Position-dependent noncommutativity in quantum mechanics

The model of the position-dependent noncommutativity in quantum mechanics is proposed. We start with given commutation relations between the operators of coordinates [(x) over cap (i), (x) over cap (j)] = omega(ij) ((x) over cap), and construct the complete algebra of commutation relations, including the operators of momenta. The constructed algebra is a deformation of a standard Heisenberg algebra and obeys the Jacobi identity. The key point of our construction is a proposed first-order Lagrangian, which after quantization reproduces the desired commutation relations. Also we study the possibility to localize the noncommutativity.

Gauge invariance and classical dynamics of noncommutative particle theory

We consider a model of classical noncommutative particle in an external electromagnetic field. For this model, we prove the existence of generalized gauge transformations. Classical dynamics in Hamiltonian and Lagrangian form is discussed; in particular, the motion in the constant magnetic field is studied in detail. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3299296]

S matrix on the Moyal plane: Locality versus Lorentz invariance

Twisted quantum field theories on the Groenewold-Moyal plane are known to be nonlocal. Despite this nonlocality, it is possible to define a generalized notion of causality. We show that interacting quantum field theories that involve only couplings between matter fields, or between matter fields and minimally coupled U(1) gauge fields are causal in this sense. On the other hand, interactions between matter fields and non-Abelian gauge fields violate this generalized causality. We derive the modified Feynman rules emergent from these features. They imply that interactions of matter with non-Abelian gauge fields are not Lorentz- and CPT-invariant.

TAXONOMIC POSITION OF GUIRATINGIA MENDESI (MEGADESMIDAE) AND THE EVOLUTION OF PERMIAN ENDEMIC BIVALVE FAUNA OF THE PARANA BASIN, BRAZIL

The unusual bivalve Guiratingia mendesi is redescribed from the original material. Detailed analysis of hinge and muscle scars allows more refined designation of its taxonomic position and affinities to other Permian bivalves from the Parana Basin. Guiratingia mendesi is characterized by very small, anteriorly expanded shells, with a great number of muscle striae within the area delimited by the pallial line. A flattened area is noted alongside the commissure of shell. The presence of a triangular blunt tooth in the right valve allows its designation to Megadesmidae. The absence of accessory muscle scars ""a"" and ""b"" and pedal elevator indicate that the genus belongs to the Plesiocyprinellinae, a group of bivalves considered endemic to the Passa Dois Group. Guiratingia mendesi is found, however, in limestones of the Palermo Formation (Middle Artinskian), nearly 100 in below the base of the Irati Formation (Late Artinskian). Until now, it was believed that within the Permian succession of Parana Basin, pre-Irati bivalves were all gondwanic or cosmopolitan. Guiratingia mendesi was an endemic, active burrower that resembles Runnegariella fragilis from the Permian Teresina Formation. This indicates that during Palermo times restricted paleogeographic conditions have existed within the huge Parana epeiric sea, favoring endemicity, probably in marine bayments close to its margins. The presence of an anteriorly expanded shell in G mendesi is a condition also seen in other Mesozoic and Cenozoic anomalodesmatans, demonstrating the recurrence of shell forms in distinct lineages of this interesting group of bivalves.

Study of partially encased composite beams with innovative position of stud bolts

In this article, static behavior of three partially encased composite beams under flexural condition is investigated in the context of studying some alternative positions for the headed studs. Shear resistance between the I-shaped beam and the concrete was provided by headed studs in two positions: vertically welded oil the bottom flange and horizontally welded on the faces of the web. Experimental results show that the headed studs provide the composite action and increase the bending strength. The most remarkable position seems to be the headed studs vertically welded oil the bottom flange. Ail analytical method to estimate the bending capacity of the encased beams is also proposed, giving a good prediction of the experimental results (C) 2008 Elsevier Ltd. All rights reserved.

Influence of the slice position on chloride migration tests for concrete in marine conditions

Chloride migration tests are used to measure the concrete capacity to inhibit chloride attack. Many researchers carry out this test in a slice of concrete extracted from the central part of cylindrical specimens, discarding about 75% of the concrete used to mold the specimens. This fact generated the question: would it be possible to extract more slices from a same specimen without losing the confidence in the results? The main purpose of this work is to answer this question. Moreover, another aim of this study was to show the difference of chloride penetration between finished faces and the formwork surfaces of concrete beams and slabs. The results indicated that it is possible to use more slices of a single specimen for a chloride migration test. Moreover, it was demonstrated that there is a significant difference of chloride penetration between the finished surface and the formwork surface of the specimens. (C) 2008 Elsevier Ltd. All rights reserved.

