| 1. |
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| 2. |
- Poyatos, R., et al.
(author)
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Global transpiration data from sap flow measurements: the SAPFLUXNET database
- 2021
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In: Earth System Science Data. - : Copernicus GmbH. - 1866-3508 .- 1866-3516. ; 13:6, s. 2607-2649
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Journal article (peer-reviewed)abstract
- Plant transpiration links physiological responses of vegetation to water supply and demand with hydrological, energy, and carbon budgets at the land-atmosphere interface. However, despite being the main land evaporative flux at the global scale, transpiration and its response to environmental drivers are currently not well constrained by observations. Here we introduce the first global compilation of whole-plant transpiration data from sap flow measurements (SAPFLUXNET, https://sapfluxnet.creaf.cat/, last access: 8 June 2021). We harmonized and quality-controlled individual datasets supplied by contributors worldwide in a semi-automatic data workflow implemented in the R programming language. Datasets include sub-daily time series of sap flow and hydrometeorological drivers for one or more growing seasons, as well as metadata on the stand characteristics, plant attributes, and technical details of the measurements. SAPFLUXNET contains 202 globally distributed datasets with sap flow time series for 2714 plants, mostly trees, of 174 species. SAPFLUXNET has a broad bioclimatic coverage, with woodland/shrubland and temperate forest biomes especially well represented (80 % of the datasets). The measurements cover a wide variety of stand structural characteristics and plant sizes. The datasets encompass the period between 1995 and 2018, with 50 % of the datasets being at least 3 years long. Accompanying radiation and vapour pressure deficit data are available for most of the datasets, while on-site soil water content is available for 56 % of the datasets. Many datasets contain data for species that make up 90 % or more of the total stand basal area, allowing the estimation of stand transpiration in diverse ecological settings. SAPFLUXNET adds to existing plant trait datasets, ecosystem flux networks, and remote sensing products to help increase our understanding of plant water use, plant responses to drought, and ecohydrological processes. SAPFLUXNET version 0.1.5 is freely available from the Zenodo repository (https://doi.org/10.5281/zenodo.3971689; Poyatos et al., 2020a). The "sapfluxnetr" R package - designed to access, visualize, and process SAPFLUXNET data - is available from CRAN.
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| 3. |
- Kattge, Jens, et al.
(author)
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TRY plant trait database - enhanced coverage and open access
- 2020
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In: Global Change Biology. - : Wiley-Blackwell. - 1354-1013 .- 1365-2486. ; 26:1, s. 119-188
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Journal article (peer-reviewed)abstract
- Plant traits-the morphological, anatomical, physiological, biochemical and phenological characteristics of plants-determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait-based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits-almost complete coverage for 'plant growth form'. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait-environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives.
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| 4. |
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| 5. |
- Stojanovic, M. G., et al.
(author)
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Localized modes in linear and nonlinear octagonal-diamond lattices with two flat bands
- 2020
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In: Physical Review A: covering atomic, molecular, and optical physics and quantum information. - : AMER PHYSICAL SOC. - 2469-9926 .- 2469-9934. ; 102:2
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Journal article (peer-reviewed)abstract
- We consider a two-dimensional octagonal-diamond network with a fine-tuned diagonal coupling inside the diamond-shaped unit cell. Its linear spectrum exhibits coexistence of two dispersive bands (DBs) and two flat bands (FBs), touching one of the DBs embedded between them. Analogous to the kagome lattice, one of the FBs will constitute the ground state of the system for a proper sign choice of the Hamiltonian. The system is characterized by two different flat-band fundamental octagonal compactons, originating from the destructive interference of fully geometric nature. In the presence of a nonlinear amplitude (on-site) perturbation, the singleoctagon linear modes continue into one-parameter families of nonlinear compact modes with the same amplitude and phase structure. However, numerical stability analysis indicates that all strictly compact nonlinear modes are unstable, either purely exponentially or with oscillatory instabilities, for weak and intermediate nonlinearities and sufficiently large system sizes. Stabilization may appear in certain ranges for finite systems and, for the compacton originating from the band at the spectral edge, also in a regime of very large focusing nonlinearities. In contrast to the kagome lattice, the latter compacton family will become unstable already for arbitrarily weak defocusing nonlinearity for large enough systems. We show analytically the existence of a critical system size consisting of 12 octagon rings, such that the ground state for weak defocusing nonlinearity is a stable single compacton for smaller systems, and a continuation of a nontrivial, noncompact linear combination of single compacton modes for larger systems. Investigating generally the different nonlinear localized (noncompact) mode families in the semi-infinite gap bounded by this FB, we find that, for increasing (defocusing) nonlinearity the stable ground state will continuously develop into an exponentially localized mode with two main peaks in antiphase. At a critical nonlinearity strength a symmetry-breaking pitchfork bifurcation appears, so that the stable ground state is single peaked for larger defocusing nonlinearities. We also investigate numerically the mobility of localized modes in this regime and find that the considered modes are generally immobile both with respect to axial and diagonal phase-gradient perturbations.
