isolates of S. aureus and all of them produced staphylococcal enterotoxins C. After analyzing the nucleotide sequence of the gene encoding the synthesis of staphylococcal protein A, S. aureus isolates were assigned into 2 phylogenetic groups, including 7 clusters. All S. aureus isolates with the presence of sec gene formed one cluster even dough they originated from milk samples from different farms.

Inerter devices are used in Formula 1 vehicles for a decade to reduce vertical and rolling displacement at the corner of the sharp racing curves and provide higher tire grip on racing challenges. To improve dynamics Formula SAE Car, several topological designs for suspension system are already proposed and published [1]. Based on our passive suspension system for quarter-car model, we carried out analysis for different parameters and under the impact from the road disturbance and demonstrated when integrated inerter device can increase ride comfort and decrease vertical displacement. Proposed solution system with integrated inerter mechanism can improve vehicle suspension systems development and have effects on dynamics and stability of a vehicle.

Spectrin and ankyrin participate in membrane organization, stability, signal transduction, and protein targeting; their interaction is critical for erythrocyte stability. Repeats 14 and 15 of βI-spectrin are crucial for ankyrin recognition, yet the way spectrin binds ankyrin while preserving its repeat structure is unknown. We have solved the crystal structure of the βI-spectrin 14,15 di-repeat unit to 2.1 Å resolution and found 14 residues critical for ankyrin binding that map to the end of the helix C of repeat 14, the linker region, and the B-C loop of repeat 15. The tilt (64°) across the 14,15 linker is greater than in any published di-repeat structure, suggesting that the relative positioning of the two repeats is important for ankyrin binding. We propose that a lack of structural constraints on linker and inter-helix loops allows proteins containing spectrin-like di-repeats to evolve diverse but specific ligand-recognition sites without compromising the structure of the repeat unit. The linker regions between repeats are thus critical determinants of both spectrin's flexibility and polyfunctionality. The putative coupling of flexibility and ligand binding suggests a mechanism by which spectrin might participate in mechanosensory regulation.

Spectrin and ankyrin participate in membrane organization, stability, signal transduction, and protein targeting; their interaction is critical for erythrocyte stability. Repeats 14 and 15 of βI-spectrin are crucial for ankyrin recognition, yet the way spectrin binds ankyrin while preserving its repeat structure is unknown. We have solved the crystal structure of the βI-spectrin 14,15 di-repeat unit to 2.1 Å resolution and found 14 residues critical for ankyrin binding that map to the end of the helix C of repeat 14, the linker region, and the B-C loop of repeat 15. The tilt (64°) across the 14,15 linker is greater than in any published di-repeat structure, suggesting that the relative positioning of the two repeats is important for ankyrin binding. We propose that a lack of structural constraints on linker and inter-helix loops allows proteins containing spectrin-like di-repeats to evolve diverse but specific ligand-recognition sites without compromising the structure of the repeat unit. The linker regions between repeats are thus critical determinants of both spectrin's flexibility and polyfunctionality. The putative coupling of flexibility and ligand binding suggests a mechanism by which spectrin might participate in mechanosensory regulation.

This investigation aimed to study a “green” non-toxic biodegradable copper corrosion inhibitor in an acidic sodium sulphate solution. The methods used in the investigation of cysteine as a copper corrosion inhibitor in an acidic sodium sulphate solution were: potentiodynamic measurements, open circuit potential measurements, and chronoamperometric measurements. Optical microscopy was used in addition to electrochemical methods. Potentiodynamic measurements show that cysteine has good inhibitory properties in an acidic medium. Polarisation curves indicate that the presence of cysteine in a sulphate solution decreases the current density and that using various cysteine concentrations results in the formation of a protective film on the surface of the electrode due to the formation of the Cu(I)-cys complex. These results are confirmed by chronoamperometric measurements. Furthermore, it is clear from microphotographs that a protective film does form on copper electrode in the presence of cysteine. The Langmuir adsorption isotherm indicates that cysteine is chemisorbed on the surface of the electrode.

