Bounds for the expected value of one-step processes

Mean-field models are often used to approximate Markov processes with large state-spaces. One-step processes, also known as birth-death processes, are an important class of such processes and are processes with state space $\{0,1,\ldots,N\}$ and where each transition is of size one. We derive explicit bounds on the expected value of such a process, bracketing it between the mean-field model and another simple ODE. Our bounds require that the Markov transition rates are density dependent polynomials that satisfy a sign condition. We illustrate the tightness of our bounds on the SIS epidemic process and the voter model.Comment: 14 pages, 4 figures, revise

Dynamic control of modern, network-based epidemic models

In this paper we make the first steps to bridge the gap between classic control theory and modern, network-based epidemic models. In particular, we apply nonlinear model predictive control (NMPC) to a pairwise ODE model which we use to model a susceptible-infectious-susceptible (SIS) epidemic on nontrivial contact structures. While classic control of epidemics concentrates on aspects such as vaccination, quarantine, and fast diagnosis, our novel setup allows us to deliver control by altering the contact network within the population. Moreover, the ideal outcome of control is to eradicate the disease while keeping the network well connected. The paper gives a thorough and detailed numerical investigation of the impact and interaction of system and control parameters on the controllability of the system. For a certain combination of parameters, we used our method to identify the critical control bounds above which the system is controllable. We foresee that our approach can be extended to even more realistic or simulation-based models with the aim of applying these to real-world situations

Status of the Dorcas gazelle (Gazella dorcas) in the area south of Green Mountain, Libya in 2007: challenges and opportunities for the future

Threats to Dorcas gazelle were examined and the rate of decrease in population was estimated in the area south of the Green Mountain in North-East Libya. The results were collected from questionnaires and focal interviews. All previous studies had reported significant decreased in Dorcas gazelle population throughout Libya during the last years of the twentieth century. The results showed that Dorcas gazelle continues to exist but in very low numbers. The number of groups of gazelle has decreased and the estimated rate of decline has increased to between 60 and 90 % in 2007. The decline has been noticeable with typical herd sizes of approximately 50 – 100 gazelle being reported before 1970, 10 – 15 gazelle seen in the 1970s, 5 – 10 gazelle in the 1980s and from the 1990s onwards, group sizes of only 3 or fewer gazelles. Shared use of habitat with domestic sheep and predators does not appear to be detrimental to Dorcas gazelle, but the main threat for this animal is humans, who lack awareness of its natural value. Some respondents believed that Dorcas gazelle had left their habitat and migrated to other safe areas, but this study showed that the number of Dorcas gazelle was decreasing rapidly, mainly because of overhunting. Further research is needed into the current distribution and numbers of surviving Dorcas gazelle. Aerial and ground surveys of areas of potential habitat should be carried out to establish the current status and distribution. There is an urgent need for the implementation of management programme to conserve the gazelle involving the participation of local people

The relationship between successional vascular plant assemblages and associated microbial communities on coal mine spoil heaps

The aim of the study was to investigate the relationships between the vascular plant species and the associated soil microbial properties at various stages of vegetation development on unclaimed hard coal mine spoil heaps in Upper Silesia (south Poland). The spontaneous vegetation, soil chemistry as well as the activity and structure of microbial communities were recorded on this specific habitat. The colliery heaps were divided into four age classes and the plant species composition and cover abundance were recorded on established plots (2 m × 2 m). The soil microbial activity under the vegetation patches was assessed using fluorescein diacetate hydrolytic activity (FDHA) and the soil microbial biomass and community composition were determined by phospholipid fatty acid (PLFA) biomarkers. Total microbial biomass in soils from the older vegetation plots was significantly higher than those in soils from the younger plots. In all studied samples, microbial communities consisted primarily of bacteria with the dominance of Gram negative bacteria over Gram positive and aerobic microorganisms were more dominant than anaerobic ones. Statistical analysis revealed a correlation between the type of vegetation and microbial community structure

Vegetation diversity on coal mine spoil heaps-how important is the texture of the soil substrate?

© 2019, The Author(s). The relationship between the size of the particle fractions of the soil substrate and the diversity of the spontaneously developing vegetation was investigated on coal mine spoil heaps in Upper Silesia (Southern Poland). The analyses were based on 2567 research plots of developed spontaneous vegetation and their associated soil substrate samples collected from 112 coal mine spoil heaps. For each research plot the prevailing particle size fraction was determined (stones, gravel, sand, silt), the species composition and abundance was recorded and the species richness (S), Shannon-Wiener diversity index (H′), Simpson (C) and Evenness (E) indices were used to determine species diversity. From a total of 119 research plots (in all particle size fraction categories), the values of 15 physicochemical properties (pH, electrical conductivity, water holding capacity, moisture, carbon content, total N, available P, Mg and exchange cations Ca, Mg, K, Na, fine particles (%), gravel (%), stone (%)) were obtained to asses their impact on the floristic composition of vegetation patches using Canonical Correspondence Analysis (CCA). Additionally, functional traits of the dominant species of each vegetation patch (life forms, life strategies and socio-ecological groups), were selected to analyse their relation to substrate texture. It was shown that the highest species richness and the highest values for Shannon-Wiener diversity index, as well as Simpson and Evenness indices, were obtained in plots formed on stones. Moreover, the greatest variation in the participation of species representing different habitats, life forms, and life strategies was found on gravelly substrates. Contrary to our expectations, the vegetation diversity (in terms of both species and their functional traits) was not highest in habitats with a high composition of fine size particles.Published versio