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| 6. |
- Dhiman, Vinit, et al.
(author)
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Multiband optical variability of the TeV blazar PG 1553+113 in 2019
- 2022
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In: Monthly notices of the Royal Astronomical Society. - : Oxford University Press (OUP). - 0035-8711 .- 1365-2966. ; 519:2, s. 2796-2811
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Journal article (peer-reviewed)abstract
- We report the flux and spectral variability of PG 1553 + 113 on intra-night (IDV) to short-term time-scales using BVRI data collected over 91 nights from 28 February to 8 November 2019 employing 10 optical telescopes: three in Bulgaria, two each in India and Serbia, and one each in Greece, Georgia, and Latvia. We monitored the blazar quasi-simultaneously for 16 nights in the V and R bands and 8 nights in the V, R, I bands and examined the light curves (LCs) for intra-day flux and colour variations using two powerful tests: the power-enhanced F-test and the nested ANOVA test. The source was found to be significantly (>99 per cent) variable in 4 nights out of 27 in R-band, 1 out of 16 in V-band, and 1 out of 6 nights in I-band. No temporal variations in the colours were observed on IDV time-scale. During the course of these observations the total variation in R-band was 0.89 mag observed. We also investigated the spectral energy distribution (SED) using B-, V-, R-, and I-band data. We found optical spectral indices in the range of 0.878 +/- 0.029 to 1.106 +/- 0.065 by fitting a power law (F-nu proportional to nu(-alpha)) to these SEDs of PG 1553 + 113. We found that the source follows a bluer-when-brighter trend on IDV time-scales. We discuss possible physical causes of the observed spectral variability.
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| 7. |
- Simic, M., et al.
(author)
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Parameter Estimation of the Single-Dispersion Fractional Cole-Impedance Model With the Embedded Hardware
- 2023
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In: IEEE Sensors Journal. - : Institute of Electrical and Electronics Engineers (IEEE). - 1530-437X .- 1558-1748. ; 23:12, s. 12978-12987
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Journal article (peer-reviewed)abstract
- Bioimpedance modeling with equivalent electrical circuits has an important role in various biomedical applications, as it facilitates understanding of underlying physical and electrochemical processes in applications such as body composition measurements and assessment of clinical conditions. However, the estimation of model parameter values is not a straightforward task, especially when complex circuits with fractional-order components [e.g., constant phase elements (CPEs)] are used. In this article, we propose a low-complexity method for parameter estimation of the Cole-impedance model suitable for low-cost embedded hardware (e.g., 8-bit microcontrollers). Our approach uses only the measured real and imaginary impedance, without any specific software package/toolbox, or initial values provided by the user. The proposed method was validated with synthetic (noiseless and noisy) data and experimental right-side, hand-to-foot bioimpedance data from a healthy adult participant. Moreover, the proposed method was compared in terms of accuracy with the recently published relevant work and commercial Electrical Impedance Spectroscopy software (Bioimp 2.3.4). The performance evaluation in terms of complexity (suitable for deployment for the microcontroller-based platform with 256 kB of RAM and 16 MHz clock speed), execution time (18 s for the dataset with 256 points), and cost (< 25) confirms the proposed method in regards to reliable bioimpedance processing using embedded hardware.
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| 8. |
- Stojanovic, A, et al.
