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As evidenced by recent survey results, majority of asteroids are slow rotators (P>12 h), but lack spin and shape models due to selection bias. This bias is skewing our overall understanding of the spins, shapes, and sizes of asteroids, as well as of their other properties. Also, diameter determinations for large (>60km) and medium-sized asteroids (between 30 and 60 km) often vary by over 30% for multiple reasons. Our long-term project is focused on a few tens of slow rotators with periods of up to 60 hours. We aim to obtain their full light curves and reconstruct their spins and shapes. We also precisely scale the models, typically with an accuracy of a few percent. We used wide sets of dense light curves for spin and shape reconstructions via light-curve inversion. Precisely scaling them with thermal data was not possible here because of poor infrared data: large bodies are too bright for WISE mission. Therefore, we recently launched a campaign among stellar occultation observers, to scale these models and to verify the shape solutions, often allowing us to break the mirror pole ambiguity. The presented scheme resulted in shape models for 16 slow rotators, most of them for the first time. Fitting them to stellar occultations resolved previous inconsistencies in size determinations. For around half of the targets, this fitting also allowed us to identify a clearly preferred pole solution, thus removing the ambiguity inherent to light-curve inversion. We also address the influence of the uncertainty of the shape models on the derived diameters. Overall, our project has already provided reliable models for around 50 slow rotators. Such well-determined and scaled asteroid shapes will, e.g. constitute a solid basis for density determinations when coupled with mass information. Spin and shape models continue to fill the gaps caused by various biases.

Results from the TESS mission showed that previous studies strngly underestimated the number of slow rotators, revealing the importance of studying those asteroids. For most slowly rotating asteroids (P > 12), no spin and shape model is available because of observation selection effects. This hampers determination of their thermal parameters and accurate sizes. We continue our campaign in minimising selection effects among main belt asteroids. Our targets are slow rotators with low light-curve amplitudes. The goal is to provide their scaled spin and shape models together with thermal inertia, albedo, and surface roughness to complete the statistics. Rich multi-apparition datasets of dense light curves are supplemented with data from Kepler and TESS. In addition to data in the visible range, we also use thermal data from infrared space observatories (IRAS, Akari and WISE) in a combined optimisation process using the Convex Inversion Thermophysical Model (CITPM). This novel method has so far been applied to only a few targets, and in this work we further validate the method. We present the models of 16 slow rotators. All provide good fits to both thermal and visible data. The obtained sizes are on average accurate at the 5% precision, with diameters in the range from 25 to 145 km. The rotation periods of our targets range from 11 to 59 hours, and the thermal inertia covers a wide range of values, from 2 to <400 SI units, not showing any correlation with the period. With this work we increase the sample of slow rotators with reliable spin and shape models and known thermal inertia by 40%. The thermal inertia values of our sample do not display a previously suggested increasing trend with rotation period, which might be due to their small skin depth.

Air-sea fluxes of CO$\\sb2$ depend on the gas-transfer coefficient (K) and the air-sea difference in the partial pressure of CO$\\sb2$ ($\\Delta p$). If K and $\\Delta p$ covary, the mean air-sea flux of CO$\\sb2$ will differ from the flux computed from means of K and $\\Delta p$. The difference is termed here the covariance term. Moreover, the partial pressure of CO$\\sb2$ in seawater (p) is a nonlinear function of several seawater properties, such as temperature (T), salinity (S), concentration of dissolved inorganic carbon (C) and alkalinity (A). As a result of this nonlinearity, air-sea fluxes computed using mean values of p for a range of seawater conditions will differ from the fluxes calculated using p computed from corresponding means of T, S, C and A. The difference is termed here the carbonate nonlinearity term. Any study of air-sea fluxes of CO$\\sb2$, whether based on observations or models, should, ideally, select time and space scales such as to minimize both these terms. In this thesis, I quantify the covariance and the nonlinearity terms at various spatial and temporal scales and explore implications of these results for studies of air-sea fluxes of CO$\\sb2$. The spatial component of the nonlinearity term is examined using data collected during the Geochemical Ocean Sections Study (GEOSECS). Standard deviation of p is a good indicator of the magnitude of the nonlinearity term. Failing to consider the spatial fluctuations at the global scale may bias direct estimates of global oceanic uptake of CO$\\sb2$ upward by 3.0 GtCy$\\sp{-1}$ (=65% of total emissions of anthroprogenic CO$\\sb2$ in 1973). Partitioning the global dataset into subsets representing high- and low-latitude waters reduces the bias to 1.4 GtCy$\\sp{-1}$. To study the temporal components of the covariance and the nonlinearity terms a new ecosystem model of the Labrador Sea is developed. The model is then used to simulate the annual cycles of K, T, S, C and A. When the annual means of these properties are used to compute air-sea fluxes of CO$\\sb2$, both the covariance and the nonlinearity terms are neglected. This results in the overestimation of the air-sea fluxes by 2.4 mol C m$\\sp{-2}\\rm y\\sp{-1}$ (=300% of the estimated total annual uptake of anthropogenic CO$\\sb2$ for the Labrador Sea) compared with the best estimate from the ecosystem model. The overstimulation would increase markedly in CO$\\sb2$-rich environments. Partitioning the annual cycle into warm and cold seasons reduces the overestimation severalfold. The Labrador Sea model is used to rank the importance of various oceanic processes for air-sea CO$\\sb2$ flux. Effects of changes in these processes on the CO$\\sb2$ flux would be larger in CO$\\sb2$-rich environments.

