A compendium of Caenorhabditis elegans regulatory transcription factors: a resource for mapping transcription regulatory networks

Background Transcription regulatory networks are composed of interactions between transcription factors and their target genes. Whereas unicellular networks have been studied extensively, metazoan transcription regulatory networks remain largely unexplored. Caenorhabditis elegans provides a powerful model to study such metazoan networks because its genome is completely sequenced and many functional genomic tools are available. While C. elegans gene predictions have undergone continuous refinement, this is not true for the annotation of functional transcription factors. The comprehensive identification of transcription factors is essential for the systematic mapping of transcription regulatory networks because it enables the creation of physical transcription factor resources that can be used in assays to map interactions between transcription factors and their target genes. Results By computational searches and extensive manual curation, we have identified a compendium of 934 transcription factor genes (referred to as wTF2.0). We find that manual curation drastically reduces the number of both false positive and false negative transcription factor predictions. We discuss how transcription factor splice variants and dimer formation may affect the total number of functional transcription factors. In contrast to mouse transcription factor genes, we find that C. elegans transcription factor genes do not undergo significantly more splicing than other genes. This difference may contribute to differences in organism complexity. We identify candidate redundant worm transcription factor genes and orthologous worm and human transcription factor pairs. Finally, we discuss how wTF2.0 can be used together with physical transcription factor clone resources to facilitate the systematic mapping of C. elegans transcription regulatory networks. Conclusion wTF2.0 provides a starting point to decipher the transcription regulatory networks that control metazoan development and function

Deficit irrigation reduces postharvest rib pinking in wholehead Iceberg lettuce, but at the expense of head fresh weight

BACKGROUND Postharvest pinking is a serious issue affecting lettuce quality. Previous studies suggested the possibility of using deficit irrigation to control discolouration; however, this approach may also affect yield. This study investigated the effect of varying irrigation deficits on iceberg lettuce (Lactuca sativa L.) to determine the relationship between irrigation deficit, pinking and fresh weight. RESULTS The deficit imposed and head fresh weight obtained depended on both the duration and timing of withholding irrigation. Withholding irrigation for a period of 2 or 3 weeks in the middle or end of the growth period significantly reduced rib pinking compared to well-watered controls. Withholding irrigation for 2 weeks at the start of the growth period or 1 week at the end did not significantly reduce pinking. Withholding irrigation also reduced head fresh weight such that minimising pinking would be predicted to incur a loss of 40% relative to well-watered controls. However, smaller benefits to pinking reduction were achieved with less effect on head fresh weight. CONCLUSION Deficit irrigation could be used to provide smaller but higher quality heads which are less likely to be rejected. The balance of these factors will determine the degree of adoption of this approach to growers

Advertising credibility across media channels : perceptions of Generation Y consumers

Generation Y consumers have become an important consumer group and, as a result, their perceptions of media credibility has become an important issue for many organisations and media planners. This study explores the credibility of traditional media advertising versus new media advertising, the credibility of broadcast-media advertising versus print-media advertising, the credibility of cellphone advertising versus Internet advertising, and the relationship between the credibility of Internet advertising and likelihood of Generation Y consumers shopping online. The target audience comprises students between the ages of 18 and 30 years at one of the largest residential universities in South Africa. Convenience sampling was used and a total of 1 345 questionnaires were completed. Some of the results indicate that Generation Y consumers rate the credibility of traditional media higher than new media and that print media has higher credibility ratings compared with broadcast media.http://www.journals.co.za/ej/ejour_comcare.htm

Postharvest temperature and water status influence postharvest splitting susceptibility in summer radish ( Raphanus sativus L.)

BACKGROUND Splitting is a problem that seriously affects appearance and marketability in a number of fruit and vegetables. In summer radish (Raphanus sativus L.), splitting can occur during growth, harvesting and postharvest. We investigated the factors affecting splitting susceptibility in summer radish cv. Celesta during postharvest handling. RESULTS Splitting susceptibility was negatively related to temperature, with higher temperature reducing splitting due to dropping impact. Radish diameter was positively associated with compression failure force, suggesting that larger radishes are more resistant to compressive splitting. An increase in radish hypocotyl water content (WC) was associated with an increase in splitting susceptibility due to impact and decrease in failure force for both compression and puncture forces. Increased hypocotyl WC may increase splitting susceptibility by increasing the water potential of the radish tissue. In agreement, we found that increased hypocotyl WC was associated with higher internal water potential in radish tissue. CONCLUSIONS We therefore recommend that the hypocotyl WC of summer radish crops be managed during the harvest and postharvest phases, and that crops are processed at higher, ambient, temperature in order to reduce splitting, before storing at low temperature and high humidity to maintain quality and shelf life

Networks and landscapes: a framework for setting goals and evaluating performance at the large landscape scale

The objective of large landscape conservation is to mitigate complex ecological problems through interventions at multiple and overlapping scales. Implementation requires coordination among a diverse network of individuals and organizations to integrate local‐scale conservation activities with broad‐scale goals. This requires an understanding of the governance options and how governance regimes achieve objectives or provide performance evaluation across both space and time. However, empirical assessments measuring network‐governance performance in large landscape conservation are limited. We describe a well‐established large landscape conservation network in North America, the Roundtable on the Crown of the Continent, to explore the application of a social–ecological performance evaluation framework. Systematic approaches to setting goals, tracking progress, and collecting data for feedback can help guide adaptation. Applying the established framework to our case study provides a means of evaluating the effectiveness of network governance in large landscape conservation