(author)
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The Influence of Menopause and Inflammation on Redox Status and Bone Mineral Density in Patients with Rheumatoid Arthritis
- 2021
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In: Oxidative medicine and cellular longevity. - : Hindawi Limited. - 1942-0994 .- 1942-0900. ; 2021, s. 9458587-
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Journal article (peer-reviewed)abstract
- Although oxidative stress is considered to be one of the key pathogenic factors in rheumatoid arthritis (RA), there is insufficient knowledge regarding the impact of menopause on redox status in this population. Thus, this study is aimed at assessing the influence of menopause within healthy women and within RA patients as well as the impact of RA in premenopausal and postmenopausal women on redox status, with special reference to bone mineral density (BMD). A total of 90 women were included in the study, 42 with RA and 48 age-matched healthy controls. They were divided into subgroups according to the presence of menopause. Following oxidative stress parameters were measured spectrophotometrically: index of lipid peroxidation (measured as TBARS), nitrites (NO2-), superoxide anion radical (O2-), hydrogen peroxide (H2O2), superoxide dismutase (SOD), catalase (CAT), and reduced glutathione (GSH). BMD was assessed by using a dual-energy X-ray absorptiometry scanner. Comorbidities and drug history were recorded. The levels of H2O2 and TBARS were elevated in patients with RA, while NO2- and O2- increased in healthy women, both in premenopausal and postmenopausal groups. SOD activity decreased in postmenopausal RA patients. BMD was reduced in postmenopausal RA women. There was a correlation between NO2- and O2- with Health Assessment Questionnaire (HAQ) index in RA patients. Given that postmenopausal state was associated with elevated oxidative stress within healthy women and that menopausal state did not affect redox homeostasis within RA patients, but the redox homeostasis was altered in both RA groups compared to healthy women, it can be presumed that impaired redox status in RA occurred due to presence of the disease, irrespective of age. Moreover, menopause attenuates BMD reduction in women with RA. These results may indicate the need for therapeutic use of antioxidants in the form of supplements in women with RA, regardless of age.
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| 9. |
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| 10. |
- Opratko, Benjamin, et al.
(author)
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Cultures of rejection in the Covid-19 crisis
- 2021
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In: Ethnic and Racial Studies. - : ROUTLEDGE JOURNALS, TAYLOR & FRANCIS LTD. - 0141-9870 .- 1466-4356. ; 44:5, s. 893-905
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Journal article (peer-reviewed)abstract
- This article offers a collectively developed analysis of the Covid-19 crisis as it relates to contemporary cultures of rejection, i.e. the socio-cultural conditions in which authoritarian and right-wing populist politics thrive, in Europe. We explore how the pandemic and its management reinforces, transforms and/or overrides existing antagonisms and institutes new ones in Serbia, Croatia, Austria, Germany and Sweden. We discuss how the Covid-19 crisis affects the rise of new statisms; gendered patterns of social reproduction; mobility and migration; digital infrastructures; and new political mobilizations.
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| 11. |
- Razmi, Nasrin, et al.
(author)
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Monitoring the effect of pH on the growth of pathogenic bacteria using electrical impedance spectroscopy
- 2023
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In: Results in Engineering (RINENG). - : ELSEVIER. - 2590-1230. ; 20
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Journal article (peer-reviewed)abstract
- pH value is a significant environmental factor controlling the bacterial growth, activity and affecting their metabolic properties. In the present study, the effect of the different pH values (5, 6, 7, 8, and 9) of the cultivation medium on the growth rate of Escherichia coli ATCC 8739, Bacillus cereus ATCC 10876 and Pseudomonas aeruginosa 134,909/2 were studied. Plate count method and spectrophotometric measurement of optical density of the cultivation broth were used to assess growth of the pathogenic bacteria. Moreover, impedance spectroscopy measurement was applied to monitor the impedance change caused by the bacterial growth and activity at different pH values. Although the results showed that the initial pH did not completely inhibit the growth of the bacteria, the bacterial growth varied with the pH change showing the interference of pH with cell metabolism. Based on the results, the optical density of the cultivation broth measured spectrophotometrically for E. coli and B. cereus has shown good correlation with cell number determined by the plate count method in each phase of bacterial cultivation. Moreover, the results indicated that for E. coli and B. cereus the impedance value of the bacteria and the medium decreased from the beginning of the experiment till its end after 96 h from the start The impedance value during the first 24 h increased for P. aeruginosa, and then was decreasing until the end of the experiment. Nevertheless, the change in the resistance of the bacteria and the medium was proportionate to the change in cell number. For E. coli and B. cereus the resistance was decreasing with the growth of the bacteria. The linear dependency between the impedance and cell number was observed at low frequencies around 10-100 Hz. For P. aeruginosa, the resistance was increasing during the first 24 h and was decreasing afterwards. Furthermore, the resistance for P. aeruginosa was decreasing with the increase in cell number. Nonetheless, the impedance of the medium with P. aeruginosa was in linear dependency on the logarithm of cell number with the best R2 at high frequencies (0.1-1 MHz).
