On Effective Constraints for the Riemann-Lanczos System of Equations

There have been conflicting points of view concerning the Riemann--Lanczos problem in 3 and 4 dimensions. Using direct differentiation on the defining partial differential equations, Massa and Pagani (in 4 dimensions) and Edgar (in dimensions n > 2) have argued that there are effective constraints so that not all Riemann tensors can have Lanczos potentials; using Cartan's criteria of integrability of ideals of differential forms Bampi and Caviglia have argued that there are no such constraints in dimensions n < 5, and that, in these dimensions, all Riemann tensors can have Lanczos potentials. In this paper we give a simple direct derivation of a constraint equation, confirm explicitly that known exact solutions of the Riemann-Lanczos problem satisfy it, and argue that the Bampi and Caviglia conclusion must therefore be flawed. In support of this, we refer to the recent work of Dolan and Gerber on the three dimensional problem; by a method closely related to that of Bampi and Caviglia, they have found an 'internal identity' which we demonstrate is precisely the three dimensional version of the effective constraint originally found by Massa and Pagani, and Edgar.Comment: 9pages, Te

Analisa Persepsi Konsumen Terhadap Komunikasi Nonverbal Resepsionis Hotel Bintang Lima Di Surabaya

Penelitian ini dilakukan untuk mengetahui persepsi konsumen tentang gambaran komunikasi nonverbal resepsionis hotel bintang lima di Surabaya. Metode penelitian yang digunakan dalam penelitian ini adalah metode kuantitatif deskriptif. Teknik analisa data yang digunakan adalah Statistical Product and Service Solutions (SPSS). Objek dalam penelitian ini adalah komunikasi nonverbal resepsionis hotel bintang lima di Surabaya dan subjeknya adalah konsumen yang pernah melakukan check-in atau check-out di hotel bintang lima di Surabaya. Hasil penelitian menunjukkan bahwa persepsi konsumen terhadap komunikasi nonverbal resepsionis hotel bintang lima di Surabaya sudah sangat baik. This study is to reveal customer perception about receptionist's nonverbal communication at five star hotel in Surabaya. The method of this research is quantitative descriptive. The data analysis used Statistical Product and Service Solutions (SPSS). The object of this research is receptionist's nonverbal communication at five star hotel in Surabaya and the subject is customer who have done check-in or check-out at five star hotel in Surabaya. The result of this research is customer perception about receptionist's nonverbal communication at five star hotel in Surabaya have been very good

Alvira : comparative genomics of viral strains

The Alvira tool is a general purpose multiple sequence alignment viewer with a special emphasis on the comparative analysis of viral genomes. This new tool has been devised specifically to address the problem of the simultaneous analysis of a large number of viral strains. The multiple alignment is embedded in a graph that can be explored at different levels of resolution

Interpreting a conformally flat pure radiation space-time

A physical interpretation is presented of the general class of conformally flat pure radiation metrics that has recently been identified by Edgar and Ludwig. It is shown that, at least in the weak field limit, successive wave surfaces can be represented as null (half) hyperplanes rolled around a two-dimensional null cone. In the impulsive limit, the solution reduces to a pp-wave whose direction of propagation depends on retarded time. In the general case, there is a coordinate singularity which corresponds to an envelope of the wave surfaces. The global structure is discussed and a possible vacuum extension through the envelope is proposed.Comment: 9 pages, Plain TeX, 2 figures. To appear in Class. Quantum Grav. Reference adde

Rayleigh and depinning instabilities of forced liquid ridges on heterogeneous substrates

Depinning of two-dimensional liquid ridges and three-dimensional drops on an inclined substrate is studied within the lubrication approximation. The structures are pinned to wetting heterogeneities arising from variations of the strength of the short-range polar contribution to the disjoining pressure. The case of a periodic array of hydrophobic stripes transverse to the slope is studied in detail using a combination of direct numerical simulation and branch-following techniques. Under appropriate conditions the ridges may either depin and slide downslope as the slope is increased, or first breakup into drops via a transverse instability, prior to depinning. The different transition scenarios are examined together with the stability properties of the different possible states of the system.Comment: Physics synopsis link: http://physics.aps.org/synopsis-for/10.1103/PhysRevE.83.01630

Isolation and sequence analysis of a cDNA clone encoding the entire catalytic subunit of phosphorylase kinase

AbstractSynthetic oligonucleotides have been used to isolate a 1.85 kb clone containing the full length coding sequence for the catalytic subunit of rabbit skeletal muscle phosphorylase kinase from a cDNA library constructed in λgt10. Sequence analysis of the clone predicted an amino acid sequence in agreement with a published primary structure. Inspection of the codon usage revealed a strong preference for G or C nucleotides at the third codon position as found for several other skeletal muscle proteins. This cDNA clone should facilitate identification of functional domains, including the calmodulin-binding site, and investigation of the molecular basis of X-linked phosphorylase kinase deficiencies

A qualitative study of stakeholder views regarding participation in locally commissioned enhanced optometric services

Objectives: To explore the views of optometrists, general practitioners (GPs) and ophthalmologists regarding the development and organisation of community-based enhanced optometric services. Design: Qualitative study using free-text questionnaires and telephone interviews. Setting: A minor eye conditions scheme (MECS) and a glaucoma referral refinement scheme (GRRS) are based on accredited community optometry practices. Participants: 41 optometrists, 6 ophthalmologists and 25 GPs. Results: The most common reason given by optometrists for participation in enhanced schemes was to further their professional development; however, as providers of ‘for-profit’ healthcare, it was clear that participants had also considered the impact of the schemes on their business. Lack of fit with the ‘retail’ business model of optometry was a frequently given reason for non-participation. The methods used for training and accreditation were generally thought to be appropriate, and participating optometrists welcomed the opportunities for ongoing training. The ophthalmologists involved in the MECS and GRRS expressed very positive views regarding the schemes and widely acknowledged that the new care pathways would reduce unnecessary referrals and shorten patient waiting times. GPs involved in the MECS were also very supportive. They felt that the scheme provided an ‘expert’ local opinion that could potentially reduce the number of secondary care referrals. Conclusions: The results of this study demonstrated strong stakeholder support for the development of community-based enhanced optometric services. Although optometrists welcomed the opportunity to develop their professional skills and knowledge, enhanced schemes must also provide a sufficient financial incentive so as not to compromise the profitability of their business

On the Symmetries of the Edgar-Ludwig Metric

The conformal Killing equations for the most general (non-plane wave) conformally flat pure radiation field are solved to find the conformal Killing vectors. As expected fifteen independent conformal Killing vectors exist, but in general the metric admits no Killing or homothetic vectors. However for certain special cases a one-dimensional group of homotheties or motions may exist and in one very special case, overlooked by previous investigators, a two-dimensional homethety group exists. No higher dimensional groups of motions or homotheties are admitted by these metrics.Comment: Plain TeX, 7 pages, No figure