Internal alignement of the SLD vertex detector

The tracking resolution and vertex finding capabilities of the SLD experiment depended upon a precise knowledge of the location and orientation of the elements of the SLD pixel vertex detector (VXD3) in 3D space. At the heart of the procedure described here to align the 96 CCDs is the matrix inversion technique of singular value decomposition (SVD). This tool was employed to unfold the detector geometry corrections from the track data in the VXD3. The algorithm was adapted to perform an optimal Â2 minimization by careful treatment of the track hit residual measurement errors. The tracking resolution obtained with the aligned geometry achieved the design performance. Comments are given on how this method could be used for other trackers

Translational Control of Cyclin B1 mRNA during Meiotic Maturation: Coordinated Repression and Cytoplasmic Polyadenylation

AbstractTranslational control is prominent during meiotic maturation and early development. In this report, we investigate a mode of translational repression in Xenopus laevis oocytes, focusing on the mRNA encoding cyclin B1. Translation of cyclin B1 mRNA is relatively inactive in the oocyte and increases dramatically during meiotic maturation. We show, by injection of synthetic mRNAs, that the cis-acting sequences responsible for repression of cyclin B1 mRNA reside within its 3′UTR. Repression can be saturated by increasing the concentration of reporter mRNA injected, suggesting that the cyclin B1 3′UTR sequences provide a binding site for a trans-acting repressor. The sequences that direct repression overlap and include cytoplasmic polyadenylation elements (CPEs), sequences known to promote cytoplasmic polyadenylation. However, the presence of a CPE per se appears insufficient to cause repression, as other mRNAs that contain CPEs are not translationally repressed. We demonstrate that relief of repression and cytoplasmic polyadenylation are intimately linked. Repressing elements do not override the stimulatory effect of a long poly(A) tail, and polyadenylation of cyclin B1 mRNA is required for its translational recruitment. Our results suggest that translational recruitment of endogenous cyclin B1 mRNA is a collaborative effect of derepression and poly(A) addition. We discuss several molecular mechanisms that might underlie this collaboration

Predicting the Unpredictable: Estimating Human Performance Parameters for Off-Nominal Events

A parameter meta-analysis was conducted to characterize human responses to off-nominal events. The probability of detecting an off-nominal event was influenced by characteristics of the offnominal event scenario (phase of flight, expectancy, and event location) and the presence of advanced cockpit technologies (head-up displays, highway-in-the-sky displays, datalink, and graphical route displays). The results revealed that the presence of these advanced technologies hindered event detection reflecting cognitive tunneling and pilot complacency effects

Attention and automation: New perspectives on mental underload and performance

There is considerable evidence in the ergonomics literature that automation can significantly reduce operator mental workload. Furthermore, reducing mental workload is not necessarily a good thing, particularly in cases where the level is already manageable. This raises the issue of mental underload, which can be at least as detrimental to performance as overload. However, although it is widely recognized that mental underload is detrimental to performance, there are very few attempts to explain why this may be the case. It is argued in this paper that, until the need for a human operator is completely eliminated, automation has psychological implications relevant in both theoretical and applied domains. The present paper reviews theories of attention, as well as the literature on mental workload and automation, to synthesize a new explanation for the effects of mental underload on performance. Malleable attentional resources theory proposes that attentional capacity shrinks to accommodate reductions in mental workload, and that this shrinkage is responsible for the underload effect. The theory is discussed with respect to the applied implications for ergonomics research

Internal Alignment of the SLD Vertex Detector

The tracking resolution and vertex finding capabilities of the SLD experiment depended upon a precise knowledge of the location and orientation of the elements of the SLD pixel vertex detector (VXD3) in 3D space. At the heart of the procedure described here to align the 96 CCDs is the matrix inversion technique of singular value decomposition (SVD). This tool was employed to unfold the detector geometry corrections from the track data in the VXD3. The algorithm was adapted to perform an optimal {chi}{sup 2} minimization by careful treatment of the track hit residual measurement errors. The tracking resolution obtained with the aligned geometry achieved the design performance. Comments are given on how this method could be used for other trackers