The role of plants and soil properties in the enzyme activities of substrates on hard coal mine spoil heaps

© 2021 The Authors. Published by Springer. This is an open access article available under a Creative Commons licence. The published version can be accessed at the following link on the publisher’s website: https://doi.org/10.1038/s41598-021-84673-0Knowledge about biotic (plant species diversity, biomass) and/or abiotic (physicochemical substrate parameters) factors that determine enzyme activity and functional diversity of the substrate on hard coal spoil heaps is limited. Spontaneously developed vegetation patches dominated by herbaceous species commonly occurring on these spoil heaps: grasses (Poa compressa, Calamagrostis epigejos) and forbs (Daucus carota, Tussilago farfara), were examined. The activity of dehydrogenase and alkaline phosphatase was twice as high in plots dominated by grass species compared with those dominated by forbs. Significant positive correlations were found between the activity of dehydrogenase and alkaline phosphatase with pH, available P, soil moisture, and water holding capacity and negative correlations between the activity of urease and soil organic carbon. Strong positive correlations were found between values for Shannon–Wiener diversity index, evenness, species richness and soil functional diversity in plots dominated by grasses. We found that the soil physicochemical parameters had a greater impact on enzyme activity of the substrate than plant biomass and species diversity. However, grasses, through their extensive root system, more effectively increased enzyme activity and health of the substrate than other herbaceous species, and as they stabilize the substrate and form dense plant cover, they can be recommended for reclamation purposes.This study was funded by the InfoRevita project (TANGO1/268600/ NCBR/2015) financed by The National Centre for Research and Development in Poland.Accepted versio

Impact of selected plant species on enzymatic activity of soil substratum on post-mining heaps

Published by Polish Society of Ecological Engineering (PTIE). This is an open access article available under a Creative Commons licence. The published version can be accessed at the following link on the publisher’s website: https://doi.org/10.12911/22998993/93867© 2019 Polish Society of Ecological Engineering (PTIE). The natural mineral resources (hard coal, sands, dolomites, lead and zinc ores) found in the Silesia and the excavation of them led to significant transformation or even degradation of the environment. The landscape of Upper Silesia was dominated by heaps created as a result of the accumulation of post-mining coal waste. These post-industrial sites are characterised by difficult conditions for the development of plant communities. Nevertheless, the heaps are spontaneously overgrowing and over time, a separate ecosystem can be observed (for heaps). The article analyzes the enzymatic activity of the substrate in relation to the selected dominant grass (Monocots) and herbaceous (Dicots) plant species. The aim of this study was to compare the activity of particular enzymes in soil substratum of the vegetation patches dominated by grass and herbaceous plants.Published versio

Diversity of vegetation dominated by selected grass species on coal-mine spoil heaps in terms of reclamation of post-industrial areas

Published by Polish Society of Ecological Engineering (PTIE). This is an open access article available under a Creative Commons licence. The published version can be accessed at the following link on the publisher’s website: https://doi.org/10.12911/22998993/93870© 2018, Polish Society of Ecological Engineering (PTIE). Grasses have a considerable potential for the adaptation to various, often extreme, habitat conditions. The aim of the work was to present the vegetation diversity of the coal-mine spoil heaps with the dominant share of grasses and to identify the main factors responsible for this diversity in the aspect of post-industrial land reclamation. The communities differ in reference to the species preferences to light, moisture, soil fertility and reaction, which is reflected in the wide variety of microhabitats in the area. It was shown that the increase in the abundance of certain grass species, including Calamagrostis epigejos, Festuca rubra, Festuca arundinacea, Phragmites australis, has a significant negative impact on the species richness, species diversity and the uniformity of distribution of species of the plant community. Preliminary analyses revealed that on post-mining waste, the biomass production of the dominant species is negatively correlated with biodiversity. The knowledge about the biology and ecology of grass species, as well as on the assembly rules may be used in the reclamation of degraded areas. Gaining the knowledge about the vegetation diversity of the coal-mine spoil heaps with the dominant share of grasses can be useful in planning the reclamation works, taking into account natural processes, which leads to the creation of a permanent vegetation cover at a given site, protecting it against water or wind erosion. In the future these areas may provide a number of important ecosystem services.Published versio

