bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mass spectral fragmentation analyses of isotopically labelled hydroxy steroids using gas chromatography/electron ionization low‐resolution mass spectrometry: A practical approach
Authors: Kollmeier Annette Sophie , Parr Maria Kristina 
Published: February 2020

RationaleGas chromatography coupled to electron ionization mass spectrometry (GC/EI‐MS) is used for routine screening of anabolic steroids in many laboratories after the conversion of polar groups into trimethylsilyl (TMS) derivatives. The aim of this work is to elucidate the origin and formation of common and subclass‐specific fragments in the mass spectra of TMS‐derivatized steroids. Especially in the context of metabolite identification or analysis of designer drugs, isotopic labelling is helpful to better understand fragment ion generation, identify unknown compounds and update established screening methods.MethodsStable isotope labelling procedures for the introduction of [2H9]‐TMS or 18O were established to generate perdeuterotrimethylsilylated, mixed deuterated and 18O‐labelled derivatives for 13 different hydroxy steroids. Fragmentation proposals were substantiated by comparison of the abundances of isotopically labelled and unlabelled fragment ions in unit mass resolution GC/MS. Specific fragmentations were also investigated by high‐resolution MS (GC/quadrupole time‐of‐flight MS, GC/QTOFMS).ResultsMethyl radical cleavage occurs primarily from the TMS groups in saturated androstanes and from the steroid nucleus in the case of enol‐TMS of oxo or α,β‐unsaturated steroid ketones. Loss of trimethylsilanol (TMSOH) is dependent on steric factors, degree of saturation of the steroid backbone and the availability of a hydrogen atom and TMSO group in the 1,3‐diaxial position. For the formation of the [M – 105]+ fragment ion, methyl radical cleavage predominates from the angular methyl groups in position C‐18 or C‐19 and is independent of the site of TMSOH loss. The common [M – 15 – 76]+ fragment ion was found in low abundance and identified as [M – CH3 – (CH3)2SiH – OH]+. For the different steroid subclasses further diagnostic fragment ions were discussed and structure proposals postulated.ConclusionsStable isotope labelling of oxo groups as well as derivatization with deuterated TMS groups enables the detection of structure‐related fragment ion generation in unit mass resolution GC/EI‐MS. This may in turn allow us to propose isomeric assignments that are otherwise almost impossible using MS only.
Cooperative path following of constrained autonomous vehicles with model predictive control and event‐triggered communications
Authors: Hung Nguyen T. , Pascoal Antonio M. , Johansen Tor A. 
Published: February 2020

SummaryWe present a solution to the problem of multiple vehicle cooperative path following (CPF) that takes explicitly into account vehicle input constraints, the topology of the intervehicle communication network, and time‐varying communication delays. The objective is to steer a group of vehicles along given spatial paths, at speeds that may be path dependent, while holding a feasible geometric formation. The solution involves decoupling the original CPF problem into two subproblems: (i) single path following of input‐constrained vehicles and (ii) coordination of an input‐constrained multiagent system. The first is solved by adopting a sampled‐data model predictive control scheme, whereas the latter is tackled using a novel distributed control law with an event‐triggered communication (ETC) mechanism. The proposed strategy yields a closed‐loop CPF system that is input‐to‐state‐stable with respect to the system's state (consisting of the path following error of all vehicles and their coordination errors) and the system's input, which includes triggering thresholds for ETC communications and communication delays. Furthermore, with the proposed ETC mechanism, the number of communications among the vehicles are significantly reduced. Simulation examples of multiple autonomous vehicles executing CPF maneuvers in 2D under different communication scenarios illustrate the efficacy of the CPF strategy proposed.
A 3D reactive collision avoidance algorithm for underactuated underwater vehicles
Authors: Wiig Martin S. , Pettersen Kristin Y. , Krogstad Thomas R. 
Published: February 2020

