18 research outputs found
Implications of poverty traps across levels
Recent research has demonstrated the multidimensional nature of poverty and the multi-level organization of social-ecological systems that display poverty traps. The traps on these different levels can reinforce each other, and therefore multi-level traps pose particular challenges for poverty alleviation. Yet, poverty trap models rarely consider more than one level of organization and only a few attributes of the system at each level. These limitations constrain our understanding of the mechanisms that generate poverty traps and may hinder or even mislead development efforts. Here, we present a series of two-level dynamical system models of poverty traps and use these models to investigate the combined influences of biophysical and economic factors, farmersā habits and community decisions on creating and alleviating persistent poverty. Our results indicate that neglecting key interactions can lead to incorrect assessments and potentially inadequate alleviation strategies. Moreover, we obtain necessary conditions for the existence of fractal poverty traps, and show that (i) cross-level interactions can open possibilities for escaping from poverty, (ii) that farmersā behavioral changes may create or impede a way out of poverty, and (iii) that the effectiveness of development interventions depends on the combined influences of biophysical and economic dynamics, farmersā behavior and community spending on agricultural and social activities.The research leading to these results received funding from the Sida-funded GRAID program at the Stockholm Resilience Centre, the European Research Council (ERC) under the European Unionās Horizon 2020 research and innovation programme (grant agreement No 682472 ā MUSES), the Swedish Research Council Formas (project grant 2014-589), and the Swedish Research Council Vetenskapsr?det (project grant 2018-06732)
Characterization of the late embryogenesis abundant (LEA) proteins family in hydrated and desiccated Ramonda serbica Panc. leaves
Endemic plant species, Ramonda serbica is a resurrection plant that can tolerate extreme
dehydration (desiccation, loss of 95% of cellular water) even over months. The
accumulation of late embryogenesis abundant proteins (LEAPs) is a crucial step in the
mechanism of desiccation tolerance. The role of LEAPs is not completely resolved, but
they are accepted as intrinsically disordered proteins (IDPs). Based on previously
established de novo transcriptome database of R. serbica leaves we identify around 160
members of LEA gene family. Identified LEAPs were classified into six groups: LEA 1-5
and seed maturation proteins (SMPs) according to protein family (Pfam) database. Based
on multiple sequence alignment, secondary structure prediction and 3D structure modeling,
we conducted LEA protein structure analysis. We showed that more than 50% of identified
LEAPs exhibited a high propensity to form Ī±-helices. As predicted by several
bioinformatic tools, more than 70% of identified LEAPs were found to be highly
disordered. Thus, these proteins are predicted to be disordered in solution, but they acquire
a secondary, predominantly Ī±-helical structure during drying, in contrast to globular
proteins, which most often causes the loss of structure upon dehydration. By using
molecular dynamic simulations, we identified the most favorable conformations of
representative LEAPs and we have studied conformational transitions driven by the water
scarcity. Structural characterization of LEAPs is a key to understand their function and
regulation of their intrinsic structural disorder-to-order transition during desiccation as a
requirement for biological function, in order to promote development of new therapeutic
strategies in neurodegenerative disorders, cell preservation technology and the
improvement of crop drought tolerance.Serbian Biochemical Society, 10th Conference, Kragujevac, Serbia, 24.09.202
Efficient production of highly purified Late Embryogenesis Abundant (LEA) protein from Arabidopsis thaliana by recombinant DNA technology
Late embryogenesis abundant (LEA) proteins are induced in cellular dehydration, such as freezing, drought, or desiccation. They can be involved in antioxidative defense, ion sequestration, and structural stabilization of both membranes and enzymes during freezing or drying, while by forming intracellular proteinaceous condensates they increase structural integrity and intracellular viscosity of cells during desiccation 1. The genome of the model plant Arabidopsis thaliana contains 51 genes encoding LEA proteins2. The majority of these LEA proteins (35%) belongs to Pfam LEA_4 (PF02987) family. In silico analysis suggested that these proteins are highly hydrophilic proteins with significant intrinsically disordered protein (IDP) properties. In order to evaluate structural properties and possible functions of LEA_4 protein family under different water content, a representative AtLEA25 protein (At2g42560, 635 aa), naturally located in the cytoplasm of seeds3 was obtained in Escherichia coli by recombinant DNA technology. Although this technology has been traditionally used to over-express and purify various globular proteins, numerous reports have shown that the IDPs, due to their structural plasicity are naturally highly susceptible to proteolytic cleavage. To conduct structural and functional studies we developed a robust method to produce highly purified (>95% pure) AtLEA25 with no detectable amount of protein breakdown products.Abstract: Serbian Biochemical Society, 10th Conference, Kragujevac, Serbia, 24.09.202
Visualization of causation in social-ecological systems
In social-ecological systems (SES), where social and ecological processes are intertwined, phenomena are usually complex and involve multiple interdependent causes. Figuring out causal relationships is thus challenging but needed to better understand and then affect or manage such systems. One important and widely used tool to identify and communicate causal relationships is visualization. Here, we present several common visualization types: diagrams of objects and arrows, X-Y plots, and X-Y-Z plots, and discuss them in view of the particular challenges of visualizing causation in complex systems such as SES. We use a simple demonstration model to create and compare exemplary visualizations and add more elaborate examples from the literature. This highlights implicit strengths and limitations of widely used visualization types and facilitates adequate choices when visualizing causation in SES. Thereupon, we recommend further suitable ways to account for complex causation, such as figures with multiple panels, or merging different visualization types in one figure. This provides caveats against oversimplifications. Yet, any single figure can rarely capture all relevant causal relationships in an SES. We therefore need to focus on specific questions, phenomena, or subsystems, and often also on specific causes and effects that shall be visualized. Our recommendations allow for selecting and combining visualizations such that they complement each other, support comprehensive understanding, and do justice to the existing complexity in SES. This lets visualizations realize their potential and play an important role in identifying and communicating causation.Peer reviewe
