WorldWideScience

Sample records for bicycle commuting

  1. Bicycle Commuting

    OpenAIRE

    Heinen, E

    2011-01-01

    Cycling is cheaper, healthier and in urban environments often faster than other transport modes. Nevertheless, even at short distances, many individuals do not cycle. This thesis aims to explain why commuters vary in their decision to bicycle. Results indicate that the individual (day-to-day) choice to commute by bicycle is affected by personal attitudes towards cycling to work, social norms, work situation, weather conditions and trip characteristics. Additionally, this thesis provides evide...

  2. Commuter Transport Mode Choice and Typologies in the Bicycle City Copenhagen

    DEFF Research Database (Denmark)

    Olesen, Anne Vingaard; Kjems, Erik; Reinau, Kristian Hegner;

    2016-01-01

    Bicycle Cities” such as Copenhagen can serve as role models: how far can we push the commuter modal shares in the direction of more sustainable transport? This paper presents a study that aims to give a state-of-the-art picture of a Copenhagen that provides wide cycling highways and the political...... will to provide for even more bicycles. We found a ratio of 1:1 of car to bicycle in the greater Copenhagen area, whereas a ratio 2:5 of cars to bicycles existed in the central city - in terms of commuters who both live and work in the city center and who thus have an effective choice between modes due...

  3. Tertiary Student Attitudes to Bicycle Commuting in a Regional Australian University

    Science.gov (United States)

    Whannell, Patricia; Whannell, Robert; White, Richard

    2012-01-01

    Purpose: The purpose of this paper is to provide executive management at a regional university with empirical data to justify, or otherwise, a substantial outlay of funds to support bicycle commuting as a viable strategy for the reduction of traffic congestion. Design/methodology/approach: A custom designed questionnaire was completed by 270…

  4. Understanding adolescents' intentions to commute by car or bicycle as adults

    DEFF Research Database (Denmark)

    Sigurdardottir, Sigrun Birna; Kaplan, Sigal; Møller, Mette;

    2013-01-01

    This study focuses on the intentions of adolescents to commute by car or bicycle as adults. The behavioral model is based on intrapersonal and interpersonal constructs from the theory of planned behavior extended to include constructs from the institutional, community and policy domains. Data from...... a survey among Danish adolescents is analyzed. It is found that car use intentions are related to positive car passenger experience, general interest in cars, and car ownership norms, and are negatively related to willingness to accept car restrictions and perceived lack of behavioral control. Cycling...... intentions are related to positive cycling experience, willingness to accept car restrictions, negative attitudes towards cars, and bicycle-oriented future vision, and are negatively related to car ownership norms. Attitudinal constructs are related to individual characteristics, such as gender, residential...

  5. Exposure to carbon monoxide, respirable suspended particulates, and volatile organic compounds while commuting by bicycle

    International Nuclear Information System (INIS)

    A portable air sampling system has been used to assess exposures to various substances while commuting by bicycle in an urban area. The major source of pollutants in this situation is motor vehicle exhaust emissions. Carbon monoxide, measured by electrochemical detection, was found at peak concentrations in excess of 62 ppm, with mean values over 16 individual 35-mm journeys being 10.5 ppm. Respirable suspended particulates, averaged over each journey period, were found at higher concentrations (mean 130 μg m-3) than would be expected in indoor situations. Mean exposure to benzene (at 56 μg m-3) and other aromatic volatile organic compounds was also relatively high. The influence of wind conditions on exposure was found to be significant. Commuting exposures to carbon monoxide, respirable suspended particulates, and aromatic VOCs were found to be higher than exposures in a busy high street and on common parkland

  6. ‘We are the future’: understanding adolescents’ intentions to commute by car or bicycle as adults

    DEFF Research Database (Denmark)

    Sigurdardottir, Sigrun Birna; Kaplan, Sigal; Møller, Mette;

    This study focuses on the intentions of adolescents to commute by car or bicycle as adults, as key elements towards promoting societal transition towards sustainable modes. The behavioral model is based on the theory of planned behavior combined with positive current travel experience, willingness...... to accept car restrictions, transport-related future vision, environmental concern and social influence. Data are retrieved from a survey among 15-years old Danish adolescents, and are analyzed with structural equation models. Results show: (i) car use intentions are positively related to positive car...... passenger experience, general interest in cars, and car-ownership norms, and are negatively related to willingness to accept car restrictions and perceived lack of behavioral control; (ii) cycling intentions are positively related to positive cycling experience, willingness to accept car restrictions...

  7. Understanding adolescents' intentions to commute by car or bicycle as adults

    DEFF Research Database (Denmark)

    Sigurdardottir, Sigrun Birna; Kaplan, Sigal; Møller, Mette; Teasdale, Thomas William

    2013-01-01

    . Cycling intentions are related to positive cycling experience, willingness to accept car restrictions, negative attitudes towards cars, and bicycle-oriented future vision, and are negatively related to car ownership norms. Attitudinal constructs are related to individual characteristics, such as gender...

  8. Utility of an alternative bicycle commute route of lower proximity to motorised traffic in decreasing exposure to ultra-fine particles, respiratory symptoms and airway inflammation – a structured exposure experiment

    Science.gov (United States)

    2013-01-01

    Background Bicycle commuting in an urban environment of high air pollution is known to be a potential health risk, especially for susceptible individuals. While risk management strategies aimed to reduce exposure to motorised traffic emissions have been suggested, only limited studies have assessed the utility of such strategies in real-world circumstances. Objectives The potential to lower exposure to ultrafine particles (UFP; < 0.1 μm) during bicycle commuting by reducing proximity to motorised traffic was investigated with real-time air pollution and intermittent acute inflammatory measurements in healthy individuals using their typical higher proximity, and an alternative lower proximity, bicycle commute route. Methods Thirty-five healthy adults (mean ± SD: age = 39 ± 11 yr; 29% female) completed two return trips, one each in the condition of their typical route (HIGH) and a pre-determined alternative route of lower proximity to motorised traffic (LOW); proximity being determined by the proportion of on-road cycle paths. Particle number concentration (PNC) and diameter (PD) were monitored in-commute in real-time. Acute inflammatory indices of respiratory symptoms (as a scalar of frequency from very low to very high / 1 to 5), lung function and spontaneous sputum (for inflammatory cell analyses) were collected immediately pre-commute, and immediately and three hours post-commute. Results In the condition of LOW, compared to in the condition of HIGH, there was a significant decrease in mean PNC (1.91 x e4 ± 0.93 × e4 ppcc vs. 2.95 × e4 ± 1.50 × e4 ppcc; p ≤ 0.001), and the mean frequency of in-commute offensive odour detection (2.1 vs. 2.8; p = 0.019), dust and soot observation (1.7 vs. 2.3; p = 0.038) and nasopharyngeal irritation (1.5 vs. 1.9; p = 0.007). There were no significant differences between LOW and HIGH in the commute distance and duration (12.8 ± 7.1 vs. 12.0 ± 6.9 km and 44 ± 17 vs. 42 ± 17 min, respectively), or other indices of

  9. A Survey on Subway & Foldable Bicycle Commuting: A Case Study in Nanjing%地铁+折叠自行车通勤出行调查——以南京市为例

    Institute of Scientific and Technical Information of China (English)

    梁晶; 石飞; 祁毅; 陈曦

    2011-01-01

    为研究地铁+折叠自行车通勤方式的效果,以南京地铁为例对使用折叠自行车的乘客和普通乘客进行了现场调查和问卷调查.分析相关数据发现:地铁+折叠自行车的通勤方式在南京已获得了较好的实践及市民的广泛认可;与私人小汽车、公共汽车、自行车、地铁+步行等交通方式相比,更加节约出行时间和出行成本,也更加低碳.随着地铁线网的加密,地铁+折叠自行车通勤方式的服务范围可达主城区总面积的92%.为更好地推广这种健康环保的出行方式、鼓励更多的人使用公共交通,从城市及交通规划、设施配置、宣传引导三个层面提出了改进建议.%In order to study the effect of subway plus foldable bicycle commuting, a survey was conducted on subway passengers with and without foldable bicycle through questionnaires and interviews in Nanjing city subway. The results show that subway plus foldable bicycle has been recognized and accepted as a practical commuting travel mode by citizens. Comparing with other travel modes such as private car, bus, bicycle, and subway & walking, the combination of subway and foldable bicycle can reduce travel time and cost, and decrease carbon emission. With the subway network expansion, the subway & bicycle commuting travel can cover 92% Nanjing main urban areas. To better promote this health and environmental friendly travel mode, improvements in urban planning, transportation facility development and public policy are proposed by the paper to encourage high utilization of public transportation.

  10. Exercise bicycle for accumulator charging

    OpenAIRE

    Nekvapil, Jan

    2014-01-01

    Bachelor thesis is about possible solution construction of exercise bicycle with electric part working as a electric source. The first part of document introduces readers to issues about lead acid accumulators and charging, electronically commutated motors and electric converters. The second part shows potential solving constitution of exercise bicycle and we choose components and devices. EC motor will be connected with exercise bicycle by chain transmission. Transfer energy is realized thro...

  11. The influence of a bicycle commuter's appearance on drivers' overtaking proximities: an on-road test of bicyclist stereotypes, high-visibility clothing and safety aids in the United Kingdom.

    Science.gov (United States)

    Walker, Ian; Garrard, Ian; Jowitt, Felicity

    2014-03-01

    This study looked at whether drivers overtaking a bicyclist changed the proximities of their passes in response to the level of experience and skill signalled by the bicyclist's appearance. Seven outfits were tested, ranging from a stereotypical sport rider's outfit, portraying high experience and skill, to a vest with 'novice cyclist' printed on the back, portraying low experience. A high-visibility bicycling jacket was also used, as were two commercially available safety vests, one featuring a prominent mention of the word 'police' and a warning that the rider was video-recording their journey, and one modelled after a police officer's jacket but with a letter changed so it read 'POLITE'. An ultrasonic distance sensor recorded the space left by vehicles passing the bicyclist on a regular commuting route. 5690 data points fulfilled the criteria for the study and were included in the analyses. The only outfit associated with a significant change in mean passing proximities was the police/video-recording jacket. Contrary to predictions, drivers treated the sports outfit and the 'novice cyclist' outfit equivalently, suggesting they do not adjust overtaking proximity as a function of a rider's perceived experience. Notably, whilst some outfits seemed to discourage motorists from passing within 1m of the rider, approximately 1-2% of overtakes came within 50 cm no matter what outfit was worn. This suggests there is little riders can do, by altering their appearance, to prevent the very closest overtakes; it is suggested that infrastructural, educational or legal measures are more promising for preventing drivers from passing extremely close to bicyclists. PMID:24333770

  12. Revitalization of Cycling in a Former Bicycle Kingdom: Beijing

    DEFF Research Database (Denmark)

    Zhao, Chunli; Carstensen, Trine Agervig; Olafsson, Anton Stahl;

    This paper scrutinizes and analyses the relevant historical policy documents chronologically - from the 1960s to the present - in order to figure out the potentials of revitalizing the bicycle mode share in Beijing. Firstly, we targeted two top-drawer conflicts of the bicycle use, which are travel......- or commuting distance and motorised vehicle-oriented urban development. Secondly, we analysed how the various related policies resulted in the changing landscape of the bicycle mode share, including increasing in the bicycle mode share, created the conflicts and declined the bicycle mode share. The...

  13. Solar Bicycle

    OpenAIRE

    S. Sridhar; HARSHENDRA. N. SHET. K

    2011-01-01

    The running costs of the present vehicles are rising day by day hence common man is looking for an alternate mode of transport, with low fuel and maintenance cost. Solar bicycle is an attempt to meet these needs. It is an environmentally sustainable and zero running cost vehicle. It uses photovoltaic cells to absorb energy from sunlight. The absorbed energy is stored in battery. The hub motor mounted on the rear wheel uses this energy to run the cycle. A fully charged battery gives a mileage ...

  14. Bikeability and methodological issues using the active commuting route environment scale (ACRES) in a metropolitan setting

    OpenAIRE

    Schantz Peter; Wahlgren Lina

    2011-01-01

    Abstract Background Route environments can positively influence people's active commuting and thereby contribute to public health. The Active Commuting Route Environment Scale (ACRES) was developed to study active commuters' perceptions of their route environments. However, bicycle commuters represent a small portion of the population in many cities and thus are difficult to study using population-based material. Therefore, the aim of this study is to expand the state of knowledge concerning ...

  15. Solar Bicycle

    Directory of Open Access Journals (Sweden)

    SRIDHAR. S

    2011-07-01

    Full Text Available The running costs of the present vehicles are rising day by day hence common man is looking for an alternate mode of transport, with low fuel and maintenance cost. Solar bicycle is an attempt to meet these needs. It is an environmentally sustainable and zero running cost vehicle. It uses photovoltaic cells to absorb energy from sunlight. The absorbed energy is stored in battery. The hub motor mounted on the rear wheel uses this energy to run the cycle. A fully charged battery gives a mileage of 15-20 km. It is also provided with manual pedaling which increases the cycle’s mileage further. Average speed of the cycle is 15-18 kmph.

  16. Exploring Bikeability in a Suburban Metropolitan Area Using the Active Commuting Route Environment Scale (ACRES

    Directory of Open Access Journals (Sweden)

    Lina Wahlgren

    2014-08-01

    Full Text Available Background and Aim: Commuting by bicycle could contribute to public health, and route environments may influence this behaviour. Therefore, the aim of this study is to assess the potential associations between appraisals of the overall route environment as hindering or stimulating for bicycle commuting, with both perceptions of commuting route environmental factors in a suburban area and background factors. Methods: The Active Commuting Route Environment Scale (ACRES was used for the assessment of bicycle commuters’ perceptions and appraisals of their route environments in the suburban parts of Greater Stockholm, Sweden. A simultaneous multiple regression analysis was used to assess the relationship between the outcome variable whether the overall route environment hinders or stimulates bicycle commuting and environmental factors (e.g., exhaust fumes, speeds of motor vehicles, greenery, as well as background factors (sex, age, education, income as predictor variables. Results and Conclusions: The results indicate that in suburban areas, the factors aesthetics, greenery and bicycle paths seem to be, independently of each other, stimulating factors for bicycle commuting. On the other hand, flows of motor vehicles, noise, and low “directness” of the route seem to be hindering factors. A comparison of these results with those obtained from an inner urban area points to the importance of studying different types of built-up areas separately.

  17. Commutative Quaternion Matrices

    OpenAIRE

    Kösal, Hidayet Hüda; Tosun, Murat

    2013-01-01

    In this study, we introduce the concept of commutative quaternions and commutative quaternion matrices. Firstly, we give some properties of commutative quaternions and their Hamilton matrices. After that we investigate commutative quaternion matrices using properties of complex matrices. Then we de?ne the complex adjoint matrix of commutative quaternion matrices and give some of their properties.

  18. The Educational Bias in Commuting Patterns: Micro-Evidence for the Netherlands

    OpenAIRE

    Groot, S.P.T.; Groot, de, H.L.F.; Veneri, P.

    2012-01-01

    This study analyses the relation between education and commuting behaviour of Dutch workers. Results show that, ceteris paribus, higher educated workers commute further, both in terms of distance and time. In addition, higher educated workers are more frequent users of public transport and of bicycles. Furthermore, we find that higher educated workers are relatively more likely to commute towards agglomerated areas and areas that pay relatively high wages, while they are more likely to live i...

  19. Bicycle Detection System

    OpenAIRE

    Yu, James; Arellano , Secundino; Carrillo , Alma; Cruz , Melinda; Kunitskiy, Dmitriy; Maynigo , Marlo; Sell , Monica

    2013-01-01

    Project Description:  Bicycle detection has become a popular feature of high demand in cities and agencies across the United States. California has recently mandated that all new limit line detector installations as well as modifications to existing limit line detection must provide bicycle detection. This has created the need to develop detection methodologies which are able to detect bicycles as well as differentiate them from vehicles. The objective of this project is to utilize Econolite ...

  20. Recumbent bicycle design

    OpenAIRE

    Basso Puig, Carlos

    2014-01-01

    The subject of this project is the design of a recumbent bicycle prototype. A recumbent bike is a type of bicycle in which the rider mounts in a reclined position. In order to do this, we will learn about these bicycles by showing the different types there are, its evolution over the years, and so on. After that, it is shown the recumbent bicycle design and all its components. It has been invented the frame and so, it is explained the material choice, a brief anthropometric study and FE...

  1. Intervenção comunitária para prevenção de acidentes de trânsito entre trabalhadores ciclistas Intervención comunitaria para la prevención de accidentes de tránsito entre trabajadores ciclistas A community intervention to prevent traffic accidents among bicycle commuters

    Directory of Open Access Journals (Sweden)

    Giancarlo Bacchieri

    2010-10-01

    resultado.OBJECTIVE: To evaluate an educational intervention designed to prevent traffic accidents among workers that use the bicycle for commuting. METHODS: A longitudinal intervention study with a stepped wedge implementation was carried out between January 2006 and May 2007. Five neighborhoods with distinct geographic characteristics were selected in the city of Pelotas, Brazil, and 42 census tracts were randomly selected from these neighborhoods. All households were screened for male bicycle commuters, resulting in a sample of 1,133 individuals. The outcomes analyzed were "traffic accidents" and "near accidents". The cyclists were interviewed monthly by phone to record traffic accidents and "near accidents". Every 15 days, from the second month of study, a group of about 60 cyclists was invited to attend the intervention meeting that included an educational component (a talk and a video presentation, distribution of a safety kit (reflective belt & sash, reflective tape and an educational booklet and a bicycle breaks check-up (maintenance performed if necessary. Poisson regression adjusted for time effect was used to assess the intervention effect. RESULTS: Nearly 45% of the cyclists did not attend the intervention. During the study period, 9% of the study individuals reported a traffic accident and 88% reported a "near accident". In total there were 106 accidents and 1,091 near accidents. There was no effect observed from the intervention on either of the outcomes. CONCLUSIONS: The intervention tested was not capable of reducing traffic accidents among bicycle commuters. Lack of interest in safety by commuters and external factors, such as road design and motorist behavior, may have together influenced this result.

  2. Bicycle Promotion Plan

    Energy Technology Data Exchange (ETDEWEB)

    Simone, G. A.

    1981-03-09

    The objective of this Bicycle Promotion Plan is to outline a set of recommendations and supporting strategies for implementation by the US DOE toward increased use of the bicycle for energy conservation. The recommendations are designed in such a way as to function in concert with: (1) bicycle programs administered by other Federal government agencies; and (2) related programs and activities already sponsored by DOE. The approach to preparation of the Plan involved a review of all current and planned bicycle promotion programs at the Federal level as well as a review of the array of lierature on the subject. The UniWorld project staff also interacted with several DOE program offices, in order to determine the extent to which they might appropriately contribute to the implementation of bicycle promotional efforts. A synthesis of all the information gathered was published in January of 1981 as a part of the project (The Bicycle Program Review). Based upon this information and an examination of the barriers to bicycle use identified by bicycle transportation specialists in the field, UniWorld developed a series of the most potentially effective recommendations and program strategies for implementation by DOE. The recommendations address activities that could be undertaken in conjunction with existing DOE programs, new developments that might be considered to fulfill critical needs in the field, and interagency efforts that DOE could play a role in.

  3. Bicycles made to measure

    NARCIS (Netherlands)

    Van Dijk, T.

    2007-01-01

    For almost a century and a half, mathematicians have been racking their brains about the bike. How can a rolling bicycle be so stable of its own accord? Delft researchers now say they have completed the model to end all models. Bicycle manufacturer Batavus intends to use it to make better bikes for

  4. Bicycle Safety in Action.

    Science.gov (United States)

    National Commission on Safety Education, Washington, DC.

    This material was designed to assist schools in teaching bicycle safety. As the population grows and competition for road space increases, it is more imperative than ever that we concentrate attention on the need for caution among pupil cyclists. The pamphlet: (1) discusses the role of bicycle safety in classroom instruction and in student…

  5. Cyclists' attitudes toward policies encouraging bicycle travel: findings from the Taupo Bicycle Study in New Zealand.

    Science.gov (United States)

    Tin Tin, Sandar; Woodward, Alistair; Thornley, Simon; Langley, John; Rodgers, Anthony; Ameratunga, Shanthi

    2010-03-01

    Utility cycling provides substantial health, environmental and economic benefits. Despite a favourable trend in leisure-time cycling, cycling is infrequently used for everyday travel needs in New Zealand. This study investigated cyclists' attitudes toward environmental and policy measures that would encourage them to cycle more, particularly for a trip to work. A cross-sectional analysis was undertaken using baseline data obtained from the Taupo Bicycle Study, a web-based longitudinal study. The study population comprised 2469 cyclists, aged 16 years or over, who had enrolled in the 2006 Wattyl Lake Taupo Cycle Challenge. The majority (88%) reported the provision of bicycle lanes as an important factor that would encourage them to cycle more often, followed by bicycle paths (76%), better bicycle security (64%), reduced motor vehicle speed (55%) and bike friendly public transport (38%). Of those who reported travelling to work at least once a week (N = 2223), varying proportions reported shower facilities at work (61%), fewer difficult intersections (43%), rising fuel costs (41%), fewer car parks (27%), bike designed to commute (26%) and rising cost of car parking (25%) as important factors that would encourage them to cycle to work more often. There were important differences in these perceived influences defined by the participants' socio-demographic characteristics and current cycling habits. PMID:19850568

  6. Spectra for commutative algebraists

    OpenAIRE

    Greenlees, J. P. C.

    2006-01-01

    The article is designed to explain to commutative algebraists what spectra (in the sense of algebraic topology) are, why they were originally defined, and how they can be useful for commutative algebra.

  7. Butchers and Bicycles

    OpenAIRE

    Kahle, Lynn; Eriksen, Steen Mandsfelt

    2016-01-01

    Morten Wagener is a Danish design, and innovator who founded the cargo and personal transportation bicycle company, ”Butchers and Bicycles,”. He identified a business opportunity to improve the future of urban transport. His idea was that most of the trikes) on the market lacked good design, maneuverability and styling. With his engineering and design background, Wagener set out to design a new trike; which would meet the needs of the target market, which his research identified as well- educ...

  8. SHAPES: A new survey on accident risks and injuries in commuter cyclists in Belgium

    OpenAIRE

    de Geus, B.; Vandenbulcke, G.; Int Panis, Luc; Torfs, R; Degraeuwe, B.; I Thomas

    2009-01-01

    The health enhancing effects of regular bicycling (e.g. commuter cycling) are well known, however this health benefit has also a negative aspect especially when safety is neglected. Bicyclists have a higher risk of being injured than any other group of road users. They are “unprotected” in traffic, despite being capable of reaching high speeds. This increases the risk and severity of the injury. Bicycle related injury statistics from police, hospital and insurance statistics are well describe...

  9. Transition to a cyclable city: policies and variables affecting cycling commuting

    OpenAIRE

    Muñoz López, Begoña; López Suárez, Elena; Monzón de Cáceres, Andrés

    2014-01-01

    The growing interest in achieving the objectives of cycling policies has increased the need to know the key variables that influence the use of the bicycle for daily mobility. This paper makes a contribution in this research line by examining a varying nature of variables – objective and psychological - and their influence on cycling commuting in the context of a “climber cycling city”: Vitoria-Gasteiz (Spain). Statistical differences of the variables were determined between cycling commut...

  10. Bicycle Culture in Denmark

    OpenAIRE

    Pedersenn, Pia; Breitenstein, Marcus Lindgaard; Nilsson, Asbjørn Lupo

    2014-01-01

    The research area involves the cycling culture in Denmark. Cycling is one of the main forms of transport in Denmark today, and it has been a big part of Denmark’s culture since the early 20th century. This project specifically looks at bicycle helmets. Today in Denmark, there is no legislation demanding cyclists to wear helmets. However we would like to investigate what the government’s stance is concerning bicycle helmets. The project will begin by looking at the efficiency of helmets. Some ...

  11. Commutative combinatorial Hopf algebras

    OpenAIRE

    Hivert, F.; Novelli, J. -C.; Thibon, J. -Y.

    2006-01-01

    We propose several constructions of commutative or cocommutative Hopf algebras based on various combinatorial structures, and investigate the relations between them. A commutative Hopf algebra of permutations is obtained by a general construction based on graphs, and its non-commutative dual is realized in three different ways, in particular as the Grossman-Larson algebra of heap ordered trees. Extensions to endofunctions, parking functions, set compositions, set partitions, planar binary tre...