Hand position on the bunch and source-sink ratio influence the banana fruit susceptibility to crown rot disease

The postharvest development of crown rot of bananas depends notably on the fruit susceptibility to this disease at harvest. It has been shown that fruit susceptibility to crown rot is variable and it was suggested that this depends on environmental preharvest factors. However, little is known about the preharvest factors influencing this susceptibility. The aim of this work was to evaluate the extent to which fruit filling characteristics during growth and the fruit development stage influence the banana susceptibility to crown rot. This involved evaluating the influence of (a) the fruit position at different levels of the banana bunch (hands) and (b) changing the source-sink ratio (So-Si ratio), on the fruit susceptibility to crown rot. The fruit susceptibility was determined by measuring the internal necrotic surface (INS) after artificial inoculation of Colletotrichum musae. A linear correlation (r = -0.95) was found between the hand position on the bunch and the INS. The So-Si ratio was found to influence the pomological characteristics of the fruits and their susceptibility to crown rot. Fruits of bunches from which six hands were removed (two hands remaining on the bunch) proved to be significantly less susceptible to crown rot (INS = 138.3 mm 2) than those from bunches with eight hands (INS = 237.9 mm 2). The banana susceptibility to crown rot is thus likely to be influenced by the fruit development stage and filling characteristics. The present results highlight the importance of standardising hand sampling on a bunch when testing fruit susceptibility to crown rot. They also show that hand removal in the field has advantages in the context of integrated pest management, making it possible to reduce fruit susceptibility to crown rot while increasing fruit size.

The influence of joint position on the dynamics of perception-action coupling

Six right-handed subjects performed rhythmic flexion and extension movements of the index finger in time with an auditory metronome. On each block of trials, the wrist of the response hand was placed in a extended, neutral or flexed position. In the flex-on-the-beat condition, subjects were instructed to coordinate maximum excursion in the direction of finger flexion with each beat of the metronome. In the extend-on-the-beat condition, subjects were instructed to coordinate maximum excursion in the direction of finger extension with each beat of the metronome. The frequency of the metronome was increased from 2.00 Hz to 3.75 Hz in 8 steps (8 s epochs) of 0.25 Hz. During trials prepared in the extend-on-the-beat pattern, all subjects exhibited transitions to either a flex-on-the-beat pattern or to phase wandering as the frequency of pacing was increased. The time at which these transitions occurred was reliably influenced by the position of the wrist. Four subjects exhibited qualitative departures from the flex-on-the-beat pattern at pacing frequencies that were greater than those at which the extend-on-the-beat pattern could be maintained. The lime at which these departures occurred was not influenced by the position of the wrist. These results are discussed with reference to the constraints imposed on the coordination dynamics by the intrinsic properties of the neuromuscular-skeletal system.

Antipronation taping and temporary orthoses - Effects on tibial rotation position after exercise

Abnormal lower-limb biomechanics-in particular, abnormal pronation of the subtalar joint with concomitant increased internal rotation of the tibia-is one of the major causes of overuse injuries of the lower limb. A randomized, controlled, within-subjects research design (N = 14) was used to investigate the effect of a temporary felt orthosis and an antipronation taping technique to control the transverse tibial rotation position immediately after application and after each of two 10-minute periods of exercise. The results showed that the taping technique was superior to both the orthosis and no intervention in controlling tibial rotation position immediately after application and after 10 minutes of exercise. After 20 minutes of exercise, neither the tape nor the orthosis was significantly superior to the control; however, the trends suggested that some residual control was maintained. Future studies are needed to determine the amount of foot pronation control required to relieve symptoms in a symptomatic population in order to determine the clinical effectiveness of these treatment methods.

Phylogenetic position of Chitinophaga pinensis in the Flexibacter-Bacteroides-Cytophaga phylum

Comparison of the 16S rRNA gene sequence determined for Chitinophaga pinensis showed that this species is most closely related to Flexibacter filiformis in the Flexibacter-Bacteroides-Cytophaga phylum, These two chitinolytic bacteria, which are characterized by transformation into spherical bodies on ageing, belong to a strongly supported lineage that also includes Cytophaga arvensicola, Flavobacterium ferrugineum and Flexibacter sancti, The lineage is distinct from the microcyst-forming species Sporocytophaga myxococcoides.

Chetoneura shennonggongensis, a new species of cave-dwelling Keroplatini from China (Diptera : Keroplatidae), with a discussion of the position of Chetoneura

Chetoneura shennonggongensis Amorim & Niu, sp. n., inhabiting caves in East China, is described based on the adult male and female, plus larva. Chetoneura Colless, previously associated with Orfelia and known from a single species from caves in Malaysia, is formally transferred to the Keroplatini. This is the first description of the larva and of the general biology of the genus. The larva of this new species is suspended in a roughly horizontal hammock of silken threads amidst mucous coated snare threads from the roof of caves, but is not bioluminescent as some species of other genera in Keroplatidae ( e. g., Arachnocampa, Keroplatus, and Orfelia). A key to separate both species of the genus is provided. The position of the genus within the Keroplatini is considered. Chetoneura is considered to be closely related to a clade containing Heteropterna and Ctenoceridion.

