Dominance hierarchies of social animal groups are influenced by complex factors such as stress. Stress experienced by an animal prior to social interactions with a conspecific may be a determinant of their future social dynamics. Additionally, long-term occupancy of a specific hierarchical rank can have psychophysiological effects, leading to vulnerability to future stress. The current study aimed to delineate differential effects of stress acting before or after hierarchy formation. Using the chronic social defeat stress (CSDS) paradigm we performed behavioural investigations to determine whether exposure to CSDS before hierarchy formation predicted the new dominance status. Moreover, in another study we investigated whether social rank predicted stress vulnerability. We found that CSDS did not impede the establishment of dominance in new hierarchies as both stress-susceptible (socially avoidant) and –resilient (social) mice were able to attain dominant ranks. In contrast, within newly established hierarchies of stress-naïve mice, the subordinate, but not dominant, mice exhibit significantly greater avoidance of novel social targets. However, following exposure to CSDS, both lowest- and highest-ranked mice exhibit strong susceptibility to stress as measured by decreased interactions with a novel social target. These results suggest that the response to chronic social stress did not determine social rank in new cohorts, but low-status mice in newly established groups exhibited lower sociability to novel social targets. Interestingly, exposure of a hierarchical social group to chronic social stress led to stress-susceptibility in both high- and low-status mice as measured by social interaction. Highlights Stress susceptibility to chronic social defeat did not impede the establishment of dominance in new hierarchies. Subordinate mice exhibit reduced social preference after hierarchy formation. Following chronic social defeat stress, both subordinate and dominant mice exhibit susceptible-like reduction in social interaction, but dominant mice exhibit the greater decrease in social preference as compared to baseline.

Summary A number of risk behaviours, such as smoking, overweight, excessive alcohol intake, insufficient physical activity, excessive and frequent intake of salt, reduced fruit and vegetable intake, increased fat intake, which constitute living habits of an individual can influence the occurrence of hypertension and hyperglycaemia. The changing of these lifestyles can reduce the risk of developing prehypertension and prediabetes. The survey was conducted at student’s campuses. The respondents were subjected to the height, weight, blood glucose and blood pressure. Respondents filled in previously created questionnaire that was approved by the Ethics Committee for Biomedical Research Faculty of Pharmacy, University of Belgrade. The percentage of respondents with a glucose value above the reference value was 14.6% (n=19), 2.4% (n=3) had values greater than 7 mmol/L without being diagnosed with diabetes, and accordingly, 2.4% (n=3) had elevated HbA1c values (above 42 mmol/mol or 6.0%). The percentage of respondents with elevated systolic and diastolic blood pressure was 14.9% and 7.4% respectively. Regarding calculated risk scores, they showed parallel increase with increas-ing of BMI (HPS), systolic and diastolic pressure (OHS), and glucose concentration (OPS). When analysing all the factors that could cause the later development of diabetes, which is associated with hypertension as well, it is observed that the student population is very much exposed to those factors. The results of this study cannot be representative for the general population of students, but they can provide recommendations for further research.

In March 2015, a few days after a major horse fair event in Bjelovar, Croatia, an equine influenza outbreak began and in the days that followed spread to more than 20 stud farms in the continental part of Croatia. The epidemiological investigation showed the importance of the national and international movement of asymptomatic carrier animals as a major risk factor for the introduction of the equine influenza virus and its spread in the naïve population. Molecular characterization and phylogenetic analyses confirmed that the EI outbreak was caused by an imported viral strain of the H3N8 subtype, phylogenetically similar to recent European strains belonging to Florida sublineage clade 2. The post-outbreak equine influenza seroprevalence in continental Croatia, based on ELISA testing, was 12.3% and varied between 1.1% and 32.6% on a county level. The highest seroprevalence in counties with predominantly sport and leisure horses highlighted animal management as a principal risk factor for equine influenza infection. On the other hand, variations in haemagglutination inhibition titres in the tested serum samples suggested different times of infection acquisition and unreported outbreaks of equine influenza in continental Croatia after the 2015 outbreak. Vaccination coverage, even after the large outbreak in 2015, was still below 10%, which suggests the lack of education of horse owners and represents a high risk for further outbreaks. In conclusion, influenza is a wide spread infection with multiple, often unrecorded, outbreaks in continental Croatia. A high risk of further outbreaks is present due to low vaccination coverage, an increase in the sport and leisure horse population and the intensive movement of those animals. In order to prevent *Corresponding author: Ljubo Barbić, PhD, DVM, Department of Microbiology and Infectious Diseases with Clinic, Faculty of Veterinary Medicine, University of Zagreb, Heinzelova 55, 10000 Zagreb, Croatia, Phone: +385 1 2390 211; Fax: +385 1 2390 211; E-mail: ljubo.barbic@vef.hr DOI: 10.24099/vet.arhiv.0033

