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A. Grams, S. Mangesius, R. Steiger, I. Radović, A. Rietzler, Lisa-Maria Walchhofer, Malik Galijašević, J. Mangesius et al.

Brain parenchyma infiltration with glioblastoma (GB) cannot be entirely visualized by conventional magnetic resonance imaging (MRI). The aim of this study was to investigate changes in the energy and membrane metabolism measured with phosphorous MR spectroscopy (31P-MRS) in the presumably “normal-appearing” brain following chemoradiation therapy (CRT) in GB patients in comparison to healthy controls. Twenty (seven female, thirteen male) GB patients underwent a 31P-MRS scan prior to surgery (baseline) and after three months of standard CRT (follow-up examination. The regions of interest “contrast-enhancing (CE) tumor” (if present), “adjacent to the (former) tumor”, “ipsilateral distant” hemisphere, and “contralateral” hemisphere were compared, differentiating between patients with stable (SD) and progressive disease (PD). Metabolite ratios PCr/ATP, Pi/ATP, PCr/Pi, PME/PDE, PME/PCr, and PDE/ATP were investigated. In PD, energy and membrane metabolism in CE tumor areas have a tendency to “normalize” under therapy. In different “normal-appearing” brain areas of GB patients, the energy and membrane metabolism either “normalized” or were “disturbed”, in comparison to baseline or controls. Differences were also detected between patients with SD and PD. 31P-MRS might contribute as an additional imaging biomarker for outcome measurement, which remains to be investigated in a larger cohort.

Dragana Šnjegota, A. V. Stronen, Barbara Boljte, D. Ćirović, M. Djan, D. Huber, Maja Jelenčič, M. Konec et al.

Abstract The Balkan Peninsula and the Dinaric Mountains possess extraordinary biodiversity and support one of the largest and most diverse wolf (Canis lupus) populations in Europe. Results obtained with diverse genetic markers show west‐east substructure, also seen in various other species, despite the absence of obvious barriers to movement. However, the spatial extent of the genetic clusters remains unresolved, and our aim was to combine fine‐scale sampling with population and spatial genetic analyses to improve resolution of wolf genetic clusters. We analyzed 16 autosomal microsatellites from 255 wolves sampled in Slovenia, Croatia, Bosnia and Herzegovina (BIH), and Serbia and documented three genetic clusters. These comprised (1) Slovenia and the regions of Gorski kotar and Lika in Croatia, (2) the region of Dalmatia in southern Croatia and BIH, and (3) Serbia. When we mapped the clusters geographically, we observed west‐east genetic structure across the study area, together with some specific structure in BIH–Dalmatia. We observed that cluster 1 had a smaller effective population size, consistent with earlier reports of population recovery since the 1980s. Our results provide foundation for future genomic studies that would further resolve the observed west‐east population structure and its evolutionary history in wolves and other taxa in the region and identify focal areas for habitat conservation. They also have immediate importance for conservation planning for the wolves in one of the most important parts of the species’ European range.

Steve W. C. Chang, Andrew B. Schultz, Ismar Volic

Institute for Mathematics and Democracy The Institute for Mathematics and Democracy (IMD)1 was created to help cast light on the important role that mathematics plays in our political systems. Founded in 2019, it is housed at Wellesley College, a liberal arts institution with a strong interest in interdisciplinary work. The mission of IMD is to promote a deeper understanding of the mathematics that underlies many socioeconomic forces and political processes so that citizens can make informed political decisions and effect meaningful change. It supports research, teaching, and outreach in mathematics and democracy, and brings together educators and activists who recognize the importance of political quantitative literacy. It acts as a facilitator, a repository, and nexus to bring research and pedagogy of disparate individuals who synthesize mathematics and democracy in their research and teaching. The timeliness of these efforts is apparent as IMD is finding a wide and growing audience among students, researchers, educators, activists, and the public at large. Over thirty mathematicians now serve as scholars and affiliates for IMD, many of whom have pursued or supervised research, run summer programs, or created curricula at the intersection of politics and mathematics. The institute has also supported over twenty student researchers, almost half of them from underrepresented groups. The activities of IMD are rooted and motivated by mathematics, but they lie at the unique interdisciplinary interface of mathematics, statistics, political science, economics, and history. Not only do they fill an evident educational and research gap, but they serve a social purpose: political

