Home About us Contact
|
Home About us Contact | ||
|
|
||
Reveal A Number (reveal a + number)
Selected AbstractsBody musculature of Beauchampiella eudactylota (Gosse, 1886) (Rotifera: Euchlanidae) with additional new data on its trophi and overall morphologyACTA ZOOLOGICA, Issue 3 2009O. Riemann Abstract This study presents the results of confocal laser scanning microscopy and fluorescence-labelled phalloidin used to visualize the system of body musculature in Beauchampiella eudactylota. Moreover, the poorly known trophi of B. eudactylota are described based on scanning electron microscopy. In total, four paired longitudinal muscles (musculi longitudinales I,IV) and three circular muscles (musculi circulares I,III) were identified. Among these are the musculus longitudinalis ventralis, the musculus longitudinalis dorsalis and the musculus circumpedalis as documented in previous studies for other rotifer species. Compared to other species, B. eudactylota is characterized by the low number of lateral longitudinal muscles and the absence of some longitudinal muscles (musculi longitudinales capitum) and circular muscles (corona sphincter, musculus pars coronalis). Moreover, scanning electron microscopic data on the trophi of B. eudactylota reveal a number of striking similarities to the trophi in some species of Epiphanidae. This suggests that either (1) these similarities represent plesiomorphic characters present both in Epiphanidae and B. eudactylota or (2) they are synapomorphic features of B. eudactylota and some species of Epiphanidae, which would question the monophyly of Euchlanidae. [source] Comparative growth in the postnatal skull of the extant North American turtle Pseudemys texana (Testudinoidea: Emydidae)ACTA ZOOLOGICA, Issue 2 2008Gabe S. Bever Abstract Bever, G.S. 2007. Comparative growth in the postnatal skull of the extant North American turtle Pseudemys texana (Testudinoidea: Emydidae). ,Acta Zoologica (Stockholm) 88: 000,000 Postnatal growth is one of the many aspects of developmental morphology that remains distinctly understudied in reptiles. Variation and ontogenetic scaling within the skull of the extant emydid turtle, Pseudemys texana is described based on 25 continuous characters. Results indicate that skull shape in this species changes little during postnatal growth relative to the only cryptodire taxa for which comparable datasets are available (Apalone ferox and Sternotherus odoratus). This relative lack of change results in the paedomorphic retention of a largely juvenile appearance in the adult form of P. texana. The skulls of males and females, despite the presence of distinct sexual dimorphism in size, grow with similar scaling patterns, and the few observed differences appear to reflect alteration of the male growth trajectory. Comparisons with A. ferox and S. odoratus reveal a number of similarities and differences that are here interpreted within a phylogenetic context. These preliminary hypotheses constitute predictive statements that phylogenetically bracket the majority of extant cryptodire species and provide baseline comparative data that are necessary for the future recognition of apomorphic transformations. Plasticity of ontogenetic scaling as a response to the homeostatic needs and behaviour of individuals commonly is evoked as a limitation of ontogenetic scaling as a means to inform phylogenetic studies. These evocations are largely unfounded considering that variability itself can evolve and thus be phylogenetically informative. [source] A cline in the Drosophila melanogaster period gene in Australia: neither down nor underJOURNAL OF EVOLUTIONARY BIOLOGY, Issue 4 2007C. P. KYRIACOU Abstract Weeks et al. (2006) have reported their inability to find a cline in the frequencies of the major Thr-Gly encoding length variant alleles of the period gene in Drosophila melanogaster in Eastern Australia. This is in contrast to a study by Sawyer et al. (2006), who found a cline on this continent from samples collected in 1993. Weeks et al. then cast doubt on the validity of a robust cline found for these variants in Europe by Costa et al. (1992), criticizing their molecular techniques and sampling methods. We show how these claims are unjustified, and reveal a number of potential problems in their own methodology. Finally by reanalysing the subset of their data which they state is more reliable, we suggest that their results from Australia may be reasonably consistent with our own. [source] Exploring Access and Equity in Higher Education: Policy and Performance in a Comparative PerspectiveHIGHER EDUCATION QUARTERLY, Issue 2 2007Patrick Clancy A comparative analysis of how access and equity are defined and how policies have evolved reveals a number of commonalities and differences between countries. The overall trend is a movement from the priority given to ,inherited merit' in the admission process through a commitment to formal equality, towards the application of some modes of affirmative action for selected under-represented groups. This overall convergence, which is accompanied by a growing appreciation of the complexity of social identities, is complemented by significant national specificity in respect of the social categories which are used to define social diversity. In the absence of appropriate comparative measures of participation a Higher Education Participation Index is developed to facilitate cross-country comparisons. A review of current attempts to measure equity in access to higher education points to the need to develop a programme of comparative research which focuses on the social characteristics of students who are currently enrolled in higher education. [source] Financial Integration in the EU: the First Phase of EU Endorsement of International Accounting Standards,JCMS: JOURNAL OF COMMON MARKET STUDIES, Issue 2 2008IAN DEWING In 2002 the EU adopted the Regulation which required European listed companies to prepare their consolidated accounts in accordance with international accounting standards from 2005 onwards. A novel set of structures for the endorsement of international accounting standards for use in the EU was put in place. This article examines the first phase of endorsement of international accounting standards in the context of the novel endorsement structures. The article concludes that problems over the endorsement of IAS 39 Financial Instruments: Recognition and Measurement reveals a number of significant policy implications for the EU including the difficulty of forming a European view, the role of private actors in EU regulation, and the issue that international standards largely reflect Anglo-Saxon accounting practices rather than continental European practices. [source] The Odyssey of Senior Public Service: What Memoirs Can Teach UsPUBLIC ADMINISTRATION REVIEW, Issue 1 2003J. Patrick Dobel This article examines the political, psychological, and moral challenges of senior public service in the executive office. The study uses memoirs published by members of the Clinton administration. The memoirs discuss the consistent background conditions of senior public service as the personality of the chief executive, the vagaries of election cycles, the tension between staff and agency executives, and the role of the media. Senior executives adopt a number of stances to address the tension between the realities of public service and the ideals they bring. The memoirs suggest several stances, such as politics as original sin, seduction, hard work and compromise, and game. The memoirs demonstrate the high cumulative cost that public service exacts on the health and personal lives of senior officials. Finally, the study reveals a number of consistent themes about how senior appointed public officials can navigate the dilemmas and challenges of senior public service at all levels of government. [source] | ||||||||||