Chemical composition and antibacterial activity of the essential oils isolated from fruits and leaves of Peucedanum austriacum(Jacq.) W.D.J. Koch were determined in order to define their medical potential. An analysis of leaf and fruit essential oils by gas chromatography (GC) and GC/mass spectrometry (GC/MS) resulted in identification of 141 different components, representing 93.6% and 96.1% of the total oils. The most abundant class of compounds in fruit essential oil was monoterpenoids (64.0%) and in the leaf essential oil sesquiterpenoids (82.0%). The major contributors of fruit essential oil were β-phellandrene (45.2%) and α-pinene (10.1%). The major constituents of leaf essential oil were caryophyllene oxide (23.1%), germacrene D (12.2%) and (E)-caryophyllene (10.2%). Minimal inhibitory (MIC) and minimal bactericidal concentrations (MBC) were determined by performing broth microdilution assay. In the antibacterial activity assay, both samples showed moderate activity against Bacillus subtilisand Staphylococcus aureuswith inhibitory effect at 0.625 and 1.25 mg/mL, weak activity against Pseudomonas aeruginosawith inhibitory effect at 5.00 mg/mL and no effect on the growth of bacteria Escherichia coliand Salmonella typhimurium. The results showed that essential oils composition of P. austriacumleaves and fruits differed considerably. Tested oils were proved selective antibacterial agents.

Cell-wall mechanical properties play a key role in the growth and the protection of plants. However, little is known about genuine wall mechanical properties and their growth-related dynamics at subcellular resolution and in living cells. Here, we used atomic force microscopy (AFM) stiffness tomography to explore stiffness distribution in the cell wall of suspension-cultured Arabidopsis thalianaas a model of primary, growing cell wall. For the first time that we know of, this new imaging technique was performed on living single cells of a higher plant, permitting monitoring of the stiffness distribution in cell-wall layers as a function of the depth and its evolution during the different growth phases. The mechanical measurements were correlated with changes in the composition of the cell wall, which were revealed by Fourier-transform infrared (FTIR) spectroscopy. In the beginning and end of cell growth, the average stiffness of the cell wall was low and the wall was mechanically homogenous, whereas in the exponential growth phase, the average wall stiffness increased, with increasing heterogeneity. In this phase, the difference between the superficial and deep wall stiffness was highest. FTIR spectra revealed a relative increase in the polysaccharide/lignin content.

The effect of purine (concentration range of 1.00 × 10−6–1.00 × 10−2 M) on the behavior of copper in a 0.5 M Na2SO4 solution (pH 7 and pH 9) was studied using the open circuit potential measurement, potentiodynamic polarization, and chronoamperometry. Potentiodynamic polarization shows that purine acts as a copper corrosion inhibitor in both alkaline and neutral sulfate solutions. The efficiency of inhibition increases as the purine concentration increases. Chronoamperometric results follow the same trend as the results of potentiodynamic polarization. The inhibition effect can also be observed visually by microscopic examination of the electrode surface. Purine is adsorbed on copper surface according to the Langmuir adsorption isotherm.

A case of exceptional assignment of prosody to loanwords is considered. In Serbo-Croatian, where in loanwords the original position of stress is generally preserved in some way, a small class of Latinate adjectives (e.g., "elementārna‘elementary’ and p"ersonālna‘personal’) become toneless and they display the postcyclic initial falling accent. An account of these data is proposed which combines a new approach to postcyclic prosody, which is shown to go hand in hand with syntactically opaque structures, and a new model of loanword integration, which views the loanword trajectory as lexicalisation. As a result, an enriched theory of both domains and their interaction arises to account for the data and shed some additional light on the position of loanwords in the architecture of the grammar/lexicon.