Context. Earlier work suggests that slowly rotating asteroids should have higher thermal inertias than faster rotators because the heat wave penetrates deeper into the sub-surface. However, thermal inertias have been determined mainly for fast rotators due to selection effects in the available photometry used to obtain shape models required for thermophysical modelling (TPM). Aims. Our aims are to mitigate these selection effects by producing shape models of slow rotators, to scale them and compute their thermal inertia with TPM, and to verify whether thermal inertia increases with the rotation period. Methods. To decrease the bias against slow rotators, we conducted a photometric observing campaign of main-belt asteroids with periods longer than 12 hours, from multiple stations worldwide, adding in some cases data from WISE and Kepler space telescopes. For spin and shape reconstruction we used the lightcurve inversion method, and to derive thermal inertias we applied a thermophysical model to fit available infrared data from IRAS, AKARI, and WISE. Results. We present new models of 11 slow rotators that provide a good fit to the thermal data. In two cases, the TPM analysis showed a clear preference for one of the two possible mirror solutions. We derived the diameters and albedos of our targets in addition to their thermal inertias, which ranged between 3\\(^{+33}_{-3}\\) and 45\\(^{+60}_{-30}\\) Jm\\(^{-2}\\)s\\(^{-1/2}\\)K\\(^{-1}\\). Conclusions. Together with our previous work, we have analysed 16 slow rotators from our dense survey with sizes between 30 and 150 km. The current sample thermal inertias vary widely, which does not confirm the earlier suggestion that slower rotators have higher thermal inertias.

Physical studies of asteroids depend on an availability of lightcurve data. Targets that are easy to observe and analyse naturally have more data available, so their synodic periods are confirmed from multiple sources. Also, thanks to availability of data from a number of apparitions, their spin and shape models can often be obtained. Almost half of bright (H<=11 mag) main-belt asteroid population with known lightcurve parameters have rotation periods considered long (P>12 hours) and are rarely chosen for photometric observations. There is a similar selection effect against asteroids with low lightcurve amplitudes (a_max<=0.25 mag). As a result such targets, though numerous in this brightness range, are underrepresented in the sample of spin and shape modelled asteroids. In the range of fainter targets such effects are stronger. These selection effects can influence what is now known about asteroid spin vs. size distribution, on asteroid internal structure and densities and on spatial orientation of asteroid spin axes. To reduce both biases at the same time, we started a photometric survey of a substantial sample of those bright main-belt asteroids that displayed both features: periods longer than 12 hours, and amplitudes that did not exceed 0.25 magnitude. First we aim at finding synodic periods of rotation, and after a few observed apparitions, obtaining spin and shape models. As an initial result of our survey we found that a quarter of the studied sample (8 out of 34 targets) have rotation periods different from those widely accepted. We publish here these newly found period values with the lightcurves. The size/frequency plot might in reality look different in the long-period range. Further studies of asteroid spins, shapes, and structure should take into account serious biases that are present in the parameters available today.

Context. The so-called Barbarian asteroids share peculiar, but common polarimetric properties, probably related to both their shape and composition. They are named after (234) Barbara, the first on which such properties were identified. As has been suggested, large scale topographic features could play a role in the polarimetric response, if the shapes of Barbarians are particularly irregular and present a variety of scattering/incidence angles. This idea is supported by the shape of (234) Barbara, that appears to be deeply excavated by wide concave areas revealed by photometry and stellar occultations. Aims. With these motivations, we started an observation campaign to characterise the shape and rotation properties of Small Main- Belt Asteroid Spectroscopic Survey (SMASS) type L and Ld asteroids. As many of them show long rotation periods, we activated a worldwide network of observers to obtain a dense temporal coverage. Methods. We used light-curve inversion technique in order to determine the sidereal rotation periods of 15 asteroids and the con- vergence to a stable shape and pole coordinates for 8 of them. By using available data from occultations, we are able to scale some shapes to an absolute size. We also study the rotation periods of our sample looking for confirmation of the suspected abundance of asteroids with long rotation periods. Results. Our results show that the shape models of our sample do not seem to have peculiar properties with respect to asteroids with similar size, while an excess of slow rotators is most probably confirmed.

