10,740 research outputs found

    SUSY sine-Gordon theory as a perturbed conformal field theory and finite size effects

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    We consider SUSY sine-Gordon theory in the framework of perturbed conformal field theory. Using an argument from Zamolodchikov, we obtain the vacuum structure and the kink adjacency diagram of the theory, which is cross-checked against the exact S-matrix prediction, first-order perturbed conformal field theory (PCFT), the NLIE method and truncated conformal space approach. We provide evidence for consistency between the usual Lagrangian description and PCFT on the one hand, and between PCFT, NLIE and a massgap formula conjectured by Baseilhac and Fateev, on the other. In addition, we extend the NLIE description to all the vacua of the theory. (C) 2003 Elsevier B.V. All rights reserved

    Dimer-dimer stacking interactions are important for nucleic acid binding by the archaeal chromatin protein Alba

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    Archaea use a variety of small basic proteins to package their DNA. One of the most widespread and highly conserved is the Alba (Sso10b) protein. Alba interacts with both DNA and RNA in vitro, and we show in the present study that it binds more tightly to dsDNA (double-stranded DNA) than to either ssDNA (single-stranded DNA) or RNA. The Alba protein is dimeric in solution, and forms distinct ordered complexes with DNA that have been visualized by electron microscopy studies; these studies suggest that, on binding dsDNA, the protein forms extended helical protein fibres. An end-to-end association of consecutive Alba dimers is suggested by the presence of a dimer-dimer interface in crystal structures of Alba from several species, and by the strong conservation of the interface residues, centred on Are and Phe(60). In the present study we map perturbation of the polypeptide backbone of Alba upon binding to DNA and RNA by NMR, and demonstrate the central role of Phe(60) in forming the dimer dimer interface. Site-directed spin labelling and pulsed ESR are used to confirm that an end-to-end, dimer dimer interaction forms in the presence of dsDNA.Publisher PDFPeer reviewe

    The physiological cost of wearing the propellant handler's ensemble at the Kennedy Space Center

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    The potential for exposure to toxins used in the propulsion systems of spacecraft dictates the use of a whole body protective suit, the Propellant Handler's Ensemble (PHE) during preflight preparation and launching. The weight, structure, and operating parameters of the PHE may be expected to have a significant impact upon the metabolic, cardiovascular, and thermal responses of the user, especially during ambient temperature extremes and high workload situations. Four male subjects participated in tests in -7, 23, and 43 C (20, 74, and 110 F) environments in two versions of the PHE, the autonomous backpack (BP) and the hoseline (HL) supplied configuration. Measurements included heart rate (HR) rectal temperature, four skin temperatures, oxygen (O2), and carbon dioxide (CO2) in the helmet area, interior suit temperature, and suit pressure. Exercise metabolism was estimated from HR, PHE weight, and treadmill speed and grade. The HR responses between each PHE configuration were not statistically different. As a percentage of HR maximum, the mean values were 79 percent (COLD), 84 percent (LAB), and 90 percent (HOT). Helmet O2 and CO2 levels were correlated with percent HR max (P less than 0.001). Rectal temperatures were similar for each PHE configuration, except in the HOT exposure where the BP version exceeded the HL configuration (P less than 0.05). In nearly every instance the HR was driven to moderately high levels, the supplied respiratory gases were not optimum, and thermal adversity was a primary stressor. Our findings suggest that medical and physical fitness standards, along with operational restrictions, should be imposed upon PHE users to avoid situations that could adversely affect the worker

    A. G. for Canada et al v. Claire Dupond: The Right to Assemble in Canada?

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    The renewal of the Federation must confirm the pre-eminence of citizens over institutions, guarantee their rights and freedoms and ensure that these rights and freedoms are inalienable. 1 These words from Prime Minister Trudeau are a reflection of the concern today for protection of individual rights and freedoms. His words also reflect the past concerns with protection of individual rights and freedoms particularly in countries which espouse democratic principles. He has recognized that the balance between individual and state interests must be struck in favour of the individual. In order to achieve this result, there must be some consensus in a nation as to what are to be rights and freedoms worthy of protection. Demonstrations, assemblies, parades and street comer orators have been an integral part of the way of life in common law countries such as the United States, Great Britain and Canada. In the United States these assertions of individual liberty are regarded as part of the fundamental freedoms which their constitutional Bill of Rights guarantees will be protected. In Canada, the Supreme Court made it clear on January 19, 1978 that they did not regard demonstrations and street assemblies as fundamental rights or, for that matter, as individual rights at all. 2 They chose, rather to place the state interest above the interest of the individual at a time of political crisis when individual rights are most in need of protection. Although this decision is ostensibly limited to parades, assemblies and demonstrations it could have future implications when other courts are attempting to define the limits of individual liberty. It is this restrictive concept of fundamental freedoms which will create most concern for the future

    Memory functions in reading and arithmetic-disabled children.