This paper reports about the occurrence of soft-muzzled trout in Montenegro. It was found only in the Zeta River, at three localities, always in low abundance. Results of genetic investigation on twelve microsatellite loci (i.e., high Fst and high heterozygozity values) as well as lack of hybridization with the putative brown trout unequivocally confirm that the soft-muzzled trout from the Zeta River is a species distinct from the putative brown (Salmo cf. farioides) and marble (Salmo marmoratus) trout that live in sympatry with it. This paper also confirms high genetic diversity of Zeta River soft - muzzled trout population. Habitat and feeding analyses revealed that soft-muzzled trout reduce the competition with syntopic putative brown trout by displacing as the bottom-dweller in their common type of habitat, as well as by narrowing its feeding niche and feeding dominantly with the benthic macroinvertebrates, the Gammarus shrimps as their far dominant feeding item. Results also revealed that they did not share the same habitat with marble trout. Due to this population low abundance and their importance on species level, Zeta River soft-muzzled trout conservation needs are urgent in terms of in situ protection and repopulation measures.

This paper discusses the problems of identifying external loads of multibucket machines for mechanization. External loads are dominantly dynamic with distinguished stochasticity in certain cases. The paper presents the procedures for determining external loads caused by resistance-to-excavation (for bucket wheel excavators) or grabbing soil (for bridge-type coal stacker-reclaimers), as well as a short description of the model upon which is based and defined the response of the stacker-reclaimer to the external changeable load. It points to the significance of the problem of identifying the external load, as well as to the potentially very detrimental and dangerous consequences of eventual shortcomings during solving the mentioned problem.

Huchen Hucho hucho from the Drina River (Serbia) revealed recently the decrease in breakpoint values for both standard length (Sl) and weight (w) in relation to the values recorded in 1999 from 110 cm to 98.4 cm and from 16.5 kg to 10.5 kg, respectively. That might indicate to the change in certain population parameters that could have an influence to the growth in the adult period of life.

The simple PVC‐based membrane containing N,N′,N″,N′′′‐tetrakis(2‐pyridylmethyl)‐1,4,8,11‐tetraazacyclotetradecane (tpmc) as an ionophore and dibutyl phthalate as a plasticizer, directly coated on a glassy carbon electrode was examined as a new sensor for Cu2+ions. The potential response was linear within the concentration range of 1.0×10−1–1.0×10−6M with a Nernstian slope of 28.8 mV/decade and detection limit of 7.0×10−7M. The electrode was used in aqueous solutions over a wide pH range (1.3–6). The sensor exhibited excellent selectivity for Cu2+ion over a number of cations and was successfully used in its determination in real samples.

ABSTRACTAmazon sailfin catfish Pterygoplichthys pardalis (Castelnau, 1855) (Loricariidae, Siluriformes) is a new non-indigenous fish species recorded in the Serbian section of the Danube River, being reported for the first time in inland waters of Europe, as well. A single, female fish was ripe and in good shape, although considering its original neotropical dispersal area and recording of occurrence in summer, with the only single female individual, its acclimatization is not likely. However, both its estimated invasive potential after the FISK protocol scoring of 26 and the risk of its introduction and establishment in the recipient area in concern after the IFRA protocol scoring of 61 should be considered moderate. That, together with the invasive history of this sailfin catfish and its congeners in south-eastern Asia and Meso-American region imposes a need for precaution.

The article presents the poem "Northwards," by Ifigenija Simonović, translated by Simonović and Kelly Lenox. First Line: The first walk. Away from the house. For the first time alone. Last Line: Without scales of lead.

The last step in ribosome-catalyzed protein synthesis is the hydrolytic release of the newly formed polypeptide from the P-site bound tRNA. Hydrolysis of the ester link of the peptidyl-tRNA is stimulated normally by the binding of release factors (RFs). However, an unacylated tRNA or just CCA binding to the ribosomal A site can also stimulate deacylation under some nonphysiological conditions. Although the sequence of events is well described by biochemical studies, the structural basis of the mechanism underlying this process is not well understood. Two new structures of the large ribosomal subunit of Haloarcula marismortui complexed with a peptidyl-tRNA analog in the P site and two oligonucleotide mimics of unacylated tRNA, CCA and CA, in the A site show that the binding of either CA or CCA induces a very similar conformational change in the peptidyl-transferase center as induced by aminoacyl-CCA. However, only CCA positions a water molecule appropriately to attack the carbonyl carbon of the peptidyl-tRNA and stabilizes the proper orientation of the ester link for hydrolysis. We, thus, conclude that both the ability of the O3'-hydroxyl group of the A-site A76 to position the water and the A-site CCA induced conformational change of the PTC are critical for the catalysis of the deacylation of the peptidyl-tRNA by CCA, and perhaps, an analogous mechanism is used by RFs.