  12. Wages and commuting

    DEFF Research Database (Denmark)

    Mulalic, Ismir; Ommeren, Jos N. van; Pilegaard, Ninette

    2011-01-01

    income tax reductions associated with commuting do not apply, one kilometre increase in commuting distance induces a wage increase of about 0.42%, suggesting an hourly compensation of about half of the hourly net wage. Our findings are consistent with wage bargaining theory and suggest a bargaining power...

  13. Wages and commuting

    DEFF Research Database (Denmark)

    Mulalic, Ismir; Ommeren, Jos N. van; Pilegaard, Ninette

    2011-01-01

    We examine the causal effect of commuting distance on workers' wages in a quasi-natural experiments setting using information on all workers in Denmark. We account for endogeneity of distance by using changes in distance that are due to firms’ relocations. For the range of commuting distances whe...

  14. Butchers and Bicycles

    DEFF Research Database (Denmark)

    Kahle, Lynn; Eriksen, Steen Mandsfelt

    2016-01-01

    Morten Wagener is a Danish design, and innovator who founded the cargo and personal transportation bicycle company, ”Butchers and Bicycles,”. He identified a business opportunity to improve the future of urban transport. His idea was that most of the trikes) on the market lacked good design......, maneuverability and styling. With his engineering and design background, Wagener set out to design a new trike; which would meet the needs of the target market, which his research identified as well- educated individuals who were very interested in aesthetics. Furthermore, Wagener was convinced that trikes were...... between order and delivery. From a marketing perspective, one of the differentiating factors of Morten’s product is the quality of the ride (compared to competing products) and so his marketing team coined the slogan “Built-to-Tilt” because even though it’s a trike it feels like riding a two...

  15. Electric power generating bicycle

    OpenAIRE

    Brito, Nuno; Ribeiro, Luís; Esteves, João Sena

    2006-01-01

    It is manifest the growing interest in both personal health and environmental issues. The device described on this paper contemplates both aspects: generating environment-friendly electric power while keeping fit. A car alternator excited through a 12V battery is coupled to a mountain bicycle, and this arrangement enables the lighting of six halogen lamps, if a cyclist pedals fast enough. Such a machine gives rise to the thought of a self-powered gymnasium. Considerable physical effort is req...

  16. Envelopes of Commutative Rings

    Institute of Scientific and Technical Information of China (English)

    Rafael PARRA; Manuel SAOR(I)N

    2012-01-01

    Given a significative class F of commutative rings,we study the precise conditions under which a commutative ring R has an F-envelope.A full answer is obtained when.F is the class of fields,semisimple commutative rings or integral domains.When F is the class of Noetherian rings,we give a full answer when the Krull dimension of R is zero and when the envelope is required to be epimorphic.The general problem is reduced to identifying the class of non-Noetherian rings having a monomorphic Noetherian envelope,which we conjecture is the empty class.

  17. The yoga of commutators

    CERN Document Server

    Hazrat, R; Vavilov, N A; Zhang, Z

    2011-01-01

    In the present paper we discuss some recent versions of localisation methods for calculations in the groups of points of algebraic-like and classical-like groups. Namely, we describe relative localisation, universal localisation, and enhanced versions of localisation-completion. Apart from the general strategic description of these methods, we state some typical technical results of the conjugation calculus and the commutator calculus. Also, we state several recent results obtained therewith, such as relative standard commutator formulae, bounded width of commutators, with respect to the elementary generators, and nilpotent filtrations of congruence subgroups. Overall, this shows that localisation methods can be much more efficient, than expected.

  18. Non-commutative P-1-bundles over commutative schemes

    OpenAIRE

    Van den Bergh, Michel

    2012-01-01

    In this paper we develop the theory of non-commutative P-1-bundles over commutative (smooth) schemes. Such non-commutative P-1-bundles occur in the theory of D-modules but our definition is more general. We can show that every non-commutative deformation of a Hirzebruch surface is given by a non-commutative P-1-bundle over P-1 in our sense.

  19. The evaluation of bicycle paths on bridges

    OpenAIRE

    Wang, Hwa-chyi; De Backer, Hans; Lauwers, Dirk; Chang, SK Jason

    2016-01-01

    Bicycle accidents have increasingly caused casualties and property damage. Many countries have therefore started to pay more attention to designing the space of bicycle paths. However, few studies have focused on the design of bicycle continuity between each bicycle path. In this study, the concept of using both spatial crash probability (P) and crash severity index (CSI) is introduced to address the bicycle safety issue on bridges in Central Business Districts (CBDs). Bicycle paths on bridge...

  20. Commuter Survey-2014

    Data.gov (United States)

    US Agency for International Development — This dataset is the USAID portion of a larger dataset developed by OMB to better understand and to quanity the carbon footprint of the daily commute of government...

  1. How to commute

    CERN Document Server

    Aste, Andreas

    2013-01-01

    A simple exposition of the rarely discussed fact that a set of free boson fields describing different, i.e. kinematically different particle types can be quantized with mutual anticommutation relations is given by the explicit construction of the Klein transformations changing anticommutation relations into commutation relations. The analogous situation for two independent free fermion fields with mutual commutation or anticommutation relations is briefly investigated.

  2. Commutation and Darboux transformation

    Indian Academy of Sciences (India)

    M V Prabhakar; H Bhate

    2015-11-01

    In this paper we show that the Darboux transformation for a large class of nonlinear evolution equations arises due to factorization and commutation. The factorization and commutation has been pointed out earlier for Schrödinger operator. We show that it extends to a large class of nonlinear differential equations which admit Lax pairs including Boussinesq, Davey–Stewartson, Bogoyavlensky–Schiff and -wave interaction equation.

  3. Sequences of commutator operations

    CERN Document Server

    Aichinger, Erhard

    2012-01-01

    Given the congruence lattice L of a finite algebra A with a Mal'cev term, we look for those sequences of operations on L that are sequences of higher commutator operations of expansions of A. The properties of higher commutators proved so far delimit the number of such sequences: the number is always at most countably infinite; if it is infinite, then L is the union of two proper subintervals with nonempty intersection.

  4. The Bicycle Assembly Line Game

    Science.gov (United States)

    Klotz, Dorothy

    2011-01-01

    "The Bicycle Assembly Line Game" is a team-based, in-class activity that helps students develop a basic understanding of continuously operating processes. Each team of 7-10 students selects one of seven prefigured bicycle assembly lines to operate. The lines are run in real-time, and the team that operates the line that yields the…

  5. Computational commutative and non-commutative algebraic geometry

    CERN Document Server

    Cojocaru, S; Ufnarovski, V

    2005-01-01

    This publication gives a good insight in the interplay between commutative and non-commutative algebraic geometry. The theoretical and computational aspects are the central theme in this study. The topic is looked at from different perspectives in over 20 lecture reports. It emphasizes the current trends in commutative and non-commutative algebraic geometry and algebra. The contributors to this publication present the most recent and state-of-the-art progresses which reflect the topic discussed in this publication. Both researchers and graduate students will find this book a good source of information on commutative and non-commutative algebraic geometry.

  6. Bicycle Rider Control: Observations, Modeling & Experiments

    NARCIS (Netherlands)

    Kooijman, J.D.G.

    2012-01-01

    Bicycle designers traditionally develop bicycles based on experience and trial and error. Adopting modern engineering tools to model bicycle and rider dynamics and control is another method for developing bicycles. This method has the potential to evaluate the complete design space, and thereby dev

  7. Associations between bicycling and carotid arterial stiffness in adolescents: The European Youth Hearts Study.

    Science.gov (United States)

    Ried-Larsen, M; Grøntved, A; Østergaard, L; Cooper, A R; Froberg, K; Andersen, L B; Møller, N C

    2015-10-01

    The aim of the study was to investigate the associations between bicycling and carotid arterial stiffness, independent of objectively measured moderate-and-vigorous physical activity. This cross-sectional study included 375 adolescents (age 15.7 ± 0.4 years) from the Danish site of the European Youth Heart Study. Total frequency of bicycle usage was assessed by self-report, and carotid arterial stiffness was assessed using B-mode ultrasound. After adjusting for pubertal status, body height, and objectively measured physical activity and other personal lifestyle and demographic factors, boys using their bicycle every day of the week displayed a higher carotid arterial compliance {standard beta 0.47 [95% confidence interval (CI) 0.07-0.87]} and distension [standard beta 0.38 (95% CI -0.04 to 0.81)]. Boys using their bicycle every day of the week furthermore displayed a lower Young's elastic modulus [standard beta -0.48 (95% CI -0.91 to -0.06)]. Similar trends were observed when investigating the association between commuter bicycling and carotid arterial stiffness. These associations were not observed in girls. Our observations suggest that increasing bicycling in adolescence may be beneficial to carotid arterial health among boys. PMID:25156494

  8. [Prevention of bicycle accidents].

    Science.gov (United States)

    Zwipp, H; Barthel, P; Bönninger, J; Bürkle, H; Hagemeister, C; Hannawald, L; Huhn, R; Kühn, M; Liers, H; Maier, R; Otte, D; Prokop, G; Seeck, A; Sturm, J; Unger, T

    2015-04-01

    For a very precise analysis of all injured bicyclists in Germany it would be important to have definitions for "severely injured", "seriously injured" and "critically injured". By this, e.g., two-thirds of surgically treated bicyclists who are not registered by the police could become available for a general analysis. Elderly bicyclists (> 60 years) are a minority (10 %) but represent a majority (50 %) of all fatalities. They profit most by wearing a helmet and would be less injured by using special bicycle bags, switching on their hearing aids and following all traffic rules. E-bikes are used more and more (145 % more in 2012 vs. 2011) with 600,000 at the end of 2011 and are increasingly involved in accidents but still have a lack of legislation. So even for pedelecs 45 with 500 W and a possible speed of 45 km/h there is still no legislative demand for the use of a protecting helmet. 96 % of all injured cyclists in Germany had more than 0.5 ‰ alcohol in their blood, 86 % more than 1.1 ‰ and 59 % more than 1.7 ‰. Fatalities are seen in 24.2 % of cases without any collision partner. Therefore the ADFC calls for a limit of 1.1 ‰. Some virtual studies conclude that integrated sensors in bicycle helmets which would interact with sensors in cars could prevent collisions or reduce the severity of injury by stopping the cars automatically. Integrated sensors in cars with opening angles of 180° enable about 93 % of all bicyclists to be detected leading to a high rate of injury avoidance and/or mitigation. Hanging lamps reduce with 35 % significantly bicycle accidents for children, traffic education for children and special trainings for elderly bicyclists are also recommended as prevention tools. As long as helmet use for bicyclists in Germany rates only 9 % on average and legislative orders for using a helmet will not be in force in the near future, coming up campaigns seem to be necessary to be promoted by the Deutscher

  9. Design of an electric bicycle

    OpenAIRE

    Cabré Viñeta, Anna

    2010-01-01

    The purpose of this study is to make an electrical bicycle. As this bike has an electrical motor, it will not be used as a sport method, the main idea is to use it as a public transport so people can move from side to side of the city without traffic, without pollution and without getting tired. Once selected the purpose of the bicycle, it is necessary to take into account the main features that it must have. A bicycle used as a transport around the city needs to be easy to ...

  10. Generalized non-commutativity

    CERN Document Server

    Jafari, Abolfazl

    2015-01-01

    We obtain generalized spatial non-commutativity consists in other than the Minkowski space time. We develop coordinates non-commutativity into more general manifolds by exploiting the translator and its manipulated form in the quantum mechanics level. Also, we employed an established local framework on a tangent space time in order to consider all of the expansions in first order of the Riemann's curvature tensor. The important point of this article is to use the homomorphism between the Minkowski and pseudo Riemann's manifolds.

  11. Frobenius Splitting in Commutative Algebra

    OpenAIRE

    Smith, Karen E.; ZHANG, WENLIANG

    2014-01-01

    This is a survey of Frobenius splitting techniques in commutative algebra, based on the first author's lectures at the introductory workshop for the special year in commutative algebra at MSRI in fall 2012.

  12. Hyperholomorphic functions on commutative algebras

    OpenAIRE

    Pogorui, Anatoliy A.

    2006-01-01

    In this paper we study properties of hyperholomorphic functions on commutative finite algebras. It is investigated the Cauchy-Riemann type conditions for hyperholomorphic functions. We prove that a hyperholomorphic function on a commutative finite algebra can be expanded in a Taylor series. We also present a technique for computing zeros of polynomials in some commutative algebras.

  13. Design of Electric Bicycle Controller

    OpenAIRE

    Jie Cong

    2009-01-01

    This article introduces a sort of intelligent brushless DC motor driver and its concrete application in electric bicycle, and discusses the hardware and software design scheme of the controller, and realizes the speed control, over-current protection and battery under-voltage protection of the brushless DC motor. And the experiment result indicates that the control effect is good, and it could fulfill the application requirement of electric bicycle.

  14. Control for an Autonomous Bicycle

    OpenAIRE

    Getz, Neil H.; Marsden, J. E.

    1995-01-01

    The control of nonholonomic and underactuated systems with symmetry is illustrated by the problem of controlling a bicycle. We derive a controller which, using steering and rear-wheel torque, causes a model of a riderless bicycle to recover its balance from a near fall as well as converge to a time parameterized path in the ground plane. Our construction utilizes new results for both the derivation of equations of motion for nonholonomic systems with symmetry, as well as the control of undera...

  15. Workshop on Commutative Algebra

    CERN Document Server

    Simis, Aron

    1990-01-01

    The central theme of this volume is commutative algebra, with emphasis on special graded algebras, which are increasingly of interest in problems of algebraic geometry, combinatorics and computer algebra. Most of the papers have partly survey character, but are research-oriented, aiming at classification and structural results.

  16. Commutative dilation theory

    Czech Academy of Sciences Publication Activity Database

    Ambrozie, Calin-Grigore; Müller, Vladimír

    Basel: Springer, 2015 - (Alpay, D.), s. 1093-1124 ISBN 978-3-0348-0666-4 Institutional support: RVO:67985840 Keywords : commuting multioperator * dilation * von Neumann inequality Subject RIV: BA - General Mathematics http://link.springer.com/referenceworkentry/10.1007%2F978-3-0348-0667-1_58

  17. Bikeability and methodological issues using the active commuting route environment scale (ACRES in a metropolitan setting

    Directory of Open Access Journals (Sweden)

    Schantz Peter

    2011-01-01

    Full Text Available Abstract Background Route environments can positively influence people's active commuting and thereby contribute to public health. The Active Commuting Route Environment Scale (ACRES was developed to study active commuters' perceptions of their route environments. However, bicycle commuters represent a small portion of the population in many cities and thus are difficult to study using population-based material. Therefore, the aim of this study is to expand the state of knowledge concerning the criterion-related validity of the ACRES and the representativity using an advertisement-recruited sample. Furthermore, by comparing commuting route environment profiles of inner urban and suburban areas, we provide a novel basis for understanding the relationship between environment and bikeability. Methods Bicycle commuters from Greater Stockholm, Sweden, advertisement- (n = 1379 and street-recruited (n = 93, responded to the ACRES. Traffic planning and environmental experts from the Municipality of Stockholm (n = 24 responded to a modified version of the ACRES. The criterion-related validity assessments were based on whether or not differences between the inner urban and the suburban route environments, as indicated by the experts and by four existing objective measurements, were reflected by differences in perceptions of these environments. Comparisons of ratings between advertisement- and street-recruited participants were used for the assessments of representativity. Finally, ratings of inner urban and suburban route environments were used to evaluate commuting route environment profiles. Results Differences in ratings of the inner urban and suburban route environments by the advertisement-recruited participants were in accord with the existing objective measurements and corresponded reasonably well with those of the experts. Overall, there was a reasonably good correspondence between the advertisement- and street-recruited participants' ratings

  18. Simulation of Population-Based Commuter Exposure to NO2 Using Different Air Pollution Models

    Directory of Open Access Journals (Sweden)

    Martina S. Ragettli

    2014-05-01

    Full Text Available We simulated commuter routes and long-term exposure to traffic-related air pollution during commute in a representative population sample in Basel (Switzerland, and evaluated three air pollution models with different spatial resolution for estimating commute exposures to nitrogen dioxide (NO2 as a marker of long-term exposure to traffic-related air pollution. Our approach includes spatially and temporally resolved data on actual commuter routes, travel modes and three air pollution models. Annual mean NO2 commuter exposures were similar between models. However, we found more within-city and within-subject variability in annual mean (±SD NO2 commuter exposure with a high resolution dispersion model (40 ± 7 µg m−3, range: 21–61 than with a dispersion model with a lower resolution (39 ± 5 µg m−3; range: 24–51, and a land use regression model (41 ± 5 µg m−3; range: 24–54. Highest median cumulative exposures were calculated along motorized transport and bicycle routes, and the lowest for walking. For estimating commuter exposure within a city and being interested also in small-scale variability between roads, a model with a high resolution is recommended. For larger scale epidemiological health assessment studies, models with a coarser spatial resolution are likely sufficient, especially when study areas include suburban and rural areas.

  19. Employee commute options guidance

    International Nuclear Information System (INIS)

    The Clean Air Act Amendments of 1990 (CAAA) require severe and extreme ozone nonattainment areas and serious carbon monoxide nonattainment areas to establish programs aimed at reducing commute trips to the worksites of large employers. The concerns that lead to the inclusion of the Employee Commute Options (ECO) provision in the Act are that more people are driving than ever before and they are driving longer distances. The purpose of the guidance is to inform the affected State and local jurisdictions of the Clean Air Act requirement, to provide guidance on preparing an approvable State Implementation Plan (SIP) revision, and to discuss various approaches which may help areas achieve Clean Air Act targets through implementation strategies that are the least burdensome and costly to both affected employers and employees

  20. Multiple Commutator Formulas

    OpenAIRE

    Hazrat, R.; Zhang, Z.

    2011-01-01

    Let A be a quasi-finite R-algebra (i.e., a direct limit of module finite algebras) with identity. Let I_i, i=0,...,m, be two-sided ideals of A, \\GL_n(A,I_i) the principal congruence subgroup of level I_i in GL_n(A) and E_n(A,I_i) be the relative elementary subgroup of level I_i. We prove a multiple commutator formula [E_n(A,I_0),\\GL_n(A,I_1),& \\GL_n(A, I_2),..., \\GL_n(A, I_m)] = [E_n(A,I_0),E_n(A,I_1),E_n(A, I_2),..., E_n(A, I_m)], which is a broad generalization of the standard commutator fo...

  1. Probing deformed quantum commutators

    Science.gov (United States)

    Rossi, Matteo A. C.; Giani, Tommaso; Paris, Matteo G. A.

    2016-07-01

    Several quantum gravity theories predict a minimal length at the order of magnitude of the Planck length, under which the concepts of space and time lose their physical meaning. In quantum mechanics, the insurgence of such a minimal length can be described by introducing a modified position-momentum commutator, which in turn yields a generalized uncertainty principle, where the uncertainty on position measurements has a lower bound. The value of the minimal length is not predicted by theories and must be estimated experimentally. In this paper, we address the quantum bound to the estimability of the minimal uncertainty length by performing measurements on a harmonic oscillator, which is analytically solvable in the deformed algebra induced by the deformed commutation relations.

  2. The yoga of commutators

    OpenAIRE

    Hazrat, R.; Stepanov, A. V.; Vavilov, N. A.; Zhang, Z.

    2011-01-01

    In the present paper we discuss some recent versions of localisation methods for calculations in the groups of points of algebraic-like and classical-like groups. Namely, we describe relative localisation, universal localisation, and enhanced versions of localisation-completion. Apart from the general strategic description of these methods, we state some typical technical results of the conjugation calculus and the commutator calculus. Also, we state several recent results obtained therewith,...

  3. Exploring bikeability in a metropolitan setting: stimulating and hindering factors in commuting route environments

    Directory of Open Access Journals (Sweden)

    Wahlgren Lina

    2012-03-01

    Full Text Available Abstract Background Route environments may influence people's active commuting positively and thereby contribute to public health. Assessments of route environments are, however, needed in order to better understand the possible relationship between active commuting and the route environment. The aim of this study was, therefore, to assess the potential associations between perceptions of whether the route environment on the whole hinders or stimulates bicycle commuting and perceptions of environmental factors. Methods The Active Commuting Route Environment Scale (ACRES was used for the assessment of bicycle commuters' perceptions of their route environments in the inner urban parts of Greater Stockholm, Sweden. Bicycle commuters (n = 827 were recruited by advertisements in newspapers. Simultaneous multiple regression analyses were used to assess the relation between predictor variables (such as levels of exhaust fumes, noise, traffic speed, traffic congestion and greenery and the outcome variable (hindering - stimulating route environments. Two models were run, (Model 1 without and (Model 2 with the item traffic: unsafe or safe included as a predictor. Results Overall, about 40% of the variance of hindering - stimulating route environments was explained by the environmental predictors in our models (Model 1, R2 = 0.415, and Model 2, R 2= 0.435. The regression equation for Model 1 was: y = 8.53 + 0.33 ugly or beautiful + 0.14 greenery + (-0.14 course of the route + (-0.13 exhaust fumes + (-0.09 congestion: all types of vehicles (p ≤ 0.019. The regression equation for Model 2 was y = 6.55 + 0.31 ugly or beautiful + 0.16 traffic: unsafe or safe + (-0.13 exhaust fumes + 0.12 greenery + (-0.12 course of the route (p ≤ 0.001. Conclusions The main results indicate that beautiful, green and safe route environments seem to be, independently of each other, stimulating factors for bicycle commuting in inner urban areas. On the other hand, exhaust

  4. Valuing public investments to support bicycling

    OpenAIRE

    Götschi, Thomas; Hintermann, Beat

    2014-01-01

    We develop a framework for assessing the net benefits of investments to promote bicycling, which explicitly accounts for internal costs of bicycling. We apply our model to eight Swiss cities using data from the Swiss national travel survey and find that increasing the level of bicycling by reducing internal costs leads to inframarginal benefits that exceed the net benefits from the additional bicycling.  We further find that Swiss cyclists only partially internalize health benefits, which aff...

  5. 45 CFR 3.27 - Bicycles.

    Science.gov (United States)

    2010-10-01

    ... 45 Public Welfare 1 2010-10-01 2010-10-01 false Bicycles. 3.27 Section 3.27 Public Welfare DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL ADMINISTRATION CONDUCT OF PERSONS AND TRAFFIC ON THE NATIONAL INSTITUTES OF HEALTH FEDERAL ENCLAVE Traffic Regulations § 3.27 Bicycles. A person may not operate a bicycle, motorbike, or similar vehicle...

  6. 36 CFR 13.1324 - Bicycles.

    Science.gov (United States)

    2010-07-01

    ... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Bicycles. 13.1324 Section 13.1324 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL... (egda) § 13.1324 Bicycles. Within the EGDA, the use of a bicycle is prohibited except on the...

  7. 36 CFR 13.1126 - Bicycles.

    Science.gov (United States)

    2010-07-01

    ... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Bicycles. 13.1126 Section 13.1126 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL... § 13.1126 Bicycles. Use of a bicycle is prohibited on the Forest Loop, Bartlett River and Bartlett...

  8. Radar channel balancing with commutation

    Energy Technology Data Exchange (ETDEWEB)

    Doerry, Armin Walter [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2014-02-01

    When multiple channels are employed in a pulse-Doppler radar, achieving and maintaining balance between the channels is problematic. In some circumstances the channels may be commutated to achieve adequate balance. Commutation is the switching, trading, toggling, or multiplexing of the channels between signal paths. Commutation allows modulating the imbalance energy away from the balanced energy in Doppler, where it can be mitigated with filtering.

  9. EP BICYCLE POOL - VIGNETTES 2002

    CERN Multimedia

    EP-SMI Help Desk

    2002-01-01

    The vignettes (insurance certificates) for 2002 become obligatory from 1 June. If you have a bicycle from the EP Pool, please bring it to the EP-SMI Help Desk (Building 124) on any working day up to 31 May between 8h.30 - 12h.00 or 13h.30 - 17h.30. EP-SMI Help Desk

  10. Challenges in Computational Commutative Algebra

    OpenAIRE

    Abbott, John

    2006-01-01

    In this paper we consider a number of challenges from the point of view of the CoCoA project one of whose tasks is to develop software specialized for computations in commutative algebra. Some of the challenges extend considerably beyond the boundary of commutative algebra, and are addressed to the computer algebra community as a whole.