Kayla Bohlke, Xiaonan Zhu, P. Sparto, M. Redfern, C. Rosano, E. Sejdić, A. Rosso

Dual-task balance studies explore interference between balance and cognitive tasks. This study is a descriptive analysis of accelerometry balance metrics to determine if a verbal cognitive task influences postural control after the task ends. Fifty-two healthy older adults (75 ± 6 years old, 30 female) performed standing balance and cognitive dual-tasks. An accelerometer recorded movement from before, during, and after the task (reciting every other letter of the alphabet). Thirty-six balance metrics were calculated for each task condition. The effect of the cognitive task on postural control was determined by a generalized linear model. Twelve variables, including anterior–posterior centroid frequency, peak frequency and entropy rate, medial-later entropy rate and wavelet entropy, and bandwidth in all directions, exhibited significant differences between baseline and cognitive task periods, but not between baseline and post-task periods. These results indicate that the verbal cognitive task did alter balance, but did not bring about persistent effects after the task had ended. Traditional balance measurements, i.e., root mean square and normalized path length, notably lacked significance, highlighting the potential to use other accelerometer metrics for the early detection of balance problems. These novel insights into the temporal dynamics of dual-task balance support current dual-task paradigms to reduce fall risk in older adults.

A. Suri, J. VanSwearingen, M. Redfern, E. Sejdić, A. Rosso

Abstract Community mobility involves walking with physical and cognitive challenges. In older adults (N=116; results here from initial analyses: N=29, Age=75±5 years, 51% females), we assessed gait speed and smoothness (harmonic-ratio) while walking on even and uneven surfaces, with or without an alternate alphabeting dual-task (ABC). ANOVA assessed surface and dual-task effects; Pearson correlations compared gait with global cognition and executive function composite z-scores. The four conditions (even, uneven, even-ABC and uneven-ABC) affected speed(m/s) (0.97±0.14 vs 0.90±0.15 vs 0.83±0.17 vs 0.79±0.16). Smoothness (2.19±0.48 vs 1.89±0.38 vs 1.92±0.53 vs 1.7±0.43) was affected by only surface (controlled for speed). Greater speed was associated with better global cognition(ρ=0.47 to 0.49, p<0.05) for all conditions and with better executive function for even-ABC(ρ=0.39, p=0.04) and uneven-ABC(ρ=0.40, p=0.03). Executive function was associated with smoothness during even(ρp=-0.42, p=0.03) and uneven(ρp=-0.39, p=0.04) walking. Type of walking challenge differentially affects gait quality and associations with cognitive function.

S. Brkić, Radovan Kastratović, Mirela Abidović Salkica

Abstract Although research of intra-industry trade (IIT) has been intensive in the last several decades, the empirical literature focusing on this phenomenon in the Western Balkans countries remains limited, especially in agricultural sector. Aiming to contribute to the existing literature, the paper analyses patterns and country-specific determinants of IIT in agri-food products between Bosnia and Herzegovina (BiH) and the European Union (EU) during the period of their mutual trade liberalisation (2008-2018). The analysis employs Grubel-Lloyd indices and Greenaway-Hine-Milner methodology for measurement of IIT, and applies an econometric panel data model using a Poisson Pseudo-maximum likelihood approach in order to estimate effects of IIT determinants. The findings suggest that intra-industry agri-food trade of BiH with the EU is of low intensity and mainly of vertical nature, viewed totally and bilaterally. We found significant positive effects of trading countries’ sizes, common border and history on IIT, and negative effects of the geographic distance and differences in agricultural productivity.

Yuzhi Zhou, Jinlong Sun, Jie Yang, Guan Gui, H. Gačanin, F. Adachi

The development of the internet of things (IoT) and smart cities, combined with the widespread usage of cooperative or independent air traffic surveillance systems such as automatic dependent surveillance-broadcast (ADS-B) bring about novel deployment paradigms in air-ground integrated vehicular net-works (AGVN). However, compared with the evolutional physical layer advancing, the communication protocols such as TCP/IP protocol, which are listed on the top of communication protocol stacks, have relatively constricted developments due to their fixed frameworks. The most obvious manifestation of this trend is that these protocols can hardly extend interfaces to maximize the benefits brought by bottom layer upgrades. In view of the above problems, in this paper, we propose a novel handover strategy based on side information of the ADS- B for AG VN. Firstly, a practical scheme of combination between TCP/IP protocol and ADS-B, which is implemented in the Network simulation, version-3 (ns-3), is proposed to adapt the AGVN handover tasks. Secondly, the configuration, timing sequence and parameters, as well as hand over strategies of the scheme are proposed in detail with the modules called by ns-3 simulator. Finally, the experimental results are provided to validate the handover strategies.

Jun Zeng, Jinlong Sun, Guan Gui, B. Adebisi, T. Ohtsuki, H. Gačanin, H. Sari

In this paper, a channel state information (CSI) feedback method is proposed based on deep transfer learning (DTL). The proposed method addresses the problem of high training cost of downlink CSI feedback network in frequency division duplexing (FDD) massive multiple-input multiple-output (MIMO) systems. In particular, we obtain the models of different wireless channel environments at low training cost by fine-tuning the pre-trained model with a relatively small number of samples. In addition, the effects of different layers on training cost and model performance are discussed. Furthermore, a model-agnostic meta-learning (MAML)-based method is proposed to solve the problem associated with large number of samples of a wireless channel environment required to train a deep neural network (DNN) as a pre-trained model. Our results show that the performance of the DTL-based method is comparable with that of the DNN trained with a large number of samples, which demonstrates the effectiveness and superiority of the proposed method. At the same time, although there is a certain performance loss compared with the DTL-based method, the MAML-based method shows good performance in terms of the normalized mean square error (NMSE).