Four new species of Paraclius Loew (Diptera: Dolichopodidae) from the Brazilian Atlantic Forest, and notes on the systematic position of Cheiromyia Dyte

Four new species of Paraclius Loew from the Brazilian Atlantic Forest are described and illustrated: P. amphiatheratus, sp. nov., P. parenti, sp. nov., P. sagittatus, sp. nov., and P. dicrophallus, sp. nov. The condition of their enlarged sperm pump, also seen in the Neotropical genus Cheiromyia Dyte, is briefly discussed. Comments on the phylogenetic position of Cheiromyia are presented in light of new data from female terminalia of that genus.

The identity of Paratrizygia conformis Tonnoir (Diptera, Mycetophilidae), with comments on its systematic position

Paratrizygia conformis, the type-species of the genus Paratrizygia, from Tasmania, is redescribed from the holotype. The wing venation and male terminalia are illustrated in detail. The question of the monophyly of the genus-which has four additional species in Chile and southern Argentina, and four species in the Atlantic Forest, in Brazil-is addressed. Comments are made on the relationships of the genus in the Azana-group of Sciophilinae. The hypothesis of monophyly of Paratrizygia is retained, as indicated by the presence of modified, elongated spines on a distal fold of tergite 9.

Management of Patients With Rheumatoid Arthritis in Latin America A Consensus Position Paper From Pan-American League of Associations of Rheumatology and Grupo Latino Americano De Estudio de Artritis Reumatoide

Objective: A consensus meeting of representatives of 18 Latin-American and Caribbean countries gathered in Renaca, Chile, for 2 days to identify problems and provide recommendations for the care of patients with rheumatoid arthritis (RA) in Latin America, a region where poverty and other health priorities make the efforts to provide effective and high quality care difficult. This report includes recommendations for health professionals, patients, and health authorities in Latin America, with an emphasis oil education and therapeutic issues. Methods: Fifty-one rheumatologists (list available only online on the JCR website) from 18 Latin-American and Caribbean countries with a special interest in RA participated in the consensus meeting. Participants were experts identified and appointed by the National Societies of Rheumatology affiliated with the Pan-American League of Associations for Rheumatology (PANLAR) and by the Grupo Latino Americano De Estudio de Artritis Reumatoide (GLADAR)-an independent group of Latin American rheumatologist researchers were also invited to the meeting. Eight topics were identified as priorities: patient, community and allied health professional education, health policy and decision making, programs for early detection and appropriate treatment of RA, role of classic disease modifying antirheumatic drugs (DMARDs), role of biologic therapy, and drug safety surveillance. To reach consensus, a survey with questions relevant to the topic of interest was sent to all participants before the meeting. During a 2 day meeting, the answers of the survey were reviewed and discussed by each group, with final recommendations on action items. Results: The specific topic of the survey was answered by 86% of the participants and 68% of them answered the entire survey. It was agreed that RA and rheumatic diseases which are currently not but should be public health priorities in Latin America, because of their prevalence and impact on quality of life. Conclusions: Strategic areas identified as priorities for our region included: early diagnosis and access to care by multidisciplinary teams, creation of databases to identify infections with the use of biologic agents in RA which are relevant to Latin America, and overall efforts to improve the care of RA patients in accordance with international standards. Implementation of educational programs aimed to improve self-management for patients with RA was also considered crucial.

Reassessment of the phylogenetic position of Caulobacter subvibrioides

Determination of the 16S rRNA gene sequence of Caulobacter subvibrioides ATCC 15264(T) (T = type strain) confirmed that this species is a member of the alpha subclass of the Proteobacteria and showed that it is phylogenetically most closely related to the Caulobacter group comprising the species Caulobacter bacteroides, Caulobacter crescentus, and Brevandimonas (Pseudomonas) diminuta, for which 16S rRNA sequences of the type strains are currently available. The closest known relative of strain ATCC 15264(T) among these species is B. diminuta (level of direct pairwise sequence similarity, 95%). On the basis of its previously determined 16S rRNA sequence (accession number M83797), C. subvibrioides is most closely related to Sphingomonas adhaesiva in the alpha-4 subgroup (level of similarity, 97.7%). Analysis of the hydroxy fatty acids of C. subvibrioides ATCC 15264(T) showed that the 2-hydroxymyristic acid which is characteristic of the genus Sphingomonas was absent.