Single hidden layer feed forward neural networks are widely used for various practical problems. However, the training process for determining synaptic weights of such neural networks can be computationally very expensive. In this paper we propose a new learning algorithm for learning the synaptic weights of the single hidden layer feedforward neural networks in order to reduce the learning time. We propose combining the upgraded bat algorithm with the extreme learning machine. The proposed approach reduces the number of evaluations needed to train a neural network and efficiently finds optimal input weights and the hidden biases. The proposed algorithm was tested on standard benchmark classification problems and functions and compared with other approaches from literature. The results have shown that our approach produces a satisfactory performance in almost all cases and that it can obtains solutions much faster than the traditional learning algorithms.

Article history: Received 20 February 2018 Received in revised form 26 April 2018 Accepted 2 May 2018 An evaluation of aerodynamic forces and moments that act on an irregularly shaped body (fragments of HE projectile) moving at high velocities was made, using numerical simulations, analytical models, and CAD methods. Using the results obtained for aerodynamic forces and moments, and known values of body exposed area, aerodynamic drag and lift coefficients were determined for different body orientations and different flow velocity. Analysis of the influence of the body front surface and body slenderness on the position of the maximum CD value (on the CD (Ma) curve) was performed.

Abstract The tumour suppressor p53, encoded by TP53, is a key player in a wide network of signalling pathways. We investigated its role in the bioactivation of the environmental carcinogen 3-nitrobenzanthrone (3-NBA)found in diesel exhaust and its metabolites 3-aminobenzanthrone (3-ABA) and N-hydroxy-3-aminobenzanthrone (N-OH-3-ABA) in a panel of isogenic human colorectal HCT116 cells differing only with respect to their TP53 status [i.e. TP53(+/+), TP53(+/−), TP53(−/−), TP53(R248W/+) or TP53(R248W/−)]. As a measure of metabolic competence, DNA adduct formation was determined using 32P-postlabelling. Wild-type (WT) p53 did not affect the bioactivation of 3-NBA; no difference in DNA adduct formation was observed in TP53(+/+), TP53(+/−) and TP53(−/−) cells. Bioactivation of both metabolites 3-ABA and N-OH-3-ABA on the other hand was WT-TP53 dependent. Lower 3-ABA- and N-OH-3-ABA-DNA adduct levels were found in TP53(+/−) and TP53(−/−) cells compared to TP53(+/+) cells, and p53’s impact was attributed to differences in cytochrome P450 (CYP) 1A1 expression for 3-ABA whereas for N-OH-3-ABA, an impact of this tumour suppressor on sulphotransferase (SULT) 1A1/3 expression was detected. Mutant R248W-p53 protein function was similar to or exceeded the ability of WT-p53 in activating 3-NBA and its metabolites, measured as DNA adducts. However, identification of the xenobiotic-metabolising enzyme(s) (XMEs), through which mutant-p53 regulates these responses, proved difficult to decipher. For example, although both mutant cell lines exhibited higher CYP1A1 induction after 3-NBA treatment compared to TP53(+/+) cells, 3-NBA-derived DNA adduct levels were only higher in TP53(R248W/−) cells but not in TP53(R248W/+) cells. Our results show that p53’s influence on carcinogen activation depends on the agent studied and thereby on the XMEs that mediate the bioactivation of that particular compound. The phenomenon of p53 regulating CYP1A1 expression in human cells is consistent with other recent findings; however, this is the first study highlighting the impact of p53 on sulphotransferase-mediated (i.e. SULT1A1) carcinogen metabolism in human cells.