  11. "Bicycles May Use Full Lane" Signage Communicates U.S. Roadway Rules and Increases Perception of Safety.

    Directory of Open Access Journals (Sweden)

    George Hess

    Full Text Available Many global challenges, including obesity, health care costs, and climate change, could be addressed in part by increasing the use of bicycles for transportation. Concern about the safety of bicycling on roadways is frequently cited as a deterrent to increasing bicycle use in the USA. The use of effective signage along roadways might help alleviate these concerns by increasing knowledge about the rights and duties of bicyclists and motorists, ideally reducing crashes. We administered a web-based survey, using Twitter for recruitment, to examine how well three US traffic control devices communicated the message that bicyclists are permitted in the center of the travel lane and do not have to "get out of the way" to allow motorists to pass without changing lanes: "Bicycles May Use Full Lane" and "Share the Road" signage, and Shared Lane Markings on the pavement. Each was compared to an unsigned roadway. We also asked respondents whether it was safe for a bicyclist to occupy the center of the travel lane. "Bicycles May Use Full Lane" signage was the most consistently comprehended device for communicating the message that bicyclists may occupy the travel lane and also increased perceptions of safety. "Share the Road" signage did not increase comprehension or perceptions of safety. Shared Lane Markings fell somewhere between. "Bicycles May Use Full Lane" signage showed notable increases in comprehension among novice bicyclists and private motor vehicle commuters, critical target audiences for efforts to promote bicycling in the USA. Although limited in scope, our survey results are indicative and suggest that Departments of Transportation consider replacing "Share the Road" with "Bicycles May Use Full Lane" signage, possibly combined with Shared Lane Markings, if the intent is to increase awareness of roadway rights and responsibilities. Further evaluation through virtual reality simulations and on-road experiments is merited.

  12. Combinatorics and commutative algebra

    CERN Document Server

    Stanley, Richard P

    1996-01-01

    Some remarkable connections between commutative algebra and combinatorics have been discovered in recent years. This book provides an overview of two of the main topics in this area. The first concerns the solutions of linear equations in nonnegative integers. Applications are given to the enumeration of integer stochastic matrices (or magic squares), the volume of polytopes, combinatorial reciprocity theorems, and related results. The second topic deals with the face ring of a simplicial complex, and includes a proof of the Upper Bound Conjecture for Spheres. An introductory chapter giving background information in algebra, combinatorics and topology broadens access to this material for non-specialists. New to this edition is a chapter surveying more recent work related to face rings, focusing on applications to f-vectors. Included in this chapter is an outline of the proof of McMullen's g-conjecture for simplicial polytopes based on toric varieties, as well as a discussion of the face rings of such special ...

  13. Probing quantum commutators

    CERN Document Server

    Rossi, Matteo A C; Paris, Matteo G A

    2016-01-01

    Quantum gravity theories predict a minimal length at the order of magnitude of the Planck length, under which the concepts of space and time lose every physical meaning. In quantum mechanics, the insurgence of such minimal length can be described by introducing a modified position-momentum commutator, which in turn yields a generalized uncertainty principle, where the uncertainty on the position measurement has a lower bound. The value of the minimal length is not predicted by theories and must be evaluated experimentally. In this paper, we address the quantum bound to estimability of the minimal uncertainty length by performing measurements on a harmonic oscillator, which is analytically solvable in the deformed algebra of the Hilbert subspace.

  14. Macroscopic modeling of pedestrian and bicycle crashes: A cross-comparison of estimation methods.

    Science.gov (United States)

    Amoh-Gyimah, Richard; Saberi, Meead; Sarvi, Majid

    2016-08-01

    The paper presents a cross-comparison of different estimation methods to model pedestrian and bicycle crashes. The study contributes to macro level safety studies by providing further methodological and empirical evidence on the various factors that influence the frequency of pedestrian and bicycle crashes at the planning level. Random parameter negative binomial (RPNB) models are estimated to explore the effects of various planning factors associated with total, serious injury and minor injury crashes while accounting for unobserved heterogeneity. Results of the RPNB models were compared with the results of a non-spatial negative binomial (NB) model and a Poisson-Gamma-CAR model. Key findings are, (1) the RPNB model performed best with the lowest mean absolute deviation, mean squared predicted error and Akaiki information criterion measures and (2) signs of estimated parameters are consistent if these variables are significant in models with the same response variables. We found that vehicle kilometers traveled (VKT), population, percentage of commuters cycling or walking to work, and percentage of households without motor vehicles have a significant and positive correlation with the number of pedestrian and bicycle crashes. Mixed land use is also found to have a positive association with the number of pedestrian and bicycle crashes. Results have planning and policy implications aimed at encouraging the use of sustainable modes of transportation while ensuring the safety of pedestrians and cyclist. PMID:27209153

  15. Characterisation of Electric Bicycles Performances

    OpenAIRE

    Cappelle, Jan; Lataire, Philippe; Maggetto, Gaston; Meeusen, Roman; Kempenaers, Farid

    2002-01-01

    The proposed paper reports on characterisation work performed in the scope of the E-tour project. This project has already been presented at EVS-18. At the ‘Vrije Universiteit Brussel’ different EPACs (Electric Power Assisted Cycles) are put at the public’s disposal for testing. To quantify the performances of these electrical bicycles we want to link the subjective experienced driving comfort to some measurable objective parameters. For this purpose we converted a treadmill in...

  16. Topics in commutative ring theory

    CERN Document Server

    Watkins, John J

    2009-01-01

    Topics in Commutative Ring Theory is a textbook for advanced undergraduate students as well as graduate students and mathematicians seeking an accessible introduction to this fascinating area of abstract algebra. Commutative ring theory arose more than a century ago to address questions in geometry and number theory. A commutative ring is a set-such as the integers, complex numbers, or polynomials with real coefficients--with two operations, addition and multiplication. Starting from this simple definition, John Watkins guides readers from basic concepts to Noetherian rings-one of

  17. Commutative and Non-commutative Parallelogram Geometry: an Experimental Approach

    OpenAIRE

    Bertram, Wolfgang

    2013-01-01

    By "parallelogram geometry" we mean the elementary, "commutative", geometry corresponding to vector addition, and by "trapezoid geometry" a certain "non-commutative deformation" of the former. This text presents an elementary approach via exercises using dynamical software (such as geogebra), hopefully accessible to a wide mathematical audience, from undergraduate students and high school teachers to researchers, proceeding in three steps: (1) experimental geometry, (2) algebra (linear algebr...

  18. Commutative and Non-commutative Parallelogram Geometry: en Experimental Approach

    OpenAIRE

    Bertram, Wolfgang

    2013-01-01

    By ''parallelogram geometry'' we mean the elementary, ''commutative'', geometry corresponding to vector addition, and by ''trapezoid geometry'' a certain ''non-commutative deformation'' of the former. This text presents an elementary approach via exercises using dynamical software (such as geogebra), hopefully accessible to a wide mathematical audience, from undergraduate students and high school teachers to researchers, proceeding in three steps: (1) experimental geometry, (2) algebra (linea...

  19. Approximate double commutants in von Neumann algebras

    OpenAIRE

    Hadwin, Don

    2011-01-01

    Richard Kadison showed that not every commutative von Neumann subalgebra of a factor von Neumann algebra is equal to its relative double commutant. We prove that every commutative C*-subalgebra of a centrally prime C*-algebra $B$ equals its relative approximate double commutant. If $B$ is a von Neumann algebra, there is a related distance formula.

  20. Intelligent Power Assist Algorithms for Electric Bicycles

    OpenAIRE

    Fan, Xuan

    2010-01-01

    This dissertation considers intelligent power-assist algorithm designs for electric bicycles. Traditional electric power-assist bicycles (EPBs) employ proportional power-assist strategy. The ratio is usually set to 1:1, which means that the motor will provide the same amount of assistive torque as the amount of the human's pedaling torque. This strategy is too rigid and does not consider the interaction between the bicycle, the human and the environment. Intelligent power-assist algorithms ar...

  1. Bicycle lessons, activity participation and empowerment

    OpenAIRE

    Kloof, A. van der; Bastiaanssen, K.; Martens, C.J.C.M.

    2014-01-01

    This paper addresses the impact of bicycle lessons for immigrant and refugee women on bicycle use and activity participation. Especially non-Western immigrant and refugee women have been identified as one of the population groups most likely to experience accessibility problems and, subsequently, transport-related social exclusion. The bicycle offers considerable potential to increase the mobility of these women. Hence, in the Netherlands and elsewhere, governments and non-governmental organi...

  2. Autonomous Bicycle: The First Self Balanced Ride

    OpenAIRE

    Ånnestad, Dag Christian

    2011-01-01

    The idea of an autonomous bicycle originates from Jens G. Balchen who wanted to make an unmanned autonomous bicycle. The idea was picked up by Amund Skavhaug who extended the idea with the concept of using an inverted pendulum to simulate a leaning rider. The previous attempts to develop a bicycle capable of performing an autonomous ride has so far all ended in failure. The main reason for the Department of Engineering Cybernetics is to develop such a bicycle is for use in recruitment and mot...

  3. Opechowski's theorem and commutator groups

    International Nuclear Information System (INIS)

    It is shown that the conditions of application of Opechowski's theorem for double groups of subgroups of O(3) are directly associated to the structure of their commutator groups. Some characteristics of the structure of classes are also discussed. (Author)

  4. A dynamic model of commutes

    OpenAIRE

    Vlist, van der, Kevin; Rouwendal, J.

    2002-01-01

    This paper studies the interaction between commuting, job mobility, and housing mobility. Many conventional models assume that the employment location has priority over the residential location and that the latter is adapted to the former. This implies that commutes which start with a job change will often be short lived because of a change in residential location that soon follows. It is also often supposed that the change in residential location is made with the intention to avoid long comm...

  5. Users, uses and potential of electric-assisted bicycles - Results of a survey in the Canton of Geneva; Usagers, usages et potentiel des velos a assistance electrique. Resultats d'une enquete menee dans le canton de Geneve

    Energy Technology Data Exchange (ETDEWEB)

    Bernardoni, S.; Iseli, A.; Munafo, S.

    2009-12-15

    The municipal, regional and national authorities wanted to assess the potential of electric-assisted bicycles in the Geneva region. A survey performed by the University of Geneva is reported. The following points were investigated: (i) Who uses an electric bicycle? (ii) How is an electric bicycle used? (iii) Why is an electric bicycle purchased? (iv) How many people could potentially use an electric bicycle in the Geneva region? (v) How much energy would be saved and what fraction of the carbon dioxide emissions would be avoided thanks to electric bicycles in the region? Some interesting results: Most current electric bicycle users are women and live in Geneva outskirts. Most users have an academic degree or equivalent and have a good job. Most of them have also a car and other bicycles without electric motor. The main uses of electric bicycles is commuting between house and job locations, leisure activities and shopping. The average annual distance per electric bicycle is about 3000 km. The majority of the electric bicycles in use are limited to 25 km/h and can be driven without any license. The users wish an extension of the bicycle track network along the roads and of the protected parking areas. The number of potential users in the City of Geneva is estimated to 9% or 15,600 new users and to 10% or 43,000 new users in the suburbs. In 2030, 7,500,000 litres-equivalent of gasoline could be annually saved in the region and more than 16,000 tons CO{sub 2} emissions avoided.

  6. 36 CFR 13.914 - Bicycle use.

    Science.gov (United States)

    2010-07-01

    ... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Bicycle use. 13.914 Section 13.914 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL... in public parking areas, or on trails and areas designated for bicycle use by the Superintendent....

  7. A study on electric bicycle energy efficiency

    Directory of Open Access Journals (Sweden)

    Ivan EVTIMOV

    2015-09-01

    Full Text Available The paper presents a construction of an experimental electric bicycle for evaluation of the energy efficiency. The bicycle is equipped with onboard computer which can store the information about motion and energy consumption. The result concerning power, energy consumption, recharging during brake process, etc. are given. Energy consumption for 3 typical city routes is studied.

  8. Bicycle parking preferences: costs versus walking time

    NARCIS (Netherlands)

    Molin, E.J.E.; Maat, K.

    2014-01-01

    Successful bicycle stimulating policies may increase the need for bicycle parking capacity, especially at main railway stations located in city centers. A potential solution for this problem involves combining paid surveyed indoor parking near the platforms and free open-air parking without surveill

  9. Bicycle helmet use and bicycling-related injury among young Canadians: an equity analysis

    Science.gov (United States)

    2013-01-01

    Introduction Cycling is a major activity for adolescents in Canada and potential differences exist in bicycling-related risk and experience of injury by population subgroup. The overall aim of this study was to inform health equity interventions by profiling stratified analytic methods and identifying potential inequities associated with bicycle-related injury and the use of bicycle helmets among Canadian youth. The two objectives of this study were: (1) To examine national patterns in bicycle ridership and also bicycle helmet use among Canadian youth in a stratified analysis by potentially vulnerable population subgroups, and (2) To examine bicycling-related injury in the same population subgroups of Canadian youth in order to identify possible health inequities. Methods Data for this study were obtained from the 6th cycle (2009/10) of the Health Behaviour in School-aged Children (HBSC) study, which is a general health survey that was completed by 26,078 students in grades 6–10 from 436 Canadian schools. Based on survey responses, we determined point prevalence for bicycle ridership, bicycle helmet use and relative risks for bicycling-related injury. Results Three quarters of all respondents were bicycle riders (n=19,410). Independent factors associated with bicycle ridership among students include being male, being a younger student, being more affluent, and being a resident of a small town. Among bicycle riders, 43% (95%CI ± 0.6%) reported never wearing and 32% (± 0.6%) inconsistently wearing a helmet. Only 26% (± 0.5%) of students reported always wearing a bicycle helmet. Helmets were less frequently used among older students and there were also important patterns by sex, geographic location and socioeconomic status. Adjusting for all other demographic characteristics, boys reported 2.02-fold increase (95% CI: 1.61 to 1.90) and new immigrants a 1.35-fold increase (95%CI: 1.00 to1.82) in the relative risk of bicycling-related injury in the past 12 months

  10. Beijing Bicycle - Stories from a Transformative Space

    DEFF Research Database (Denmark)

    Bagger-Petersen, Mai Corlin

    2012-01-01

    production of space that reveals how transnational and translocal mechanisms affect the cinematic language, transforming the images and stories chosen for the cinematic representation. Wang Xiaoshuai’s Beijing Bicycle (Shiqi Sui de Danche) (2001) is a result of transnational currents weaving the carpet of...... the global. Beijing Bicycle is thematically similar to Vittorio de Sicas neorealist classic Bicycle Thieves (1948) and Akira Kurosawas filmnoir classic Stray Dog (1949). Both films describe a disillusioned post-war society in an impoverished Italy and a humiliated Japan respectively. The stories told...... Xiaoshuai’s Beijing Bicycle can be understood as the result of stories-so-far, as the cinematic representation of the globalized ”space” within the setting of the national. Beijing Bicycle is a production of space as well as a space of production, since it tells a new story in the trajectory of stories...

  11. STRESS ANALYSIS OF BICYCLE FRAME

    Directory of Open Access Journals (Sweden)

    Mr.M.V.Pazare

    2014-06-01

    Full Text Available This paper deals with the stress analysis of bicycle frame by using Finite Element Method. The analysis is carried out in Ansys, The F.E.A. results are compared with theoretical results. In theoretical analysis the frame is treated as truss like structure and the stresses in various members of frame like top tube, down tube, seat tube, chain stay and seat stay are determined, considering various condition like, static start up, steady state paddling, vertical impact, horizontal impact, rear wheel braking. Also Finite Element Analysis is done considering the above conditions. From the analysis it is found that there is a good agreement between analytical and F.E.A. results. Result of all the cases reveals that maximum stress is found in top tube of the bicycle frame as compared to other frame members and is equal to 24.84 MPa which is less than yield strength in tension (i.e.Syt = 290 MPa for the material (aluminum T 6061 selected.

  12. Modeling Obstruction and Restoration of Urban Commutation Networks in the Wake of a Devastating Earthquake in Tokyo

    Directory of Open Access Journals (Sweden)

    Toshihiro Osaragi

    2015-07-01

    Full Text Available In the aftermath of a devastating earthquake, public transportation is presumed paralyzed and thus unavailable; large numbers of people are expected to experience difficulty in commuting. In recent years, implementation of district continuity plans (DCPs and business continuity plans (BCPs has become a major concern for local governments and private firms, respectively. In this paper, we propose a pair of simulation models seeking to examine business commutation networks in terms of their possible obstruction and eventual restoration. The first of these model commuting intentions by analyzing individual daily commutes. The second offers a mobility model of commuters’ physical endurance for travel alternatives on foot or by bicycle. Next, we proceed to gauge the number of commuters likely to experience difficulty and adjudge their spatial distribution while taking into account such attributes as gender and employment. Lastly, we attempt to assess rates and patterns in the reduction of commutation constraints based on simulations that assume a restoration of rail infrastructure or its equivalent.

  13. Johnson Space Center's Free Range Bicycle Program.- Fall 2015 Intern Report

    Science.gov (United States)

    Lee-Stockton, Willem

    2015-01-01

    NASA's Johnson Space Center is a big place, encompassing 1,620 acres and more than a hundred buildings. Furthermore, there are reportedly 15 thousand employees, all of which have somewhere to be. To facilitate the movement of all these people JSC has historically relied on human power. Pedaling their way towards deep space, bicycles have been the go to method. Currently there are about 200 Free Range Bicycles at JSC. Free Range Bicycles belong to nobody, except NASA, and are available for anybody to use. They are not to be locked or hidden (although frequently are) and the intention is that there will always be a bike to hop on to get where you're going (although it may not be the bike you rode in on). Although not without its own shortcomings, the Free Range Bicycle Program has continued to provide low cost, simple transportation for NASA's JSC. In addition to the approximately 200 Free Range Bicycles, various larger divisions (like engineering) will often buy a few dozen bikes for their team members to use or individuals will bring their own personal bike to either commute or use on site. When these bicycles fall into disrepair or are abandoned (from retirees etc) they become a problem at JSC. They are an eye sore, create a safety hazard and make it harder to find a working bike in a time of need. The Free Range Program hopes to address this first problem by "tagging out" abandoned or out of service bicycles. A bright orange "DO NOT OPERATE" tag is placed on the bike and given a serial number for tracking purposes. See picture to the right. If the bike has an active owner with intentions to repair the bike the bottom of the tag has instructions for how to claim the abandoned bicycle. After being tagged the owner of the bicycle has 30 days to claim the bicycle and either haul it off site or get it repaired (and labeled) in accordance with Johnson's Bicycle Policy. If the abandoned bicycle is not claimed within 30 days it becomes the property of the Government. The

  14. P-commutative topological *-algebras

    International Nuclear Information System (INIS)

    If P(A) denotes the set of all continuous positive functionals on a unital complete Imc *-algebra and S(A) the extreme points of P(A), and if the spectrum of an element χ Ε A coincides with the set {f(χ): f Ε S(A)}, then A is shown to be P-commutative. Moreover, if A is unital symmetric Frechet Q Imc *-algebra, then this spectral condition is, in fact, necessary. Also, an isomorphism theorem between symmetric Frechet P-commutative Imc *-algebras is established. (author). 12 refs

  15. On CNC Commuting Contractive Tuples

    Indian Academy of Sciences (India)

    T Bhattacharyya; J Eschmeier; J Sarkar

    2006-08-01

    The characteristic function has been an important tool for studying completely non-unitary contractions on Hilbert spaces. In this note, we consider completely non-coisometric contractive tuples of commuting operators on a Hilbert space $\\mathcal{H}$. We show that the characteristic function, which is now an operator-valued analytic function on the open Euclidean unit ball in $\\mathbb{C}^n$, is a complete unitary invariant for such a tuple. We prove that the characteristic function satisfies a natural transformation law under biholomorphic mappings of the unit ball. We also characterize all operator-valued analytic functions which arise as characteristic functions of pure commuting contractive tuples.

  16. Duality for commutative group stacks

    OpenAIRE

    Brochard, Sylvain

    2014-01-01

    We study in this article the dual of a (strictly) commutative group stack $G$ and give some applications. Using the Picard functor and the Picard stack of $G$, we first give some sufficient conditions for $G$ to be dualizable. Then, for an algebraic stack $X$ with suitable assumptions, we define an Albanese morphism $a_X : X\\to A^1(X)$ where $A^1(X)$ is a torsor under the dual commutative group stack $A^0(X)$ of $Pic_{X/S}$. We prove that $a_X$ satisfies a natural universal property. We give ...

  17. Differential operators on non-commutative algebras

    OpenAIRE

    Hazewinkel, Michiel

    2013-01-01

    There is a relatively well-known description of the algebra of (higher order) left differential operators on commutative algebras. This note gives a construction of similar flavor for algebras of differential operators on not necessarily commutative algebras.

  18. Commutative subalgebras of the Grassmann algebra

    OpenAIRE

    Domokos, M.; Zubor, M.

    2014-01-01

    The maximal dimension of a commutative subalgebra of the Grassmann algebra is determined. It is shown that for any commutative subalgebra there exists a commutative subalgebra which is spanned by monomials and has the same dimension. It follows that the maximal dimension of a commutative subalgebra can be expressed in terms of the maximal size of an intersecting system of subsets of odd size in a finite set.

  19. Survey of options on legalizing bicycling (VB)

    DEFF Research Database (Denmark)

    Zwahlen, Jurg; Sulewski, Sharon; Sacovitch, Stephen;

    1999-01-01

    opposition against the proposal was.The goal of this project was to identify categories of users that were opposed to bicycling on the Dosseringen of the Østerbro and Nørrebro District lakes in Copenhagen. The identification of the opposition and its strength, rationale and organization was in terms of age......, gender, residency, frequency of use and their utilization of the area (i.e. walking, jogging, bicycling) as compared to the support for bicycling in the area. This was an Interactive Qualifying Project (IQP), that was designed to merge technical and scientific knowledge with society, and stresses the...

  20. Non-commutative and commutative vacua effects in a scalar torsion scenario

    Directory of Open Access Journals (Sweden)

    Haidar Sheikhahmadi

    2015-10-01

    Full Text Available In this work, the effects of non-commutative and commutative vacua on the phase space generated by a scalar field in a scalar torsion scenario are investigated. For both classical and quantum regimes, the commutative and non-commutative cases are compared. To take account the effects of non-commutativity, two well known non-commutative parameters, θ and β, are introduced. It should be emphasized, the effects of β which is related to momentum sector has more key role in comparison to θ which is related to space sector. Also the different boundary conditions and mathematical interpretations of non-commutativity are explored.

  1. Segal algebras in commutative Banach algebras

    OpenAIRE

    INOUE, Jyunji; TAKAHASI, Sin-Ei

    2014-01-01

    The notion of Reiter's Segal algebra in commutative group algebras is generalized to a notion of Segal algebra in more general classes of commutative Banach algebras. Then we introduce a family of Segal algebras in commutative Banach algebras under considerations and study some properties of them.

  2. 8 CFR 211.5 - Alien commuters.

    Science.gov (United States)

    2010-01-01

    ... 8 Aliens and Nationality 1 2010-01-01 2010-01-01 false Alien commuters. 211.5 Section 211.5 Aliens...: IMMIGRANTS; WAIVERS § 211.5 Alien commuters. (a) General. An alien lawfully admitted for permanent residence.... An alien commuter engaged in seasonal work will be presumed to have taken up residence in the...

  3. A study of commuter airline economics

    Science.gov (United States)

    Summerfield, J. R.

    1976-01-01

    Variables are defined and cost relationships developed that describe the direct and indirect operating costs of commuter airlines. The study focused on costs for new aircraft and new aircraft technology when applied to the commuter airline industry. With proper judgement and selection of input variables, the operating costs model was shown to be capable of providing economic insight into other commuter airline system evaluations.

  4. Database improvements for motor vehicle/bicycle crash analysis

    OpenAIRE

    Lusk, Anne C; Asgarzadeh, Morteza; Farvid, Maryam S

    2015-01-01

    Background: Bicycling is healthy but needs to be safer for more to bike. Police crash templates are designed for reporting crashes between motor vehicles, but not between vehicles/bicycles. If written/drawn bicycle-crash-scene details exist, these are not entered into spreadsheets. Objective: To assess which bicycle-crash-scene data might be added to spreadsheets for analysis. Methods: Police crash templates from 50 states were analysed. Reports for 3350 motor vehicle/bicycle crashes (2011) w...