AbstractAvoiding collisions is an essential goal of the control system of autonomous vehicles. This paper presents a reactive algorithm for avoiding obstacles in a three‐dimensional space, and shows how the algorithm can be applied to an underactuated underwater vehicle. The algorithm is based on maintaining a constant avoidance angle to the obstacle, which ensures that a guaranteed minimum separation distance is achieved. The algorithm can thus be implemented without knowledge of the obstacle shape. The avoidance angle is designed to compensate for obstacle movement, and the flexibility of operating in 3D can be utilized to implement traffic rules or operational constraints. We exemplify this by incorporating safety constraints on the vehicle pitch and by making the vehicle seek to move behind the obstacle, while also minimizing the required control effort. The underactuation of the vehicle induces a sway and heave movement while turning. To avoid uncontrolled gliding into the obstacle, we account for this movement using a Flow frame controller, which controls the direction of the vehicle's velocity rather than just the pitch and yaw. We derive conditions under which it is ensured that the resulting maneuver is safe, and these results are verified trough simulations and through full‐scale experiments on the Hugin HUS autonomous underwater vehicle. The latter demonstrates the performance of the proposed algorithm when applied to a case with unmodeled disturbances and sensor noise, and shows how the modular nature of the collision avoidance algorithm allows it to be applied on top of a commercial control system.
Controlling the Facet of ZnO during Wet Chemical Etching Its (0001¯) O‐Terminated Surface
Authors: Sun Mei , Yu Bocheng , Hong Mengyu , Li Zhiwei , Lyu Fengjiao , Li Xing , Li Zhihong , Wei Xianlong , Zhang Zheng , Zhang Yue , Chen Qing 
Published: February 2020

AbstractSpecial surface plays a crucial role in nature as well as in industry. Here, the surface morphology evolution of ZnO during wet etching is studied by in situ liquid cell transmission electron microscopy and ex situ wet chemical etching. Many hillocks are observed on the (000) O‐terminated surface of ZnO nano/micro belts during in situ etching. Nanoparticles on the apex of the hillocks are observed to be essential for the formation of the hillocks, providing direct experimental evidence of the micromasking mechanism. The surfaces of the hillocks are identified to be {01} crystal facets, which is different from the known fact that {01} crystal facets appear on the (000) O‐terminated surface of ZnO after wet chemical etching. O2 plasma treatment is found to be the key factor for the appearance of {01} instead of {01} crystal facets after etching for both ZnO nano/micro belts and bulk materials. The synergistic effect of acidic etching and O‐rich surface caused by O2 plasma treatment is proposed to be the cause of the appearance of {01} crystal facets. This method can be extended to control the surface morphology of other materials during wet chemical etching.
Generalized piezoelectric thermoelasticity problems with strain rate and transient thermo‐electromechanical responses analysis
Authors: Li Chenlin , Guo Huili , Tian Xiaogeng , He Tianhu 
Published: February 2020

AbstractPiezoelectric materials have become one of the most promising candidates for a new class of smart structures which are widely used as sensors and actuators in control systems due to their superior electromechanical performance and high‐efficiency in electro‐mechanical energy conversion. In recent years, although there are many papers of theoretical modeling of generalized piezoelectric thermoelasticity that considered the piezoelectric‐thermoelastic coupling of piezoelectric structures serving in the extreme fast heating environment (e.g. ultra‐fast laser), the strain relaxation effect has not been considered yet. This work aims to investigate the generalized piezoelectricity problem with strain rate with the aid of extended thermodynamic principles, and corresponding generalized variational theorem is also strictly formulated to provide a complete rationale for numerical method by using semi‐inverse method. For numerical evaluation, transient thermo‐electromechanical responses of a one‐dimensional semi‐infinite piezoelectric medium with one end subjecting to a sudden thermal loading are considered and solved by applying Laplace transformation methods. Then the transient responses of temperature, displacement, strain, stress and electric potential are obtained and illustrated graphically, and the influences of strain relaxation parameters on them are also analyzed and discussed.
Untangling Context and Composition
Authors: Leyland Alastair H. , Groenewegen Peter P. 
Published: February 2020