The extraction of a coal-tar pitch with supercritical carbon dioxide was performed under optimal pressure, flow rate, and three different constant temperatures. The extraction kinetics was examined for each temperature and it was surprisingly found that the extraction rate of most components was governed by the first-order kinetics. It was assumed that this deviation from typical models of supercritical fluid extraction kinetics was caused by high pitch concentrations and low solubilities of the components.

In order to illuminate the phylogeography of brown trout (Salmo trutta) populations in the Balkan state of Serbia, the 561 bp 5'-end of mtDNA control region of 101 individuals originating from upland tributaries of the Danubian, Aegean and Adriatic drainages were sequenced and compared to corresponding brown trout sequences obtained in previous studies. Among 15 haplotypes found, 14 were considered native, representing the Danubian and Adriatic lineages of the brown trout, while one haplotype (ATcs1), found only in two individuals originating from two stocked rivers, corresponded to the Atlantic lineage and was considered introduced. Native haplotypes exhibited a strong geographic pattern of distribution: the Danubian haplotypes were strictly confined to the Danubian drainage, while the Adriatic haplotypes dominated in the Aegean and Adriatic drainages; most of the total molecular variance (69%) was attributed to differences among the drainages. Phylogenetic reconstruction, supplemented with seven haplotypes newly described in this study, suggested a sister position of the Atlantic-Danubian and Adriatic-Mediterranean-marmoratus ("southern") phylogenetic group, and pointed to the existence of a distinct clade, detected within the "southern" group. The data obtained confirmed our expectation of the existence of high genetic diversity in Balkan trout populations, and we recommend more widespread surveys covering trout stocks from the region.

This study examines the interspecific variability and phenetic relationships in six southern Adriatic mullet species: Mugil cephalus(Linnaeus, 1758), Chelon labrosus(Risso, 1826), Liza aurata(Risso, 1810), Liza ramada(Risso, 1826), Liza saliens(Risso, 1810), and Oedalechilus labeo(Cuvier, 1829). Twenty-three morphometric characteristics of the visceral skeleton and the dermatocranium of mullets were analyzed. The major distinguishing characters were those of the jaws. M. cephaluswas clearly separated from the other species; O. labeodiffered to a somewhat smaller extent; and C. labrosuswas the least distinguished species. The species of the genus Lizawere phenetically most similar, while the other species of mullet differed significantly from them. The greatest distances were between M. cephalusand C. labrosus, as well as between M. cephalusand O. labeo.This study examines the interspecific variability and phenetic relationships in six southern Adriatic mullet species: Mugil cephalus(Linnaeus, 1758), Chelon labrosus(Risso, 1826), Liza aurata(Risso, 1810), Liza ramada(Risso, 1826), Liza saliens(Risso, 1810), and Oedalechilus labeo(Cuvier, 1829). Twenty-three morphometric characteristics of the visceral skeleton and the dermatocranium of mullets were analyzed. The major distinguishing characters were those of the jaws. M. cephaluswas clearly separated from the other species; O. labeodiffered to a somewhat smaller extent; and C. labrosuswas the least distinguished species. The species of the genus Lizawere phenetically most similar, while the other species of mullet differed significantly from them. The greatest distances were between M. cephalusand C. labrosus, as well as between M. cephalusand O. labeo.

The present paper describes a simple, selective and sensitive kinetic method for the determination of trace amounts of molybdenum(VI) based on its inhibitory effect on the reaction oxidation of 4-hydroxycoumarine by KMnO4in the presence of hydrochloric acid, at pH 1.75 at 25°C. The rate of the indicator reaction was followed spectrophotometrically by measuring the decrease in the absorbance of KMnO4at 525 nm. The development method includes optimization of the reagent concentration and temperature. The calibration graph was linear in the range of concentrations from 20 to 200 ng/cm3of molybdenum(VI). The probable relative error was in the interval 3.10-10.52% for the concentration range of 200-20 ng/cm3molybdenum(VI), respectively. The interference effects of the foreign ions were determined to assess the selectivity of the method. The developed method was found to have relatively good selectivity, sensitivity, simplicity and rapidity. The proposed method was applied to the determination of molybdenum(VI) in a particular type of steel and alloy (hastelloy).