  5. A Sociological Analysis of the Relationship between Attitude towards Bicycle and Using Bicycle in Short Trips in Isfahan

    Directory of Open Access Journals (Sweden)

    Siroos Ahmadi

    2013-07-01

    The main goal of this research is to investigate relationship between attitude toward bicycle and using bicycle among the men in Isfahan. Based on the descriptive research findings, mean using bicycle score is low in Iran. This situation is not satisfactory for a metropolis such as Isfahan that has an increasing population and motor vehicles, and also has many difficulties in urban base facilities and must be changed. In addition to mean attitude toward bicycle is high that is an opportunity for urban planners. Inferential findings show that attitude toward bicycle has a significant impact on using bicycle. In other words, increase attitude toward bicycle means an increase in using bicycle for short trips. This research finding theoretically confirm relation between attitude and behavior. Moreover it is compatible with results of the research that show there is significant relationship between attitude toward bicycle and using bicycle. There is an inverse significant relationship between age and using bicycle and with rising age using bicycle is decreased. This research finding shows that urban infrastructure in Isfahan for using bicycle is not available and consequently with rising age, bicycle risk is increased. There is a direct significant relationship between income rate and using bicycle and with increasing income rate, using bicycle is also increased. This research finding is rooted in social prestige bicycle and higher classes prefer to use motor vehicle for transportation instead of bicycle. There is a significant relationship between marital status and using bicycle and single men use bicycle more than married men but there is no significant relationship between education level and using bicycle. This research findings show that with rising education level in spite of rising income, using bicycle is not decreased. And finally there is no significant relationship between employed and unemployed persons in using bicycle. On the basis of the evidences such

  6. Pedaling into high gear for bicycle policy in Canada : lessons from bike summit 2008 in Toronto

    International Nuclear Information System (INIS)

    The 2008 bike summit provided a forum for the discussion of international and Canadian best practices related to bicycles and bicycling policy. The aim of the summit was to assist communities across Canada to improve conditions for cycling in the urban environment and help to generate a cultural shift towards greater acceptance of cycling on roads. This paper discussed lessons learned during the summit and outlined new methods of improving cycling in communities. The City of London has recently increased the amount of cyclists using its roads by 200 per cent. Cycling infrastructure is more affordable than constructing major public transit or road infrastructure. Savings in healthcare costs will be accrued over time as a result of the healthier lifestyles promoted by regular cycling activity. Bicycle trips can help to alleviate over-demand on heavy transit routes. Encouraging commuters to cycle will also reduce the amounts of greenhouse gases (GHGs) emitted in urban areas. Lane width reductions will help to reduce speeds as drivers are forced to pay more attention when driving. Public bike sharing programs and bike stations are now being used in many North American cities. It was concluded that strong advocacy is needed to ensure the growth and acceptance of cycling in urban centres. 23 figs

  7. Workers' marginal costs of commuting

    DEFF Research Database (Denmark)

    van Ommeren, Jos; Fosgerau, Mogens

    2009-01-01

    This paper applies a dynamic search model to estimate workers' marginal costs of commuting, including monetary and time costs. Using data on workers' job search activity as well as moving behaviour, for the Netherlands, we provide evidence that, on average, workers' marginal costs of one hour of...

  8. 36 CFR 1004.30 - Bicycles.

    Science.gov (United States)

    2010-07-01

    ... routes designated for bicycle use; provided, however, that the Board may close any Presidio Trust road or... consistent with the protection of natural, scenic and aesthetic values, safety considerations and...

  9. 36 CFR 4.30 - Bicycles.

    Science.gov (United States)

    2010-07-01

    ... road or parking area to bicycle use pursuant to the criteria and procedures of §§ 1.5 and 1.7 of this... consistent with the protection of a park area's natural, scenic and aesthetic values, safety...

  10. Non-Commutative Q-Binomial Formula

    OpenAIRE

    Nalci, Sengul; Pashaev, Oktay

    2012-01-01

    In this paper, we found new q-binomial formula for Q-commutative operators. Expansion coefficients in this formula are given by q-binomial coefficients with two bases (q,Q), determined by Q-commutative q-Pascal triangle. Our formula generalizes all well-known binomial formulas in the form of Newton, Gauss, symmetrical, non-commutative and Binet-Fibonacci binomials. By our non-commutative q-binomial, we introduce q-analogue of function of two non-commutative variables, which could be used in s...

  11. Design of Controller in Electric Bicycle

    OpenAIRE

    Zhidong Zhang; Jingfeng Shen; Baohui Li

    2011-01-01

    Base on PIC16F72, a design of brushless DC motor controller strategy applied to the electric bicycle control system was presented in the paper. Through analyzed some possible problems when electric bicycle running daily. Function of over-current protection, under-voltage protection and helping were accomplished. Schematic diagrams of each function and drive circuit were given in the paper, the controller was debugged in rated voltage 36V and power rating 250W brushless DC motor, experiment tu...

  12. Profiling bicycle tourists: a case of Croatia

    OpenAIRE

    Kovačić, Nataša

    2015-01-01

    Purpose – The purpose of the primary research is to gather information about the behaviour of bicycle tourism demand. Primarily by studying domestic bicycle tourists, the research results were expected to provide valuable market parameters, comparable with the determinants of previous relevant studies. Design and Methodology – Research was carried out by surveying different segments of bicyclists, recognized in earlier conceptual contributions. Electronic data collection techniques were ap...

  13. A note on maximal commutators and commutators of maximal functions

    Czech Academy of Sciences Publication Activity Database

    Mujdat, A.; Gogatishvili, Amiran; Koca, K.; Mustafayev, R.

    2015-01-01

    Roč. 67, č. 2 (2015), s. 581-593. ISSN 0025-5645 R&D Projects: GA ČR GA13-14743S; GA ČR GA201/08/0383 Institutional support: RVO:67985840 Keywords : macimal operator * commutator * BMO Subject RIV: BA - General Mathematics Impact factor: 0.615, year: 2014 http://projecteuclid.org/euclid.jmsj/1429624595

  14. Is the three-foot bicycle passing law working in Baltimore, Maryland?

    Science.gov (United States)

    Love, David C; Breaud, Autumn; Burns, Sean; Margulies, Jared; Romano, Max; Lawrence, Robert

    2012-09-01

    Maryland (MD) recently became one of fourteen states in the United States to enact a traffic law requiring motor vehicles to pass bicyclists at a distance of greater than three feet. To our knowledge, motorist compliance with the law has never been assessed. This study measured the distance between overtaking motor vehicles and cyclists [e.g. vehicle passing distance (VPD)], to develop baseline metrics for tracking implementation of the three-foot passing law in Baltimore, MD and to assess risk factors for dangerous passes. During September and October 2011, cyclists (n=5) measured VPD using a previously published video technique (Parkin and Meyers, 2010). Cyclists logged a total of 10.8h of video footage and 586 vehicle passes on 34 bicycle commuting trips. The average trip lasted 19.5±4.9 min and cyclists were passed on average 17.2±11.8 times per trip. VPDs of three feet or less were common when cycling in standard lanes (17%; 78 of 451 passes) and lanes with a shared lane marking (e.g. sharrows) (23%; 11 of 47 passes). No passes of three feet or less occurred in bicycle lanes (0 of 88 passes). A multiple linear regression model was created, which explained 26% of the variability in VPD. Significant model variables were lane width, bicycle infrastructure, cyclist identity, and street identity. Interventions, such as driver education, signage, enforcement, and bicycle infrastructure changes are needed to influence driving behavior in Baltimore to increase motorist compliance with the three-foot law. PMID:22664711

  15. Real structures on almost-commutative spectral triples

    OpenAIRE

    Ćaćić, Branimir

    2012-01-01

    We refine the reconstruction theorem for almost-commutative spectral triples to a result for real almost-commutative spectral triples, clarifying, in the process, both concrete and abstract definitions of real commutative and almost-commutative spectral triples. In particular, we find that a real almost-commutative spectral triple algebraically encodes the commutative *-algebra of the base manifold in a canonical way, and that a compact oriented Riemannian manifold admits real (almost-)commut...

  16. Non-commutative Nash inequalities

    Energy Technology Data Exchange (ETDEWEB)

    Kastoryano, Michael [NBIA, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen (Denmark); Temme, Kristan [Institute for Quantum Information and Matter, California Institute of Technology, Pasadena California 91125 (United States)

    2016-01-15

    A set of functional inequalities—called Nash inequalities—are introduced and analyzed in the context of quantum Markov process mixing. The basic theory of Nash inequalities is extended to the setting of non-commutative L{sub p} spaces, where their relationship to Poincaré and log-Sobolev inequalities is fleshed out. We prove Nash inequalities for a number of unital reversible semigroups.

  17. Commuting graphs of matrix algebras

    International Nuclear Information System (INIS)

    The commuting graph of a ring R, denoted by Γ(R), is a graph whose vertices are all non- central elements of R and two distinct vertices x and y are adjacent if and only if xy = yx. The commuting graph of a group G, denoted by Γ(G), is similarly defined. In this paper we investigate some graph theoretic properties of Γ(Mn(F)), where F is a field and n ≥ 2. Also we study the commuting graphs of some classical groups such as GLn(F) and SLn(F). We show that Γ(Mn(F)) is a connected graph if and only if every field extension of F of degree n contains a proper intermediate field. We prove that apart from finitely many fields, a similar result is true for Γ(GLn(F)) and Γ(SLn(F)). Also we show that for two fields E and F and integers m, n ≥> 2, if Γ(Mm(E)) ≅ Γ(Mn(F)), then m = n and vertical bar E vertical bar = vertical bar F vertical bar. (author)

  18. Street lighting disturbs commuting bats.

    Science.gov (United States)

    Stone, Emma Louise; Jones, Gareth; Harris, Stephen

    2009-07-14

    Anthropogenic disturbance is a major cause of worldwide declines in biodiversity. Understanding the implications of this disturbance for species and populations is crucial for conservation biologists wishing to mitigate negative effects. Anthropogenic light pollution is an increasing global problem, affecting ecological interactions across a range of taxa and impacting negatively upon critical animal behaviors including foraging, reproduction, and communication (for review see). Almost all bats are nocturnal, making them ideal subjects for testing the effects of light pollution. Previous studies have shown that bat species adapted to foraging in open environments feed on insects attracted to mercury vapor lamps. Here, we use an experimental approach to provide the first evidence of a negative effect of artificial light pollution on the commuting behavior of a threatened bat species. We installed high-pressure sodium lights that mimic the intensity and light spectra of streetlights along commuting routes of lesser horseshoe bats (Rhinolophus hipposideros). Bat activity was reduced dramatically and the onset of commuting behavior was delayed in the presence of lighting, with no evidence of habituation. These results demonstrate that light pollution may have significant negative impacts upon the selection of flight routes by bats. PMID:19540116

  19. Public Bicycle Share Programs and Head Injuries

    Science.gov (United States)

    Pless, Barry; Moore, Lynne; Nathens, Avery B.; Hunte, Garth; Rivara, Frederick P.

    2014-01-01

    Objectives. We evaluated the effect of North American public bicycle share programs (PBSPs), which typically do not offer helmets with rentals, on the occurrence of bicycle-related head injuries. Methods. We analyzed trauma center data for bicycle-related injuries from 5 cities with PBSPs and 5 comparison cities. We used logistic regression models to compare the odds that admission for a bicycle-related injury would involve a head injury 24 months before PBSP implementation and 12 months afterward. Results. In PBSP cities, the proportion of head injuries among bicycle-related injuries increased from 42.3% before PBSP implementation to 50.1% after (P < .01). This proportion in comparison cities remained similar before (38.2%) and after (35.9%) implementation (P = .23). Odds ratios for head injury were 1.30 (95% confidence interval = 1.13, 1.67) in PBSP cities and 0.94 (95% confidence interval = 0.79, 1.11) in control cities (adjusted for age and city) when we compared the period after implementation to the period before. Conclusions. Results suggest that steps should be taken to make helmets available with PBSPs. Helmet availability should be incorporated into PBSP planning and funding, not considered an afterthought following implementation. PMID:24922150

  20. Rail commuting duration and passenger stress.

    Science.gov (United States)

    Evans, Gary W; Wener, Richard E

    2006-05-01

    Over 100 million Americans commute to work every weekday. Little is known, however, about how this aspect of work, which may indeed be the most stressful aspect of the job for some, affects human health and well-being. The authors studied a sample of 208 male and female suburban rail commuters who took the train to Manhattan, New York. The greater the duration of the commute, the larger the magnitude of salivary cortisol elevations in reference to resting baseline levels, the less the commuter's persistence on a task at the end of the commute, and the greater the levels of perceived stress. These effects were not moderated by gender. Commuting stress is an important and largely overlooked aspect of environmental health. PMID:16719613

  1. Non-commutativity in polar coordinates

    CERN Document Server

    Edwards, James P

    2016-01-01

    We reconsider the fundamental commutation relations for non-commutative $\\mathbb{R}^{2}$ described in polar coordinates with non-commutativity parameter $\\theta$. Previous analysis found that the natural transition from Cartesian coordinates to polars led to a representation of $\\left[\\hat{r}, \\hat{\\varphi}\\right]$ as an everywhere diverging series. We compute the Borel resummation of this series, showing that it can subsequently be extended throughout parameter space and hence provide an interpretation of this commutator. Our analysis provides a complete solution for arbitrary $r$ and $\\theta$ that reproduces the earlier calculations at lowest order. We compare our results to previous literature in the (pseudo-)commuting limit, finding a surprising spatial dependence for the coordinate commutator when $\\theta \\gg r^{2}$. We raise some questions for future study in light of this progress.

  2. Commutative Hopf algebras of permutations and trees

    OpenAIRE

    Hivert, F.; Novelli, J. -C.; Thibon, J. -Y.

    2005-01-01

    We propose several constructions of commutative or cocommutative Hopf algebras based on various combinatorial structures, and investigate the relations between them. A commutative Hopf algebra of permutations is obtained by a general construction based on graphs, and its non-commutative dual is realized in three different ways, in particular as the Grossman-Larson algebra of heap ordered trees. Extensions to endofunctions, parking functions, set partitions, planar binary trees and rooted fore...

  3. Product and Commutativity of Slant Toeplitz Operators

    Institute of Scientific and Technical Information of China (English)

    Chaomei LIU; Yufeng LU

    2013-01-01

    In this paper,the product and commutativity of slant Toeplitz operators are discussed.We show that the product of kth1-order slant Toeplitz operators and kth2-order slant Toeplitz operators must be a (k1k2)th-order slant Toeplitz operator except for zero operators,and the commutativity and essential commutativity of two slant Toeplitz operators with different orders are the same.

  4. The Quantum Commutator of a Perfect Fluid

    OpenAIRE

    Roberts, Mark D.

    1998-01-01

    A perfect fluid is quantized by the canonical method. The constraints are found and this allows the Dirac brackets to be calculated. Replacing the Dirac brackets with quantum commutators formally quantizes the system. There is a momentum operator in the denominator of some coordinate quantum commutators. It is shown that it is possible to multiply throughout by this momentum operator. Factor ordering differences can result in a viscosity term. The resulting quantum commutator algebra is \\vspa...

  5. Bicycling to school improves the cardiometabolic risk factor profile

    DEFF Research Database (Denmark)

    Ostergaard, Lars; Børrestad, Line A B; Tarp, Jakob;

    2012-01-01

    To investigate whether bicycling to school improves cardiometabolic risk factor profile and cardiorespiratory fitness among children.......To investigate whether bicycling to school improves cardiometabolic risk factor profile and cardiorespiratory fitness among children....

  6. On the stability of a bicycle on rollers

    Energy Technology Data Exchange (ETDEWEB)

    Cleary, Patricia A [Department of Geosciences, University of Wisconsin-Parkside, Kenosha, WI 53141 (United States); Mohazzabi, Pirooz, E-mail: pirooz.mohazzabi@uwp.edu [Department of Physics, University of Wisconsin-Parkside, Kenosha, WI 53141 (United States)

    2011-09-15

    Riding a bicycle on the newest form of indoor training, rollers, presents a unique experiment on bicycle stability. The stability factors eliminated by riding on rollers are discussed in terms of refined handling and control of the centre of mass on a bicycle. This paper is intended for undergraduate physics majors as well as any other general readership interested in the dynamics of bicycle stability.

  7. On the Stability of a Bicycle on Rollers

    Science.gov (United States)

    Cleary, Patricia A.; Mohazzabi, Pirooz

    2011-01-01

    Riding a bicycle on the newest form of indoor training, rollers, presents a unique experiment on bicycle stability. The stability factors eliminated by riding on rollers are discussed in terms of refined handling and control of the centre of mass on a bicycle. This paper is intended for undergraduate physics majors as well as any other general…

  8. An Analysis of Florida Physical Educators' Knowledge of Bicycle Laws

    Science.gov (United States)

    Connaughton, Daniel P.; Egberts, John B.; Spengler, J. O.; Zhang, James J.; Jin, Liyan

    2012-01-01

    Bicycling among youth is a popular activity, but like all modes of travel it is not without risk. Florida has a particularly high rate of bicycle-related fatalities and injuries. To reduce such risks, the Florida Department of Transportation and Florida Department of Education have developed a youth bicycle safety educational program (Florida…

  9. Calculation of the commutator anomaly

    International Nuclear Information System (INIS)

    It is well-known that, for the non-Abelian gauge theory coupled to the chiral fermions, which is described by a Lagrangian, the anomaly of the non-Abelian current is given by the descent form of the Chern-Simon five form; D*Ja = (-1/24π2)tr[d(AdA + 1/2A3)], where A = Aμdxμ = -itaAμadxμ. Recently, Faddeev argued that, for such an anomalous system, the gauge symmetry would be represented in a generalized sense of projective representation; V(g1)V(g2)Ψ(A) = exp[iα2(g1, g2; A)] X V(g1g2)Ψ(A), where Ψ(A) is the wave functional and the phase factor α2 depends on both the group elements and the gauge field configuration A. Here, it is convenient to consider the infinitesimal version of the above argument. The generator of infinitesimal gauge transformation in the temporal gauge A0 = 0 is given by Ga(x) = δiEia + gfabcAibEic - gΨ-barγ0taΨ, and the infinitesimal form of the previous product rule can be written as the equal time commutation relation; [Ga(x), Gb(y)] = ifabcGc(x)δ3(x-y) + ab(x,y,A), where is related to α2. In this equation, the first term is what is expected as the normal commutation relation of the generator, while the second term is an anomaly, which is designated here as the commutator anomaly. Then the present study concentrates on operations to determine the anomaly term. (Nogami, A.)

  10. Successful Swiss solar bicycles in Australia

    International Nuclear Information System (INIS)

    The article takes a look at the Swiss 'Spirit of Bike' team's success in the 'Power Challenge' race across Australia using solar-bicycles based on commercially available models. Apart from the sporting aspects of race, technical details on the cycles and their supply of solar power are given. Also, the history behind the success of the team is presented and the monitoring of man (and woman) and machine during the race is described. The article also discusses the electric bicycles that are commercially available and the potential of these energy-efficient vehicles in Switzerland

  11. Non-commutative q-expansions

    OpenAIRE

    Kakde, Mahesh

    2014-01-01

    In this short note we partially answer a question of Fukaya and Kato by constructing a $q$-expansion with coefficients in a non-commutative Iwasawa algebra whose constant term is a non-commutative p-adic zeta function.

  12. Commutative Moufang loops and alternative algebras

    OpenAIRE

    Grishkov, Alexander N.; Shestakov, Ivan P.

    2008-01-01

    We compute the orders of free commutative Moufand loops of exponent 3 with $n\\leq 7$ free generators and find embeddings of such loops into a loop of invertible elements of the free commutative alternative algebra with identity $x^3=0$.

  13. Universal Lie algebra extensions via commutative structures

    OpenAIRE

    Yanovski, A B

    2001-01-01

    We consider some special type extensions of an arbitrary Lie algebra, which we call universal extensions. We show that these extensions are in one-to-one correspondence with finite dimensional associative commutative algebras. We also construct a special kind of these extensions, that correspond to a finite commutative monoids.

  14. Commutativity and ideals in category crossed products

    DEFF Research Database (Denmark)

    Öinert, Per Johan; Lundström, Patrik

    2010-01-01

    In order to simultaneously generalize matrix rings and group graded crossed products, we introduce category crossed products. For such algebras we describe the centre and the commutant of the coefficient ring. We also investigate the connection between on the one hand maximal commutativity of the...

  15. Non-commutative Kerr black hole

    OpenAIRE

    Di Grezia, Elisabetta; Esposito, Giampiero

    2009-01-01

    This paper applies the first-order Seiberg-Witten map to evaluate the first-order non-commutative Kerr tetrad. The classical tetrad is taken to follow the locally non-rotating frame prescription. We also evaluate the tiny effect of non-commutativity on the efficiency of the Penrose process of rotational energy extraction from a black hole.

  16. Happiness and Satisfaction with Work Commute

    Science.gov (United States)

    Olsson, Lars E.; Garling, Tommy; Ettema, Dick; Friman, Margareta; Fujii, Satoshi

    2013-01-01

    Research suggests that for many people happiness is being able to make the routines of everyday life work, such that positive feelings dominate over negative feelings resulting from daily hassles. In line with this, a survey of work commuters in the three largest urban areas of Sweden show that satisfaction with the work commute contributes to…

  17. On the Skill of Balancing While Riding a Bicycle

    OpenAIRE

    Cain, Stephen M; Ashton-Miller, James A.; Perkins, Noel C.

    2016-01-01

    Humans have ridden bicycles for over 200 years, yet there are no continuous measures of how skill differs between novice and expert. To address this knowledge gap, we measured the dynamics of human bicycle riding in 14 subjects, half of whom were skilled and half were novice. Each subject rode an instrumented bicycle on training rollers at speeds ranging from 1 to 7 m/s. Steer angle and rate, steer torque, bicycle speed, and bicycle roll angle and rate were measured and steering power calcula...

  18. Children and bicycles: what is really happening? Studies of fatal and non-fatal bicycle injury.

    OpenAIRE

    Acton, C. H.; Thomas, S; Nixon, J. W.; Clark, R; Pitt, W R; Battistutta, D.

    1995-01-01

    OBJECTIVES: The objectives of the study were to ascertain the causes of accidents, injuries, and deaths in children who ride bicycles. Fatality and injury rates were also studied in order to compare with other studies. METHODS: Two studies of children were undertaken in children aged less than 15 years. In the first (retrospective fatality study), children who died as a result of a bicycle incident during the period 1981-92 were reviewed. In the second (prospective injury study) data were obt...

  19. Solutions to the Triangular Bicycle Flags Problem

    Science.gov (United States)

    Hartweg, Kim

    2005-01-01

    Students in a fifth-grade general education class and a second-grade gifted class participated in the Triangular Bicycle Flags problem. The results indicated that providing students with geometric experiences at the correct van Hiele level is necessary for helping students move from one level of understanding to the next.

  20. What do we know about bicycle helmets?

    NARCIS (Netherlands)

    Bogerd, C.P. Halldin, P. Houtenbos, M. Otte, D. Rossi, R.M. Walker, L. Willinger, R. & Shinar, D.

    2012-01-01

    Cycling is an excellent sustainable alternative to driving for many journeys. But cyclists have fewer safety options than car-users, with a helmet being the main safety device that is available. However, there are indications that increasing bicycle helmet usage through legislation causes confoundin

  1. Bicyclic semigroups of left I-quotients

    CERN Document Server

    Ghroda, Nassraddin

    2011-01-01

    In this article we study left I-orders in the bicyclic monoid $\\mathcal{B}$. We give necessary and sufficient conditions for a subsemigroup of $\\mathcal{B}$ to be a left I-oreder in $\\mathcal{B}$. We then prove that any left I-order in $\\mathcal{B}$ is straight.

