Identity of a Tilapia Pheromone Released by Dominant Males that Primes Females for Reproduction

Knowledge of the chemical identity and role of urinary pheromones in fish is scarce, yet it is necessary in order to understand the integration of multiple senses in adaptive responses and the evolution of chemical communication [1]. In nature, Mozambique tilapia (Oreochromis mossambicus) males form hierarchies, and females mate preferentially with dominant territorial males, which they visit in aggregations or leks [2]. Dominant males have thicker urinary bladder muscular walls than subordinates or females and store large volumes of urine, which they release at increased frequency in the presence of subordinate males or preovulatory, but not postspawned, females [3–5]. Females exposed to dominant-male urine augment their release of the oocyte maturation-inducing steroid 17α,20β-dihydroxypregn-4-en-3-one (17,20β-P) [6]. Here we isolate and identify a male Mozambique tilapia urinary sex pheromone as two epimeric (20α- and 20β-) pregnanetriol 3-glucuronates. We show that both males and females have high olfactory sensitivity to the two steroids, which cross-adapt upon stimulation. Females exposed to both steroids show a rapid, 10-fold increase in production of 17,20β-P. Thus, the identified urinary steroids prime the female endocrine system to accelerate oocyte maturation and possibly promote spawning synchrony. Tilapia are globally important as a food source but are also invasive species, with devastating impact on local freshwater ecosystems [7, 8]. Identifying the chemical cues that mediate reproduction may lead to the development of tools for population control [9–11].

Calculus of variations on time scales and applications to economics

We consider some problems of the calculus of variations on time scales. On the beginning our attention is paid on two inverse extremal problems on arbitrary time scales. Firstly, using the Euler-Lagrange equation and the strengthened Legendre condition, we derive a general form for a variation functional that attains a local minimum at a given point of the vector space. Furthermore, we prove a necessary condition for a dynamic integro-differential equation to be an Euler-Lagrange equation. New and interesting results for the discrete and quantum calculus are obtained as particular cases. Afterwards, we prove Euler-Lagrange type equations and transversality conditions for generalized infinite horizon problems. Next we investigate the composition of a certain scalar function with delta and nabla integrals of a vector valued field. Euler-Lagrange equations in integral form, transversality conditions, and necessary optimality conditions for isoperimetric problems, on an arbitrary time scale, are proved. In the end, two main issues of application of time scales in economic, with interesting results, are presented. In the former case we consider a firm that wants to program its production and investment policies to reach a given production rate and to maximize its future market competitiveness. The model which describes firm activities is studied in two different ways: using classical discretizations; and applying discrete versions of our result on time scales. In the end we compare the cost functional values obtained from those two approaches. The latter problem is more complex and relates to rate of inflation, p, and rate of unemployment, u, which inflict a social loss. Using known relations between p, u, and the expected rate of inflation π, we rewrite the social loss function as a function of π. We present this model in the time scale framework and find an optimal path π that minimizes the total social loss over a given time interval.

Bush and Lula's political identity constructions: are they so different? A critical discourse analysis of presidential speeches of North and South America

Dissertação de mest., Linguística, Faculdade de Ciências Humanas e Sociais, Universidade do Algarve, 2007

The discursive construction of place-identity: british lifestyle migrants in the Algarve

Tese dout., Philosophy, Lancaster University, 2011

The discursive construction of Portuguese national identity in the media thirty years after the 1974 revolution

Tese dout., Philosophy, Lancaster University, 2010

Digital unterwegs ohne das virtuelle soziale Netzwerk – qualitative Studie über Facebook-Verweigerung und Virtual Identity Suicide

Das virtuelle soziale Netzwerk Facebook feiert seinen zehnten Geburtstag. Mit über einer Milliarde aktiver Nutzer ist es seit seiner Entstehung zur weltweit größten Internetplattform zur Kommunikation avanciert. Dennoch gibt es in Deutschland eine große Anzahl an Menschen, die sich zwar täglich im Internet bewegt, aber auf eine Mitgliedschaft bei Facebook verzichtet. In dieser Arbeit werden die Gründe untersucht, warum manche Personen Facebook nicht nutzen. Die Leitfrage der Arbeit lautet: „Warum nutzen ausgewählte deutsche Internetnutzer Facebook nicht?“. Es wird zwischen zwei unterschiedlichen Personenkreisen, den Nicht- und den Ex-Nutzern, unterschieden. Basierend auf Leitfadeninterviews mit 25 Befragten, die mittels einer qualitativen Inhaltsanalyse ausgewertet werden, werden elf verschiedene Gründe für eine Verweigerung von Facebook identifiziert. Für die Nicht-Nutzer stellt die Art der Kommunikation den zentralen Grund dar, Facebook nicht zu verwenden. Die Ex-Nutzer wiederum sehen den fehlenden Nutzen der Anwendung als wichtigstes Argument gegen Facebook.

Identity, Well-being and Effectiveness: the Emotional Contexts of Teaching

This paper draws on findings from a four‐year longitudinal research project, commissioned by the Department for Education and Skills (DfES), which investigated Variations in Teachers’ Work, Lives and Effectiveness (VITAE). Drawing on data gathered from 300 teachers working in 100 primary and secondary schools in England, the research identified associations between commitment and effectiveness (perceived and in terms of pupil attainment) and found that there were more, and less, effective teachers in each of six professional life phases. It found that teachers in each of these phases experienced a number of different scenarios that challenged their abilities to sustain their commitment (i.e. remain resilient). This paper discusses how these impact, positively and negatively, on teachers’ capacities for sustaining their initial commitment and associations between identity, well‐being and effectiveness. It finds that teacher identities are neither intrinsically stable nor intrinsically fragmented, but that they can be more, or less, stable and more or less fragmented at different times and in different ways according to the influence of the interaction of a number of personal, professional and situated factors. The extent to which teachers are able to and are supported in managing the scenarios they experience will determine their sense of effectiveness.