The exchange current density and the peak current density of the hydrogen electrode reaction on LmNi3.55Co0.75Mn0.4Al0.3 alloy electrode in an aqueous 1M KOH solution, at low hydrogen contents (<0.1 H/M) and elevated temperatures (42-60°C), were studied using potentiostatic polarization techniques. Both measured quantities increased linearly with the increase in hydrogen content in the alloy. On the basis of the difference between the activation energy of the charge transfer and the hydrogen diffusion, it was concluded that the charge transfer reaction represented the rate-determining step of the hydrogen electrode reaction under applied experimental conditions. The decrease of each of these two activation energies with increasing hydrogen content was evidenced, which indicated the existence of other processes occurring in the electrode bulk accompanying the hydrogen diffusion.

Abstract:: Properties of collinear and planar periodic orbits for the positronium negative ion are examined with respect to the possibilities for semiclassical quantization. In contrast to other two-electron atomic systems as helium and H- the relevant orbits for quantization are fully stable and permit a full torus quantization. However, for lower excitations the area of stability in phase-space is too small for a reliable torus quantization. Instead, a quasi-separability of the three-body system is used to apply effective one-dimensional (WKB) quantization.

Germination of lettuce seeds cv. May Queen iscompletely prevented either with 10 µM tetcyclacisor with continuous FR illumination. GA3and the N-substituted phtalimide, AC 94,377, werepartially effective in overcoming tetcyclacis-inducedinhibition but ineffective on photoinhibited seeds. FCcompletely reversed tetcyclacis inhibition and inducedca. 60% germination in continuous FR light. Aninteraction between FC and GA3(as well asbetween FC and AC 94,377) was evident in stimulationof germination under both inhibitory conditions.Interaction was calculated as a ratio of thepercentage of seeds germinated under the simultaneousaction of stimulators compared to their additiveeffect. This was 2.54 for tetcyclacis- and 2.95 forphotoinhibited seeds. It is concluded that thistype of interaction is promotive synergism. Themagnitude of the interaction was highest if theapplication of FC was delayed after GA3application, and the optimal time lag was 6 h fortetcyclacis-inhibited, or 24 h for photoinhibited seeds.

A semi-classical calculation of the discrete electronic spectrum for a hydrogenic atom located near a rigid wall, and the corresponding graphics of some of the energy levels as function of the nucleus–wall distance are presented. Calculations are based on the exact analytic solution of Newton equations of motion within a model which considers elastic collisions (EC) at the wall, followed by a primitive WKB quantization. This system can be used as a model for 2D and 3D quantum devices, such as shallow state of an impurity atom or Wannier-Mott exciton near to interfaces.

Floods affect people. Seldom, if ever, is complete control of floodwaters or prevention of all damages feasible. Making flood management decisions during the planning stage, flood fighting stage and post flood recovery stage, require comprehensive sets of criteria in order to properly account for all flood impacts. In most cases, economic criteria have been used to evaluate all flood impacts. This deficiency is addressed in the paper through the examination of data collected in the Canadian part of Red River Valley (Winnipeg and its surrounding) which has experienced the ‘Flood of the Century’ during April and May 1997. Both, quantitative and qualitative measures of social impacts are recommended for each stage of the flood management process and each type of the flood damage reduction measures to assist at different levels of decision making.

We study near-Lagrange collinear configurations in the three-dimensional three-body problem, with arbitrary gravitating masses. A general method, previously developed for Coulombian systems, which provides a unique formalism for treating few-body systems close to the breakup threshold, has been employed to study the motion of three bodies both for bounded and unbounded configurations. The dependence of the triple-escape function on the small total energy E has been evaluated, as well as ‘rovibronic configurations’ for bounded motion. An approximate characteristic constant is found for symmetrical systems, ?'/??, where ?' and ? are the vertical libration mode and rotational mode angular frequencies, respectively, and ? is the threshold exponent. For equal-mass systems this constant acquires the value 1.05288.