  2. Inferring Passenger Type from Commuter Eigentravel Matrices

    CERN Document Server

    Legara, Erika Fille

    2015-01-01

    A sufficient knowledge of the demographics of a commuting public is essential in formulating and implementing more targeted transportation policies, as commuters exhibit different ways of traveling. With the advent of the Automated Fare Collection system (AFC), probing the travel patterns of commuters has become less invasive and more accessible. Consequently, numerous transport studies related to human mobility have shown that these observed patterns allow one to pair individuals with locations and/or activities at certain times of the day. However, classifying commuters using their travel signatures is yet to be thoroughly examined. Here, we contribute to the literature by demonstrating a procedure to characterize passenger types (Adult, Child/Student, and Senior Citizen) based on their three-month travel patterns taken from a smart fare card system. We first establish a method to construct distinct commuter matrices, which we refer to as eigentravel matrices, that capture the characteristic travel routines...

  3. Safety effects of permanent running lights for bicycles

    DEFF Research Database (Denmark)

    Madsen, Jens Chr. Overgaard; Andersen, T.; Lahrmann, Harry

    2013-01-01

    3845 cyclists was carried out in Odense, Denmark in order to examine, if permanent running lights mounted to bicycles would improve traffic safety for cyclists. The permanent running lights were mounted to 1845 bicycles and the accident rate was recorded through 12 months for this treatment group and...... 2000 other bicyclists, the latter serving as a control group without bicycle running lights. The safety effect of the running lights is analysed by comparing incidence rates – number of bicycle accidents recorded per man-month – for the treatment group and the control group. The incidence rate......, including all recorded bicycle accidents with personal injury to the participating cyclist, is 19% lower for cyclists with permanent running lights mounted; indicating that the permanent bicycle running light significantly improves traffic safety for cyclists. The study shows that use of permanent bicycle...

  4. Canonical commutation relation preserving maps

    International Nuclear Information System (INIS)

    We study maps preserving the Heisenberg commutation relation ab-ba=1. We find a one-parameter deformation of the standard realization of the above algebra in terms of a coordinate and its dual derivative. It involves a non-local 'coordinate' operator while the dual 'derivative' is just the Jackson finite-difference operator. Substitution of this realization into any differential operator involving x and d/dx results in an isospectral deformation of a continuous differential operator into a finite-difference one. We extend our results to the deformed Heisenberg algebra ab-qba=1. As an example of potential applications, various deformations of the Hahn polynomials are briefly discussed. (author)

  5. Weaving commutators: beyond Fock space

    CERN Document Server

    Arzano, Michele

    2012-01-01

    The symmetrization postulate and the associated Bose/Fermi (anti)-commutators for field mode operators are among the pillars on which local quantum field theory lays its foundations. They ultimately determine the structure of Fock space and are closely connected with the local properties of the fields and with the action of symmetry generators on observables and states. We here show that the quantum field theory describing relativistic particles coupled to three dimensional Einstein gravity as a topological defect must be constructed using a deformed algebra of creation and annihilation operators. This reflects a non-trivial group manifold structure of the classical momentum space and a modification of the Leibniz rule for the action of symmetry generators governed by Newton's constant. We outline various arguments suggesting that, at least at the qualitative level, these three-dimensional results could also apply to real four-dimensional world thus forcing us to re-think the ordinary multiparticle structure ...

  6. Traffic conflicts on bicycle paths: a systematic observation of behaviour from video

    NARCIS (Netherlands)

    Horst, A.R.A. van der; Goede, M. de; Hair-Buijssen, S.H.H.M. de; Methorst, R.

    2014-01-01

    In The Netherlands, on bicycle paths, single-bicycle accidents, bicycle-bicycle and bicycle-moped accidents constitute a considerable share of all bicyclist injuries. Over three quarters of all hospitalised bicyclist victims in the Netherlands cannot be directly related to a crash with motorised tra

  7. On the interrelations between migration and commuting

    Directory of Open Access Journals (Sweden)

    Lukić Vesna

    2013-01-01

    Full Text Available In this paper, we emphasise the significance of studying the interrelations between commuting and migration. The aim of the paper is to point out the factors which affect these interrelations (demographic and socio-economic characteristics of migrants and commuters, labour market, real estate market, information, life style, etc., with the special emphasis on the role of commuting distance onto the chosen mobility type. Besides theorethical frameworks and results of the selected foreign researches up to date, the overview of research of interrelations between migration and commuting in Serbia has also been presented. While earlier studies conducted by Gawryszenski (1978, Termote (1980 and Reitsma&Vergoossen (1987 pointed to the replacement of migration types between each other within country, in recent literature the interaction between migration and commuting has been studied in a trans-boundary context of the contemporary EU. Modern trend of long distance commuting instead of migration and the concept of substitution/replacement regarding migration and commuting have also been discussed. In Serbia, there is a positive correlation between commuting outflows and immigration in rural settlements of Vojvodina province. Namely, commuting and migration are complement, which is the characteristic of both processes sub-urbanisation and ex-urbanisation (Lukić, 2012. In addition to ownership of real estate and previous migration experience, marital status influenced the chosen mobility type in Serbia as well. Adjustment to changes of Serbian labour market is mostly conducted via migration (Miletić, Lukić, Miljanović, 2011. Interrelations between migration and commuting are very significant due to the tendency of transformation of some commuters into migrants. This process has its consequences, both on demographic as well as the overall socio-economic development of the area of commuters’ origin and destination. However, even though the surveys

  8. Two-dimensional black holes and non-commutative spaces

    International Nuclear Information System (INIS)

    We study the effects of non-commutative spaces on two-dimensional black hole. The event horizon of two-dimensional black hole is obtained in non-commutative space up to second order of perturbative calculations. A lower limit for the non-commutativity parameter is also obtained. The observer in that limit in contrast to commutative case see two horizon

  9. Exploratory mapping of commuter flows in England and Wales

    DEFF Research Database (Denmark)

    Nielsen, Thomas Alexander Sick; Harder, Henrik

    2008-01-01

    The paper uses the origin–destination commute data published from the 1991 and 2001 Census to explore the developments in commuting and interaction patterns within England and Wales. Focus is on the geographical variations and a map of commuter flows is presented. Commuting is stretched out along a...

  10. Physiological and cognitive responses when riding an electrically assisted bicycle versus a classical bicycle.

    Science.gov (United States)

    Theurel, J; Theurel, A; Lepers, R

    2012-01-01

    The present study compared the physiological responses and the subsequent cognitive performance when riding an electrically assisted (EB) versus a classical (CB) bicycle. Oxygen uptake, heart rate and leg extensor muscles electromyographic (EMG) activity were recorded in 10 subjects during a 30-min intermittent cycling exercise performed with EB versus CB. Cognitive performance was evaluated by a mail sorting test, performed at rest and after each cycling session. Averaged oxygen uptake and heat rate were significantly (P cycling than during CB cycling. The EMG activities of the vastus lateralis, rectus femoris and gastrocnemius medialis muscles were significantly (P cycling than during EB cycling. The time to complete the mail sorting test was significantly (P cycling than after CB cycling. Because EB cycling reduced muscle strains and physiological stress, it might offer benefits for those using bicycles in their work, such as postal workers and police officers. STATEMENT OF RELEVANCE: This study compared physiological and cognitive responses when riding an electrically assisted versus a classical bicycle. The results showed that the electrically assisted bicycle led to reduced muscle strains and physiological stress and, therefore, might offer benefits for those using bicycles in their work, such as postal workers and police officers. PMID:22506555

  11. Fatal falls from bicycles: a case report.

    Science.gov (United States)

    Venara, A; Mauillon, D; Gaudin, A; Rouge-Maillart, C; Jousset, N

    2013-03-10

    Though rare occurrences, fatal falls from bicycles are generally linked to the absence of a protective helmet and/or a collision with another vehicle. The case presented here is exceptional due to its circumstances and the consequences of the accident: a fall with no obstacle at a low speed that brought about multiple traumas and the death of a cyclist wearing a protective helmet. Comparing this against a review of cyclist accidentology literature, this case is unique. The increased use of autopsy in terms of forensic accidentology is to be encouraged so as not to misunderstand the possibility of such lesion-based consequences following a simple fall from a bicycle. PMID:23312586

  12. Determinantes e padrões de utilização da bicicleta e acidentes de trânsito sofridos por ciclistas trabalhadores da cidade de Pelotas, Rio Grande do Sul, Brasil Determinants and patterns of bicycle use and traffic accidents among bicycling workers in Pelotas, Rio Grande do Sul, Brazil

    Directory of Open Access Journals (Sweden)

    Giancarlo Bacchieri

    2005-10-01

    Full Text Available Um estudo transversal de base-populacional foi realizado em Pelotas, sul do Brasil, objetivando pesquisar os determinantes e padrões de utilização da bicicleta como modo de transporte para o trabalho. Foram também descritos os acidentes ocorridos nos últimos 12 meses no deslocamento de ida e volta para o trabalho e a utilização de equipamentos de segurança na bicicleta. A amostra incluiu 1.705 trabalhadores com 15 anos ou mais de idade, residentes na zona urbana, que utilizavam modos de transporte para o trabalho. Análises bruta e ajustada foram realizadas por meio de regressão de Poisson, considerando o efeito do delineamento. A prevalência de utilização da bicicleta foi de 17,2% (IC95%: 15,4-19,0. Trabalhadores homens, com baixa escolaridade e nível econômico mais baixo apresentaram as maiores prevalências. Menos de 1,0% das bicicletas possuía os equipamentos de segurança exigidos pelo Código de Trânsito Brasileiro e 15,0% não tinham freios. Aproximadamente 6,0% desses trabalhadores sofreram acidentes de trânsito com lesões corporais nos últimos 12 meses. Concluímos que trabalhadores que utilizam bicicleta como modo de transporte são prioritários para intervenções preventivas relacionadas a acidentes de trânsito.A population-based cross-sectional study was conducted in Pelotas, southern Brazil, focusing on the determinants and patterns of bicycle use as a mode of commuting by workers. Accidents during commuting and use of safety equipment were also studied. The sample included 1,705 workers (> 15 years of age living in the urban area of Pelotas and using various modes of transportation during commuting. Crude and adjusted analyses were performed using Poisson regression, taking the design effect into account. Prevalence of bicycle use was 17.2% (95%CI: 15.4%-19.0%. Male workers and those with low schooling and low income presented higher prevalence. Less than 1.0% of the bicycles featured the safety equipment

  13. Maximum Estrada Index of Bicyclic Graphs

    CERN Document Server

    Wang, Long; Wang, Yi

    2012-01-01

    Let $G$ be a simple graph of order $n$, let $\\lambda_1(G),\\lambda_2(G),...,\\lambda_n(G)$ be the eigenvalues of the adjacency matrix of $G$. The Esrada index of $G$ is defined as $EE(G)=\\sum_{i=1}^{n}e^{\\lambda_i(G)}$. In this paper we determine the unique graph with maximum Estrada index among bicyclic graphs with fixed order.

  14. The Optimal Choice of Commuting Speed: Consequences for Commuting Time, Distance and Costs

    OpenAIRE

    van Ommeren, Jos; Dargay, Joyce

    2004-01-01

    This discussion paper resulted in a publication in the 'Journal of Transport Economics and Policy', 2006, 40(2), 279-296. In this paper, we derive a structural model for commuting speed. We presume that commuting speed is chosen to minimise commuting costs, which encompass both monetary and time costs. At faster speed levels, the monetary costs increase, but the time costs fall. Using data from Great Britain, we demonstrate that the income elasticity of commuting speed is 0.126. The ratio of ...

  15. Covariant non-commutative space-time

    Science.gov (United States)

    Heckman, Jonathan J.; Verlinde, Herman

    2015-05-01

    We introduce a covariant non-commutative deformation of 3 + 1-dimensional conformal field theory. The deformation introduces a short-distance scale ℓp, and thus breaks scale invariance, but preserves all space-time isometries. The non-commutative algebra is defined on space-times with non-zero constant curvature, i.e. dS4 or AdS4. The construction makes essential use of the representation of CFT tensor operators as polynomials in an auxiliary polarization tensor. The polarization tensor takes active part in the non-commutative algebra, which for dS4 takes the form of so (5, 1), while for AdS4 it assembles into so (4, 2). The structure of the non-commutative correlation functions hints that the deformed theory contains gravitational interactions and a Regge-like trajectory of higher spin excitations.

  16. Covariant non-commutative space–time

    Directory of Open Access Journals (Sweden)

    Jonathan J. Heckman

    2015-05-01

    Full Text Available We introduce a covariant non-commutative deformation of 3+1-dimensional conformal field theory. The deformation introduces a short-distance scale ℓp, and thus breaks scale invariance, but preserves all space–time isometries. The non-commutative algebra is defined on space–times with non-zero constant curvature, i.e. dS4 or AdS4. The construction makes essential use of the representation of CFT tensor operators as polynomials in an auxiliary polarization tensor. The polarization tensor takes active part in the non-commutative algebra, which for dS4 takes the form of so(5,1, while for AdS4 it assembles into so(4,2. The structure of the non-commutative correlation functions hints that the deformed theory contains gravitational interactions and a Regge-like trajectory of higher spin excitations.

  17. Opportunities and benefits. [commuter air travel

    Science.gov (United States)

    Galloway, T. L.

    1983-01-01

    The service characteristics and changes affecting commuter airline operations are summarized. Community and passenger considerations are addressed and the benefits identified in NASA-sponsored aircraft studies are discussed.

  18. Free Use of Bicycles at CERN

    CERN Multimedia

    2000-01-01

    Imagine you have just arrived at CERN. You are from Russia or Japan and have no car but you do need to get around and do not like depending on public transport. What do you do? You go to the EP Service Point (Building 124) and meet Boris Cabaud to get a CERN bicycle. Use of the bicycle is free but you have to fill in an application form which needs to be signed by your Group or Division Secretary. Then the application is filled in, you are put on the waiting list and it might take you from one to four weeks to get your bike depending on the season. “Normally the bikes are only for Users in the EP division as they are paid for by the EP budget,” says Boris, “but some other divisions have made arrangements to cover the costs.” Boris takes care of 350 bicycles at present. Each bike can be lent for maximum one year. During the winter the bikes can be stored in building 301 as it is difficult to ride them in the snow. If a bike is broken or lost all costs will be billed to the group or team account of the bo...

  19. Applying riding-posture optimization on bicycle frame design.

    Science.gov (United States)

    Hsiao, Shih-Wen; Chen, Rong-Qi; Leng, Wan-Lee

    2015-11-01

    Customization design is a trend for developing a bicycle in recent years. Thus, the comfort of riding a bike is an important factor that should be paid much attention to while developing a bicycle. From the viewpoint of ergonomics, the concept of "fitting object to the human body" is designed into the bicycle frame in this study. Firstly, the important feature points of riding posture were automatically detected by the image processing method. In the measurement process, the best riding posture was identified experimentally, thus the positions of feature points and joint angles of human body were obtained. Afterwards, according to the measurement data, three key points: the handlebar, the saddle and the crank center, were identified and applied to the frame design of various bicycle types. Lastly, this study further proposed a frame size table for common bicycle types, which is helpful for the designer to design a bicycle. PMID:26154206

  20. Active commuting to school in Portuguese adolescents: Using PALMS to detect trips

    DEFF Research Database (Denmark)

    Pizarro, Andreia Nogueira; Schipperijn, Jasper; Andersen, Henriette Bondo;

    2016-01-01

    Abstract The declining levels of physical activity (PA) have led to active commuting to school (ACS) being seen as a key strategy to increase PA levels in school-aged children. In Portugal, no data exists on the patterns of this behavior, an essential step for developing evidence-based and...... effective interventions. The purpose of this study is to explore the travel to school behavior using an objective methodology. Methods 155 adolescents (mean age 15.9±1.1 years) wore an accelerometer and a GPS for 7 consecutive days. Home and school addresses were geocoded to identify home-school trips. The...... web-based tool PALMS was used to combine GPS and accelerometer data, categorize Moderate to Vigorous Physical Activity (MVPA) and classify trip mode of home-school trips into: walking, bicycling or vehicle. Results 609 trips were identified as home-school trips. Walking was the most frequent trip mode...

  1. Homotopy Invariant Commutative Algebra over fields

    OpenAIRE

    Greenlees, J. P. C.

    2016-01-01

    These notes illustrates the power of formulating ideas of commutative algebra in a homotopy invariant form. They can then be applied to derived categories of rings or ring spectra. These ideas are powerful in classical algebra, in representation theory of groups, in classical algebraic topology and elsewhere. The notes grew out of a series of lectures given during the `Interactions between Representation Theory, Algebraic Topology and Commutative Algebra' (IRTATCA) at the CRM (Barcelona) in S...

  2. How do motorways shape commuting patterns?

    DEFF Research Database (Denmark)

    Hovgesen, Henrik Harder; Nielsen, Thomas Alexander Sick

    2004-01-01

    urbanization and spatial interaction patterns in the last 20 years. This paper presents results on how the building of the motorway network has shaped spatial interactions patterns in Denmark over a ten year period. The question asked is how travel time reductions and changing motorway access is related to...... change in the commute pattern. And whether the relations between these factors and commuting are a new course of development or a continuation of past trends....

  3. Studying commuting behaviours using collaborative visual analytics

    OpenAIRE

    Beecham, R.; J. Wood; Bowerman, A.

    2014-01-01

    Mining a large origin–destination dataset of journeys made through London’s Cycle Hire Scheme (LCHS), we develop a technique for automatically classifying commuting behaviour that involves a spatial analysis of cyclists’ journeys. We identify a subset of potential commuting cyclists, and for each individual define a plausible geographic area representing their workplace. All peak-time journeys terminating within the vicinity of this derived workplace in the morning, and originating from this ...

  4. Black Hole with Non-Commutative Hair

    OpenAIRE

    Klimcik, C; Kolnik, P.; Pompos, A.

    1993-01-01

    The specific nonlinear vector $\\sigma$-model coupled to Einstein gravity is investigated. The model arises in the studies of the gravitating matter in non-commutative geometry. The static spherically symmetric spacetimes are identified by direct solving of the field equations. The asymptotically flat black hole with the ``non-commutative'' vector hair appears for the special choice of the integration constants, giving thus another counterexample to the famous ``no-hair'' theorem.

  5. New commutation relations for quantum gravity

    CERN Document Server

    Soo, Chopin

    2016-01-01

    A new set of fundamental commutation relations for quantum gravity is presented. The basic variables are the eight components of the unimodular part of the spatial dreibein and eight SU(3) generators which correspond to Klauder's momentric variables. The commutation relations are not canonical, but they have well defined group theoretical meanings. All fundamental entities are dimensionless; and quantum wave functionals are preferentially selected to be in the dreibein representation.

  6. Fertility and commuting behaviour in Germany

    OpenAIRE

    Johannes Huinink; Michael Feldhaus

    2012-01-01

    "Fertility behavior is closely related to other dimensions of the individual life course, which are strongly interrelated themselves. Regarding the impact of job-related spatial mobility, empirical findings show a negative correlation between having children and commuting, particularly for women. Up to now, fertility intentions have not been thoroughly investigated in this respect. Longitudinal studies are lacking, too. In this paper, the effects of commuting arrangements of men and women on ...

  7. Non-commutativity measure of quantum discord

    Science.gov (United States)

    Guo, Yu

    2016-01-01

    Quantum discord is a manifestation of quantum correlations due to non-commutativity rather than entanglement. Two measures of quantum discord by the amount of non-commutativity via the trace norm and the Hilbert-Schmidt norm respectively are proposed in this paper. These two measures can be calculated easily for any state with arbitrary dimension. It is shown by several examples that these measures can reflect the amount of the original quantum discord. PMID:27122226

  8. Non-commutativity measure of quantum discord.

    Science.gov (United States)

    Guo, Yu

    2016-01-01

    Quantum discord is a manifestation of quantum correlations due to non-commutativity rather than entanglement. Two measures of quantum discord by the amount of non-commutativity via the trace norm and the Hilbert-Schmidt norm respectively are proposed in this paper. These two measures can be calculated easily for any state with arbitrary dimension. It is shown by several examples that these measures can reflect the amount of the original quantum discord. PMID:27122226

  9. Psychological Delaying Model of Bicycle Passing Events on Physically Separated Bicycle Roadways in China*

    Science.gov (United States)

    Zhao, De; Wang, Wei; Li, Zhibin; Shan, Xiaonian; Sun, Xin

    Bicycle facilities are quite common in China but there are not enough quantitative methods to evaluate the Level of Service (LOS) of bicycle roadways. The number of passing events, which considers the interactions between bicyclists, has been proved to be a proper indicator for evaluating bicycle LOS under the special traffic and roadway conditions in China. The primary objective of this study is to propose a model considering the delay effects of passing events and rider's overtaking motivation. Field data was collected on South Zhongshan Road and Huaihai Road in Nanjing city of China with 639 bicyclists investigated. Then a new mathematical model was built to evaluate those effects through probability and regression analyses. It was found that the delay effect of passing events and rider's overtaking motivation are significant influencing factors which cannot be omitted. Correlation test shows the fitted relationship is greater between the model prediction and field data comparing with the previous model.

  10. Will a bicycle friendly policy make passenger travel more sustainably?

    OpenAIRE

    Christensen, Linda; Jensen, Thomas Christian

    2009-01-01

    The purpose of this paper is to analyse the possibility to transfer a larger part of the short car trips to walking or bicycling in order to obtain environmental and health benefits. The project contains a logistic choice model used to explain which circumstances are particularly important for choosing walking and bicycling, and how very different instruments can promote walking and bicycling at the expense of short car trips. Furthermore, the paper describes the most important factors when c...

  11. Technical analysis and market study of electric bicycles

    OpenAIRE

    Matasyan, Artur

    2015-01-01

    This thesis project was done in collaboration with a Prismattery LLC, which is based in Tallinn, Estonia and is interested in entering the market of electric bicycles. For that reason in this report a detailed study concerning the market of electrical bicycles, its current situation and trends were performed and a promising target market was indicated. The market study showed that although in different countries the specifications and preferred types of electric bicycles may vary,...

  12. Bicycle-Sharing System Analysis and Trip Prediction

    OpenAIRE

    Zhang, Jiawei; Pan, Xiao; Li, Moyin; Yu, Philip S.

    2016-01-01

    Bicycle-sharing systems, which can provide shared bike usage services for the public, have been launched in many big cities. In bicycle-sharing systems, people can borrow and return bikes at any stations in the service region very conveniently. Therefore, bicycle-sharing systems are normally used as a short-distance trip supplement for private vehicles as well as regular public transportation. Meanwhile, for stations located at different places in the service region, the bike usages can be qu...

  13. Non-commutativity in the brain.

    Science.gov (United States)

    Tweed, D B; Haslwanter, T P; Happe, V; Fetter, M

    1999-05-20

    In non-commutative algebra, order makes a difference to multiplication, so that a x b not equal to b x a. This feature is necessary for computing rotary motion, because order makes a difference to the combined effect of two rotations. It has therefore been proposed that there are non-commutative operators in the brain circuits that deal with rotations, including motor circuits that steer the eyes, head and limbs, and sensory circuits that handle spatial information. This idea is controversial: studies of eye and head control have revealed behaviours that are consistent with non-commutativity in the brain, but none that clearly rules out all commutative models. Here we demonstrate non-commutative computation in the vestibulo-ocular reflex. We show that subjects rotated in darkness can hold their gaze points stable in space, correctly computing different final eye-position commands when put through the same two rotations in different orders, in a way that is unattainable by any commutative system. PMID:10353248

  14. Non-commutative standard model: model building

    International Nuclear Information System (INIS)

    A non-commutative version of the usual electro-weak theory is constructed. We discuss how to overcome the two major problems: (1) although we can have non-commutative U(n) (which we denote by U*(n)) gauge theory we cannot have non-commutative SU(n) and (2) the charges in non-commutative QED are quantized to just 0,±1. We show how the latter problem with charge quantization, as well as with the gauge group, can be resolved by taking the U*(3) x U*(2) x U*(1) gauge group and reducing the extra U(1) factors in an appropriate way. Then we proceed with building the non-commutative version of the standard model by specifying the proper representations for the entire particle content of the theory, the gauge bosons, the fermions and Higgs. We also present the full action for the non-commutative standard model (NCSM). In addition, among several peculiar features of our model, we address the inherentCP violation and new neutrino interactions. (orig.)

