Search results for "mekanismit"
showing 10 items of 47 documents
Causal complexity of new product development processes : a mechanism-based approach
2018
The outcomes of new product development (NPD) processes are dependent on the interplay of several interdependent activities. One product development activity can be dependent on the presence or absence of other activities, different kinds of NDP processes may lead to the same outcome, and specific kinds of activities may have a positive effect in one process but no effect in other processes. However, we currently lack means to examine and explain this causal complexity inherent in NPD processes. To address this issue, we introduce mechanism-based approach as a way to capture conjunctural and equifinal causal relations. We build this approach on the philosophical literature on mechanism-base…
Nanoscale etching of III-V semiconductors in acidic hydrogen peroxide solution: GaAs and InP, a striking contrast in surface chemistry
2019
In this study of nanoscale etching for state-of-the-art device technology, the importance of surface chemistry, in particular the nature of the surface oxide, is demonstrated for two III-V materials. Striking differences in etching kinetics were found for GaAs and InP in sulphuric and hydrochloric acidic solutions containing hydrogen peroxide. Under similar conditions, etching of GaAs was much faster, while the dependence of the etch rate on pH, and on H2O2 and acid concentrations also differed markedly for the two semiconductors. Surface analysis techniques provided information on the product layer present after etching: strongly non-stoichiometric porous (hydr)oxides on GaAs and a thin st…
Increasing intensity of deimatic behaviour in response to repeated simulated attacks: a case study on the mountain katydid (Acripeza reticulata)
2022
Abstract How and when deimatic behaviours are performed can change during encounters between predators and prey. Some predators attack repeatedly, investigating and manipulating prey, and in response, an individual’s deimatic behaviour may intensify or may diminish in favour of escaping. The presence of a resource can further force a trade-off between displaying and escaping. Here, we examined the intensity of the katydid’s deimatic behaviour, a visual display, the propensity of their escape response under repeated simulated attacks, and how these responses change in the presence of foraging resources. We found that display intensity increased with repeated simulated attacks and that femal…
De novo Synthesis of Chemical Defenses in an Aposematic Moth
2018
Many animals protect themselves from predation with chemicals, both self-made or sequestered from their diet. The potential drivers of the diversity of these chemicals have been long studied, but our knowledge of these chemicals and their acquisition mode is heavily based on specialist herbivores that sequester their defenses. The wood tiger moth (Arctia plantaginis, Linnaeus, 1758) is a well-studied aposematic species, but the nature of its chemical defenses has not been fully described . Here, we report the presence of two methoxypyrazines, 2-sec-butyl-3-methoxypyrazine and 2-isobutyl-3-methoxypyrazine, in the moths’ defensive secretions. By raising larvae on an artificial diet, we confir…
A synthesis of deimatic behaviour
2022
Deimatic behaviours, also referred to as startle behaviours, are used against predators and rivals. Although many are spectacular, their proximate and ultimate causes remain unclear. In this review we aim to synthesise what is known about deimatic behaviour and identify knowledge gaps. We propose a working hypothesis for deimatic behaviour, and discuss the available evidence for the evolution, ontogeny, causation, and survival value of deimatic behaviour using Tinbergen's Four Questions as a framework. Our overarching aim is to direct future research by suggesting ways to address the most pressing questions in this field. peerReviewed
The long and winding road of enterprise architecture implementation in the Finnish public sector
2018
This thesis examines the implementation of enterprise architecture (EA) in the Finnish public sector. EA is a systematic approach for analysing, visualising, developing and governing the functions and structures of organisations. It describes how organisations businesses, information and systems function as a whole. Research and practice have shown the implementation of EA is challenging and slow to advance. Finland provides a prolific area for research since the use of EA is mandatory in public sector, which is rare amongst countries taking a whole-of-government EA approach. In order to research EA as a method for systemic change, a suitable theoretical framing was necessary. The context, …
Maintenance of variation in warning signals under opposing selection pressures
2008
Kaikki eliöt ovat jotain kautta yhteydessä toisiin eliöihin erilaisten vuorovaikutussuhteiden kautta. Tyypillisesti vihollisiakaan ei ole vain yhtä, vaan useita erilaisia, joiden määrät ja tiheydet vaihtelevat luonnossa. Useisiin vastakkaisiin ja vaihteleviin valintapaineisiin on hankalaa sopeutua.Tilanne on haaste myös tutkijalle, sillä on vaikeampaa tutkia useampia valintapaineita samanaikaisesti kuin vain yhtä kerrallaan. Eläinten väritys antaa kuitenkin hyvän mahdollisuuden useiden samanaikaisten valintapaineiden tutkimiselle. Väritystä ja sen muuntelua on helppo havaita ja värityksellä on suuri merkitys eläimen hengissä selviytymisen kannalta.Carita Lindstedtin väitöskirjatutkimuksen l…
Oxidative Dehydrogenation of Ethanol on Gold : Combination of Kinetic Experiments and Computation Approach to Unravel the Reaction Mechanism
2021
Abstract Selective alcohol dehydrogenation on heterogeneous catalysts is a key industrial reaction for production of aldehydes, ketones, and carboxylic compounds. Design of catalysts with improved activity and selectivity requires understanding of the reaction mechanism and kinetics. Herein, experiments, density functional theory (DFT) and kinetic modelling were combined to elucidate the mechanism and kinetics of ethanol oxidative dehydrogenation to acetaldehyde on gold catalysts. Catalytic experiments clearly emphasized the role of oxygen in this reaction. Ethanol conversion was rather independent on the gold cluster size. Formation of minor products, acetic acid and ethyl acetate was stru…
Experimental and computational investigation on the formation pathway of [RuCl2(CO)2(ERR′)2] (E = S, Se, Te; R, R′ = Me, Ph) from [RuCl2(CO)3]2 and E…
2022
The pathways to the formation of the series of [RuCl2(CO)2(ERR′)2] (E = S, Se, Te; R, R′ = Me, Ph) complexes from [RuCl2(CO)3]2 and ERR′ have been explored experimentally in THF and CH2Cl2, and computationally by PBE0-D3/def2-TZVP calculations. The end-products and some reaction intermediates have been isolated and identified by NMR spectroscopy, and their crystal structures have been determined by X-ray diffraction. The relative stabilities of the [RuCl2(CO)2(ERR′)2] isomers follow the order cct > ccc > tcc > ttt ≈ ctc (the terms c/t refer to cis/trans arrangement of the ligands in the order of Cl, CO, and ERR′). The yields were rather similar in both solvents, but the reactions were signi…
Two traditions of cognitive sociology : an analysis and assessment of their cognitive and methodological assumptions
2022
Cognitive sociology has been split into cultural and interdisciplinary traditions that position themselves differently in relation to the cognitive sciences and make incompatible assumptions about cognition. This article provides an analysis and assessment of the cognitive and methodological assumptions of these two traditions from the perspective of the mechanistic theory of explanation. We argue that while the cultural tradition of cognitive sociology has provided important descriptions about how human cognition varies across cultural groups and historical periods, it has not opened up the black box of cognitive mechanisms that produce and sustain this variation. This means that its expla…