A self-structured adaptive decision feedback equalizer

In a decision feedback equalizer (DFE), the structural parameters, including the decision delay, the feedforward filter (FFF), and feedback filter (FBF) lengths, must be carefully chosen, as they greatly influence the performance. Although the FBF length can be set as the channel memory, there is no closed-form expression for the FFF length and decision delay. In this letter, first we analytically show that the two-dimensional search for the optimum FFF length and decision delay can be simplified to a one-dimensional search and then describe a new adaptive DFE where the optimum structural parameters can he self-adapted.

Opportunity cost based analysis of corporate eco-efficiency: A methodology and its application to the CO2-efficiency of German companies

In this paper, we propose the return-to-cost-ratio (RCR) as an alternative approach to the analysis of operational eco-efficiency of companies based on the notion of opportunity costs. RCR helps to overcome two fundamental deficits of existing approaches to eco-efficiency. (1) It translates eco-efficiency into managerial terms by applying the well-established notion of opportunity costs to eco-efficiency analysis. (2) RCR allows to identify and quantify the drivers behind changes in corporate eco-efficiency. RCR is applied to the analysis of the CO2-efficiency of German companies in order to illustrate its usefulness for a detailed analysis of changes in corporate eco-efficiency as well as for the development of effective environmental strategies. (C) 2010 Elsevier Ltd. All rights reserved.

Constitutive activation of the Raf-MAPK pathway causes negative feedback inhibition of Ras-PI3K-AKT and cellular arrest through the EphA(2) receptor

The Raf-mitogen-activated protein kinase (MAPK) and phosphatidylinositide 3-kinase (PI3K)-AKT pathways are two downstream effectors of the small GTPase Ras. Although both pathways are positively regulated by Ras, the Raf-MAPK and PI3K-AKT pathways have been shown to control opposing functions within the cell, suggesting a need for cross-talk regulation. The PI3K -AKT pathway can inhibit the Raf-MAPK pathway directly during processes such as muscle differentiation. Here we describe the ability of the Raf-MAPK pathway to negatively regulate the PI3K-AKT pathway during cellular arrest. Constitutive activation of Raf or methyl ethyl ketone 1 (MEK1) leads to inhibition of AKT and cellular arrest. Furthermore, we show that activation of Raf-MEK1 signaling causes negative feedback inhibition of Ras through the ephrin receptor EphA(2). EphA(2)-mediated negative feedback inhibition is required for Raf-induced AKT inhibition and cell cycle arrest, therefore establishing the inhibition of the Ras-PI3K-AKT pathway as a necessary event for the Raf-MEK1-regulated cellular arrest.

Peer Rating for Feedback in Group Projects

The National Student Survey (NSS) in the UK has since 2005 questioned final year
undergraduate students on a broad range of issues relating to their university experience.
Across disciplines and universities students have expressed least satisfaction in the areas of
assessment and feedback. In response to these results many educational practitioners have
reviewed and revised their procedures and the UK Higher Education Academy (HEA) has
produced guidelines of best practice to assist academics in improving these specific areas.
The Product Design and Development (PDD) degree at Queen’s University Belfast is
structured with an integrated curriculum with group Design Build Test (DBT) projects as the
core of each year of the undergraduate programme. Based on the CDIO syllabus and
standards the overall learning outcomes for the programme are defined and developed in a
staged manner, guided by Bloom’s taxonomy of learning domains.
Feedback in group DBT projects, especially in relation to the development of personal and
professional skills, represents a different challenge to that of individual assignment feedback.
A review of best practice was carried out to establish techniques which could be applied to
the particular context of the PDD degree without modification and also to identify areas
where a different approach would need to be applied.
A revised procedure was then developed which utilised the structure of the PDD degree to
provide a mechanism for enhanced feedback in group project work, while at the same time
increasing student development of self and peer evaluation skills. Key to this improvement
was the separation of peer ratings from assessment in the perception of the students and the
introduction of more frequent face to face feedback interviews.
This paper details the new procedures developed and additional issues which have been
raised and addressed, with reference to the published literature, during 3 years of operation.

Impact of operator experience on information feedback and reusability

Keeping a record of operator experience remains a challenge to operation management and a major source of inefficiency in information management. The objective is to develop a framework that enables an explicit presentation of experience based on information use. A purposive sampling method is used to select four small and medium-sized enterprises as case studies. The unit of analysis is the production process in the machine shop. Data collection is by structured interview, observation and documentation. A comparative case analysis is applied. The findings suggest experience is an accumulation of tacit information feedback, which can be made explicit in information use interoperatability matrix. The matrix is conditioned upon information use typology, which is strategic in waste reduction. The limitations include difficulty of participant anonymity where the organisation nominates a participant. Areas for further research include application of the concepts to knowledge management and shop floor resource management.

Feedback via Ca²⁺-activated ion channels modulates endothelin 1 signaling in retinal arteriolar smooth muscle

PURPOSE: To investigate the role of feedback by Ca²?-sensitive plasma-membrane ion channels in endothelin 1 (Et1) signaling in vitro and in vivo. Methods. Et1 responses were imaged from Fluo-4-loaded smooth muscle in isolated segments of rat retinal arteriole using two-dimensional (2-D) confocal laser microscopy. Vasoconstrictor responses to intravitreal injections of Et1 were recorded in the absence and presence of appropriate ion channel blockers using fluorescein angiograms imaged using a confocal scanning laser ophthalmoscope. Results. Et1 (10 nM) increased both basal [Ca²?](i) and the amplitude and frequency of Ca²?-waves in retinal arterioles. The Ca²?-activated Cl?-channel blockers DIDS and 9-anthracene carboxylic acid (9AC) blocked Et1-induced increases in wave frequency, and 9AC also inhibited the increase in amplitude. Iberiotoxin, an inhibitor of large conductance (BK) Ca²?-activated K?-channels, increased wave amplitude in the presence of Et1 but had no effect on frequency. None of these drugs affected basal [Ca²?](i). The voltage-operated Ca²?-channel inhibitor nimodipine inhibited wave frequency and amplitude and also lowered basal [Ca²?](i) in the presence of Et1. Intravitreal injection of Et1 caused retinal arteriolar vasoconstriction. This was inhibited by DIDS but not by iberiotoxin or penitrem A, another BK-channel inhibitor. Conclusions. Et1 evokes increases in the frequency of arteriolar Ca²?-waves in vitro, resulting in vasoconstriction in vivo. These responses, initiated by release of stored Ca²?, also require positive feedback via Ca²?-activated Cl?-channels and L-type Ca²?-channels.

Pharmacy Students’ Views of Faculty Feedback on Academic Performance

Objective: To investigate students' views on and satisfaction with faculty feedback on their academic performance.

Methods: A 41-item survey instrument was developed based on a literature review relating to effective feedback. All pharmacy undergraduate students were invited via e-mail to complete the self-administered electronic questionnaire relating to their views on feedback, including faculty feedback received to date regarding their academic performance.

Results: A response rate of 61% (343/561) was obtained. Only 32.3% of students (107/331) agreed that they were satisfied with the feedback they received; dissatisfaction with examination feedback was particularly high. The provision of faculty feedback was perceived to be variable in terms of quality and quantity.

Conclusions: There are some inconsistencies relating to provision of feedback within the MPharm degree program at Queen's University Belfast. Further work is needed to close the gap between student expectations and the faculty's delivery of feedback on academic performance.