Wenjuan Shi, Yanjing Sun, Miao Liu, Hua Xu, Guan Gui, T. Ohtsuki, B. Adebisi, H. Gačanin et al.

This paper proposes an unmanned aerial vehicle (UAV)-aided full-duplex non-orthogonal multiple access (FD-NOMA) method to improve spectrum efficiency. Here, UAV is utilized to partially relay uplink data and achieve channel differentiation. Successive interference cancellation algorithm is used to eliminate the interference from different directions in FD-NOMA systems. Firstly, a joint optimization problem is formulated for the uplink and downlink resource allocation of transceivers and UAV relay. The receiver determination is performed using an access-priority method. Based on the results of the receiver determination, the initial power of ground users (GUs), UAV, and base station is calculated. According to the minimum sum of the uplink transmission power, the Hungarian algorithm is utilized to pair the users. Secondly, the subchannels are assigned to the paired GUs and the UAV by a message-passing algorithm. Finally, the transmission power of the GUs and the UAV is jointly fine-tuned using the proposed access control methods. Simulation results confirm that the proposed method achieves higher performance than state-of-the-art orthogonal frequency division multiple-access method in terms of spectrum efficiency, energy efficiency, and access ratio of the ground users.

Abstract The security of using applications in cloud services and on the Internet is an important topic in the field of engineering. In this paper, two laboratory tests for data transmission protection, specifically designed for different security analysis techniques, are presented and explained. During lab tests on public Wi-Fi networks from the MIDM (“Man in the Middle”) attacks, various monitoring techniques were applied, using a special lab test scenario with Kali Linux penetration tools by creating an SSH tunnel on an Android mobile device. These test benches allow easy data capturing, and the captured data is processed using available software programs. Expected outcomes, practical improvement and security performance assessment are presented in detail, and considered in terms of their value in security engineering. The aim of this paper is to detect and overcome some of the weaknesses of the application of security protocols in a Wi-Fi network environment.

Purpose – Purpose of this study is to understand how diaspora tourists as a specific tourist segment symbolically extend their holiday in the country of origin upon returning to the country of current living. Methodology – Aim of the research was to disclose underlying meanings of this specific consumption pattern. Data was collected through 24 semi-structured in-depth interviews with diaspora members from Bosnia and Herzegovina. Analysis was inductive, starting with microanalysis, proceeding then with axial coding around the revealed concept. Throughout analysis the comparative method was applied, alongside researcher's diary and memos as analytic tools. Findings – The concept of ‘bridging’ explains how diaspora tourists cross over from one reality to another on a symbolical level, i.e. when travelling back from the country of origin. It also is a symbolical bridging between complex of identities: the past identities and the present identity, which they have constructed in countries of current living. They seem to use two major strategies: storytelling and product stocking. Contribution – This paper reveals a new concept among diaspora tourists, i.e. their approach to extend their visit to the country of their origin on a symbolical level by using symbolically laden products. The research is further contributing by disclosing that diaspora tourists apply two different strategies in order to symbolically extend their home country holiday: the story telling strategy and the stocking strategy. Finally, it also suggests that the stocking strategy has two phases; the first phase being 'symbolic representation filling phase' and the second phase labelled as 'mainstream trend purchase phase'.

I. Masic, A. Kurjak, S. Janković, O. Sinanović, D. Donev, B. Djulbegovic, Kenan I. Arnautovic, M. Zildžić et al.

It is very well known that science is world activity and that there is no good and bad work in the field of scientific research. Nowadays scientific productivity of the individuals, learned societies on regional or state level are measurable parameters. In most of the systems it does include the number of original scientifi papers, quality of journals measured by impact factor and scientific citation index (1-4). There are also additional measurable parameters but for the purpose of this meeting we will avoid discussion about them. New field of scientometrics using the help of impartial and ruthless machines (computers) do help very significantly in evaluation of scientific productivity anywhere in the world. Unfortunately, there are many misused conclusions and interpretation on the data offered by computers. It is clear that some vital important changes are urgently needed. Today’s conference should use rare opportunity having together experts in the field to discuss the problems visible now. This author intends to discuss facts and doubts in writing review articles and chapters in the book (5). Some important flexibility in citation, in particular self citation, should be analyzed. An illustrative examples from author’s own experience will be shown and discussed at the meeting.

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