  15. Potential risk and its influencing factors for separated bicycle paths.

    Science.gov (United States)

    Xu, Cheng; Yang, Ying; Jin, Sheng; Qu, Zhaowei; Hou, Lei

    2016-02-01

    In this paper, we propose two potential risk indicators to define and evaluate the safety of bicycle path at the microscopic level. Field bicycle data were collected from three survey sites under different traffic conditions. These two risk indicators based on speed dispersion were proposed and calculated during each 5-min interval. The risk influences of various widths of bicycle path and traffic conditions were analyzed by using one-way ANOVA. We further proposed a generalized linear model (GLM) for modeling and analyzing the relationships between bicycle risks and v/c ratio and percentages of electric bicycles, male cyclists, young cyclists, and loaded cyclists. The stepwise regression models were applied for determination of coefficients. The results show that the influences of gender and age of cyclists on potential risks are not significant. The risks increase with the width of bicycle path and percentage of electric bicycles, while only for wider bicycle path (4-lane case in this study), the risks are associated with whether or not cyclists are loaded. The findings could contribute for analysis and evaluation of the safety for bicycle path. PMID:26647016

  16. Gr\\"obner-Shirshov Bases for Commutative Algebras with Multiple Operators and Free Commutative Rota-Baxter Algebras

    OpenAIRE

    Qiu, Jianjun

    2013-01-01

    In this paper, the Composition-Diamond lemma for commutative algebras with multiple operators is established. As applications, the Gr\\"obner-Shirshov bases and linear bases of free commutative Rota-Baxter algebra, free commutative $\\lambda$-differential algebra and free commutative $\\lambda$-differential Rota-Baxter algebra are given, respectively. Consequently, these three free algebras are constructed directly by commutative $\\Omega$-words.

  17. Fertility and Commuting Behaviour in Germany

    Directory of Open Access Journals (Sweden)

    Johannes Huinink

    2012-12-01

    Full Text Available Fertility behaviour is closely related to other dimensions of the individual life course, which are strongly interrelated themselves. Regarding the impact of job-related spatial mobility, empirical findings show a negative correlation between having children and commuting, particularly for women. Up to now, fertility intentions have not been thoroughly investigated in this respect. Longitudinal studies are lacking, too. In this paper, the effects of commuting arrangements of men and women on the intention of having a child within the next two years as well as the probability of realising this intention are addressed. The assumption is, that after accounting for other important factors (employment status, level of qualification, type of consensual union, number of children, residential mobility, medium- and long-distance commuting is negatively related to the fertility intention of women and its realisation. For men, effects are assumed to be nonexistent or even slightly positive. Longitudinal data from the first three waves of the German “Panel Analysis of Intimate Relationships and Family Dynamics” (pairfam are used to test the hypotheses. Firstly, a cross-sectional, multivariate probit-regression (with correlated errors on the intention to have a child within two years, on being childless and on medium- and long- distance commuting is applied. The model shows no significant correlation between commuting and the intention to have a child; it does however show a correlation between medium- and long distance commuting and the probability of women to be childless. Secondly, a longitudinal difference model on changing fertility intentions between panel wave 1 and wave 3 is estimated. For women, a positive effect can be found of interrupting medium- and long-distance commuting or, surprisingly, continuing medium- and long-distance commuting on the intention to have a child within two years. Thirdly, for men and women who reported a fertility

  18. Associations of Physical Activity, Sports Participation and Active Commuting on Mathematic Performance and Inhibitory Control in Adolescents.

    Directory of Open Access Journals (Sweden)

    Sidsel L Domazet

    Full Text Available To examine objectively measured physical activity level, organized sports participation and active commuting to school in relation to mathematic performance and inhibitory control in adolescents.The design was cross-sectional. A convenient sample of 869 sixth and seventh grade students (12-14 years was invited to participate in the study. A total of 568 students fulfilled the inclusion criteria and comprised the final sample for this study. Mathematic performance was assessed by a customized test and inhibitory control was assessed by a modified Eriksen flanker task. Physical activity was assessed with GT3X and GT3X+ accelerometers presented in sex-specific quartiles of mean counts per minute and mean minutes per day in moderate-to-vigorous physical activity. Active commuting and sports participation was self-reported. Mixed model regression was applied. Total physical activity level was stratified by bicycling status in order to bypass measurement error subject to the accelerometer.Non-cyclists in the 2nd quartile of counts per minute displayed a higher mathematic score, so did cyclists in the 2nd and 3rd quartile of moderate-to-vigorous physical activity relative to the least active quartile. Non-cyclists in the 3rd quartile of counts per minute had an improved reaction time and cyclists in the 2nd quartile of counts per minute and moderate-to-vigorous physical activity displayed an improved accuracy, whereas non-cyclists in the 2nd quartile of counts per minute showed an inferior accuracy relative to the least active quartile. Bicycling to school and organized sports participation were positively associated with mathematic performance.Sports participation and bicycling were positively associated with mathematic performance. Results regarding objectively measured physical activity were mixed. Although, no linear nor dose-response relationship was observed there was no indication of a higher activity level impairing the scholastic or cognitive

  19. Bicycle Sharing in Developing Countries : A proposal towards sustainable transportation in Brazilian median cities

    OpenAIRE

    Dias Batista, Edgard

    2010-01-01

    Bicycle-sharing programs are a new trend in urban transportation. The main difference of a bicycle-sharing program with a regular bicycle rental is that is possible to get a bicycle in one station and return it in any other station. There are many models of bicycle sharing, each model with its pros and cons. This study analyzes the bicycle-sharing models in order to build a proposal of a bicycle-sharing program suitable for Brazilian median cities. The study begins with an overview of bicycle...

  20. On the Commuting Graph Of Non-commutative Rings of order( p^nq

    Directory of Open Access Journals (Sweden)

    Ebrahim Vatandoost

    2014-07-01

    Full Text Available ‎Let $R$ be a non-commutative ring with unity‎. ‎The commuting graph‎‎of $R$ denoted by $\\Gamma(R$‎, ‎is a graph with vertex set‎‎$R\\setminus Z(R$ and two vertices $a$ and $b$ are adjacent iff‎‎$ab=ba$‎. ‎In this paper‎, ‎we consider the commuting graph of non-commutative‎rings of order $pq $ and $p^2q$ with $Z(R=0$ and non-commutative rings with‎unity of order $p^3q$‎. ‎It is proved that $C_R(a$ is a commutative ring for every‎$0 \

  1. Bicycle Helmet Laws are Associated with a Lower Fatality Rate from Bicycle-Motor Vehicle Collisions

    Science.gov (United States)

    Meehan, William P.; Lee, Lois K.; Fischer, Christopher M.; Mannix, Rebekah C.

    2013-01-01

    Objective To assess the association between bicycle helmet legislation and bicycle-related deaths sustained by children involved in bicycle-motor vehicle collisions. Study design We conducted a cross sectional study of all bicyclists aged 0-16 years included in the Fatality Analysis Reporting System (FARS) who died between January 1999 and December 2010. We compared fatality rates per age-specific state populations between states with helmet laws and those without helmet laws. We used a clustered Poisson multivariate regression model to adjust for factors previously associated with rates of motor vehicle fatalities: elderly driver licensure laws, legal blood alcohol limit ( 0.08 between states with helmet laws and those without helmet laws. The mean unadjusted rates of fatalities were lower in states with helmet laws (2.0/1,000,000 vs. 2.5/1,000,000; p= 0.03). After adjusting for potential confounding factors, states with mandatory helmet laws continued to be associated with a lower rate of fatalities (adjusted Incidence Rate Ratio 0.84; 95% CI 0.70, 0.98). Conclusions Bicycle helmet safety laws are associated with a lower incidence of fatalities among child bicyclists involved in motor vehicle collisions. PMID:23706604

  2. Commutative deductive systems of pseudo BCK-algebras

    OpenAIRE

    Ciungu, Lavinia Corina

    2016-01-01

    In this paper we generalize the axiom systems given by M. Pa{\\l}asi\\'nski, B. Wo\\'zniakowska and by W.H. Cornish for commutative BCK-algebras to the case of commutative pseudo BCK-algebras. A characterization of commutative pseudo BCK-algebras is also given. We define the commutative deductive systems of pseudo BCK-algebras and we generalize some results proved by Yisheng Huang for commutative ideals of BCI-algebras to the case of commutative deductive systems of pseudo BCK-algebras. We prove...

  3. Connections between migrations and commuting in Vojvodina

    Directory of Open Access Journals (Sweden)

    Lukić Vesna

    2012-01-01

    Full Text Available Various forms of population mobility are usually studied independently and thus lacking information if there is a connection between migration processes and if so, whether it is positive or negative. Based on the correlation method, this paper presents a study of the relationship between migration and commuting by the example of Vojvodina. Population and economic activities in Vojvodina are unevenly distributed and mainly concentrated to certain areas. Considering that the majority of rural population is no longer engaged in agriculture and that there are not enough local jobs in rural areas, numerous rural residents commute to work to cities. So, the majority of commuting flows in Vojvodina are flows of labour force from rural to urban areas. Results of statistical analysis, based on data about migrations to rural settlements of Vojvodina and data about divergent commuters, have shown a positive correlation between the two types of population mobility for all observed settlements (defined as addition, and that a significant proportion of migration variations can be explained by variations in the scope of commuting flows.

  4. Dynamics and local policy in labour commuting

    Directory of Open Access Journals (Sweden)

    Samo Drobne

    2012-01-01

    Full Text Available Background: In the paper, the influence of the selected parameters, which are population, travel time to work by car, employment rate and average gross earnings, to labour commuting flows in Slovenia is analysed for the period 2000 – 2009. Furthermore, the dynamics of the analysed parameters have been studied to be implemented in the local policy application. Objectives: The main goal of this research has been to study the stickiness and attractiveness of Slovenian municipalities regarding the analysed parameters to support local labour commuting policy. Methods/Approach: The influence of the analysed parameters to the labour commuting flows has been studied in the extended gravity model. The change of the influence of parameters on commuting flows has been studied separately for each year in the analysed period. Additionally, the calculation of the extended gravity model has been performed for the whole analysed period. Results: The results show that the analysed parameters more attracted than dispatched the inter-municipal labour commuting flows in Slovenia in the study period. The results of the study of the dynamics of the analysed parameters have been implemented in the case study at the local level. Conclusions: The results provide the important empirical contribution to physical planners at the state, regional and/or local level for creating development policies. The results show that some factors in the gravity model can be compensated with the change of the others and vice-versa.

  5. On Wiener polarity index of bicyclic networks

    Science.gov (United States)

    Ma, Jing; Shi, Yongtang; Wang, Zhen; Yue, Jun

    2016-01-01

    Complex networks are ubiquitous in biological, physical and social sciences. Network robustness research aims at finding a measure to quantify network robustness. A number of Wiener type indices have recently been incorporated as distance-based descriptors of complex networks. Wiener type indices are known to depend both on the network’s number of nodes and topology. The Wiener polarity index is also related to the cluster coefficient of networks. In this paper, based on some graph transformations, we determine the sharp upper bound of the Wiener polarity index among all bicyclic networks. These bounds help to understand the underlying quantitative graph measures in depth.

  6. Bicycle braking friction measurements on winter roads

    OpenAIRE

    Rekilä, Katja

    2015-01-01

    This master’s thesis study has been carried out during a student exchange in the Norwegian University of science and technology in the Research Centre for Winter maintenance. The master’s thesis consists of two parts: I) a process report and II) a manuscript for a scientific paper. In addition, appendix is marked as part III. Bicycling is considered an attractive way of traveling since it improves health, is flexible and often fastest mode of travelling in urban areas. Therefore it is bec...

  7. Solar Electric Bicycle Body Modeling and Simulation

    Directory of Open Access Journals (Sweden)

    Zhikun Wang

    2013-10-01

    Full Text Available A new solar electric bicycle design and study were carried out on in this paper. Application of CAD technology to establish three-dimension geometric model, using the kinetic analysis on the frame and other parts for numerical simulation and static strength analysis for the vehicle model design, virtual assembly, complete frame dynamics analysis and vibration analysis, with considering other factors, first on the frame structure improvement, second on security of design calculation analysis and comparison, finally get the ideal body design.

  8. Arizona Traffic Safety Education, K-8. Bicycle Safety, Grade 3.

    Science.gov (United States)

    Mesa Public Schools, AZ.

    One in a series designed to assist Arizona elementary and junior high school teachers in developing children's traffic safety skills, this curriculum guide for grade 3 contains seven lessons on bicycles and an appendix on conducting a bicycle rodeo. Introductory information provided for the teacher includes basic highway safety concepts, stressing…

  9. 77 FR 39927 - Vehicles and Traffic Safety-Bicycles

    Science.gov (United States)

    2012-07-06

    ... bicycle operator subject to most of the other traffic regulations in Part 4. 52 FR 10675, April 2, 1987... Responses to Public Comments The NPS published the proposed rule at 73 FR 76987 (December 18, 2008) and a... the special regulation requirement to ensure maximum public input on decisions to allow bicycle use...

  10. Bicycle facilities on road segments and intersections of distributor roads.

    NARCIS (Netherlands)

    2008-01-01

    A sustainably safe road environment requires bicycle facilities that separate motorized traffic from relatively vulnerable road users like cyclists. Research indicates that on distributor roads the road sections with adjoining or separate bicycle tracks are safer than the road sections without any b

  11. Bicycle Freewheeling with Air Drag as a Physics Experiment

    Science.gov (United States)

    Janssen, Paul; Janssens, Ewald

    2015-01-01

    To familiarize first-year students with the important ingredients of a physics experiment, we offer them a project close to their daily life: measuring the effect of air resistance on a bicycle. Experiments are done with a bicycle freewheeling on a downhill slope. The data are compared with equations of motions corresponding to different models…

  12. Infiuence of Bicycle Traffic on Capacity of Typical Signalized Intersection

    Institute of Scientific and Technical Information of China (English)

    CHEN Xiaoming; SHAO Chunfu; YUE Hao

    2007-01-01

    Bicycle traffic has a significant effect on the capacity of signalized intersections. This paper divides the influence of bicyclists on vehicular flow into four types with the time durations estimated based on probability, shock wave, and gap acceptance theory. Vehicular saturation flow rate is predicted for various conditions on the basis of the speed-flow curve for the capacity of typical intersections influenced by bicycle traffic.The model overcomes the limitations of the Highway Capacity Manual (HCM, 2000) method for left-turns due to data collection, and takes into account the effect of trapped bicycles on the through vehicular traffic.The numerical results show that the left-turn and through capacities predicted by the model are lower than those of the HCM method. The right-turn capacity is close to that of the HCM method at Iow bicycle volumes and higher than that of the HCM method at high bicycle volumes.

  13. Will a bicycle friendly policy make passenger travel more sustainably?

    DEFF Research Database (Denmark)

    Christensen, Linda; Jensen, Thomas Christian

    The purpose of this paper is to analyse the possibility to transfer a larger part of the short car trips to walking or bicycling in order to obtain environmental and health benefits. The project contains a logistic choice model used to explain which circumstances are particularly important for...... choosing walking and bicycling, and how very different instruments can promote walking and bicycling at the expense of short car trips. Furthermore, the paper describes the most important factors when choosing between bicycling and walking and car driving, respectively, in case of trips of up to 22 km...... and bicycling. The study shows that instruments that improve the cyclists’ speed and increase the car drivers’ time consumption and costs will influence the competition conditions significantly. The total transfer potential will be between 12 and 16 % of the car trips in case of short tours...

  14. Bicyclic Peptide Inhibitor of Urokinase-Type Plasminogen Activator

    DEFF Research Database (Denmark)

    Roodbeen, Renée; Paaske, Berit; Jiang, Longguang;

    2013-01-01

    The development of protease inhibitors for pharmacological intervention has taken a new turn with the use of peptidebased inhibitors. Here, we report the rational design of bicyclic peptide inhibitors of the serine protease urokinase-type plasminogen activator (uPA), based on the established...... monocyclic peptide, upain-2. It was successfully converted to a bicyclic peptide, without loss of inhibitory properties. The aim was to produce a peptide cyclised by an amide bond with an additional stabilising across-the-ring covalent bond. We expected this bicyclic peptide to exhibit a lower entropic...... burden upon binding. Two bicyclic peptides were synthesised with affinities similar to that of upain-2, and their binding energetics were evaluated by isothermal titration calorimetry. Indeed, compared to upain-2, the bicyclic peptides showed reduced loss of entropy upon binding to uPA. We also...

  15. Survey of how staff commute to work

    CERN Multimedia

    2014-01-01

    A survey was initiated by the Canton of Geneva (Direction Générale des Transports) and the Swiss Permanent Mission to the United Nations, and is aimed at better understanding how staff in International Organisations commute to/from work so as to better plan future works (road access, public transport, etc.). The ILO, WHO, UNAIDs, Global Fund, IFRC, CERN and UNOG are taking part in this important survey.   People living in Switzerland or France are invited to respond to this survey. The purpose of this survey is to better understand: - your commuting habits, - your willingness to explore alternative commuting options, - your expectations and needs. All data provided to this external company (www.mobilidee.ch) will be kept confidential and will only be used for this particular study. CERN has received all guarantees of confidentiality from this company. Many thanks for your collaboration! GS Department

  16. Commutative algebra constructive methods finite projective modules

    CERN Document Server

    Lombardi, Henri

    2015-01-01

    Translated from the popular French edition, this book offers a detailed introduction to various basic concepts, methods, principles, and results of commutative algebra. It takes a constructive viewpoint in commutative algebra and studies algorithmic approaches alongside several abstract classical theories. Indeed, it revisits these traditional topics with a new and simplifying manner, making the subject both accessible and innovative. The algorithmic aspects of such naturally abstract topics as Galois theory, Dedekind rings, Prüfer rings, finitely generated projective modules, dimension theory of commutative rings, and others in the current treatise, are all analysed in the spirit of the great developers of constructive algebra in the nineteenth century. This updated and revised edition contains over 350 well-arranged exercises, together with their helpful hints for solution. A basic knowledge of linear algebra, group theory, elementary number theory as well as the fundamentals of ring and module theory is r...

  17. Beating the traffic with commuting alternatives

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-05-01

    This pamphlet describes how, by encouraging commuting options, local governments can help reduce air pollution, fuel consumption, and traffic congestion. Minimizing these problems makes the community more appealing to businesses, residents, and visitors and boosts the local economy. Approaches to alternative transportation are as varied as the communities devising and using them. But the critical factor is initiative from local governments, often one of communities largest employers. They can use and promote commuting alternatives among their employees. Local governments can also promote alternative transportation among other employers and the general public. They can provide information on commuting options, improve the infrastructure, and use local authority to require and reward those changes necessary to make alternative transportation a widely accepted part of community life. Best of all, local governments can lead by example and establish a template for other employers to follow.

  18. Structural design of a composite bicycle fork

    International Nuclear Information System (INIS)

    Highlights: • Case study about composite bicycle fork design. • Special requirements for a Student Team project. • FE model to evaluate stiffness, strength and potential failure modes. • Comparison of two manufacturing approaches. • FE model stiffness validation on the manufactured fork. - Abstract: Despite the wide literature on the mechanical behaviour of carbon/epoxy composites, it is rare to find practical methodological approaches in finite element design of structural components made by laminate layup. Through the case study of a special bicycle fork needed in a Student Team prototype, this paper proposes a simplified methodology as starting point for educational and manufacturing purposes. In order to compare two manufacturing solutions in terms of stiffness, strength and failure mode, a numerical model was implemented. Since the project requirements imposed to avoid standard destructive testing, the model validation was based on a posteriori linear stiffness comparison with the manufactured component. The slight discrepancies between experimental and numerical results were discussed in order to check their origin and to assess the reliability of the model. The overall methodology, even if complain with only a part of the safety standard requirements, shows to be reliable enough and can be the basis for further extension and refinement

  19. The Design of Sport Bicycle Speed Odometer

    Directory of Open Access Journals (Sweden)

    Dongbing Liu

    2013-04-01

    Full Text Available As bicycle sport equipment, a sport bike needs a speed and distance measuring device, due to the characteristic of road cycling, thereby mastering the state of motion. According to external conditions such as temperature, wind speed, the bike can make the appropriate adjustment to achieve the best movement effect. The bicycle speed odometer is a major accessibility tool that satisfies with needs of the people with fast development. This study elaborated a bike speed odometer design based on Hall element, taking AT89C52 single chip as the core, measuring speed with A44E Hall sensor, to finish the bike mileage/speed measurement and statistics by displaying bike mileage and speed in real time. By using the Hall elements, the hardware of speed odometer input the number of pulse of per circle into the single-chip computer system. Then the signal processed by the single-chip computer displays. The software is programmed with assembly language and modular design idea. The design of the hardware circuit is simple and the subroutine has universal property, which fully meet the design requirements and possess a wide range of application and dissemination value.

  20. Noncommutative Grobner Bases for Almost Commutative Algebras

    OpenAIRE

    Li, Huishi

    2007-01-01

    Let $K$ be an infinite field and $K =K$ the free associative algebra generated by $X=\\{X_1,...,X_n\\}$ over $K$. It is proved that if $I$ is a two-sided ideal of $K$ such that the $K$-algebra $A=K /I$ is almost commutative in the sense of [3], namely, with respect to its standard $\\mathbb{N}$-filtration $FA$, the associated $\\mathbb{N}$-graded algebra $G(A)$ is commutative, then $I$ is generated by a finite Gr\\"obner basis. Therefor, every quotient algebra of the enve...

  1. Two Approaches to Non-Commutative Geometry

    CERN Document Server

    Kisil, V V

    1997-01-01

    Looking to the history of mathematics one could find out two outer approaches to Geometry. First one (algebraic) is due to Descartes and second one (group-theoretic)--to Klein. We will see that they are not rivalling but are tied (by Galois). We also examine their modern life as philosophies of non-commutative geometry. Connections between different objects (see keywords) are discussed. Keywords: Heisenberg group, Weyl commutation relation, Manin plain, quantum groups, SL(2, R), Hardy space, Bergman space, Segal-Bargmann space, Szeg"o projection, Bergman projection, Clifford analysis, Moebius transformations, functional calculus, Weyl calculus (quantization), Berezin quantization, Wick ordering, quantum mechanics.

  2. A somewhat gentle introduction to differential graded commutative algebra

    OpenAIRE

    Beck, Kristen A.; Sather-Wagstaff, Sean

    2013-01-01

    Differential graded (DG) commutative algebra provides powerful techniques for proving theorems about modules over commutative rings. These notes are a somewhat colloquial introduction to these techniques. In order to provide some motivation for commutative algebraists who are wondering about the benefits of learning and using these techniques, we present them in the context of a recent result of Nasseh and Sather-Wagstaff. These notes were used for the course "Differential Graded Commutative ...

  3. A reconstruction theorem for almost-commutative spectral triples

    OpenAIRE

    Ćaćić, Branimir

    2012-01-01

    We propose an expansion of the definition of almost-commutative spectral triple that accommodates non-trivial fibrations and is stable under inner fluctuation of the metric, and then prove a reconstruction theorem for almost-commutative spectral triples under this definition as a simple consequence of Connes's reconstruction theorem for commutative spectral triples. Along the way, we weaken the orientability hypothesis in the reconstruction theorem for commutative spectral triples, and follow...

  4. On strongly clean matrices over commutative clean rings

    OpenAIRE

    Burgess, Walter

    2014-01-01

    The literature about strongly clean matrices over commutative rings is quite extensive. The sharpest results are about matrices over commutative local rings, for example those by Borooah, Diesl and Dorsey. The purpose of this note is to show that, using Pierce sheaf techniques, many of the known results about matrices over commutative local rings can be extended to those over commutative clean rings in general.

  5. Helmet wearing among users of a public bicycle-sharing program in the district of columbia and comparable riders on personal bicycles.

