Silnie wypukłe procesy stochastyczne

Rozprawa składa się z czterech rozdziałów. Rozdział pierwszy zawiera przede wszystkim podstawowe defi nicje związane z różnego rodzaju wypukłościami procesów stochastycznych, oraz pomocnicze lematy, które zostały wykorzystane w dalszej części pracy. W rozdziale drugim prezentowane są stochastyczne odpowiedniki klasycznych twierdzeń z analizy rzeczywistej, które charakteryzuj¡ wypukłe i silnie wypukłe funkcje (zobacz. [24]; lub [13]). Pojawia się tam między innymi charakteryzacja silnie wypukłego procesu stochastycznego za pomocą podparcia, pierwszej pochodnej, oraz za pomocą drugiej pochodnej. Zaprezentowane zostaną także nierówności typu: Jensena (dyskretna i całkowa), Hermite'a-Hadamarda, a także Fejera. Rozdział trzeci poświęcony jest procesom silnie wypukłym w sensie Jensena. Można w nim znaleźć między innymi odpowiedniki nierówności Jensena, twierdzenia Kuhna, twierdzenia typu Bernsteina-Doetscha i twierdzenia Sierpińskiego. W rozdziale czwartym zostały natomiast opisane procesy silnie wypukłe w sensie Wrighta. Między innymi można znaleźć w nim charakteryzację silnie wypukłych procesów stochastycznych w sensie Wrighta, która jest odpowiednikiem dobrze znanej charakteryzacji Ng'ego [18] dla funkcji wypukłych w sensie Wrighta, oraz twierdzenie o silnie wypukłym w sensie Jensena procesie majoryzowanym przez silnie wklęsły w sensie Jensena proces stochastyczny

East European chironomid-based calibration model for past summer temperature reconstructions

Understanding local patterns and large-scale processes in past climate necessitates a detailed network of temperature reconstructions. In this study, a merged temperature inference model using fossil chironomid (Diptera: Chironomidae) datasets from Finland and Poland was constructed to fill the lack of an applicable training set for East European sites. The developed weighted averaging partial least squares (WA-PLS) inference model showed favorable performance statistics, suggesting that the model can be useful for downcore reconstructions. The combined calibration model includes 212 sites, 142 taxa, and a temperature gradient of 11.3-20.1 degrees C. The 2-component WA-PLS model has a cross-validated coefficient of determination of 0.88 and a root mean squared prediction error of 0.88 degrees C. We tested the new East European temperature transfer function in chironomid stratigraphies from a Finnish high-resolution short-core sediment record and a Polish paleolake (Zabieniec) covering the past similar to 20 000 yr. In the Finnish site, the chironomid-inferred temperatures correlated closely with the observed instrumental temperatures, showing improved accuracy compared to estimates by the original Finnish calibration model. In addition, the long-core reconstruction from the Polish site showed logical results in its general trends compared to existing knowledge on the past regional climate trends; however, it had distinct differences when compared with hemispheric climate oscillations. Hence, based on these findings, the new temperature model will enable more detailed examination of long-term temperature variability in Eastern Europe, and consequently, reliable identification of local and regional climate variability of the past.Peer reviewe

Air temperature and water level inferences from northeastern Lapland (69 degrees N) since the Little Ice Age

Independent Arctic records of temperature and precipitation from the same proxy archives are rare. Nevertheless, they are important for providing detailed information on long-term climate changes and temperature-precipitation relationships in the context of large-scale atmospheric dynamics. Here, we used chironomid and cladoceran fossil assemblages to reconstruct summer air-temperature and water-level changes, during the past 400 years, in a small lake located in Finnish Lapland. Temperatures remained persistently cold over the Little Ice Age (LIA), but increased in the 20th century. After a cooler phase in the 1970s, the climate rapidly warmed to the record-high temperatures of the most recent decades. The lake-level reconstruction suggested persistently wet conditions for the LIA, followed by a dry period between similar to 1910 and 1970 CE, when the lake apparently became almost dry. Since the 1980s, the lake level has returned to a similar position as during the IAA. The temperature development was consistent with earlier records, but a significant local feature was found in the lake-level reconstruction the LIA appears to have been continuously wet, without the generally depicted dry phase during the 18th and 19th centuries. Therefore, the results suggest local precipitation patterns and enforce the concept of spatially divergent LIA conditions.Peer reviewe

Quantitative proteomics revealed C6orf203/MTRES1 as a factor preventing stress-induced transcription deficiency in human mitochondria