The new concept for optimization within the water resources master plan is the main topic of this paper. The proposed concept consists of using optimization in the two major phases of the complex procedure of master plan formulation. Optimization is first used for evaluating the possibilities of a multipurpose reservoir. This problem is solved when determining the water resources available for satisfying the water demand. This type of analysis is not often used in water resources analysis but it is found to be very useful at this stage of the master plan formulation. A single objective stochastic optimization algorithm, having a specific form of the objective function, is rcconmended for the solution of this problem.

Conclusions Our results indicate that both calcium intake and hormonal factors are important for the maintenance of bone structure. These findings might be relevant in setting up standards for calcium requirement.

The aim of this study was to carry out simulations and perform experimental quasi-static delamination tests in modes I and II to characterize the mechanical behavior at a hybrid interface. For that purpose, contact angle, infrared spectroscopy, and energy balance model results were obtained to characterize the physical interfacial energy behavior. The simulations and experimental tests presented similar values and trends, indicating that this is a viable method for predicting the critical fracture toughness of hybrid laminated composites. The low interfacial energy of the stitching (PS) and the epoxy matrix showed a decrease in the experimental strain energy release. The hybrid interface (carbon/glass/epoxy) showed an improvement in fracture toughness, which was physically elucidated through the synergy of high CF/epoxy interfacial energy strain combined with the toughness interaction via organosilane in GF/epoxy interface. In addition, the directional change in the micro-cracks generated between the two interfaces (rough fracture) requires an increase in energy to propagate the delamination as a result of the synergy between the CF and GF stiffness, also confirmed by the physical-based model.

Because Artemisia vulgarisL. and Artemisia albaTurra are traditional medicinal plants used for the treatment of different diseases, we evaluated the cytotoxic/apoptotic activity of ethyl acetate extracts from these natural products against human colon cancer cells SW-480. The extracts contained a large amount of the total polyphenols and flavonoids. The phenolic profile showed the presence of phenolic acids (gallic, p-coumaric, vanillic, and ferulic acids) and flavonoids (rutin, myricetin, luteolin, quercetin, and apigenin). 3-[4,5-Dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide assay indicated that antiproliferative activities of both A. vulgarisand A. albaextracts increased with the extension of time exposure, with decreasing IC50values. Mitomycin C (MMC) alone had antiproliferative activity, but in combination with plant extracts caused stronger effect with lower IC50values. Flow cytometry analyses showed that A. albaextract induced higher percentage of SW-480 cells in the early stage of apoptosis (33.5 ± 1.6 vs 0.7 ± 0.1, P< 0.05), whereas the A. vulgarisextract significantly increased the percentage of cells in necrosis (82.4 ± 5.0 vs 53.9 ± 2.3, P< 0.05). In conclusion, A. albaextract can be considered a potential source of bioactive components with anticancer activity or be used as a dietary food supplement or supplement to chemotherapy due to its synergistic effect with the MMC.

Cytomegalovirus (CMV) has a high prevalence worldwide, is often fatal for immunocompromised patients, and causes bone marrow suppression. Deficiency of signal transducer and activator of transcription 1 (STAT1) results in severely impaired antiviral immunity. We have used cell-type restricted deletion of Stat1to determine the importance of myeloid cell activity for the defense against murine CMV (MCMV). We show that myeloid STAT1 limits MCMV burden and infection-associated pathology in the spleen but does not affect ultimate clearance of infection. Unexpectedly, we found an essential role of myeloid STAT1 in the induction of extramedullary hematopoiesis (EMH). The EMH-promoting function of STAT1 was not restricted to MCMV infection but was also observed during CpG oligodeoxynucleotide-induced sterile inflammation. Collectively, we provide genetic evidence that signaling through STAT1 in myeloid cells is required to restrict MCMV at early time points post-infection and to induce compensatory hematopoiesis in the spleen.