    Science.gov (United States)

    Kraemer, John D; Roffenbender, Jason S; Anderko, Laura

    2012-08-01

    Bicycle-sharing programs are increasingly popular and have the potential to increase physical activity and decrease air pollution, but anecdotal evidence suggests helmet use is lower among users of bicycle-sharing programs than cyclists on private bicycles. We conducted a cross-sectional study to assess helmet use among users of a bicycle-sharing program in Washington, DC. Helmet use was significantly lower among cyclists on shared bicycles than private bicycles, highlighting a need for targeted helmet promotion activities. PMID:22698021

  6. Helmet Wearing Among Users of a Public Bicycle-Sharing Program in the District of Columbia and Comparable Riders on Personal Bicycles

    Science.gov (United States)

    Roffenbender, Jason S.; Anderko, Laura

    2012-01-01

    Bicycle-sharing programs are increasingly popular and have the potential to increase physical activity and decrease air pollution, but anecdotal evidence suggests helmet use is lower among users of bicycle-sharing programs than cyclists on private bicycles. We conducted a cross-sectional study to assess helmet use among users of a bicycle-sharing program in Washington, DC. Helmet use was significantly lower among cyclists on shared bicycles than private bicycles, highlighting a need for targeted helmet promotion activities. PMID:22698021

  7. Non-Commutative Formal Groups In Positive Characterstic

    OpenAIRE

    Leitner, Frederick

    2006-01-01

    We describe geometric non-commutative formal groups in terms of a geometric commutative formal group with a Poisson structure on its splay algebra. We describe certain natural properties of such Poisson structures and show that any such Poisson structure gives rise to a non-commutative formal group.

  8. The maximal commutative subalgebra of a Leavitt path algebra

    OpenAIRE

    Canto, Cristóbal Gil; Nasr-Isfahani, Alireza

    2015-01-01

    For any unital commutative ring $R$ and for a graph $E$, we identify a maximal commutative subalgebra of the Leavitt path algebra of $E$ with coefficients in $R$. Besides we are able to characterize injectivity of representations which gives a generalization of Cuntz-Krieger uniqueness theorem, and by other hand, to generalize and simplify the result about commutative Leavitt path algebras over fields.

  9. Improving bicycle safety: The role of paediatricians and family physicians.

    Science.gov (United States)

    Leblanc, John C; Huybers, Sherry

    2004-05-01

    Cycling is a complex activity requiring motor, sensory and cognitive skills that develop at different rates from childhood to adolescence. While children can successfully ride a two-wheeled bicycle at age five or six, judgment of road hazards are poor at that age and matures slowly until adult-like judgment is reached in early adolescence. Safe cycling depends on the care, skills and judgment of cyclists and motorists; roadway design that promotes safe coexistence of bicycles and motor vehicles; and the use of safety devices, including bicycle helmets, lights and reflective tape. Whereas, research into optimal roadway design and educational programs for drivers to improve road safety has yielded contradictory results, the benefits of bicycle helmet use and programs to enhance their use have been clearly shown. This paper has the following objectives for paediatricians and family physicians: To understand the relationship between bicycle safety and children's motor and cognitive skills.To understand the effectiveness and limitations of strategies to improve bicycle safety.To describe activities to promote bicycle safety that physicians can undertake in clinical settings and in the community. PMID:19657515

  10. Young tableaux and homotopy commutative algebras

    OpenAIRE

    Dubois-Violette, Michel; Popov, Todor

    2012-01-01

    A homotopy commutative algebra, or $C_{\\infty}$-algebra, is defined via the Tornike Kadeishvili homotopy transfer theorem on the vector space generated by the set of Young tableaux with self-conjugated Young diagrams. We prove that this $C_{\\infty}$-algebra is generated in degree 1 by the binary and the ternary operations.

  11. First steps in brave new commutative algebra

    OpenAIRE

    Greenlees, J. P. C.

    2006-01-01

    This is an expository account of completion and local cohomology in brave new commutative algebra, especially as it applies to completion theorems and their duals in equivariant topology. The first part is fairly direct, but the second considers Morita theory and Gorenstein ring spectra. This draws on work of the author with Benson, Dwyer, Iyengar and May, amongst others.

  12. Poincare duality and commutative differential graded algebras

    OpenAIRE

    Lambrechts, Pascal; Stanley, Don

    2007-01-01

    We prove that every commutative differential graded algebra whose cohomology is a simply-connected Poincare duality algebra is quasi-isomorphic to one whose underlying algebra is simply-connected and satisfies Poincare duality in the same dimension. This has application in particular to the study of CDGA models of configuration spaces on a closed manifold.

  13. Algebra cohomology over a commutative algebra revisited

    OpenAIRE

    Pirashvili, Teimuraz

    2003-01-01

    The aim of this paper is to give a relatively easy bicomplex which computes the Shukla, or Quillen cohomology in the category of associative algebras over a commutative algebra $A$, in the case when $A$ is an algebra over a field.

  14. Special functions and q-commuting variables

    OpenAIRE

    Koornwinder, Tom H.

    1996-01-01

    This paper is mostly a survey, with a few new results. The first part deals with functional equations for q-exponentials, q-binomials and q-logarithms in q-commuting variables and more generally under q-Heisenberg relations. The second part discusses translation invariance of Jackson integrals, q-Fourier transforms and the braided line.

  15. (non)commutative f-un geometry

    OpenAIRE

    Bruyn, Lieven Le

    2009-01-01

    Stressing the role of dual coalgebras, we modify the definition of affine schemes over the 'field with one element'. This clarifies the appearance of Habiro-type rings in the commutative case, and, allows a natural noncommutative generalization, the study of representations of discrete groups and their profinite completions being our main motivation.

  16. Non-commutative Sylvester's determinantal identity

    OpenAIRE

    Konvalinka, Matjaz

    2007-01-01

    Sylvester's identity is a classical determinantal identity with a straightforward linear algebra proof. We present a new, combinatorial proof of the identity, prove several non-commutative versions, and find a $\\beta$-extension that is both a generalization of Sylvester's identity and the $\\beta$-extension of the MacMahon master theorem.

  17. The telescope conjecture for semihereditary commutative rings

    OpenAIRE

    Bazzoni, Silvana

    2013-01-01

    The paper has been withdrawn, since there is a mistake in Proposition 5.2. The result on the telescope conjecture for semihereditary rings is correct, but the characterization of the smashing subcategories of the derived category of commutative rings is not complete.

  18. Non-commutative arithmetic circuits with division

    Czech Academy of Sciences Publication Activity Database

    Hrubeš, Pavel; Wigderson, A.

    2015-01-01

    Roč. 11, Article 14 (2015), s. 357-393. ISSN 1557-2862 EU Projects: European Commission(XE) 339691 - FEALORA Institutional support: RVO:67985840 Keywords : arithmetic circuits * non-commutative rational function * skew field Subject RIV: BA - General Mathematics http://theoryofcomputing.org/articles/v011a014/

  19. Z-polynomials and ring commutativity

    OpenAIRE

    Buckley, S.M.; McHale, D.

    2012-01-01

    We characterise polynomials f with integer coefficients such that a ring with unity R is necessarily commutative if f(x) is central for all x Ɛ R. We also solve the corresponding problem without the assumption that the ring has a unity.

  20. Minimal Varieties of Representable Commutative Residuated Lattices

    Czech Academy of Sciences Publication Activity Database

    Horčík, Rostislav

    2012-01-01

    Roč. 100, č. 6 (2012), s. 1063-1078. ISSN 0039-3215 R&D Projects: GA ČR GAP202/10/1826 Institutional research plan: CEZ:AV0Z10300504 Keywords : commutative residuated lattice * subvariety lattice * minimal variety * substructural logic * maximally consistent logic Subject RIV: BA - General Mathematics Impact factor: 0.342, year: 2012

  1. Commutative monads as a theory of distributions

    DEFF Research Database (Denmark)

    Kock, Anders

    2012-01-01

    It is shown how the theory of commutative monads provides an axiomatic framework for several aspects of distribution theory in a broad sense, including probability distributions, physical extensive quantities, and Schwartz distributions of compact support. Among the particular aspects considered...... here are the notions of convolution, density, expectation, and conditional probability....

  2. Anomalous commutator corrections to sum rules

    International Nuclear Information System (INIS)

    In this paper we consider the contributions of anomalous commutators to various QCD sum rules. Using a combination of the Bjorken-Johnson-Low limit with the operator product expansion the results are presented in terms of the vacuum condensates of gauge-invariant operators. It is demonstrated that the anomalous contributions are non-negligible and reconcile various apparently contradictory calculations

  3. Non-commutative arithmetic circuits with division

    Czech Academy of Sciences Publication Activity Database

    Hrubeš, Pavel; Wigderson, A.

    2015-01-01

    Roč. 11, Article 14 (2015), s. 357-393. ISSN 1557-2862 EU Projects: European Commission(XE) 339691 - FEALORA Institutional support: RVO:67985840 Keywords : arithmetic circuits * non-commutative rational function * skew field Subject RIV: BA - General Mathematics http://theoryofcomputing.org/ articles /v011a014/

  4. Hermiticity of quantum observables versus commutation relations

    International Nuclear Information System (INIS)

    In order to obtain sum rules and spectral representations the Hermiticity property = of observables is used. It is shown that for certain Ψ and Φ the property turn out to be inconsistent with the commutation relations that contain Α. The known Schwinger paradox is explained by this inconsistency

  5. A Cohomology Theory for Commutative Monoids

    Directory of Open Access Journals (Sweden)

    María Calvo-Cervera

    2015-10-01

    Full Text Available Extending Eilenberg–Mac Lane’s cohomology of abelian groups, a cohomology theory is introduced for commutative monoids. The cohomology groups in this theory agree with the pre-existing ones by Grillet in low dimensions, but they differ beyond dimension two. A natural interpretation is given for the three-cohomology classes in terms of braided monoidal groupoids.

  6. Spin in the path integral: anti-commuting versus commuting variables

    OpenAIRE

    Scholtz, F. G.; Theron, A. N.; Geyer, H. B.

    1994-01-01

    We discuss the equivalence between the path integral representations of spin dynamics for anti-commuting (Grassmann) and commuting variables and establish a bosonization dictionary for both generators of spin and single fermion operators. The content of this construction in terms of the representations of the spin algebra is discussed in the path integral setting. Finally it is shown how a `free field realization' (Dyson mapping) can be constructed in the path integral.

  7. The frequency of single-bicycle crashes (SBCs) in countries with varying bicycle mode shares

    DEFF Research Database (Denmark)

    Schepers, Paul; Agerholm, Niels; Amoros, Emmanuelle;

    In  order  to  encourage  cycling,  we  need  to  reduce  the  hazards  that  cyclists  face. Single-bicycle crashes or ‘bicycle-only crashes’ are falls and obstacle collisions in which only one cyclist is involved. Between 60 and 95% of cyclists admitted to hospital or treated at an emergency...... department are victims of single-bicycle crashes. As proportion of the total number of traffic casualties  the  share  exceeds  20%  in  most  countries  with  medium  to  high  levels  of cycling.  This paper  discusses  the  prevalence  of  the  problem  and  describes  measures  that  may  both reduce the...

  8. Use and activity levels on newly built bicycle playgrounds

    DEFF Research Database (Denmark)

    Schipperijn, Jasper; Hansen, Christine Kier; Rask, Simon

    2015-01-01

    Increasing the use of urban green space (UGS) as well as increasing cycling could potentially help address the growing inactivity problem. Three bicycle playgrounds were designed based on a participatory process and afterwards constructed in the UGS along a cycle-route on the historic outer defence...... close to one of the sites. A future study involving objective before and after measures when a new bicycle playground is build will be needed to reveal if bicycle playgrounds can provide additional activity to its users, or ‘just’ a different type of activity, in a different location....

  9. Efficiency of choice set generation methods for bicycle routes

    DEFF Research Database (Denmark)

    Halldórsdóttir, Katrín; Rieser-Schussler, Nadine; Axhausen, Kay W.;

    2014-01-01

    The current study analyses the efficiency of choice set generation methods for bicycle routes and proposes the extension of cost functions to bicycle-oriented factors not limited to distance and time. Three choice set generation methods for route choice were examined in their ability to generate...... scenic routes, dedicated cycle lanes, and road type. Data consisted of 778 bicycle trips traced by GPS and carried out by 139 persons living in the Greater Copenhagen Area, in Denmark. Results suggest that both the breadth first search on link elimination and the doubly stochastic generation function...

  10. Symbolic derivation of bicycle kinematics with toroidal wheels

    Directory of Open Access Journals (Sweden)

    Wang Everett X.

    2015-01-01

    Full Text Available Bicycle kinematics with toroidal wheels is presented in this paper. Using symbolic mathematic tool Maple, we obtain two holonomic and four nonholonomic constraint equations due to front and rear wheels of a bicycle. We show that the two holonomic constraints cannot be expressed in quartic form for bicycle rear body pitch angle unless the minor (crown radius of the torus are the same for both the front and rear wheels. In addition, we show that all the constraints can be written in differential form, from which a constraint matrix is constructed, according to standard procedure for developing dynamics in robotics.

  11. Bamboo Bicycle – Past or Future?

    Directory of Open Access Journals (Sweden)

    Suzana Jakovljević

    2016-01-01

    Full Text Available In this article the experiment was carried out to establish tensile strength values of two different bamboo species, which are obtained by the static tensile test. The tensile strength results of two tested species Tonkin Cane and Ku Zhu bamboo are presented and compared with traditional materials used for bicycle frame to determine their suitability for designing a frame. Physiology and other properties of bamboo were elaborated as well. The purpose of this study was to gain more knowledge on bamboo and prove his suitability in use as an alternative for ecologically unacceptable materials. Therefore, application of the natural materials is essential for the sustainable development. The fact that they have unlimited resources the use of bamboo has great potential and this article explains why.

  12. Bicyclic graphs with maximal revised Szeged index

    CERN Document Server

    Li, Xueliang

    2011-01-01

    The revised Szeged index $Sz^*(G)$ is defined as $Sz^*(G)=\\sum_{e=uv \\in E}(n_u(e)+ n_0(e)/2)(n_v(e)+ n_0(e)/2),$ where $n_u(e)$ and $n_v(e)$ are, respectively, the number of vertices of $G$ lying closer to vertex $u$ than to vertex $v$ and the number of vertices of $G$ lying closer to vertex $v$ than to vertex $u$, and $n_0(e)$ is the number of vertices equidistant to $u$ and $v$. Hansen used the AutoGraphiX and made the following conjecture about the revised Szeged index for a connected bicyclic graph $G$ of order $n \\geq 6$:

  13. Bicycling induced pudendal nerve pressure neuropathy.

    Science.gov (United States)

    Silbert, P L; Dunne, J W; Edis, R H; Stewart-Wynne, E G

    1991-01-01

    Pudendal neuropathies are well recognised as part of more generalised peripheral neuropathies; however, focal abnormalities of the pudendal nerve due to cycling-related injuries have been infrequently reported. We describe two patients who developed pudendal neuropathies secondary to pressure effects on the perineum from racing-bicycle saddles. Both were male competitive athletes, one of whom developed recurrent numbness of the penis and scrotum after prolonged cycling; the other developed numbness of the penis, an altered sensation of ejaculation, with disturbance of micturition and reduced awareness of defecation. Both patients improved with alterations in saddle position and riding techniques. We conclude that pudendal nerve pressure neuropathy can result from prolonged cycling, particularly when using a poor riding technique. PMID:1821826

  14. The effect of tyre and rider properties on the stability of a bicycle

    OpenAIRE

    Bulsink, V.E.; Doria, A.; Belt, van de, M.; Koopman, H.F.J.M.

    2015-01-01

    To work towards an advanced model of the bicycle-rider-environment system, an open-loop bicycle-rider model was developed in the commercial multibody dynamics software ADAMS. The main contribution of this article to bicycle dynamics is the analysis of tyre and rider properties that influence bicycle stability. A system identification method is used to extract linear stability properties from time domain analysis. The weave and capsize eigenmodes of the bicycle-rider system are analysed. The e...

  15. Exploring characteristics and motives of long distance commuter cyclists

    DEFF Research Database (Denmark)

    Hansen, Karsten Bruun; Sick Nielsen, Thomas

    2014-01-01

    , commuter cyclists (45 km from home to work) have more mobility options, higher incomes, and a longer education than other commuter cyclists. The main motive for longer distance cycling is physical exercise, followed by reduced costs and time used for traveling. The long distance commuter cyclists surveyed......Longer distance cycling is a commuting mode that contributes to sustainability and public health objectives, but little is known about current long distance cyclist's motives. The paper explores longer distance commuter cyclists, their characteristics, practice and motives. Longer distance...

  16. An international review of the frequency of single-bicycle crashes (SBCs) and their relation to bicycle modal share

    DEFF Research Database (Denmark)

    Schepers, Paul; Agerholm, Niels; Amoros, Emmanuelle; Benington, Rob; Bjørnskau, Torkel; Dhondt, Stijn; de Geus, Bas; Hagemeister, Carmen; Loo, Becky P. Y.; Niska, Anna

    2015-01-01

    Objectives To study cyclists’ share of transport modes (modal share) and single-bicycle crashes (SBCs) in different countries in order to investigate if the proportion of cyclist injuries resulting from SBCs is affected by variation in modal share. Methods A literature search identified figures...... SBC casualties among the total number of road crash casualties increases proportionally less than the increase in bicycle modal share. Conclusions While most fatal injuries among cyclists are due to motor vehicle–bicycle crashes, most hospital admissions and emergency department attendances result...

  17. Fluid Mechanics of a High Performance Racing Bicycle Wheel

    Science.gov (United States)

    Mercat, Jean-Pierre; Cretoux, Brieuc; Huat, Francois-Xavier; Nordey, Benoit; Renaud, Maxime; Noca, Flavio

    2013-11-01

    In 2012, MAVIC released the most aerodynamic bicycle wheel on the market, the CXR 80. The french company MAVIC has been a world leader for many decades in the manufacturing of bicycle wheels for competitive events such as the Olympic Games and the Tour de France. Since 2010, MAVIC has been in a research partnership with the University of Applied Sciences in Geneva, Switzerland, for the aerodynamic development of bicycle wheels. While most of the development up to date has been performed in a classical wind tunnel, recent work has been conducted in an unusual setting, a hydrodynamic towing tank, in order to achieve low levels of turbulence and facilitate quantitative flow visualization (PIV). After a short introduction on the aerodynamics of bicycle wheels, preliminary fluid mechanics results based on this novel setup will be presented.

  18. Associations between bicycling and carotid arterial stiffness in adolescents

    DEFF Research Database (Denmark)

    Ried-Larsen, M; Grøntved, A; Østergaard, Lars;

    2015-01-01

    The aim of the study was to investigate the associations between bicycling and carotid arterial stiffness, independent of objectively measured moderate-and-vigorous physical activity. This cross-sectional study included 375 adolescents (age 15.7 ± 0.4 years) from the Danish site of the European...... Youth Heart Study. Total frequency of bicycle usage was assessed by self-report, and carotid arterial stiffness was assessed using B-mode ultrasound. After adjusting for pubertal status, body height, and objectively measured physical activity and other personal lifestyle and demographic factors, boys...... using their bicycle every day of the week displayed a higher carotid arterial compliance {standard beta 0.47 [95% confidence interval (CI) 0.07-0.87]} and distension [standard beta 0.38 (95% CI -0.04 to 0.81)]. Boys using their bicycle every day of the week furthermore displayed a lower Young's elastic...

  19. The safety impact of a yellow bicycle jacket

    DEFF Research Database (Denmark)

    Lahrmann, Harry; Madsen, Tanja Kidholm Osmann

    2016-01-01

    The hypothesis of this project is that the safety of cyclists can be improved by increasing their visibility in traffic. This is explored by testing whether or not a high-visibility bicycle jacket (colour and reflectors) will increase the safety of cyclists. The project has been carried out as a...... randomized controlled trial with 6,800 volunteer cyclists. After random selection, half of the group – the test group – got the bicycle jacket at once and promised to wear it each time they biked during a year. The other half of the group composed a control group that got the bicycle jacket after the closing...... of the project, i.e. after a year. The safety effect of the bicycle jacket was analysed by comparing the number of self-reported accident for the test and control group. The self-reported accidents showed that the test group had 38 % fewer personal injury accidents with other road users – so...

  20. Interventions in Bicycle Infrastructure, Lessons from Dutch and Danish Cases

    DEFF Research Database (Denmark)

    van Goeverden, K.; Nielsen, Thomas Alexander Sick; Harder, Henrik;

    2015-01-01

    evident. At the time, in both countries large scale interventions in bicycle infrastructure were introduced and evaluated extensively in order to create knowledge on efficient promoting of cycling in urban areas. The interventions included the construction of new bicycle routes on urban arterials in some...... larger cities and an area wide comprehensive upgrade of the bicycle network one medium sized city (Delft). The evaluations were based on before and after studies where in the case of Delft also a long-term after study was performed. The evaluations produced a wealth of information about the impacts of...... interventions in bicycle infrastructure on travel choices, safety, design appreciation, and other factors. These clarify under which conditions certain measures are effective or not and inform about the effectiveness of improving a single route versus upgrading a whole network. The information from the studies...

  1. Carbon monoxide levels in popular passenger commuting modes traversing major commuting routes in Hong Kong

    International Nuclear Information System (INIS)

    Vehicle exhaust is a major source of air pollution in metropolitan cities. Commuters are exposed to high traffic-related pollutant concentrations. Public transportation is the most popular commuting mode in Hong Kong and there are about 10.8 million passenger trips every day. Two-thirds of them are road commuters. An extensive survey was conducted to measure carbon monoxide in three popular passenger commuting modes, bus, minibus, and taxi, which served, respectively, 3.91 million, 1.76 million and 1.31 million passenger trips per day in 1998. Three types of commuting microenvironments were selected: urban-urban, urban-suburban and urban-rural. Results indicated that in-vehicle CO level increased in the following order: bus, minibus and taxi. The overall average in-vehicle CO level in air-conditioned bus, minibus and taxi were 1.8, 2.9 and 3.3ppm, respectively. The average concentration level between air-conditioned buses (1.8ppm) and non-air-conditioned buses (1.9ppm) was insignificant. The fluctuation of in-vehicle CO level of non-air-conditioned vehicle followed the variation of out-vehicle CO concentration. Our result also showed that even in air-conditioned vehicles, the in-vehicle CO concentration was affected by the out-vehicle CO concentration although there exists a smoothing out effect. The in-vehicle CO level was the highest in urban-suburban commuting routes and was followed by urban-urban routes. The in-vehicle CO level in urban-rural routes was the lowest. The highest CO level was recorded after the vehicle traversed through tunnel.. The average CO exposure level of public road transportation commuters in Honk Kong was lower than most other cities. Factors governing the CO levels were also discussed. (Author)

  2. Improving bicycle safety: The role of paediatricians and family physicians

    OpenAIRE

    LeBlanc, John C.; Huybers, Sherry

    2004-01-01

    Cycling is a complex activity requiring motor, sensory and cognitive skills that develop at different rates from childhood to adolescence. While children can successfully ride a two-wheeled bicycle at age five or six, judgment of road hazards are poor at that age and matures slowly until adult-like judgment is reached in early adolescence. Safe cycling depends on the care, skills and judgment of cyclists and motorists; roadway design that promotes safe coexistence of bicycles and motor vehicl...

  3. Modeling the Distribution Characteristics of Urban Public Bicycle Rental Duration

    OpenAIRE

    Shuichao Zhang; Kangkang He; Sheng Dong; Jibiao Zhou

    2016-01-01

    In order to model the distribution characteristics of public bicycle rental durations, individual journey data for three cities in China (Ningbo, Hangzhou, and Beijing), for weekdays, was obtained. The distribution curves for public bicycle rental duration in the three cities were found to be extremely similar, with small differences among the weekdays. The basic parameters such as the average rental duration, the rental duration corresponding to the maximum rental frequency, and the rental d...

  4. BICYCLE TRANSPORT IN URBAN TRANSPORT OF KONYA CITY

    OpenAIRE

    LORASOKKAY, Mehmet Ali; AĞIRDIR, M. Levent

    2011-01-01

    The use of motor vehicles in the cities of Turkey is increasing with every passing day due to the cities rapidly expanding in Turkey. The share of environment-friendly transportation types entirely based on manpower such as pedestrian and bicycle transports in urban areas continuously decreases due to expanding urban residential areas. For urban transportation, bicycle is an individual, independent and fast transportation vehicle similar to motor vehicles in terms of its properties such as it...

