881 resultados para 1468
Resumo:
We describe some unsolved problems of current interest; these involve quantum critical points in
ferroelectrics and problems which are not amenable to the usual density functional theory, nor to
classical Landau free energy approaches (they are kinetically limited), nor even to the Landau–
Kittel relationship for domain size (they do not satisfy the assumption of infinite lateral diameter)
because they are dominated by finite aperiodic boundary conditions.
Response of soil microbial biomass to 1,2-dichlorobenzene addition in the presence of plant residues
Resumo:
The impact of 1,2-dichlorobenzene on soil microbial biomass in the presence and absence of fresh plant residues (roots) was investigated by assaying total vital bacterial counts, vital fungel hyphal length, total culturable bacterial counts, and culturable fluorescent pseudomonads. Diversity of the fluorescent pseudomonads was investigated using fatty acid methyl ester (FAME) characterization in conjunction with metabolic profiling of the sampled culturable community (Biolog). Mineralization of [14C]1,2- dichlorobenzene was also assayed. Addition of fresh roots stimulated 1,2- dichlorobenzene mineralization by over 100%, with nearly 20% of the label mineralized in root-amended treatments by the termination of the experiment. Presence of roots also buffered any impacts of 1,2-dichlorobenzene on microbial numbers. In the absence of roots, 1,2-dichlorobenzene greatly stimulated total culturable bacteria and culturable pseudomonads in a concentration-dependent manner. 1,2-Dichlorobenzene, up to concentrations of 50 μg/g soil dry weight had little or no deleterious effects on microbial counts. The phenotypic diversity of the fluorescent pseudomonad population was unaffected by the treatments, even though fluorescent pseudomonad numbers were greatly stimulated by both roots and 1,2-dichlorobenzene. The presence of roots had no detectable impact on the bacterial community composition. No phenotypic shifts in the natural population were required to benefit from the presence of roots and 1,2-dichlorobenzene. The metabolic capacity of the culturable bacterial community was altered in the presence of roots but not in the presence of 1,2-dichlorobenzene. It is argued that the increased microbial biomass and shifts in metabolic capacity of the microbial biomass are responsible for enhanced degradation of 1,2-dichlorobenzene in the presence of decaying plant roots.
Resumo:
This paper considers the value of a normative account of the relationship between agents and institutions for contemporary efforts to explain ever more complex and disorganized forms of social life. The character of social institutions, as they relate to practices, agents and norms, is explored through an engagement with the common claim that family life has been deinstitutionalized. The paper argues that a normative rather than empirical definition of institutions avoids a false distinction between institutions and practices. Drawing on ideas of social freedom and creative action from critical theory, the changes in family life are explained not as an effect of deinstitutionalization, but as a shift from an organized to a disorganized institutional type. This is understood as a response to changes in the wider normative structure, as a norm of individual freedom has undermined the legitimacy of the organized patriarchal nuclear family, with gender ascribed roles and associated duties. Contemporary motherhood is drawn on to illustrate the value of analysing the dynamic interactions between institutions, roles and practices for capturing both the complexity and the patterned quality of social experience.
Resumo:
Food preparation and storage behaviors in the home deviating from the ‘best practice’ food safety recommendations may result in food borne illnesses. Currently, there are limited tools available to fully evaluate the consumer knowledge, perceptions and behavior in the area of refrigerator safety. The current study aimed to develop a valid and reliable tool in the form of a questionnaire (CFSQCRSQ) for assessing systematically all these aspects. Items relating to refrigerator safety knowledge (n=17), perceptions (n=46), reported behavior (n=30) were developed and pilot tested by an expert reference group and various consumer groups to assess face and content validity (n=20), item difficulty and item consistency (n=55) and construct validity (n=23). The findings showed that the CFSQCRSQ has acceptable face and content validity with acceptable levels of item difficulty. Item consistency was observed for 12 out of 15 refrigerator safety knowledge. Further, all five of the subscales of consumer perceptions of refrigerator safety practices relating to risk of developing foodborne disease food poisoning showed acceptable internal consistency (Cronbach’s α value > 0.8). Construct validity of the CFSQCRSQ was shown to be very good (p=0.022). The CFSQCRSQ exhibited acceptable test-retest reliability at 14 days with majority of knowledge items (93.3%) and reported behavior items (96.4%) having correlation coefficients of greater than 0.70. Overall, the CFSQCRSQ was deemed valid and reliable in assessing refrigerator safety knowledge and behavior and therefore has the potential for future use in identifying groups of individuals at increased risk of deviating from recommended refrigerator safety practices as well as the assessment of refrigerator safety knowledge, behavior for use before and after an intervention.
