Grasp planning under uncertainty

The planning of dexterous grasps for multifingered robot hands operating in uncertain environments is covered. A sensor-based approach to the planning of a reach path prior to grasping is first described. An on-line, joint space finger path planning algorithm for the enclose phase of grasping was then developed. The algorithm minimizes the impact momentum of the hand. It uses a Preshape Jacobian matrix to map task-level hand preshape requirements into kinematic constraints. A master slave scheme avoids inter-finger collisions and reduces the dimensionality of the planning problem

Nonparametric Transient Classification using Adaptive Wavelets

Classifying transients based on multi band light curves is a challenging but crucial problem in the era of GAIA and LSST since the sheer volume of transients will make spectroscopic classification unfeasible. Here we present a nonparametric classifier that uses the transient's light curve measurements to predict its class given training data. It implements two novel components: the first is the use of the BAGIDIS wavelet methodology - a characterization of functional data using hierarchical wavelet coefficients. The second novelty is the introduction of a ranked probability classifier on the wavelet coefficients that handles both the heteroscedasticity of the data in addition to the potential non-representativity of the training set. The ranked classifier is simple and quick to implement while a major advantage of the BAGIDIS wavelets is that they are translation invariant, hence they do not need the light curves to be aligned to extract features. Further, BAGIDIS is nonparametric so it can be used for blind searches for new objects. We demonstrate the effectiveness of our ranked wavelet classifier against the well-tested Supernova Photometric Classification Challenge dataset in which the challenge is to correctly classify light curves as Type Ia or non-Ia supernovae. We train our ranked probability classifier on the spectroscopically-confirmed subsample (which is not representative) and show that it gives good results for all supernova with observed light curve timespans greater than 100 days (roughly 55% of the dataset). For such data, we obtain a Ia efficiency of 80.5% and a purity of 82.4% yielding a highly competitive score of 0.49 whilst implementing a truly "model-blind" approach to supernova classification. Consequently this approach may be particularly suitable for the classification of astronomical transients in the era of large synoptic sky surveys.Comment: 14 pages, 8 figures. Published in MNRA

K-ATP channel gene expression is induced by urocortin and mediates its cardioprotective effect

Background-Urocortin is a novel cardioprotective agent that can protect cardiac myocytes from the damaging effects of ischemia/reperfusion both in culture and in the intact heart and is effective when given at reperfusion.Methods and Results-We have analyzed global changes in gone expression in cardiac myocytes after urocortin treatment using gene chip technology. We report that urocortin specifically induces enhanced expression of the Kir 6.1 cardiac potassium channel subunit. On the basis of this finding, we showed that the cardioprotective effect of urocortin both in isolated cardiac cells and in the intact heart is specifically blocked by both generalized and mitochondrial-specific K-ATP channel blockers, whereas the cardioprotective effect of cardiotrophin-1 is unaffected. Conversely, inhibiting the Kir 6.1 channel subunit greatly enhances cardiac cell death after ischemia.Conclusions-This is, to our knowledge, the first report of the altered expression of a K-ATP. channel subunit induced by a cardioprotective agent and demonstrates that K-ATP, channel opening is essential for the effect of this novel cardioprotective agent

Corrigendum: Service quality perceptions of campus-based food outlets

No abstract available

Service quality perceptions of campus-based food outlets

Orientation: In a competitive retail business environment, the essence of service quality is invariably amplified. Within a university context, the same applies, given that the student population of customers is relatively finite and yet there are a variety of food outlets on campuses. Research purpose: This study aims to investigate the existence (or lack of it) of a relationship between gender, race and price and the dependent variable of students’ service quality perception of campus-based food outlets. Although gender and race are the most obvious defining demographic features of a student population, the variable of price is usually a major consideration for student purchases. Motivation for the study: The study is an applied research as it is focused on addressing an issue with real-life business implications. Research design, approach and method: It employs the use of data collected in a cross-sectional manner from 200 respondents selected through non-probability sampling. Main findings: The findings of the study indicate that no significant differences exist in service quality perception when gender is considered. Conversely, results show that the service quality perceptions of racial groups differ. The study also finds that a weak but positive correlation exists between price and service quality perceptions. Practical/managerial implications: These results indicate practical implications as they can become useful condiments for refining the offerings and services of the studied campus-based food outlets in the quest to meet or exceed customer expectations. Contribution/value-add: From an academic perspective, the study builds on existing knowledge by exposing the association that the independent variables of gender, race and price have with students’ service quality perception in the specific context of campus-based food outlets in Gauteng, South Africa