Towards reviving post-Olympic Athens as a cultural destination

This paper examines the effects of global change on the status and qualities of the Greek national capital, Athens, focusing on how they affect the development of cultural tourism in the city. Although Athens constituted one of the most significant destinations for Greek tourism in the past, in recent years it started to weaken. Athens is characterised by a series of problems, among them are the degradation of its environment and quality of life and traffic congestion. However, in terms of tourism development, the Olympic Games helped in re-imaging the city and upgrading its infrastructure. This study based on semi-structured interviews with top officials reveals how global change has affected Athens’ socio-cultural/economic status, identity and image. Despite the tourism policy/planning responses to global changes, Athens’ tourism continues to decline leaving unexplored potential such as its rich cultural heritage, new multicultural identity and the New Acropolis Museum. The paper suggests that cultural elements of capital cities must be multidimensional including a variety of attractions and amenities. The use of cultural heritage assets needs to be in line with global developments in order for cities to effectively leverage heritage for cultural tourism

Evaluation of a DSGE Model of Energy in the United Kingdom Using Stationary Data

I examine the impact of energy price shock (oil prices shock and gas prices shock) on the economic activities in the United Kingdom using a dynamic stochastic general equilibrium model with a New Keynesian Philips Curve. I decomposed the changes in output caused by all of the stationary structural shocks. I found that the fall in output during the financial crisis period is driven by domestic demand shock, energy prices shock and world demand shock. I found the energy prices shock’s contribution to fall in output is temporary. Such that, the UK can borrow against such a temporary fall. This estimated model can create additional input to the policymaker’s choice of models

Antibacterial, Anti-HIV-1 Protease and Cytotoxic Activities of Aqueous Ethanolic Extracts from Combretum Adenogonium Steud. Ex A. Rich (Combretaceae).

\ud \ud Records have shown that Combretum adenogonium Steud. Ex A. Rich (Combretaceae) is used in traditional medicine systems of several tribes in Tanzania. This study focused on the investigation of antibacterial activity, anti-HIV-1 protease activity, toxicity properties and classes of phytochemicals in extracts from C. adenogonium Steud. Ex A. Rich (Combretaceae) to evaluate potential of these extracts for development as herbal remedies. Dried plant material were ground to fine powder and extracted using 80% aqueous ethanol to afford root, leaf and stem bark extracts. The extracts were assayed for anti-HIV-1 protease activities, antibacterial activities using microdilution methods and cytotoxicity using brine shrimps lethality assay. Screening for major phytochemical classes was carried out using standard chemical tests. All extracts exhibited antibacterial activity to at least one of the test bacteria with MIC-values ranging from 0.31-5.0 mg/ml. Two extracts, namely, root and stem bark exhibited anti-HIV-1 PR activity with IC50 values of 24.7 and 26.5 μg/ml, respectively. Stem bark and leaf extracts showed mild toxicity with LC50 values of 65.768 μg/ml and 76.965 μg/ml, respectively, whereas roots were relatively non-toxic (LC50 = 110.042 μg/ml). Phytochemical screening of the extracts indicated presence of flavonoids, terpenoids, alkaloids, tannins, glycosides and saponins. These results provide promising baseline information for the potential development of C. adenogonium extracts in treatment of bacterial and HIV/AIDS-related opportunistic infections

Fair trade learning: ethical standards for community-engaged international volunteer tourism

The purpose of this paper is to articulate a set of ethical standards for international volunteer tourism. The standards are focused on promoting fair trade learning principles in the management and operation of volunteer programmes. Because of the unique social mission, research, and evaluation capacities of higher education, we propose first applying these principles specifically to international volunteer programmes operating at the university-community nexus. These standards have emerged through a collaborative, in-person and online process during the last two years with input by numerous concerned global citizens, international education practitioners and researchers, nongovernmental organization representatives, and community members. The document shared below represents current ‘best practice’ for maximizing the benefits and minimizing the negative impacts of volunteer tourism programmes for both host communities and volunteers