AbstractThis chapter contains a tutorial that helps to untangle contextual and compositional effects. We start from a typical, empty table and then proceed to fill this table. The example data set concerns patterns of incidence of cardiovascular disease in small areas in Scotland. The outcome or dependent variable is whether or not a survey respondent had self-reported doctor-diagnosed cardiovascular disease. The first step in the analysis is to estimate a null model. We then estimate the fixed effects of two individual-level variables, social class and smoking status, one by one. The final model looks at the fixed effects of all three variables. With these steps the empty table can be filled and we can interpret the results in terms of context and composition.In this chapter, we describe the analysis of these data using MLwiN.
Exploration Through Process Drama with Kindergarten Children
Authors: Ødemotland Siv 
Published: February 2020

AbstractProcess drama refers to social, educational and artistic activity carried out by a teacher in a classroom. Specifically, process drama can be used to explore an everyday problem or a specific situation or theme through artistic activities or unscripted drama and play. A teacher may choose activities from a variety of drama conventions and create activities that challenge children to actively investigate questions, issues or dilemmas from different angles. Drama activities in kindergarten are closely related to children’s role-play, and the two mutually influence one another. For example, when participating in process drama, children may regard the activity as play that involves meaning, joy and excitement. This implies that process drama is one means of openly encouraging children to explore. The teacher’s own knowledge, skills and playfulness also influence this process.Few research studies have examined the concept of process drama or the concept of exploration in process drama for children aged 3–6. This chapter will expand knowledge in this field by examining the following research question: How does exploration occur in the activities of process drama? Examples will be taken from the observations of an early childhood educational setting. This chapter will specifically examine how process drama can be performed in settings with children aged 3–6 and how exploration plays a part. Furthermore, the teacher’s role in the activities of process drama will be analysed and discussed. Vygotsky’s concepts of play and child development are crucial for this discussion. The chapter will therefore discuss possible practices and means of child engagement in exploration (Vygotsky LS: Play and its role in the mental development of the child. In: Bruner J, Jolly A, Sylva K (eds) Play: its role in development and evolution. Basic Books, New York, pp 537–554, 1967).
Children’s Exploration as a Key in Children’s Play and Learning Activity in Social and Cultural Formation
Authors: Hedegaard Mariane 
Published: February 2020

AbstractChildren are active and intentional from birth, and from infancy explorative activity is central (Bruner, 1972, Stern, 2000, Vygotsky, Child psychology. The collected works of L. S. Vygotsky, vol 5. Plenum Press, New York, 1998), but children’s learning and development must be seen in relation to a society’s cultural and educational practice. Three different educational approaches to early childhood education (Maria Montessori, Bert van Oers, and Roland Tharp) have contributed to turning the focus on learning in early childhood away from receptive learning to exploration as the central activity. Montessori’s contribution was to let the child become an agent in his or her own learning activity, by providing opportunities and materials for children’s exploration. Van Oers focuses on creating opportunities for children’s cooperation through playful activities that model well-known adult activities. Tharp and colleagues put weight on children’s possibility to model community activities. However, none of these approaches is clear about how the cultural formation aspect within early childhood is different from the cultural formation in the school. The chapter will conclude with an outline of ideas for an educational approach that proscribed instruction and instead support exploration in kindergarten that relate to experiences from everyday local settings. This approach gives a possibility for cultural formation that may be relevant for children’s transcendence to school.
Beyond Bullying: Understanding Children’s Exploration of Inclusion and Exclusion Processes in Kindergarten
Authors: Skoglund Ruth Ingrid 
Published: February 2020