Organic aerosol and global climate modelling: a review

The present paper reviews existing knowledge with regard to Organic Aerosol (OA) of importance for global climate modelling and defines critical gaps needed to reduce the involved uncertainties. All pieces required for the representation of OA in a global climate model are sketched out with special attention to Secondary Organic Aerosol (SOA): The emission estimates of primary carbonaceous particles and SOA precursor gases are summarized. The up-to-date understanding of the chemical formation and transformation of condensable organic material is outlined. Knowledge on the hygroscopicity of OA and measurements of optical properties of the organic aerosol constituents are summarized. The mechanisms of interactions of OA with clouds and dry and wet removal processes parameterisations in global models are outlined. This information is synthesized to provide a continuous analysis of the flow from the emitted material to the atmosphere up to the point of the climate impact of the produced organic aerosol. The sources of uncertainties at each step of this process are highlighted as areas that require further studies

Deregulation of methylation of transcribed-ultra conserved regions in colorectal cancer and their value for detection of adenomas and adenocarcinomas

Expression of Transcribed Ultraconserved Regions (T-UCRs) is often deregulated in cancer. The present study assesses the expression and methylation of three T-UCRs (Uc160, Uc283 and Uc346) in colorectal cancer (CRC) and explores the potential of T-UCR methylation in circulating DNA for the detection of adenomas and adenocarcinomas. Expression levels of Uc160, Uc283 and Uc346 were lower in neoplastic tissues from 64 CRC patients (statistically significant for Uc160, p<0.001), compared to non-malignant tissues, while methylation levels displayed the inverse pattern (p<0.001, p=0.001 and p=0.004 respectively). In colon cancer cell lines, overexpression of Uc160 and Uc346 led to increased proliferation and migration rates. Methylation levels of Uc160 in plasma of 50 CRC, 59 adenoma patients, 40 healthy subjects and 12 patients with colon inflammation or diverticulosis predicted the presence of CRC with 35% sensitivity and 89% specificity (p=0.016), while methylation levels of the combination of all three T-UCRs resulted in 45% sensitivity and 74.3% specificity (p=0.013). In conclusion, studied T-UCRs’ expression and methylation status are deregulated in CRC while Uc160 and Uc346 appear to have a complicated role in CRC progression. Moreover their methylation status appears a promising non-invasive screening test for CRC, provided that the sensitivity of the assay is improved

The evolutionary pathway from a biologically inactive polypeptide sequence to a folded, active structural mimic of DNA

The protein Ocr (overcome classical restriction) from bacteriophage T7 acts as a mimic of DNA and inhibits all Type I restriction/modification (RM) enzymes. Ocr is a homodimer of 116 amino acids and adopts an elongated structure that resembles the shape of a bent 24 bp DNA molecule. Each monomer includes 34 acidic residues and only six basic residues. We have delineated the mimicry of Ocr by focusing on the electrostatic contribution of its negatively charged amino acids using directed evolution of a synthetic form of Ocr, termed pocr, in which all of the 34 acidic residues were substituted for a neutral amino acid. In vivo analyses confirmed that pocr did not display any antirestriction activity. Here, we have subjected the gene encoding pocr to several rounds of directed evolution in which codons for the corresponding acidic residues found in Ocr were specifically re-introduced. An in vivo selection assay was used to detect antirestriction activity after each round of mutation. Our results demonstrate the variation in importance of the acidic residues in regions of Ocr corresponding to different parts of the DNA target which it is mimicking and for the avoidance of deleterious effects on the growth of the host

Impact of target site distribution for Type I restriction enzymes on the evolution of methicillin-resistant Staphylococcus aureus (MRSA) populations.

A limited number of Methicillin-resistant Staphylococcus aureus (MRSA) clones are responsible for MRSA infections worldwide, and those of different lineages carry unique Type I restriction-modification (RM) variants. We have identified the specific DNA sequence targets for the dominant MRSA lineages CC1, CC5, CC8 and ST239. We experimentally demonstrate that this RM system is sufficient to block horizontal gene transfer between clinically important MRSA, confirming the bioinformatic evidence that each lineage is evolving independently. Target sites are distributed randomly in S. aureus genomes, except in a set of large conjugative plasmids encoding resistance genes that show evidence of spreading between two successful MRSA lineages. This analysis of the identification and distribution of target sites explains evolutionary patterns in a pathogenic bacterium. We show that a lack of specific target sites enables plasmids to evade the Type I RM system thereby contributing to the evolution of increasingly resistant community and hospital MRSA