Resumo:
When and why did the Portuguese become the shortest Europeans? In order to find the answer to this question, we trace the trend in Portuguese living standards from the 1720s until recent times. We find that during the early nineteenth century average height in Portugal did not differ significantly from average height in most other European countries, but that when, around 1850, European anthropometric values began to climb sharply, Portugal's did not. In a panel analysis of 12 countries, we find that delay in human-capital formation was the chief factor hindering any improvement in the biological standard of living in Portugal.
Resumo:
This paper discusses the literature on the established determinants of productivity in the retail sector. It also draws attention to some neglected strands of research which provide useful insights into strategies that could allow productivity enhancements in this area of the economy. To date, very few attempts have been made to integrate different specialisms in order to explain what drives productivity in retail. Here this paper rectifies this omission by putting together studies from economics, geography, knowledge management and employment studies. It is the authors' view that quantitative studies of retail productivity should focus on total factor productivity in retailing as the result of competition/composition effects, planning regulations, information and communications technology, the multinational operation element and workforce skills. Further, the fact that retail firms possess advantages that are transferable between locations suggests that investment in strategies enhancing the transfer of explicit and tacit knowledge between and within businesses are crucial to achieve productivity gains.
Resumo:
The 2005 French and Dutch negative votes on the Constitution open up a space of conceptualisation, not only of Europe's relation to its demos, but significantly to its failures. Through a critical analysis of mainly Niklas Luhmann's systems theory, the article proposes taking a distance from traditional constitutional dogmatics that are no longer capable of dealing with the paradox of contemporary society, and more specifically with the eventual resurgence of the European project as one of absence and stasis: the two terms are used to explain the need, on the one hand, to maintain the 'absent community' of Europe, and, on the other, to start realising that any conceptualisation of the European project will now have to take place in that space of instability and contingency revealed by the constitutional failure. The relation between law and politics, the location of a constitution, the distinction between social and normative legitimacy, the connection between European identity and demos, and the concept of continuity between constitutional text and context are revisited in an attempt to trace the constitutional failure as the constitutional moment par excellence.
Resumo:
At a time when the electoral system is coming under renewed scrutiny, this article examines the origins and creation of the present system in 1884-5, and its subsequent survival. This is the first such analysis to draw upon Public Record Office and party archives. Whilst showing that the political classes have been quite prepared to consider the merits of alternatives, particularly S.T.V., for Ireland or in colonial settings, they have usually been seen as less appropriate for Westminster. In exploring why that should be the case this article seeks to provide a new explanation for the longevity of the electoral arrangements of 1885.
Resumo:
Reforms which increase the stock of education in a society have long been held by policy-makers as key to improving rates of intergenerational social mobility. Yet, despite the intuitive plausibility of this idea, the empirical evidence in support of an effect of educational expansion on social fluidity is both indirect and weak. In this paper we use the raising of the minimum school leaving age from 15 to 16 years in England and Wales in 1972 to estimate the effect of educational participation and qualification attainment on rates of intergenerational social class mobility. Because, in expectation, children born immediately before and after the policy was implemented are statistically exchangeable, the difference in the amount of education they received may be treated as exogenously determined. The exogenous nature of the additional education gain means that differences in rates of social mobility between cohorts affected by the reform can be treated as having been caused by the additional education. The data for the analysis come from the ONS Longitudinal Study, which links individual records from successive decennial censuses between 1971 and 2001. Our findings show that, although the reform resulted in an increase in educational attainment in the population as a whole and a weakening of the association between attainment and class origin, there was no reliably discernible increase in the rate of intergenerational social mobility.