Reform, Standards and Teacher Identity: Challenges of Sustaining Commitment

Teacher commitment has been found to be a critical predictor of teachers’ work performance, absenteeism, retention, burnout and turnover, as well as having an important influence on students’ motivation, achievement, attitudes towards learning and being at school (Firestone (1996). Educational Administration Quarterly, 32(2), 209–235; Graham (1996). Journal of Physical Education, Recreation and Dance, 67(1), 45–47; Louis (1998). School Effectiveness and School Improvement, 9(1), 1–27; Tsui & Cheng (1999). Educational Research and Evaluation, 5(3), 249–268). It is also a necessary ingredient to the successful implementation, adaptation or resistance reform agendas. Surprisingly, however, the relationship between teachers’ motivation, efficacy, job satisfaction and commitment, and between commitment and the quality of their work has not been the subject of extensive research. Some literature presents commitment as a feature of being and behaving as a professional (Helsby, Knight, McCulloch, Saunders, & Warburton (1997). A report to participants on the professional cultures of Teachers Research Project, Lancaster University, January). Others suggest that it fluctuates according to personal, institutional and policy contexts (Louis (1998). School Effectiveness and School Improvement, 9(1), 1–27) and identify different dimensions of commitment which interact and fluctuate (Tyree (1996). Journal of Educational Research, 89(5), 295–304). Others claim that teachers’ commitment tends to decrease progressively over the course of the teaching career (Fraser, Draper, & Taylor (1998). Evaluation and Research in Education, 12 (2), 61–71; Huberman (1993). The lives of teachers. London: Cassell). In this research, experienced teachers in England and Australia were interviewed about their understandings of commitment. The data suggest that commitment may be better understood as a nested phenomena at the centre of which is a set of core, relatively permanent values based upon personal beliefs, images of self, role and identity which are subject to challenge by change which is socio-politically constructed.

Changing Professional Identity in the Transition from Practitioner to Lecturer in Higher Education: an Interpretive Phenomenological Analysis

This research explores the experiences of five professional practitioners from disciplines including teaching, youth work, sport and health who had become lecturers in Higher Education. Their experiences are considered using Interpretative Phenomenological Analysis and tentative conclusions are reached on the meaning of such experiences for the individuals. The work extends previous studies (Shreeve 2010, 2011; Gourlay 2011a, 2011b; Boyd & Harris 2010) to consider the relationship between knowledge and influence and how institutional preference for knowledge gained from research impacts on the validity of knowledge derived from professional experience. The research finds shared feelings associated with inauthenticity and loss arising from concerns that the contribution of the professional in Higher Education is undervalued. The research challenges the assumption that professional practitioners adopt the professional identity of a lecturer in Higher Education instead finding that they create their own professional identities in the liminal space between the professional and academic domains, but points to difficulties associated with constructed nature of such professional identities within the institutional structure of a Higher Education institution.

Before identity, gender and human rights

This is the beginning of an exploration of before as the thesis ‘before’ (temporally) and ‘be-fore’ (spatially) difference. Before denotes the origin and the desired destination. Before (in the double sense of ‘before’ and ‚be-in-the-fore’) opens up a space of pre-difference, of origin and of forgotten memory, as well as a space of desire, objective, illusion of teleology, unity, completion. Applied to the two domains of Human Rights and Sex/Gender, the space of ‘before’ yields two slightly different vistas: in human rights, a premodern, functionally undifferentiated society which had to invent human rights as its safeguards of functional differentiation. In Sex/Gender, 'before' brings a self-referential construction: that of ipseity, as the form of identity beyond comparison that does not play with id but with ipsum. Ipseity is inoperable but not useless. It is inoperable because it cannot be observed from anywhere without suffering rupture. It is not useless because it offers a ground for the reconceptualisation of difference, both through awe and desire.

Purity of Blood and Caste. Identity Narratives among Early Modern Goan Elites

This essay analyses the roles played by purity of blood and caste in seventeenth-and eighteenth-century identity narratives of Goan clites. Goa and its population are usually excluded from the mainstream literature of Indian social history, and seldom related to the early-modern Atlantic world, making this case study all the more valuable as a place to think the topic of blood and caste. The early establishment and the longevity of the Portuguese imperial presence (1510-1961) in Goa, its location at the crossroads of multiple cultural geographies (Iberian and Indian, and later, also Dutch, British and French), as well as the systematic process of religious conversion of its inhabitants and the questions of legal equality that conversion entailed, all intensified the types, textures, layers and meanings of experiences of social differentiation in this colonial context. This mapping of the experiences of purity of blood and caste in early-modem Goa therefore illuminates from a new angle the role of European imperial powers in the mUltiple expressions of racial classification.

Book review: Jiří Přibáň, legal symbolism: on law, time and European identity

This is a book review of Jiří Přibáň, Legal Symbolism: On Law, Time and European Identity, Ashgate, Aldershot, 2007, 226 pp, ISBN: 978-0-7546-7073-5