Increased Production of the Soluble Tumor-Associated Antigens CA19-9, CA125, and CA15-3 in Rheumatoid Arthritis

Some tumor-associated antigens (TAAs) are expressed on inflammatory cells. We previously detected carcinoembryonic antigen (CEA; CD66) in the rheumatoid (RA) synovium. The production of CEA, CA19-9, CA125, and CA15.3, may be increased in patients with RA, scleroderma, lupus, and SjÖgren's syndrome (SS). Some of these TAAs contain sialylated carbohydrate motifs and they are involved in tumor-associated cell adhesion and metastasis. We assessed levels of TAAs in the sera of RA patients and healthy subjects. Serum TAA levels were correlated with disease markers including serum rheumatoid factor (RF), C-reactive protein (CRP), and anti-CCP antibody levels, DAS28, age disease duration. TAAs including CEA, CA15-3, CA72-4, CA125, and CA19-9, and neuron-specific enolase (NSE) were assessed by immunoassay in the sera of 75 patients with RA and 50 age- and sex-matched healthy controls. Normal upper limits for these TAAs were 3.4 Μg/L, 25 kU/L, 6.9 kU/L, 35 kU/L, 34 kU/L, and 16.3 Μg/L, respectively. There were significantly more RA patients showing abnormally high levels of CA125 (10.8% versus 7.1%), CA19-9 (8.1% versus 0%), and CA15-3 (17.6% versus 14.3%) in comparison to controls ( P < 0.05). The mean absolute serum levels of CA125 (23.9 ± 1.8 versus 16.8 ± 2.2 kU/L) and CA19-9 (14.2 ± 1.2 versus 10.5 ± 1.6 kU/L) were also significantly higher in RA compared to controls ( P < 0.05). Among RA patients, serum CEA showed significant correlation with RF ( r = 0.270; P < 0.05). None of the assessed TAAs showed any correlation with CRP, anti-CCP, DAS28, age or disease duration. The concentration of some TAAs may be elevated in the sera of patients with established RA in comparison to healthy subjects. CEA, CA19-9, CA125, and CA15-3 contain carbohydrate motifs and thus they may be involved in synovitis-associated adhesive events. Furthermore, some TAAs, such as CEA, may also correlate with prognostic factors, such as serum RF levels.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73224/1/annals.1422.037.pd

Do the dominant plant species impact the substrate and vegetation composition of post-coal mining spoil heaps?

This is an accepted manuscript of an article published by Elsevier in Ecological Engineering on 03/12/2019, available online: https://doi.org/10.1016/j.ecoleng.2019.105685 The accepted version of the publication may differ from the final published version�� 2019 Dominant species influence both species and functional composition of the vegetation as well as soil properties of the substrate. However, knowledge about the role played by dominant species in the process of shaping their habitat within post-industrial ecosystems is still limited. We aimed to assess the impact of four dominant species (Calamagrostis epigejos, Daucus carota, Poa compressa and Tussilago farfara) on soil abiotic and biotic properties, and to detect differences in species and functional composition of the vegetation types studied. We hypothesized that (1) dominant species of higher mean biomass cause lower aboveground biodiversity and (2) dominant species of higher mean biomass have a higher impact than the others on soil properties. We measured soil chemistry (TOC, N, P, K, Na, Mg content, EC, pH and enzyme activities) as well as biomass, species diversity and functional diversity of vegetation on 15 study plots (28.3 m2) for each species studied. The DCA analysis revealed a clear distinction between the patches dominated by studied species. Vegetation patches dominated by Calamagrostis epigejos were correlated with amount of biomass, canopy height CWM and specific leaf CWM. Patches dominated by Daucus carota were related to the light requirements (EIV-L), Total Organic Carbon (TOC) and K content. The vegetation patches dominated by Poa compressa were related to dehydrogenase activity, higher Mg content and species richness of the vegetation patches. The highest TOC content was recorded for T. farfara substrates, and the lowest for C. epigejos substrates. The content of potassium does not differ statistically significantly in the substrates from sites dominated by D. carota and P. compressa. The highest values of Mg content were recorded for D. carota and were statistically different from Poa compressa sites, while the higher phosphorus content (statistically significantly different) was recorded for patches dominated by T. farfara and P. compressa. Despite our assumptions, the species with the highest mean biomass (Calamagrostis epigejos) did not cause lower species or functional diversity. In contrast, Tussilago farfara has the highest impact on postindustrial site habitats on coal mine heaps, as extreme values of four soil substratum parameters were recorded on these plots. This species also decreased both species and functional diversity of vegetation. The knowledge about relationship existing between plants (aboveground vegetation) and soil organisms seems important in order to undertake suitable reclamation measures and to restore variety of functions as well as to create diverse vegetation based on native species.Published versio