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| 12. |
- Saygili, Yasemin, et al.
(author)
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Liquid State and Zombie Dye Sensitized Solar Cells with Copper Bipyridine Complexes Functionalized with Alkoxy Groups
- 2020
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In: The Journal of Physical Chemistry C. - : AMER CHEMICAL SOC. - 1932-7447 .- 1932-7455. ; 124:13, s. 7071-7081
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Journal article (peer-reviewed)abstract
- Copper redox mediators can be employed in dye sensitized solar cells (DSCs) both as liquid electrolytes or as solid state hole transport materials (HTMs). The solid state devices that employ copper complex HTMs can be simply obtained by solvent evaporation in liquid state devices. During this evolution, the copper complex molecules present in the electrolyte solvent slowly aggregate in the pores of the TiO2 film and also close the gap between the TiO2 film and counter electrode. However, the crystallization of the HTM that infiltrated in the mesoscopic TiO2 pores can lead to low photovoltaic performance. In order to prevent this problem, we designed two copper redox mediators [Cu(beto)(2)](1+) (beto = 4,4'-diethoxy-6,6'-dimethyl-2,2'-bipyridine) and [Cu(beto(2Ox))(2)](1+) (beto(2Ox) = 4,4'-bis(2-methoxyethoxy)-6,6'-dimethyl-2,2'-bipyridine) with extended side chains. First, we studied these complexes in liquid state devices in reference to the [Cu(tmby)(2)](2+/1+) complex (tmby = 4,4',6,6'-tetramethyl-2,2'-bipyridine). The solar-to- electrical power conversion efficiencies for liquid state devices were over 10% for all of the complexes by using the organic Y123 dye under 1000 Wm(-2) AM1.5G illumination. However, solid state devices showed significantly diminished charge transport properties and short circuit current density values even though the crystallization was reduced.
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| 13. |
- Stojanovic, A, et al.
(author)
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Increased Expression of Extracellular Vesicles Is Associated With the Procoagulant State in Patients With Established Rheumatoid Arthritis
- 2021
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In: Frontiers in immunology. - : Frontiers Media SA. - 1664-3224. ; 12, s. 718845-
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Journal article (peer-reviewed)abstract
- This study sought to identify different subpopulations of extracellular vesicles (EVs) in plasma from female patients with established rheumatoid arthritis (RA) in relation to the activation of coagulation and fibrin formation in these patients. Forty women were included in the study, 20 patients and 20 age-matched healthy controls. The mean disease duration in patients was 13.0 (5.0–25.0) years, with medium to high disease activity despite ongoing treatment with low-dose prednisolone and methotrexate. There were no differences between the investigated groups regarding the presence of traditional cardiovascular risk factors. The concentration of phosphatidylserine-positive (PS+) EVs; platelet (CD42a+), leucocyte (CD45+), monocyte (CD14+), and endothelial (CD144+)-derived EVs; and EVs-expressing tissue factor (CD142+), P-selectin (CD62P+), and E-selectin (CD62E+) were determined by flow cytometry analysis. Overall hemostasis potential (OHP) was assessed to follow the hemostatic disturbances, including the parameters for overall coagulation potential (OCP) and overall fibrinolytic potential (OFP). Fibrin clot turbidity was measured together with clot lysis time, and scanning electron microscopy was performed. Increased concentrations of PS+, CD42a+, CD142+, CD45+, CD14+, and CD62P+ EVs were found in plasma from patients with RA compared to healthy controls, and the concentrations of PS+, CD42a+, CD14+, and CD62P+ EVs were positively correlated with the inflammatory parameters in RA patients. Positive correlations were also found between the levels of PS+ and CD42a+ EVs and OCP as well as between the levels of PS+, CD42a+, and CD62P+EVs and OHP. The levels of PS+, CD42a+, CD14+, CD62P+, and CD62E+ EVs were negatively correlated with OFP. Elevated levels of circulating EVs of different cell origins were found in patients with established RA, in relation to the inflammatory burden and coagulation activation in the disease.