Maintenance of mitochondrial gene expression is crucial for cellular homeostasis. Stress conditions may lead to a temporary reduction of mitochondrial genome copy number, raising the risk of insufficient expression of mitochondrial encoded genes. Little is known how compensatory mechanisms operate to maintain proper mitochondrial transcripts levels upon disturbed transcription and which proteins are involved in them. Here we performed a quantitative proteomic screen to search for proteins that sustain expression of mtDNA under stress conditions. Analysis of stress-induced changes of the human mitochondrial proteome led to the identification of several proteins with poorly defined functions among which we focused on C6orf203, which we named MTRES1 (Mitochondrial Transcription Rescue Factor 1). We found that the level of MTRES1 is elevated in cells under stress and we show that this upregulation of MTRES1 prevents mitochondrial transcript loss under perturbed mitochondrial gene expression. This protective effect depends on the RNA binding activity of MTRES1. Functional analysis revealed that MTRES1 associates with mitochondrial RNA polymerase POLRMT and acts by increasing mitochondrial transcription, without changing the stability of mitochondrial RNAs. We propose that MTRES1 is an example of a protein that protects the cell from mitochondrial RNA loss during stress

New insights into lake responses to rapid climate change : the Younger Dryas in Lake Goscia(z) over dot, central Poland

The sediment profile from Lake Goscia(z) over dot in central Poland comprises a continuous, seasonally resolved and exceptionally well-preserved archive of the Younger Dryas (YD) climate variation. This provides a unique opportunity for detailed investigation of lake system responses during periods of rapid climate cooling (YD onset) and warming (YD termination). The new varve record of Lake Goscia(z) over dot presented here spans 1662 years from the late Allerod (AL) to the early Preboreal (PB). Microscopic varve counting provides an independent chronology with a YD duration of 1149+14/-22 years, which confirms previous results of 1140 +/- 40 years. We link stable oxygen isotopes and chironomid-based air temperature reconstructions with the response of various geochemical and varve microfacies proxies especially focusing on the onset and termination of the YD. Cooling at the YD onset lasted similar to 180 years, which is about a century longer than the terminal warming that was completed in similar to 70 years. During the AL/YD transition, environmental proxy data lagged the onset of cooling by similar to 90 years and revealed an increase of lake productivity and internal lake re-suspension as well as slightly higher detrital sediment input. In contrast, rapid warming and environmental changes during the YD/PB transition occurred simultaneously. However, initial changes such as declining diatom deposition and detrital input occurred already a few centuries before the rapid warming at the YD/PB transition. These environmental changes likely reflect a gradual increase in summer air temperatures already during the YD. Our data indicate complex and differing environmental responses to the major climate changes related to the YD, which involve different proxy sensitivities and threshold processes.Peer reviewe

Changes in habitat conditions in a Late Glacial fluviogenic lake in response to climatic fluctuations (Warta River valley, central Poland)

The Warta River val ley was greatly in flu enced by the ice sheet of the Last Gla cial Max i mum (LGM). A small peatland lo cated in the Warta drain age sys tem is here used as a palaeoarchive of cli ma tic and hab i tat changes dur ing the Late Gla cial (Weichselian). The ugi pound sed i ment pro file was in ves ti gated us ing multi-proxy (pol len, Chironomidae, Cladocera and geo chem is try) anal y ses that re corded changes in a fluviogenic sed i men tary de pres sion. Af ter the Poznan Phase (LGM), ugi pound func tioned as an ox bow lake that was cut off from the ac tive river chan nel as a re sult of flu vial ero sion. Since that time, the Warta River has flowed only along the sec tion now oc cu pied by the Jeziorsko Res er voir. Sed i men ta tion of lac us trine de pos its started at the be gin ning of the Late Gla cial. Sum mer tem per a ture re con struc tions in di cate cool Old est and Youn ger Dryas, but no clear cool ing in the Older Dryas. Dur ing the Youn ger Dryas the palaeolake was com pletely oc cu pied by a peatland (fen), which pe ri od i cally dried out dur ing the Ho lo cene. In ves ti ga tion of this site has tracked the re ac tion of the hab i tat to cli ma tic, hy dro log i cal and geomorphological changes through out the Late Weichselian.Peer reviewe

Multi-proxy inferred hydroclimatic conditions at Bęczkowice fen (central Poland); the influence of fluvial processes and human activity in the stone age