Negotiating local versus global needs in the International Long Term Ecological Research Network's socio-ecological research agenda

Over the past decade, Long-Term Socio-Ecological Research (LTSER) has been established to better integrate social science research and societal concerns into the goals and objectives of the International Long Term Ecological Research (ILTER) network, an established global network of long-term ecological monitoring sites. The Horizon 2020 eLTER project, currently underway, includes as one of its key objectives to evaluate the performance of LTSER platforms. This article reflects part of this evaluation: Six LTSER platforms were assessed through site visits of the lead author, coupled with reflections and insights of the platform managers, who are also coauthors. We provide background for the mission and goals of LTSER, and then assess the six international LTSER platforms – Baltimore Ecosystem Study LTER, USA; Braila Islands LTSER, Romania; Cairngorms LTSER, UK; Doñana LTSER, Spain; Omora Ethnobotanical Park Cape Horn LTER, Chile; and Sierra Nevada LTSER, Spain. 
 While based on a strong theoretical foundation in socio-ecological research, there has been a steep learning curve for scientists to apply the concept in practice at LTSER platforms. Key aspects of LTSER platforms have proven challenging, including management, interdisciplinary integration, and stakeholder collaboration. We characterize the tensions between top-down desires for network harmonization, bottom-up demands such as local policy relevance, and platform-level constraints such as time and budget. We discuss challenges, such as local context dominating the character of LTSER platforms, and the fact that scientists are disincentivized from engaging in transdisciplinary work. However, we also show positive impacts that have been achieved, including contributions to policy, land-use planning, and natural resource management. Overall, we conclude that while the international network offers important advantages to its members, a better balance between local and global goals could be achieved, and members may need to temper their expectations of what the network can and cannot offer at the local level

Accounting and social movements: An exploration of critical accounting praxis

A central tenet of critical accounting research maintains the need to challenge and change existing social relations; moving towards a more emancipated and equitable social order. The question of how critical accounting research upholds this principle has been intermittently discussed. This paper aims to engage with, and further, this discussion by contributing to research linking accounting information to social movements. The paper reviews the literature on accounting and social movements, central to which is the work of Gallhofer and Haslam; using their work as a departure point we discussion the nature of accounting information and focus on social movement unionism (SMU). Drawing on Bakhtinian dialogics and classical Marxism we develop an alternative theoretical framework to analyse an example of accounting information and social movements, covering a trade union pay dispute. The paper concludes with a discussion of the class nature of accounting information, including an exploration of the implications for accounting praxis and agency in the struggles for an emancipated world. The paper builds on the limited amount of existing work in this area; exploring the ‘class belongingness’ of accounting information and developing an understanding which can help guide the praxis of critical accounting researchers

States and transitions in black-hole binaries

With the availability of the large database of black-hole transients from the Rossi X-Ray Timing Explorer, the observed phenomenology has become very complex. The original classification of the properties of these systems in a series of static states sorted by mass accretion rate proved not to be able to encompass the new picture. I outline here a summary of the current situation and show that a coherent picture emerges when simple properties such as X-ray spectral hardness and fractional variability are considered. In particular, fast transition in the properties of the fast time variability appear to be crucial to describe the evolution of black-hole transients. Based on this picture, I present a state-classification which takes into account the observed transitions. I show that, in addition to transients systems, other black-hole binaries and Active Galactic Nuclei can be interpreted within this framework. The association between these states and the physics of the accretion flow around black holes will be possible only through modeling of the full time evolution of galactic transient systems.Comment: 30 pages, 11 figures, To appear in Belloni, T. (ed.): The Jet Paradigm - From Microquasars to Quasars, Lect. Notes Phys. 794 (2009

Accretion and ejection in black-hole X-ray transients

Aims: We summarize the current observational picture of the outbursts of black-hole X-ray transients (BHTs), based on the evolution traced in a hardness-luminosity diagram (HLD), and we offer a physical interpretation. Methods: The basic ingredient in our interpretation is the Poynting-Robertson Cosmic Battery (PRCB, Contopoulos & Kazanas 1998), which provides locally the poloidal magnetic field needed for the ejection of the jet. In addition, we make two assumptions, easily justifiable. The first is that the mass-accretion rate to the black hole in a BHT outburst has a generic bell-shaped form. This is guaranteed by the observational fact that all BHTs start their outburst and end it at the quiescent state. The second assumption is that at low accretion rates the accretion flow is geometrically thick, ADAF-like, while at high accretion rates it is geometrically thin. Results: Both, at the beginning and the end of an outburst, the PRCB establishes a strong poloidal magnetic field in the ADAF-like part of the accretion flow, and this explains naturally why a jet is always present in the right part of the HLD. In the left part of the HLD, the accretion flow is in the form of a thin disk, and such a disk cannot sustain a strong poloidal magnetic filed. Thus, no jet is expected in this part of the HLD. The counterclockwise traversal of the HLD is explained as follows: the poloidal magnetic field in the ADAF forces the flow to remain ADAF and the source to move upwards in the HLD rather than to turn left. Thus, the history of the system determines the counterclockwise traversal of the HLD. As a result, no BHT is expected to ever traverse the entire HLD curve in the clockwise direction. Conclusions: We offer a physical interpretation of accretion and ejection in BHTs with only one parameter, the mass transfer rate.Comment: Accepted for publication in A&