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    Two subtypes of learning-disabled (LD) children, with primary deficiencies in Reading (RD) and mechanical Arithmetic (AD) were compared to a group of age-matched normals on several memory tasks. Memory tasks were classified according to type and modality of material input, method of response, phonetic properties and visual features of the material encoded, and stage of memory process required. Results showed a double dissociation between the RD and AD groups: RD children evidenced mild difficulty with verbal memory tasks while AD children exhibited difficulty with nonverbal memory tasks. This latter result was particularly robust, suggesting marked difficulties in nonverbal and novel mnestic encoding for AD children. In addition, differences were found between groups with respect to the phonetic characteristics of stimuli and response format of memory task consistent with previous research on these LD subtypes. Modality and visual feature variables were not found to effect the performances of the groups in a predictable fashion. The various inter-task differences were discussed in the larger context of neuropsychological functions and academic strengths and weaknesses of the RD and AD groups. Specific remedial recommendations were offered to take best advantage of respective mnestic strengths in each group.Dept. of Psychology. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis1988 .B735. Source: Dissertation Abstracts International, Volume: 49-04, Section: B, page: 1380. Thesis (Ph.D.)--University of Windsor (Canada), 1988

    Agricultural Productivity in the United States

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    Increased productivity is a key to a healthy and thriving economy. Consequently, the trend in productivity, economywide, is one of the most closely watched of our common economic performance indicators. Agriculture, in particular, has been a very successful sector of the U.S. economy in terms of productivity growth. The U.S. farm sector has provided an abundance of output while using inputs efficiently. Agricultural productivity growth has been an important source of U.S. economic growth throughout the century, but the years since 1940 have seen an even faster growth in agricultural productivity. The annual average increase in productivity from 1948 to 1994 was 1.94 percent. This reflects an annual growth in output of 1.88 percent per year and an actual decline in agricultural inputs of 0.06 percent per year. This report describes changes in U.S. agricultural productivity, and its output and input components, for 1948-94. The report also discusses factors that have affected productivity trends and provides detailed, technical information about the USDA system for calculating productivity.productivity, efficiency, agricultural production, outputs, inputs, Productivity Analysis,

    Effect of training and familiarity on responsiveness to human cues in domestic dogs (<i>Canis familiaris</i>)

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    Domestic dogs (Canis familiaris) seem to possess an evolved competency to follow human-given cues, often out-performing their wild progenitor the wolf (Canis lupus) on cue-following tasks. However, domestication may not be solely responsible for the socio-cognitive skills of dogs, with ontogenetic experience also playing a role. This research evaluated the effects of intensive training on cue-following behaviour using an unreinforced object-choice paradigm. The responses of dogs that were trained to competitive levels were compared to those of pet dogs with only basic training, and dogs living in an animal shelter that demonstrated no or only rudimentary following of basic commands. Using a cue-following task where three types of cues were presented by familiar and unfamiliar human partners, the number of cues followed by each training group were recorded. All dogs found cues where gesture was combined with a congruent head and eye movement easier to follow than either gesture or eye gaze alone. Whether the cue-giver was familiar or not had a significant effect on number of cues followed in homed dogs, and the performance of shelter dogs was comparable to the other groups when faced with an unfamiliar cue-giver. Contrary to predictions, level of training did not improve performance on the cue-following task. This work does provide support for the presence of an evolved adaptation to exploit social cues provided by humans that can be augmented by familiarity with the cue giver. However, additional joint activity as experienced in an intensive training regime does not seem to increase accuracy in following human-given cues

    Couching in Nigeria: prevalence, risk factors and visual acuity outcomes.

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    PURPOSE: Couching is an ancient treatment for cataract which is still practiced in some of the poorer developing countries, particularly in sub-Saharan Africa. The purpose of this study is to describe risk factors for couching and visual acuity outcomes in a nationally representative sample of adults aged 40 years and above in Nigeria. METHODS: Probability in proportion size methods were used to identify a representative sample. Of the 15,375 adults enumerated, 13,582 were interviewed and examined. Examination included logMar acuities, slit lamp examination and dilated fundoscopy with digital fundus imaging. RESULTS: Almost half of the 583 eyes undergoing a procedure for cataract had been couched (249 eyes, 42.7%). Individuals living in rural areas (P = 0.033) and in the two underserved northern administrative zones (P = 0.33; P = 0.002) were more likely to have been couched. Visual outcomes were poor according to World Health Organization categories, with 55.8% of people and 73.1% of eyes having a presenting visual acuity of less than 3/60 and only 9.7% and 2.4% of people and eyes respectively having a good outcome (6/18 or better). None were wearing an aphakic correction, and with correction acuities improved but 42.6% of eyes were still blind (< 3/60). CONCLUSIONS: Couching is still widely practiced in Nigeria and visual outcomes are very poor. The population needs to be made aware of the risks associated with the procedure, and services for high quality, affordable cataract surgery need to be expanded, particularly in rural areas and in the north of the country

    Effects of static stretching on squat performance in Division I female athletes

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    International Journal of Exercise Science 9(3): 359-367, 2016. Static stretching was once recognized as a method of preparation for physical activity that would inhibit performance and increase risk of injury. However, a growing body of research suggests that static stretching may not have an inhibitory effect. Regardless, the data have not examined gender differences or the fatigue index (FI) and flexibility effects of static stretching on the back squat over multiple sets. Therefore, the purpose of this study was to examine the relationship between a static-stretch condition (SC) and control condition (CC) on flexibility and the FI of Division I female athletes during 4 sets of the back squat. Eighteen subjects (mean ± SD; age 20 ± 1 yrs; height 164.5 ± 14.6 cm; mass 74.1 ± 26.8 kg; waist circumference 73.2 ± 5.4 cm) participated in 3 testing days over the course of 3 weeks. Each subject’s 1RM back squat was assessed during the first day of testing and verified during the second. On the third testing day, subjects assigned to the SC held 3 lower-body stretches twice for 30 second intervals and those assigned to the CC rested during the corresponding 7 minutes and 50 second time period. The subjects also performed a fatiguing squat protocol consisting of 4 sets of maximum repetitions on the third day of testing. A significant (p=0.04) interaction was noted for flexibility. No significant interaction (p=0.41) was observed between the FI of the CC (41.8 ± 24.1%) or the SC (27.6 ± 45.2%). These results indicate that static stretching does not have a significant effect on multiple sets of the back squat. Therefore, coaches may allow their athletes to engage in static stretching prior to resistance exercise ad libitum
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