Permanence of age-structured populations in a spatio-temporal variable environment
It is widely recognized that various biotic and abiotic factors cause changes in the size of a population and its age distribution. Population structure, intra-specific competition, temporal variability and spatial heterogeneity are identified as the most important factors that, alone or in combination, influence population dynamics. Despite being well-known, these factors are difficult to study, both theoretically and empirically. However, in an increasingly variable world, permanence of a growing number of species is threatened by climate changes, habitat fragmentation or reduced habitat quality. For purposes of conservation of species and land management, it is crucially important to have a good analysis of population dynamics, which will increase our theoretical knowledge and provide practical guidelines. One way to address the problem of population dynamics is to use mathematical models. The choice of a model depends on what we want to study or what we aim to achieve. For an extensive theoretical study of population processes and for obtaining qualitative results about population growth or decline, analytical models with various level of complexity are used. The competing interests of realism and solvability of the model are always present. This means that, on one hand, we always aim to make a model that will truthfully reflect reality, while on the other hand, we need to keep the model mathematically solvable. This prompts us to carefully choose the most prominent ecological factors relevant to the problem at hand and to incorporate them into a model. Ideally, the results give new insights into population processes and complex interactions between the mentioned factors and population dynamics. The objective of the thesis is to formulate, analyze, and apply various mathematical models of population dynamics. We begin with a classical linear age-structured model and gradually add temporal variability, intra-specific competition and spatial heterogeneity. In this way, every subsequent model is more realistic and complex than the previous one. We prove existence and uniqueness of a nonnegative solution to each boundary-initial problem, and continue with investigation of the large time behavior of the solution. In the ecological terms, we are establishing conditions under which a population can persist in a certain environment. Since our aim is a qualitative analysis of a solution, we often examine upper and lower bounds of a solution. Their importance is in the fact that they are obtained analytically and parameters in their expression have biological meaning. Thus, instead of analyzing an exact solution (which often proves to be difficult), we analyze the corresponding upper and lower solutions. We apply our models to demonstrate the influence of seasonal changes (or some other periodic temporal variation) and spatial structure of the habitat on population persistence. This is particularly important in explaining behavior of migratory birds or populations that inhabits several patches, some of which are of low quality. Our results extend the previously obtained results in some aspects and point out that all factors (age structure, density dependence, spatio-temporal variability) need to be considered when setting up a population model and predicting population growth
Pairs of projections on a Hilbert space:properties and generalized invertibility
This thesis is concerned with the problem of characterizing sums, differences, and products of two projections on a separable Hilbert space. Other objective is characterizing the Moore-Penrose and the Drazin inverse for pairs of operators. We use reasoning similar to one presented in the famous P. Halmosā two projection theorem: using matrix representation of two orthogonal projection depending on the relations between their ranges and null-spaces gives us simpler form of their matrices and allows us to involve matrix theory in solving problems. We extend research to idempotents, generalized and hypergeneralized projections and their combinations
Influence of Adaption to the Euro to Consumer Behaviour and Price Perception in Latvia
2014. gadÄ, realizÄjot ES intergrÄcijas politiku, Latvija plÄno stÄties eiro zonÄ un ieviest jaunu valÅ«tu, aizvietojot nacionÄlo valÅ«tu ā latu. Eiro ievieÅ”ana neapÅ”aubÄmi sniegs Latvijai jaunas attÄ«stÄ«bas iespÄjas un noteiktas priekÅ”rocÄ«bas tÄs ekonomikas subjektiem. TomÄr, naudas nomaiÅas rezultÄtÄ Latvijas sabiedrÄ«ba sastapsies ar monetÄro Å”oku - nominÄlÄs cenas tiks kvantitatÄ«vi palielinÄtas, kas var ietekmÄt patÄrÄtÄju uzvedÄ«bu un cenu uztveri.
MaÄ£istra darba ietvaros tika veikta aptauja. Aptaujas rezultÄtu analÄ«ze liecina, ka lÄ«dz ar eiro ievieÅ”anu LatvijÄ ir iespÄjams naudas ilÅ«zijas efekts, kad patÄrÄtÄji uztvers eiro cenas kÄ dÄrgÄkas nekÄ tÄdas paÅ”as cena latos, rÄÄ·inot pÄc fiksÄtÄ valÅ«tas kursa.
AtslÄgvÄrdi: eiro, naudas ilÅ«zija, cenu uztvere, atsauces cena, patÄrÄtÄja uzvedÄ«baLatvia plans adoption to the euro in 2014, that would be an accomplishment of another step of integration policy to EU. In result of money changeover, Latvian lat will be substituted by euro. No doubt euro will provide Latvia lots of opportunities and additional potential for development. On the other side, because of euro changeover, Latvian consumers will face a nominal shock, when nominal information of prices will rise. That might have an effect on consumer behaviour and price perception.
Author made a survey during the research. Results shows that there might be a money illusion effect in Latvia when the euro will be adopted, because consumers tend to evalute euro prices as more expensive than the same prices in lats.
Keywords:euro, price perception, consumer behaviour, money illusion, reference pric
On the Moore-Penrose and the Drazin inverse of two projections on Hilbert space
For two given orthogonal, generalized or hypergeneralized projectionsP and Q on Hilbert space H, we gave their matrix representation. We also gave canonical forms of the Moore-Penrose and the Drazin inverses of their product, difference and sum. In addition, it is showed when these operators are EP and some simple correlations between mentioned operators are established