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| 14. |
- Stojanovic, D., et al.
(author)
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Indoor positioning system for occupation density control
- 2020
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In: Proc. Annu. Conf. Assoc. Comput. Aided Des. Archit.: Distrib. Prox., ACADIA. - : ACADIA. - 9780578952130 ; , s. 102-109
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Conference paper (peer-reviewed)abstract
- The reported research focuses on occupational density as an increasingly important archi tectural measure and uses occupancy simulation to optimize distancing criteria imposed by the COVID-19 pandemic. The paper addresses the following questions: How to engage computational techniques (CTs) to improve the accuracy of two existing types of indoor positioning systems? How to employ simulation methods in establishing critical occupation density to balance social distancing needs and the efficient use of resources? The larger objective and the aim of further research is to develop an autonomous system capable of establishing an accurate number of people present in a room and informing occupants if space is available according to prescribed sanitary standards. The paper presents occupancy simulation approximating input that would be provided by the outlined multisensor data fusion technique aiming to improve the accuracy of the existing indoor localization solutions. The projected capacity to capture information related to social distancing and occupants' positioning is used to ground a method for determining a room-specific occupational density threshold. Our early results indicate that the type of activities, equipment, and furniture in a room, addressed through occupants' positioning, may impact the frequency of distancing incidents. Our initial findings centered on simulation modeling indicate that data, composed of the two sets (occupant count and the number of recorded distancing incidents) can be overlapped to help establish room-specific standards rather than apply generic measures. In conclusion, we discuss the opportunities and challenges of the nrnnnsed system and its role after the nandemin.
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| 15. |
- Swann, JR, et al.
(author)
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Considerations for the design and conduct of human gut microbiota intervention studies relating to foods
- 2020
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In: European journal of nutrition. - : Springer Science and Business Media LLC. - 1436-6215 .- 1436-6207. ; 6059:18, s. 3347-3368
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Journal article (peer-reviewed)abstract
- With the growing appreciation for the influence of the intestinal microbiota on human health, there is increasing motivation to design and refine interventions to promote favorable shifts in the microbiota and their interactions with the host. Technological advances have improved our understanding and ability to measure this indigenous population and the impact of such interventions. However, the rapid growth and evolution of the field, as well as the diversity of methods used, parameters measured and populations studied, make it difficult to interpret the significance of the findings and translate their outcomes to the wider population. This can prevent comparisons across studies and hinder the drawing of appropriate conclusions. This review outlines considerations to facilitate the design, implementation and interpretation of human gut microbiota intervention studies relating to foods based upon our current understanding of the intestinal microbiota, its functionality and interactions with the human host. This includes parameters associated with study design, eligibility criteria, statistical considerations, characterization of products and the measurement of compliance. Methodologies and markers to assess compositional and functional changes in the microbiota, following interventions are discussed in addition to approaches to assess changes in microbiota–host interactions and host responses. Last, EU legislative aspects in relation to foods and health claims are presented. While it is appreciated that the field of gastrointestinal microbiology is rapidly evolving, such guidance will assist in the design and interpretation of human gut microbiota interventional studies relating to foods.
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| 16. |
- Tanikawa, T., et al.
(author)
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Volt-per-Ångstrom terahertz fields from X-ray free-electron lasers
- 2020
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In: Journal of Synchrotron Radiation. - 0909-0495 .- 1600-5775. ; 27, s. 796-798
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Journal article (peer-reviewed)abstract
- The electron linear accelerators driving modern X-ray free-electron lasers can emit intense, tunable, quasi-monochromatic terahertz (THz) transients with peak electric fields of V Ångstrom(-1) and peak magnetic fields in excess of 10 T when a purpose-built, compact, superconducting THz undulator is implemented. New research avenues such as X-ray movies of THz-driven mode-selective chemistry come into reach by making dual use of the ultra-short GeV electron bunches, possible by a rather minor extension of the infrastructure.
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