Resumo:
We investigate the risk effects of bank acquisitions of insurance companies and securities firms between 1991 and 2012 using a newly constructed dataset of M&A deals. We examine risk changes before and after deal announcements by decomposing risk into systematic and idiosyncratic components. Subsequently, we investigate the relationship between risk and diversification by modelling the determinants of risks. We find that bank combinations with securities firms yield higher risks than combinations with insurance companies. Bank size is an important and consistent determinant of risk whereas diversification is not. Our results inform the continuing debate on diversification versus functional separation of bank activities.
Resumo:
This work describes how genetic programming is applied to evolving controllers for the minimum time swing up and inverted balance tasks of the continuous state and action: limited torque acrobot. The best swing-up controller is able to swing the acrobot up to a position very close to the inverted ‘handstand’ position in a very short time, shorter than that of Coulom (2004), who applied the same constraints on the applied torque values, and to take only slightly longer than the approach by Lai et al. (2009) where far larger torque values were allowed. The best balance controller is able to balance the acrobot in the inverted position when starting from the balance position for the length of time used in the fitness function in all runs; furthermore, 47 out of 50 of the runs evolve controllers able to maintain the balance position for an extended period, an improvement on the balance controllers generated by Dracopoulos and Nichols (2012), which this paper is extended from. The most successful balance controller is also able to balance the acrobot when starting from a small offset from the balance position for this extended period.
Resumo:
What are we to do with the writing of Biesta? Raising the same question in relation to Jacques Rancière, in a 2010 study co-authored with Charles Bingham, Gert J. J. Biesta takes the writer of ‘a short, disparaging review of …The Ignorant Schoolmaster’ to task for “schooling” Rancière on the inadequacies of the book reviewed (Biesta & Bingham 2010, 145-148). Readers of Biesta cheering on from the sidelines at this point are placed in an uncomfortable double bind if they are to take this suggestion seriously when reviewing his own work. We are not, Biesta and Bingham (2010, 148) suggest, to police interpretations like a vigilant schoolmaster in possession of superior knowledge but rather ‘proceed as a child who looks forward to the sound of the bell’ and to ‘speak as if truant’.
Resumo:
The paper looks into the dynamics of information society policy and its implementation in the Greek context. It argues that information society development is a contested process, influenced by pre-existing state, economy and society relations. Based on this, it looks into the different aspects of the idiosyncratic path which the evolution of the Greek information society has followed, particularly after 2000. Using Bob Jessop's strategic-relational approach (SRA) to the state as an analytical framework and drawing on a number of in-depth interviews with relevant political actors, it provides insights into policy implementation by examining: the public management of information technology projects, how such projects were received in bureaucratic structures and practices, as well as the relationship between the state and the information and communication technology (ICT) sector in public procurement processes. The emphasis is on the period 2000–2008, during which a major operational programme on the information society in Greece was put into effect. The paper also touches upon the post-2008 experience, suggesting that information society developments might include dynamics operating independently and even in contradiction to the state agenda.
Resumo:
Against Beck’s claims that conventional sociological concepts and categories are zombie categories, this paper argues that Durkheim’s theoretical framework in which suicide is a symptom of an anomic state of society can help us understand the diversity of trajectories that transnational migrants follow and that shape their suicide rates within a cosmopolitan society. Drawing on ethnographic data collected on eight suicides and three attempted suicide cases of second-generation male Alevi Kurdish migrants living in London, this article explains the impact of segmented assimilation/adaptation trajectories on the incidence of suicide and how their membership of a ‘new rainbow underclass’, as a manifestation of cosmopolitan society, is itself an anomic social position with a lack of integration and regulation.
Resumo:
Although modern systems of mass education are typically defined in their opposition to violence, it has been argued that it is only through an insistent and critical focus upon violence that radical thought can be sustained. This article seeks to take up this challenge in relation to Walter Benjamin’s lesser-known writings on education. Benjamin retained throughout his life a deep suspicion about academic institutions and about the pedagogic, social and economic violence implicated in the idea of cultural transmission. He nonetheless remained committed to the possibility of another kind of revolutionary potential inherent to true education and, when he comes to speak of this in his Critique of Violence, it is remarkable that he describes it as manifesting an educative violence. This article argues that Benjamin’s philosophy works toward a critique of educative violence that results in a distinction between a ‘first’ and ‘second’ kind of education and asks whether destruction might have a positive role to play within pedagogical theories in contrast to current valorisations of creativity and productivity.