AbstractFor several years, there was resistance to the use of the concept of bullying in Norwegian kindergartens and to labelling individual children as bullies or victims – as exhibiting certain characteristics or lacking certain skills. This chapter investigates a theoretical framework beyond the perception of bullying as being as resulting from individual factors. An alternative approach is the democratic theoretical perspective, in which children are considered as explorers of complex, dynamic relations, which can lead to their inclusion or exclusion. The research questions are: How can children’s bullying in free play be seen as explorations in inclusion and exclusion processes? How are children’s explorations of social processes during free play supported or restricted by institutional practice? Children’s exploration of their own and others’ changing positions and power in a group are seen as part of their democratic and cultural formation. Hedegaard’s model for child development (Chap. 2) provides possibilities for analysing children’s exploration of social processes at a relational, institutional and societal level. An illustrative example is an observation protocol regarding three boys in an outdoor free-play setting. The boys explore their positions and how material and physical factors affect their access to power, resulting in internal exclusion of one of the boys. It is difficult to detect inclusion and exclusion processes because of their simultaneity: they co-occur in a way that does not result in the total exclusion of either. The cultural value of outdoor free play expects children to be self-directed and provides them with possibilities to hide their exploration of inclusion and exclusion processes, ensuring a lack of involvement from practitioners. (I use the term practitioners for all employees working with children in Norwegian early education institutions, named kindergartens. These employees consist of formally educated kindergarten teachers as well as skilled workers and assistants with no formal education at the university level).
Institutional Conditions for Exploration: Chinese Kindergarten Teachers’ Perspectives and Practices
Authors: Hu Aihua 
Published: February 2020

AbstractAnchored in cultural-historical framework, this chapter investigates Chinese kindergarten teachers’ perspectives on how their conceptions and practices are framed with the aim to understand the institutional conditions for kindergarteners’ explorative activities. Data are drawn from documents, open-ended questionnaires, and online interviews. The major documents include policies and curricula of early childhood education (ECE) teacher education/training, ECE-related policies, curricula at different levels and exploratory activity plans shared by the teachers. Kindergarten teachers from Huining (Gansu province), Kunming (Yunnan), and Shanghai have answered the online open-ended questionnaires. In addition, online interviews have been conducted with six kindergarten teachers who have answered the questionnaire and three principals for different purposes. Cultural-historical framework has also been utilized to guide the data analysis process and the discussion of the findings. This study finds that national policies as a form of societal condition in one way or another directs institution (teacher education/training and kindergartens) practices which shape teachers’ conceptions and practices of children’s exploration. Additionally, the teachers from the three kindergarten hold different conceptions of children’s exploration and organize various explorative activities for kindergarteners, each with their own distinctive features influenced by institutional conditions including local cultures, climate, and environment, and resources. This study illustrates that cultural-historical framework can also be utilized to explore the development of teachers and adults in addition to children and youths.
Kindergarten as a Budding Explorative Scientific Community
Authors: Hammer Anne Synnøve Ekrene 
Published: February 2020

AbstractIn this chapter I argue in favour of a science education in kindergarten characterized by children’s and teachers’ shared exploration of science-related phenomena and objects. The concept of exploration is related to science as inquiry and the practices of science, which are key perspectives in the science education field today (Crawford, From inquiry to scientific practices in the science classroom. In Lederman NG, Abell SK (eds), Handbook of research on science education, Vol. II. Routledge, New York, 2014, pp. 515–541; Osborne, Scientific practices and inquiry in the science classroom. In Lederman NG, Abell S (eds), Handbook of research on science education, Vol. II. Taylor & Fransis, New York, 2014, pp. 579–599). These perspectives coincide with the concept of sciencing, introduced by Neuman (Sciencing for young children. In Baker KB (ed), Ideas that work with young children. National Association for the Education of Young Children, Washington, DC, 1972, pp. 137–151) to denote the importance of young children’s involvement in the processes or practices of science. Neuman’s three categories of sciencing are used as a basis for characterizing kindergarten as a budding explorative scientific community. I elaborate on how the cultural-historical theory of child development originally formulated by Vygotsky (The collected work of L.S. Vygotsky, In Hall MJ, (trans.) Rieber RW (ed) Child psychology, Vol. 5. Plenum, New York) supports an approach to science through which children have the opportunity to take part in an explorative scientific community. Further, I discuss how some of the characteristics of such a community can both bridge and challenge today’s views on what constitutes good educational practice in kindergarten. Finally, I discuss the competences teachers need in order to facilitate such an approach and consider the implications this may have for kindergarten teacher education.
What First, What Later? Patterns in the Legal Recognition of Same-Sex Partners in European Countries
Authors: Waaldijk Kees 
Published: February 2020

