The multi-peak adaptive landscape of crocodylomorph body size evolution

Background: Little is known about the long-term patterns of body size evolution in Crocodylomorpha, the > 200-million-year-old group that includes living crocodylians and their extinct relatives. Extant crocodylians are mostly large-bodied (3–7 m) predators. However, extinct crocodylomorphs exhibit a wider range of phenotypes, and many of the earliest taxa were much smaller ( Results: Crocodylomorphs reached an early peak in body size disparity during the Late Jurassic, and underwent an essentially continual decline since then. A multi-peak Ornstein-Uhlenbeck model outperforms all other evolutionary models fitted to our data (including both uniform and non-uniform), indicating that the macroevolutionary dynamics of crocodylomorph body size are better described within the concept of an adaptive landscape, with most body size variation emerging after shifts to new macroevolutionary regimes (analogous to adaptive zones). We did not find support for a consistent evolutionary trend towards larger sizes among lineages (i.e., Cope’s rule), or strong correlations of body size with climate. Instead, the intermediate to large body sizes of some crocodylomorphs are better explained by group-specific adaptations. In particular, the evolution of a more aquatic lifestyle (especially marine) correlates with increases in average body size, though not without exceptions. Conclusions: Shifts between macroevolutionary regimes provide a better explanation of crocodylomorph body size evolution on large phylogenetic and temporal scales, suggesting a central role for lineage-specific adaptations rather than climatic forcing. Shifts leading to larger body sizes occurred in most aquatic and semi-aquatic groups. This, combined with extinctions of groups occupying smaller body size regimes (particularly during the Late Cretaceous and Cenozoic), gave rise to the upward-shifted body size distribution of extant crocodylomorphs compared to their smaller-bodied terrestrial ancestors.</p

A New Minimal Average Weight Representation for Left-to-Right Point Multiplication Methods

This paper introduces a new radix-2 representation with the same average weight as the width-$w$ nonadjacent form ($w$-NAF). In both $w$-NAF and the proposed representations, each nonzero digit is an odd integer with absolute value less than $M$. However, for $w$-NAF, $M$ is of the form $2^{w-1}$, while for the proposed representation it can be any positive integer. Therefore, using the proposed integer representation we can use the available memory efficiently, which is attractive for devices with limited memory. Another advantage of the proposed representation over $w$-NAF is that it can be obtained by scanning the bits from left-to-right. This property is also useful for memory-constrained devices because it can reduce both time and space complexityof fast point multiplication techniques

Rolling bearings for electromobility

Snahou tejto bakalárskej práce je priblížiť problematiku týkajúcu sa použitia valivých ložísk v elektromobiloch. V úvode bude obsahovať históriu, rozdelenie a krátky opis ložísk. V dalsej časti bude nasledovať popis využitia, kladených požiadaviek a parametrov na valivé ložiská automobiloch so spaľovacím motorom. V hlavnej časti práce bude rozobratie parametrov a požiadavok ložisk využívaných v elektromobiloch a hybridných vozidlách. Následovať bude zoznámenie s dynamickými učinkami vplývajúcimi na ložiská a aj na ich kritické požiadavky. Na záver bude porovnanie medzi dvoma spomínanými druhmi áut a možný vývoj tohto druhu ložísk.The aim of this bachelor thesis is to describe the problems related to the use of rolling bearings in electric vehicles. Introduction includes history, distribution, and a brief description of the bearings. In the next section, there will be a description of the use, requirements and parameters for rolling bearings of combustion engine cars. In the main part of the thesis, the parameters and requirements of bearings used in electric vehicles and hybrid vehicles will be analyzed. I will continue with familiarization with dynamic actions affecting bearings and their critical requirements. In conclusion, the two types of cars and the possible development of this type of bearings will be compared.