Search results for "Fins"

Regional endothermy as a trigger for gigantism in some extinct macropredatory sharks

2017

Otodontids include some of the largest macropredatory sharks that ever lived, the most extreme case being Otodus (Megaselachus) megalodon. The reasons underlying their gigantism, distribution patterns and extinction have been classically linked with climatic factors and the evolution, radiation and migrations of cetaceans during the Paleogene. However, most of these previous proposals are based on the idea of otodontids as ectothermic sharks regardless of the ecological, energetic and body size constraints that this implies. Interestingly, a few recent studies have suggested the possible existence of endothermy in these sharks thus opening the door to a series of new interpretations. Accord…

Squamation and ecology of thelodonts

2017

Thelodonts are an enigmatic group of Paleozoic jawless vertebrates that have been well studied from taxonomical, biostratigraphic and paleogeographic points of view, although our knowledge of their ecology and mode of life is still scant. Their bodies were covered by micrometric scales whose morphology, histology and the developmental process are extremely similar to those of extant sharks. Based on these similarities and on the well-recognized relationship between squamation and ecology in sharks, here we explore the ecological diversity and lifestyles of thelodonts. For this we use classic morphometrics and discriminant analysis to characterize the squamation patterns of a significant num…

Periodic Controls in Step 2 Strictly Convex Sub-Finsler Problems

2020

We consider control-linear left-invariant time-optimal problems on step 2 Carnot groups with a strictly convex set of control parameters (in particular, sub-Finsler problems). We describe all Casimirs linear in momenta on the dual of the Lie algebra. In the case of rank 3 Lie groups we describe the symplectic foliation on the dual of the Lie algebra. On this basis we show that extremal controls are either constant or periodic. Some related results for other Carnot groups are presented. peerReviewed

Coffins in Finland : the history of production, design and attitudes

2017

AbstractCoffins as death-related objects have changed in Finland during the past 150 years and the Finnish funeral industry has been created to answer the changing needs of customers. No longer do people build coffins in the household, or only buy a coffin and some other items from the funeral company: now professionals manage entire funerals. Coffin designs have become simpler and less socially discriminating and the colour formerly reserved for children and young people, white, has become the most popular colour for a coffin. Attitudes towards coffins have also changed, from mild dislike of having a coffin in the home to general demand of hiding coffins even in funeral companies’ premises…

Mitä oppilaat pitävät varhaisesta A1-kielen opetuksesta ja millainen käsitys heillä on omasta osaamisestaan?

2022

Vuoden 2020 alusta kieltenopiskelu on aloitettu Suomessa vuosiluokalla 1. Opetussuunnitelman perusteissa korostetaan, että opetuksen tulee olla ikätasolle sopivaa ja herättää myönteinen asenne kielenoppimiseen sekä vahvistaa oppilaan pystyvyyttä. Artikkelissa tarkastellaan suomen- ja ruotsinkielisten koulujen oppilaiden asennoitumista ja osaamiskäsityksiä. Tutkimuksen kohteen on englannin kielen (suomenkieliset koulut, n=106) ja suomi toisena kotimaisena kielenä -oppiaineen (ruotsinkieliset koulut, n=86) opiskelu. Tutkimus osoitti, että oppilaat pitivät pääosin niin opiskelemastaan kielestä kuin sen opiskelusta. He kokivat osaavansa tervehtimiseen, numeroihin ja väreihin liittyviä ilmaisuja…

Wulff shape characterizations in overdetermined anisotropic elliptic problems

2017

We study some overdetermined problems for possibly anisotropic degenerate elliptic PDEs, including the well-known Serrin's overdetermined problem, and we prove the corresponding Wulff shape characterizations by using some integral identities and just one pointwise inequality. Our techniques provide a somehow unified approach to this variety of problems.

Stress concentration for closely located inclusions in nonlinear perfect conductivity problems

2019

We study the stress concentration, which is the gradient of the solution, when two smooth inclusions are closely located in a possibly anisotropic medium. The governing equation may be degenerate of $p-$Laplace type, with $1<p \leq N$. We prove optimal $L^\infty$ estimates for the blow-up of the gradient of the solution as the distance between the inclusions tends to zero.

Die totale Sonnenfinsternis vom 8./21. August 1914 im Baltikum mit populären Erläuterungen dieses Phänomens [Die totale Sonnenfinsternis...im Baltiku…

1914

Degradation and stabilization of the polyolefins and of the filled-polyolefins

2009

Copolymerization of ethylene with norbornene or 1-octene using supported ionic liquid systems

2016

Copolymerization of ethylene with norbornene (E/NB) and ethylene with 1-octene (E/Oct) is performed using supported ionic liquid (SIL) systems, in which metallocene (Cp2VCl2) or post-metallocene [VCl2(salenCl2)] vanadium catalysts are immobilized in pyridinium chloroaluminate ionic liquid supported on silica. The studied SIL catalysts show higher activities as well as stability than their non-supported analogues. In addition, higher activities and better comonomer incorporation are observed for norbornene (above 30 mol%). The comonomer incorporation has considerable influence on copolymer molecular weight (M w), melting temperature, crystallinity degree, and microstructure of the copolymers…