AbstractAmong the 21 European countries surveyed for the LawsAndFamilies Database, there is a clear trend (fortified by European law) of offering same-sex couples the opportunity to formalise their relationship as marriage and/or as registered partnership, and of attaching more and more rights and responsibilities to the informal cohabitation, the registered partnership and/or the civil marriage of two people of the same sex. This chapter focusses on the timing of all these changes. In a five periods analysis, it establishes whether major partnership rights were extended to same-sex couples at the time of the introduction of registered partnership, or before, or at the time of the opening up of marriage, or between those two moments, or after the opening up of marriage. Thereby, and by calculating the same-sex legal recognitionconsensus among the countries surveyed for each of 26 selected rights, it finds nine typical sequences: Attitudes before rights; Rights before status; Bad-times rights before good-times rights; Responsibilities before benefits; Individual partner rights before couple rights; Partnership before marriage; Immigration rights among the first to be gained; Parenting rights among the last to be gained; Legal recognition before social legitimacy.
LGBT Desires in Family Land: Parenting in Iceland, from Social Acceptance to Social Pressure
Authors: Digoix Marie 
Published: February 2020

AbstractMore than 20 years ago, Iceland opened civil union to same-sex couples with its confirmed partnership law (staðfest samvist, 1996). Since then, the country has attained a high level of equality between same-sex and different-sex couples in the domain of family law, and the law has strong provisions against discrimination toward LGBT people. The increasing visibility and acceptance of LGBT people is raising questions about the social process of integration. LGBT people are confronted with heterosexual norms, a confrontation that is difficult to bypass. In this context, some may find that they are losing their identity. Iceland is a familialist society, and a key entry into the social acceptance of homosexuality has been through marriage and parenting. There is a clear gender gap in family-making. Lesbians have access to ART whereas adoption is scarcely available and surrogacy still illegal, reducing access to parenthood for gay men. However, in Iceland’s small LGBT community, parenting desire has increasingly become a reality for both females and males. Based on a survey consisting of 30 interviews, the paper studies how parenthood meets a wide range of personal desires, but also how it has become a normative pressure.
Basic Elements: Cash Flow, Tax, Expectation, Cost of Capital, Value
Authors: Kruschwitz Lutz , Löffler Andreas 
Published: February 2020

AbstractValuation is being talked about everywhere. Finance experts, CPAs, investment bankers, and business consultants are discussing the advantages and disadvantages of discounted cash flow (DCF) methods since years. This book takes part in the discussion, and intends to make a theoretical contribution to it.
Chile
Authors: Madero-Cabib Ignacio , De-Amesti José , Herrera María-Soledad 
Published: February 2020

AbstractDuring the last three decades Chile has experienced an unprecedented demographic transition due to increased life expectancy and decreased childbirth. This is expected to cause important challenges to economic, health and cultural dimensions among older people in Chile. Furthermore, this is a developing country characterised by a liberal labour market and pension policies and by a male breadwinner culture-locating women in care and domestic tasks at the expense of labour market participation. This means that gender plays a key role in the challenges associated with an ageing population. We discuss public policies and recent academic research on the economic, health, and cultural dimensions of ageing in Chile.