Transcriptional Integration of Wnt and Nodal Signals in the Establishment of the Spemann Organizer

Establishment of the vertebrate body axis requires the formation of the organizer domain during early embryogenesis. In amphibians, this domain is referred to as the Spemann Organizer and is essential for germ layer patterning and formation of the embryonic body axes. The Wnt and Nodal signaling pathways are both essential for organizer formation, but how these signals are integrated to influence gene expression in the organizer is largely unknown. The Wnt pathway activates expression of two transactivators, Siamois (Sia) and Twin (Twn), which mediate organizer formation downstream of Wnt. Expression of Sia or Twn is sufficient to induce an ectopic axis, suggesting they play an essential role in organizer formation. However, whether Sia/Twn play equivalent roles in organizer formation, or whether both are required for all aspects of organizer formation in not clear. Here, we report that knockdown of Sia/Twn together, but not individually, disrupts organizer gene expression and axis formation. We identify the Sia/Twn binding site within the promoter of the organizer gene Goosecoid (Gsc). Sia/Twn form homodimers and heterodimers through direct homeodomain interaction and both dimer forms are found at the endogenous Gsc promoter. The Gsc promoter also contains a Nodal responsive distal element, suggesting that Sia/Twn cooperate with Nodal signals in the transcription of Gsc. We find that Wnt and Nodal effectors synergize to activate transcription of three organizer genes, Gsc, Cerberus (Cer), and Chordin (Chd). Sia/Twn and the Nodal effectors FoxH1 and Smad2/3 occupy the promoters of these genes in vivo and their occupancy increases with active signaling from both pathways. This suggests that a complex consisting of Sia/Twn and Nodal effectors forms at organizer gene promoters. Consistent with this, p300 is recruited to organizer gene promoters in response to Sia/Twn or Nodal signals. Thus, Sia/Twn interact with Nodal effectors to regulate the spatial and temporal expression of organizer genes, suggesting a general mechanism for the regulation of organizer gene expression in the early embryo

The ethical infrastructure of legal practice in larger law firms: values, policy and behaviour

The article examines the impact of the cultures and organisational structures of large law firms on individual lawyers' ethics. The paper suggests that large law firms in Australia should consciously design and implement 'ethical infrastructures' to both counteract pressures for misbehaviour and positively promote ethical behaviour and discussion. The paper goes on to explain what implementing ethical infrastructures in law firms could and should mean by reference to what Australian law firms are already doing and US innovations in this area. Finally, the paper warns that the 'ethical infrastructure' of a firm should not be seen merely as the formal ethics policies explicitly enunciated by management. Formal and legalistic ethical infrastructures that fail to support or encourage the development of individual lawyers' awareness oftheir own ethical values and ethical judgment in practice will be useless

Tidal dissipation in creeping ice and the thermal evolution of Europa

The thermal and mechanical evolution of Europa and comparable icy satellites—the physics behind creating and sustaining a subsurface water ocean—depends almost entirely on the mechanical dissipation of tidal energy in ice to produce heat, the mechanism(s) of which remain poorly understood. In deformation experiments, we combine steady–state creep and low-frequency, small-strain periodic loading, similar conditions in which tectonics and tidal flexing are occurring simultaneously. The data reveal that the relevant, power-law attenuation in ice (i) is non-linear, depending on strain amplitude, (ii) is independent of grain size, and (iii) exceeds in absorption the prediction of the Maxwell solid model by an order of magnitude. The Maxwell solid model is widely used to model the dynamics of planetary ice shells, so this discrepancy is important. The prevalent understanding of damping in the geophysical context is that it is controlled by chemical diffusion on grain boundaries, which renders attenuation strongly dependent on grain size. In sharp contrast, our results indicate instead the importance of intracrystalline dislocations and their spatial interactions as the critical structural variable affecting dissipation. These dislocation structures are controlled by stress and realized by accumulated plastic strain. Thus, tectonics and attenuation are coupled, which, beyond the icy satellite/subsurface ocean problem, has implications also for understanding the attenuation of seismic waves in deforming regions of the Earth's upper mantle