The colonization of early terrestrial ecosystems by embryophytes (i.e. land plants) irreversibly changed global biogeochemical cycles (Berner & Kothavala, 2001; Berner et al., 2007; Song et al., 2012). However, when and how the process of plant terrestrialization took place is still intensely debated (Kenrick & Crane, 1997; Kenrick et al., 2012; Edwards et al., 2014; Edwards & Kenrick, 2015). Current knowledge suggests that the earliest land plants evolved from charophycean green algae (Karol et al., 2001) most probably during Early-Middle Ordovician times (Rubinstein et al., 2010; and references cited therein). They were represented by small nonvascular bryophyte-like organisms (Edwards & Wellman, 2001; Wellman et al., 2003; Kenrick et al., 2012). The oldest fossil evidence from dispersed spores of presumable bryophytic nature is known from a Middle Ordovician locality (c. 470 million years ago (Ma), Rubinstein et al., 2010; Fig. 1) from Argentina (Gondwana palaeocontinent). The dispersed spore fossil record also suggests that the first radiation of vascular plants probably occurred during Late Ordovician times (c. 450 Ma, Steemans et al., 2009). However, unequivocal macrofossils of vascular plants appear much later, during mid-Silurian (c. 430 Ma, Edwards et al., 1992). This macrofossil evidence comes from the fossil-genus Cooksonia, an early polysporangiophyte (i.e. a plant with bifurcating axes and more than one sporangium), which is considered the earliest vascular land plant (Edwards et al., 1992; Fig. 1). Further advances in knowledge about the origin and early dispersion of polysporangiophytes are needed for a better understanding of the initial plant diversification. Unfortunately, unravelling the initial steps of polysporangiophyte evolution is hindered by gaps in the fossil record of the earliest plants as well as by limitations of inference based on molecular clocks (Kenrick et al., 2012; Edwards & Kenrick, 2015).

Genetic and environmental factors appear to contribute to the pathogenesis of systemic lupus erythematosus (SLE). Viral infections have been reported to be associated with the disease. A number of exogenous viruses have been linked to the pathogenesis of SLE, of which Epstein-Barr virus (EBV) has the most evidence of an aetiological candidate. In addition, human endogenous retroviruses (HERV), HRES-1, ERV-3, HERV-E 4-1, HERV-K10 and HERV-K18 have also been implicated in SLE. HERVs are incorporated into human DNA, and thus can be inherited. HERVs may trigger an autoimmune reaction through molecular mimicry, since homology of amino acid sequences between HERV proteins and SLE autoantigens has been demonstrated. These viruses can also be influenced by oestrogen, DNA hypomethylation, and ultraviolet light (UVB) exposure which have been shown to enhance HERV activation or expression. Viral infection, or other environmental factors, could induce defective apoptosis, resulting in loss of immune tolerance. Further studies in SLE and other autoimmune diseases are needed to elucidate the contribution of both exogenous and endogenous viruses in the development of autoimmunity. If key peptide sequences could be identified as molecular mimics between viruses and autoantigens, then this might offer the possibility of the development of blocking peptides or antibodies as therapeutic agents in SLE and other autoimmune conditions.

The stratigraphic variability and geochemistry of Llandovery/Wenlock (L/W) Series boundary sediments in Poland reveals that hemipelagic sedimentation under an anoxic/euxinic water column was interrupted by low-density bottom currents or detached diluted turbid layers that resulted in intermittent seafloor oxygenation. Total organic carbon values and inorganic proxies throughout the Wilkow 1 borehole section suggest variable redox conditions. U/Mo ratios > 1 throughout much of the Aeronian and Telychian Stages, together with an absence of pyrite framboids, suggest oxygenated conditions prevailed. However, elevated total organic carbon near the Aeronian/Telychian boundary, together with increased U/Th and V/(V + Ni) ratios and populations of small pyrite framboids are consistent with the development of dysoxic/anoxic conditions at that time. U/Th, V/Cr and V/(V + Ni) ratios, as well as Uauthig and Mo concentrations, suggest that during the Ireviken black shale deposition, bottom-water conditions deteriorated from oxic during Telychian time to mostly suboxic/anoxic immediately prior to the L/W boundary, before a brief reoxygenation at the end of the Ireviken black shale sedimentation in the Sheinwoodian Stage. Rapid fluctuations in U/Mo during the Ireviken Event are characteristic of fluctuating redox conditions that culminated in an anoxic/euxinic seafloor in Sheinwoodian time. Following Ireviken black shale deposition, conditions once again became oxygen deficient with the development of a euxinic zone in the water column. The Aeronian to Sheinwoodian deep-water redox history was unstable, and rapid fluctuations of the chemocline across the L/W Series boundary probably contributed to the Ireviken Event extinctions, which affected mainly pelagic and hemipelagic fauna.