Fens have been forming in the river valleys of central Poland since the Bølling and went through a transformation from fully aquatic to semiterrestrial habitats during the Younger Dryas/Holocene transition. This drove plant and invertebrate communities and left a distinct pattern in chemical sediment composition, which is why river valley peatlands are sensitive palaeo-archives of climatic, hydrological and edaphic changes. Here we reconstruct the Late Weichselian history of the Bęczkowice fen in the upper Luciąża River valley using geochemical, pollen, Cladocera and Chironomidae proxies. Pollen-based age estimation indicates that the analysed peat sequence dates from the Bølling to Early Holocene. The layers 190-170 cm and 125-105 cm of the studied core were reworked by fluvial processes. Chironomidae and Cladocera communities indicate mostly limnetic conditions during the Allerød and early Younger Dryas. Peatland pools were supplied mostly by Luciąża River floods, but also by groundwater. Since the onset of the Holocene, the water level has dropped, eliminating aquatic midges and water fleas, and supporting taxa typical of astatic waters and wet soil.Peer reviewe

Environmental changes during Mesolithic-Neolithic transition in Kuyavia Lakeland, Central Poland

Funding Information: The field research was carried out as part of the project “Settlement of the Funnel Beaker Culture in the Wietrzychowice Cultural Park”, thanks to the funds of the Professor Konrad Jażdżewski Foundation for Archaeological Research and the County Labor Office - “Exploreres” program. Thanks are also due to Mrs. B. Lewandowska and Mr. A. Myrta for their invaluable help during the field works of Śmieły site, and to Kacper Świerk for his help in Chironomidae subfossils analysis. Publisher Copyright: © 2021 Elsevier Ltd and INQUAThe Wietrzychowice Cultural Park protects one of the last preserved megalithic barrows constructed by the Funnel Beaker Culture societies at the Kuyavia Lakeland (Central Poland). The nearby archaeological site at Śmieły located on the shore of Karaśnia Lake provided numerous Mesolithic and Neolithic remains such as flint artefacts, potsherds, arrowheads, and mammal bones with traces of human processing. The lake and peat sediments at the Śmieły site provided a unique opportunity to investigate man-environment relationships during the transition period from Mesolithic to Neolithic. The age-depth model for the deposits was based on five radiocarbon dates as well as archaeological artefacts. The multi-proxy study, including geochemistry, pollen, plant macrofossils, Mollusca, Cladocera and Chironomidae analyses, were conducted to recognize palaeoenvironmental changes between 7500 and 3500 BCE. Combining environmental and archaeological data, we attempt to distinguish between natural phenomena triggered by climate factors with those induced by human activity. The data indicated hydrological changes associated with natural factors: (1) the phase of aquatic ecosystem since 7500 to 5800 BCE, (2) the phase of water shallowing between 5800 and 4600 BCE, and (3) the development of alder fen in the lake shore zone since ca. 4600 BCE. Vegetation changes suggest early landscape transformations in Central Poland already due to the activity of Mesolithic societies. Fossil pollen and plant macroremains data combined with detailed map of modern soil distribution in the area allowed to identify pattern of vegetation distribution around the Mesolithic campsite. Neolithic discontinuity of habitation process between ca. 4600 and 4000 BCE (in the times of Brześć Kujawski Group of Lendyel Culture) can be associated with climate change resulting in Karaśnia Lake level lowering.Peer reviewe

Versatile approach for functional analysis of human proteins and efficient stable cell line generation using FLP-mediated recombination system

Deciphering a function of a given protein requires investigating various biological aspects. Usually, the protein of interest is expressed with a fusion tag that aids or allows subsequent analyses. Additionally, downregulation or inactivation of the studied gene enables functional studies. Development of the CRISPR/Cas9 methodology opened many possibilities but in many cases it is restricted to non-essential genes. Recombinase-dependent gene integration methods, like the Flp-In system, are very good alternatives. The system is widely used in different research areas, which calls for the existence of compatible vectors and efficient protocols that ensure straightforward DNA cloning and generation of stable cell lines. We have created and validated a robust series of 52 vectors for streamlined generation of stable mammalian cell lines using the FLP recombinase-based methodology. Using the sequence-independent DNA cloning method all constructs for a given coding-sequence can be made with just three universal PCR primers. Our collection allows tetracycline-inducible expression of proteins with various tags suitable for protein localization, FRET, bimolecular fluorescence complementation (BiFC), protein dynamics studies (FRAP), co-immunoprecipitation, the RNA tethering assay and cell sorting. Some of the vectors contain a bidirectional promoter for concomitant expression of miRNA and mRNA, so that a gene can be silenced and its product replaced by a mutated miRNA-insensitive version. Our toolkit and protocols have allowed us to create more than 500 constructs with ease. We demonstrate the efficacy of our vectors by creating stable cell lines with various tagged proteins (numatrin, fibrillarin, coilin, centrin, THOC5, PCNA). We have analysed transgene expression over time to provide a guideline for future experiments and compared the effectiveness of commonly used inducers for tetracycline-responsive promoters. As proof of concept we examined the role of the exoribonuclease XRN2 in transcription termination by RNAseq