A Comparison Study of On-campus and Online Learning Outcomes for a Research Methods Course

Using a pretest/posttest design, student learning outcomes were examined for online learning and on-campus versions of the same course taught by the same instructor. The course was a master’s-level research methods course taught in a counselor education program. Although both groups of students (online and on-campus) scored significantly higher on the posttest than on the pretest, there were no significant differences in performance between the two groups. Similarly, examination of the students’ course (teaching) evaluations did not reveal any significant difference in mean course ratings between the on-campus and online learning versions of the course

Refutations and the logic of practice

When arguments are refuted in mathematics classrooms, the ways in which they are refuted can reveal something about the logic of practice evolving in the classroom, as well as about the epistemology that guides the teachers’ teaching. We provide four examples that illustrate refutations related to the logic of practice, in which sufficiency and relevance are grounds for refutation, as opposed to falsehood. Refutaciones y la lógica de la práctica Cuando los argumentos son refutados en las aulas de matemáticas, las maneras en que estos son refutados pueden revelar algo acerca del desarrollo de la lógica de la práctica en el aula, así como de la epistemología que guía la enseñanza. Presentamos cuatro ejemplos que ilustran refutaciones relacionadas con la lógica de la práctica, en los que la suficiencia y pertinencia y no la falsedad son los motivos de refutación.Handle: http://hdl.handle.net/10481/1601

Refutaciones y la Lógica de la Práctica

When arguments are refuted in mathematics classrooms, the ways in which they are refuted can reveal something about the logic of practice evolving in the classroom, as well as about the epistemology that guides the teachers’ teaching. We provide four examples that illustrate refutations related to the logic of practice, in which sufficiency and relevance are grounds for refutation, as opposed to falsehood.Cuando se refutan argumentos en el aula, las maneras en que se refutan pueden revelar algo acerca del desarrollo de la lógica de la práctica en el aula, así como de la epistemología que guía la enseñanza. Presentamos cuatro ejemplos que ilustran refutaciones relacionadas con la lógica de la práctica, en los que la suficiencia y pertinencia, y no la falsedad, son los motivos de refutación

Refutations and the logic of practice

When arguments are refuted in mathematics classrooms, the ways in which they are refuted can reveal something about the logic of practice evolving in the classroom, as well as about the epistemology that guides the teachers’ teaching. We provide four examples that illustrate refutations related to the logic of practice, in which sufficiency and relevance are grounds for refutation, as opposed to falsehood. Refutaciones y la lógica de la práctica Cuando los argumentos son refutados en las aulas de matemáticas, las maneras en que estos son refutados pueden revelar algo acerca del desarrollo de la lógica de la práctica en el aula, así como de la epistemología que guía la enseñanza. Presentamos cuatro ejemplos que ilustran refutaciones relacionadas con la lógica de la práctica, en los que la suficiencia y pertinencia y no la falsedad son los motivos de refutación.Handle: http://hdl.handle.net/10481/1601

Confident Living Program for Senior Adults Experiencing Combined Vision and Hearing Loss

Educational Objectives 1. Identify needs common among older adults who have combined vision and hearing loss. 2. Describe a model program that provides information, resources, and training to older adults experiencing combined vision and hearing loss. 3. Describe how the program benefits not only consumers, but also family, friends, caregivers, students, and service providers

“RIPSSL”: A New Reflective Inquiry Protocol to Lift the Lid on Students’ Significant Extra-Curricular Learning Outcomes from Study Abroad

Education abroad generally has no overarching curriculum outside the formal study component. This paper presents the Reflective Inquiry Protocol for Surfacing Significant Learning (RIPSSL), a new approach for understanding and articulating significant learning from education abroad. Tests of RIPSSL show education abroad students use it to move beyond “it was great” when considering learning from their experiences. Our findings are important for educators and students as they work to recognize and articulate the value of education abroad. RIPSSL provides a reflective educational approach to evidence learning from life experiences by surfacing students’ significant learning in their own words