  5. On the Skill of Balancing While Riding a Bicycle.

    Science.gov (United States)

    Cain, Stephen M; Ashton-Miller, James A; Perkins, Noel C

    2016-01-01

    Humans have ridden bicycles for over 200 years, yet there are no continuous measures of how skill differs between novice and expert. To address this knowledge gap, we measured the dynamics of human bicycle riding in 14 subjects, half of whom were skilled and half were novice. Each subject rode an instrumented bicycle on training rollers at speeds ranging from 1 to 7 m/s. Steer angle and rate, steer torque, bicycle speed, and bicycle roll angle and rate were measured and steering power calculated. A force platform beneath the roller assembly measured the net force and moment that the bicycle, rider and rollers exerted on the floor, enabling calculations of the lateral positions of the system centers of mass and pressure. Balance performance was quantified by cross-correlating the lateral positions of the centers of mass and pressure. The results show that all riders exhibited similar balance performance at the slowest speed. However at higher speeds, the skilled riders achieved superior balance performance by employing more rider lean control (quantified by cross-correlating rider lean angle and bicycle roll angle) and less steer control (quantified by cross-correlating steer rate and bicycle roll rate) than did novice riders. Skilled riders also used smaller steering control input with less variation (measured by average positive steering power and standard deviations of steer angle and rate) and less rider lean angle variation (measured by the standard deviation of the rider lean angle) independent of speed. We conclude that the reduction in balance control input by skilled riders is not due to reduced balance demands but rather to more effective use of lean control to guide the center of mass via center of pressure movements. PMID:26910774

  6. On the Skill of Balancing While Riding a Bicycle.

    Directory of Open Access Journals (Sweden)

    Stephen M Cain

    Full Text Available Humans have ridden bicycles for over 200 years, yet there are no continuous measures of how skill differs between novice and expert. To address this knowledge gap, we measured the dynamics of human bicycle riding in 14 subjects, half of whom were skilled and half were novice. Each subject rode an instrumented bicycle on training rollers at speeds ranging from 1 to 7 m/s. Steer angle and rate, steer torque, bicycle speed, and bicycle roll angle and rate were measured and steering power calculated. A force platform beneath the roller assembly measured the net force and moment that the bicycle, rider and rollers exerted on the floor, enabling calculations of the lateral positions of the system centers of mass and pressure. Balance performance was quantified by cross-correlating the lateral positions of the centers of mass and pressure. The results show that all riders exhibited similar balance performance at the slowest speed. However at higher speeds, the skilled riders achieved superior balance performance by employing more rider lean control (quantified by cross-correlating rider lean angle and bicycle roll angle and less steer control (quantified by cross-correlating steer rate and bicycle roll rate than did novice riders. Skilled riders also used smaller steering control input with less variation (measured by average positive steering power and standard deviations of steer angle and rate and less rider lean angle variation (measured by the standard deviation of the rider lean angle independent of speed. We conclude that the reduction in balance control input by skilled riders is not due to reduced balance demands but rather to more effective use of lean control to guide the center of mass via center of pressure movements.

  7. Test verification and design of the bicycle frame parameters

    Science.gov (United States)

    Zhang, Long; Xiang, Zhongxia; Luo, Huan; Tian, Guan

    2015-07-01

    Research on design of bicycles is concentrated on mechanism and auto appearance design, however few on matches between the bike and the rider. Since unreasonable human-bike relationship leads to both riders' worn-out joints and muscle injuries, the design of bicycles should focus on the matching. In order to find the best position of human-bike system, simulation experiments on riding comfort under different riding postures are done with the lifemode software employed to facilitate the cycling process as well as to obtain the best position and the size function of it. With BP neural network and GA, analyzing simulation data, conducting regression analysis of parameters on different heights and bike frames, the equation of best position of human-bike system is gained at last. In addition, after selecting testers, customized bikes based on testers' height dimensions are produced according to the size function. By analyzing and comparing the experimental data that are collected from testers when riding common bicycles and customized bicycles, it is concluded that customized bicycles are four times even six times as comfortable as common ones. The equation of best position of human-bike system is applied to improve bikes' function, and the new direction on future design of bicycle frame parameters is presented.

  8. Bicycle helmet use and non-use - recently published research.

    Science.gov (United States)

    Uibel, Stefanie; Müller, Daniel; Klingelhoefer, Doris; Groneberg, David A

    2012-01-01

    Bicycle traumata are very common and especially neurologic complications lead to disability and death in all stages of the life. This review assembles the most recent findings concerning research in the field of bicycle traumata combined with the factor of bicycle helmet use. The area of bicycle trauma research is by nature multidisciplinary and relevant not only for physicians but also for experts with educational, engineering, judicial, rehabilitative or public health functions. Due to this plurality of global publications and special subjects, short time reviews help to detect recent research directions and provide also information from neighbour disciplines for researchers. It can be stated that to date, that although a huge amount of research has been conducted in this area more studies are needed to evaluate and improve special conditions and needs in different regions, ages, nationalities and to create successful prevention programs of severe head and face injuries while cycling.Focus was explicit the bicycle helmet use, wherefore sledding, ski and snowboard studies were excluded and only one study concerning electric bicycles remained due to similar motion structures within this review. The considered studies were all published between January 2010 and August 2011 and were identified via the online databases Medline PubMed and ISI Web of Science. PMID:22632628

  9. An international review of the frequency of single-bicycle crashes (SBCs) and their relation to bicycle modal share

    DEFF Research Database (Denmark)

    Schepers, Paul; Agerholm, Niels; Amoros, Emmanuelle;

    2015-01-01

    Objectives To study cyclists’ share of transport modes (modal share) and single-bicycle crashes (SBCs) in different countries in order to investigate if the proportion of cyclist injuries resulting from SBCs is affected by variation in modal share. Methods A literature search identified figures...... (largely from western countries) on SBC casualties who are fatally injured, hospitalised or treated at an emergency department. Correlation and regression analyses were used to investigate how bicycle modal share is related to SBCs. Results On average, 17% of fatal injuries to cyclists are caused by SBCs...... SBC casualties among the total number of road crash casualties increases proportionally less than the increase in bicycle modal share. Conclusions While most fatal injuries among cyclists are due to motor vehicle–bicycle crashes, most hospital admissions and emergency department attendances result...

  10. Associations of Physical Activity, Sports Participation and Active Commuting on Mathematic Performance and Inhibitory Control in Adolescents

    DEFF Research Database (Denmark)

    Domazet, Sidsel L; Tarp, Jakob; Huang, Tao;

    2016-01-01

    OBJECTIVES: To examine objectively measured physical activity level, organized sports participation and active commuting to school in relation to mathematic performance and inhibitory control in adolescents. METHODS: The design was cross-sectional. A convenient sample of 869 sixth and seventh grade...... students (12-14 years) was invited to participate in the study. A total of 568 students fulfilled the inclusion criteria and comprised the final sample for this study. Mathematic performance was assessed by a customized test and inhibitory control was assessed by a modified Eriksen flanker task. Physical...... level was stratified by bicycling status in order to bypass measurement error subject to the accelerometer. RESULTS: Non-cyclists in the 2nd quartile of counts per minute displayed a higher mathematic score, so did cyclists in the 2nd and 3rd quartile of moderate-to-vigorous physical activity relative...

  11. Non-commutative time-frequency tomography

    CERN Document Server

    Man'ko, V I

    1999-01-01

    The characterization of non-stationary signals requires joint time and frequency information. However, time (t) and frequency (omega) being non-commuting variables there cannot be a joint probability density in the (t,omega) plane and the time-frequency distributions, that have been proposed, have difficult interpretation problems arising from negative or complex values and spurious components. As an alternative we propose to obtain time-frequency information by looking at the marginal distributions along rotated directions in the (t,omega) plane. The rigorous probability interpretation of the marginal distributions avoids all interpretation ambiguities. Applications to signal analysis and signal detection are discussed as well as an extension of the method to other pairs of non-commuting variables.

  12. Mapping commuter cycling risk in urban areas.

    Science.gov (United States)

    Yiannakoulias, Nikolaos; Bennet, Scott A; Scott, Darren M

    2012-03-01

    Cycling is becoming an increasingly important transportation option for commuters. Cycling offers exercise opportunities and reduces the burden of motor vehicle travel on society. Mapping the risk of collision between cyclists and motor vehicles in urban areas is important to understanding safe cyclist route opportunities, making informed transportation planning decisions, and exploring patterns of injury epidemiology. To date, many geographic analyses and representations of cyclist risk have not taken the concept of exposure into account. Instead, risk is either expressed as a rate per capita, or as a count of events. Using data associated with the City of Hamilton, Canada, we illustrate a method for mapping commuter cyclist collision risk per distance travelled. This measure can be used to more realistically represent the underlying geography of cycling risk, and provide more geographically and empirically meaningful information to those interested in understanding how cycling safety varies over space. PMID:22269497

  13. Fixed points via a generalized local commutativity

    Directory of Open Access Journals (Sweden)

    Gerald F. Jungck

    2001-02-01

    Full Text Available Let g:X→X. The concept of a semigroup of maps which is “nearly commutative at g” is introduced. We thereby obtain new fixed point theorems for functions with bounded orbit(s which generalize a recent theorem by Huang and Hong, and results by Jachymski, Jungck, Ohta, and Nikaido, Rhoades and Watson, and others.

  14. Health Impacts of the School Commute

    OpenAIRE

    Lee, Murray; Orenstein, Marla; Richardson, Maxwell J.; Ragland, David R

    2008-01-01

    A dramatic decline in walking and cycling to school has been observed in many geographic and cultural regions, and most children in the US are now driven to school in private vehicles. There are a number of health implications associated with the choice of commute mode, including traffic safety, exposure to air pollution, and levels of physical activity and obesity, and the risks and benefits of each must be weighed. This paper reviews current evidence on these risks and benefits for each hea...

  15. Commutator Criteria for Magnetic Pseudodifferential Operators

    OpenAIRE

    Iftimie, Viorel; Mantoiu, Marius; Purice, Radu

    2009-01-01

    The gauge covariant magnetic Weyl calculus has been introduced and studied in previous works. We prove criteria in terms of commutators for operators to be magnetic pseudo-differential operators of suitable symbol classes. The approach is completely intrinsic; neither the statements nor the proofs depend on a choice of a vector potential. We apply this criteria to inversion problems, functional calculus, affiliation results and to the study of the evolution group generated by a magnetic pseud...

  16. Dynamics and local policy in labour commuting

    OpenAIRE

    Samo Drobne; Marija Bogataj; Anka Lisec

    2012-01-01

    Background: In the paper, the influence of the selected parameters, which are population, travel time to work by car, employment rate and average gross earnings, to labour commuting flows in Slovenia is analysed for the period 2000 – 2009. Furthermore, the dynamics of the analysed parameters have been studied to be implemented in the local policy application. Objectives: The main goal of this research has been to study the stickiness and attractiveness of Slovenian municipalities regarding th...

  17. Gradient-prolongation commutativity and graph theory

    OpenAIRE

    Musy, François; Nicolas, Laurent; Perrussel, Ronan

    2007-01-01

    6 pages International audience This Note gives conditions that must be imposed to algebraic multilevel discretizations involving at the same time nodal and edge elements so that a gradient-prolongation commutativity condition will be satisfied; this condition is very important, since it characterizes the gradients of coarse nodal functions in the coarse edge function space. They will be expressed using graph theory and they provide techniques to compute approximation bases at each level.

  18. Delayed commutation in quantum computer networks

    OpenAIRE

    Garcia-Escartin, Juan Carlos; Chamorro-Posada, Pedro

    2005-01-01

    In the same way that classical computer networks connect and enhance the capabilities of classical computers, quantum networks can combine the advantages of quantum information and communications. We propose a non-classical network element, a delayed commutation switch, that can solve the problem of switching time in packet switching networks. With the help of some local ancillary qubits and superdense codes we can route the information after part of it has left the network node.

  19. Expanded commuting in the metropolitan region of Belo Horizonte: evidence for reverse commuting

    Directory of Open Access Journals (Sweden)

    Carlos Lobo

    2015-08-01

    Full Text Available AbstractLarge Brazilian cities, particularly those that have experienced rapid population growth since the middle of the last century, have exhibited significant signs of population dispersion in their peripheries in recent decades. A study of the population’s spatial redistribution in the Metropolitan Region of Belo Horizonte (MRBH confirms this finding. In the process of dispersion, the levels of urban commuting increase, and commuting becomes a relevant indicator of the degree of integration within the metropolis. This paper evaluates the current magnitude and main features of reverse commuting, as characterized by the daily displacements of the population that resides not in the periphery but rather in the core. Flows from the metropolitan core towards the peripheral municipalities are examined using sample microdata on the MRBH municipalities from the 2000 and 2010 demographic censuses by combining the variables of "municipality of residence" and "municipality of work/study." The results indicate an increase in reverse commuting in both absolute and relative terms. When this flow is compared totraditional commuting (periphery/center, the relative values are considerable. In some cases, this relationship reaches notably high values, as the case of Confins (the municipality where the international airport is located, and also municipalities that are part of a relatively old conurbation, such as Nova Lima and Betim.

  20. Classical mechanics in non-commutative phase space

    Institute of Scientific and Technical Information of China (English)

    WEI Gao-Feng; LONG Chao-Yun; LONG Zheng-Wen; QIN Shui-Jie; Fu Qiang

    2008-01-01

    In this paper the laws of motion of classical particles have been investigated in a non-commutative phase space.The corresponding non-commutative relations contain not only spatial non-commutativity but also momentum non-commutativity.First,new Poisson brackets have been defined in non-commutative phase space.They contain corrections due to the non-commutativity of coordinates and momenta.On the basis of this new Poisson brackets,a new modified second law of Newton has been obtained.For two cases,the free particle and the harmonic oscillator,the equations of motion are derived on basis of the modified second law of Newton and the linear transformation (Phys.Rev.D,2005,72:025010).The consistency between both methods is demonstrated.It is shown that a free particle in commutative space is not a free particle with zero-acceleration in the non-commutative phase space.but it remains a free particle with zero-acceleration in non-commutative space if only the coordinates are non-commutative.

  1. Classical mechanics in non-commutative phase space

    International Nuclear Information System (INIS)

    In this paper the laws of motion of classical particles have been investigated in a non-commutative phase space. The corresponding non-commutative relations contain not only spatial non-commutativity but also momentum non-commutativity. First, new Poisson brackets have been defined in non-commutative phase space. They contain corrections due to the non-commutativity of coordinates and momenta. On the basis of this new Poisson brackets, a new modified second law of Newton has been obtained. For two cases, the free particle and the harmonic oscillator, the equations of motion are derived on basis of the modified second law of Newton and the linear transformation (Phys. Rev. D, 2005, 72: 025010). The consistency between both methods is demonstrated. It is shown that a free particle in commutative space is not a free particle with zero-acceleration in the non-commutative phase space, but it remains a free particle with zero-acceleration in non-commutative space if only the coordinates are non-commutative. (authors)

  2. Lorentz-invariant non-commutative QED

    International Nuclear Information System (INIS)

    Lorentz-invariant non-commutative QED (NCQED) is constructed so as to be a part of the Lorentz-invariant non-commutative Standard Model (NCSM), a subject to be treated in later publications. Our NCSM is based on Connes' observation that the total fermion field in the Standard Model can be regarded as a bi-module over a flavor-color algebra. In this paper, it is shown that there exist two massless gauge fields in NCQED that are interchanged by the C' transformation. Since C' is reduced to the conventional charge conjugation C in the commutative limit, in the same limit, the two gauge fields become identical to the photon field which couples to only four spinors, with charges ±2, ±1. Following Carlson, Carone and Zobin, our NCQED respects Lorentz invariance, employing the Doplicher-Fredenhagen-Roberts algebra instead of the usual algebra with constant θμν. In the new version, θμν becomes an integration variable. We show, using a simple NC scalar model, that the θ integration yields an invariant damping factor instead of the oscillating one in the nonplanar self-energy diagram in the one-loop approximation. The Seiberg-Witten map shows that the θ expansion of NCQED generates exotic but well-motivated derivative interactions beyond QED, with allowed charges being only 0, ±1, ±2. (author)

  3. On the motivic commutative ring spectrum BO

    CERN Document Server

    Panin, Ivan

    2010-01-01

    We construct an algebraic commutative ring T- spectrum BO which is stably fibrant and (8,4)- periodic and such that on SmOp/S the cohomology theory (X,U) -> BO^{p,q}(X_{+}/U_{+}) and Schlichting's hermitian K-theory functor (X,U) -> KO^{[q]}_{2q-p}(X,U) are canonically isomorphic. We use the motivic weak equivalence Z x HGr -> KSp relating the infinite quaternionic Grassmannian to symplectic $K$-theory to equip BO with the structure of a commutative monoid in the motivic stable homotopy category. When the base scheme is Spec Z[1/2], this monoid structure and the induced ring structure on the cohomology theory BO^{*,*} are the unique structures compatible with the products KO^{[2m]}_{0}(X) x KO^{[2n]}_{0}(Y) -> KO^{[2m+2n]}_{0}(X x Y). on Grothendieck-Witt groups induced by the tensor product of symmetric chain complexes. The cohomology theory is bigraded commutative with the switch map acting on BO^{*,*}(T^{2}) in the same way as multiplication by the Grothendieck-Witt class of the symmetric bilinear space .

  4. Mumbai : the bicycle friendly city, bicycle masterplan & design guidelines for central mumbai

    OpenAIRE

    Hellström, Lina

    2011-01-01

    Mumbai – the city of contrasts, is home for more than 20 million people. It is the financial centre and the most modern city in India. As most cities within developing countries Mumbai is striving to imitate the western model of growth and lifestyle to achieve a “developed” status. Motorization, especially private motorized modes, has become prioritized because they are seen as a big part of this development. This neglecting has also led to a significant prejudice against bicycle riding as a ...

  5. ROUTE CHOICE MODELLING FOR BICYCLE TRIPS

    Directory of Open Access Journals (Sweden)

    Ehsan Beheshtitabar

    2014-06-01

    Full Text Available This paper intends to find out which parameters have the highest influence on bicyclists’ route-choice-behaviour and how they contribute. There are many attributes considered throughout different studies that are favoured by cyclists. The attributes are the basis for generating a function which predicts the route choice of cyclists. The paper aims at making a comparison between distance-based routes and attribute-based routes. The model for creating the bicycle route choice program is based on the network model of Norrköping, Sweden. The preferred attributes of the model each assign a weight in the cost function of the model for each link of the urban network. The algorithm of the lowest cost function route searches the shortest path in terms of assigned link costs over the whole network. For comparing the results of the cost function and the shortest route (between an origin-destination, the model has a shortest path finding algorithm between different Origin and Destination pairs implemented. It has been viewed that around 25% of all cumulative routes do not show any distance differences between the shortest path distance and attributes based solution. With the used weights of the Standard scenario, it can be seen that the trade-off between shortest distance and safety respectively comfort can be optimized, fulfilling both criteria (distance and safety/comfort.

  6. Prevalência e fatores associados à inatividade física nos deslocamentos para escola em adolescentes Prevalence of physical inactivity and associated factors among adolescents commuting to school

    Directory of Open Access Journals (Sweden)

    Carla Menêses Santos

    2010-07-01

    Full Text Available O objetivo deste estudo foi verificar a prevalência e identificar fatores associados à inatividade física nos deslocamentos para escola em adolescentes. Trata-se de um estudo epidemiológico transversal baseado na análise secundária de dados de uma amostra de 4.207 adolescentes (14-19 anos. Os dados foram coletados por meio de um questionário previamente validado (GSHS-OMS. Foram classificados como "inativos nos deslocamentos" aqueles que relataram que não se deslocavam ativamente para ir à escola e/ou aqueles que o fazem, mas despendem menos de 20 minutos no trajeto de ida e volta. Observou-se que 43% (IC95%: 41,5-44,5 dos adolescentes são fisicamente inativos nos deslocamentos. Verificou-se que o local de residência e a escolaridade materna foram estatisticamente associados ao desfecho (inatividade física nos deslocamentos para escola (p The aim of this study was to verify the prevalence of physical inactivity and associated factors among adolescents commuting to school. This was an epidemiological study based on secondary data from a sample of 4,207 adolescents (14-19 years. Data were collected through a previously validated questionnaire (GSHS-WHO. Adolescents were classified as "inactive in commuting" when they reported not commuting to school actively (e.g., walking or bicycling and/or spent less than 20 minutes getting to and from school. 43% (95%CI: 41.5-44.5 of adolescents were physically inactive in commuting. Place of residence and maternal schooling were statistically associated with outcome (inactivity in commuting to school (p < 0.01. Among male adolescents, physical inactivity in commuting was significantly associated with age (p = 0.02 and skin color (p = 0.04. Inactivity in commuting was relatively common when compared to other studies.

  7. Non-commutative computer algebra and molecular computing

    OpenAIRE

    Svetlana Cojocaru; Victor Ufnarovski

    2001-01-01

    Non-commutative calculations are considered from the molecular computing point of view. The main idea is that one can get more advantage in using molecular computing for non-commutative computer algebra compared with a commutative one. The restrictions, connected with the coefficient handling in Grobner basis calculations are investigated. Semigroup and group cases are considered as more appropriate. SAGBI basis constructions and possible implementations are discussed.

  8. Generalized Uncertainty Relations in the Non-commutative Plane

    Science.gov (United States)

    Chung, Won Sang

    2015-09-01

    In this paper we study two-dimensional noncommutative quantum mechanics (NCQM) with the generalized uncertainty relations . We find the new NCQM algebra from the generalized uncertainty relations. We construct a operator commuting with and discuss two possibilities; One is the case that also commutes with and another is the case that does not commute with . For both case we consider a motion of a charged particle in a magnetic field with a harmonic oscillator potential in the noncommutative plane.

  9. Fuzzy commutative algebra and its application in mechanical engineering

    International Nuclear Information System (INIS)

    Based on literature data, this paper discusses the whole mathematical structure about point-fuzzy number set F(R). By introducing some new operations about addition, subtraction, multiplication, division and scalar multiplication, we prove that F(R) can form fuzzy linear space, fuzzy commutative ring, fuzzy commutative algebra in order. Furthermore, we get that A is fuzzy commutative algebra for any fuzzy subset. At last, we give an application of point-fuzzy number to mechanical engineering

  10. 2-Local derivations on matrix algebras over commutative regular algebras

    OpenAIRE

    Ayupov, Sh. A.; Kudaybergenov, K. K.; Alauadinov, A. K.

    2012-01-01

    The paper is devoted to 2-local derivations on matrix algebras over commutative regular algebras. We give necessary and sufficient conditions on a commutative regular algebra to admit 2-local derivations which are not derivations. We prove that every 2-local derivation on a matrix algebra over a commutative regular algebra is a derivation. We apply these results to 2-local derivations on algebras of measurable and locally measurable operators affiliated with type I von Neumann algebras.

  11. Non-commutative Hopf algebra of formal diffeomorphisms

    OpenAIRE

    Brouder, Christian; Frabetti, Alessandra; Krattenthaler, Christian

    2004-01-01

    The subject of this paper are two Hopf algebras which are the non-commutative analogues of two different groups of formal power series. The first group is the set of invertible series with the multiplication, while the second group is the set of formal diffeomorphisms with the composition. The motivation to introduce these Hopf algebras comes from the study of formal series with non-commutative coefficients. Invertible series with non-commutative coefficients still form a group, and we interp...

  12. Exploring characteristics and motives of long distance commuter cyclists

    DEFF Research Database (Denmark)

    Hansen, Karsten Bruun; Sick Nielsen, Thomas

    2014-01-01

    , commuter cyclists (45 km from home to work) have more mobility options, higher incomes, and a longer education than other commuter cyclists. The main motive for longer distance cycling is physical exercise, followed by reduced costs and time used for traveling. The long distance commuter cyclists surveyed......, budgets to promote active travel to work as well as the role of psychological benefits as a factor in promoting and sustaining cycling practices....

  13. Exploring characteristics and motives of long distance commuter cyclists

    DEFF Research Database (Denmark)

    Hansen, Karsten Bruun; Nielsen, Thomas Alexander Sick

    2014-01-01

    , commuter cyclists (>5 km from home to work) have more mobility options, higher incomes, and a longer education than other commuter cyclists. The main motive for longer distance cycling is physical exercise, followed by reduced costs and time used for traveling. The long distance commuter cyclists surveyed......, budgets to promote active travel to work as well as the role of psychological benefits as a factor in promoting and sustaining cycling practices....

  14. Hybrid circuit modules for motor commutation and control

    Science.gov (United States)

    Dekramer, C.

    1972-01-01

    Thick film hybrid techniques are used to develop circuitry for a brushless dc motor commutator. The power commutator contains the driving circuit and an amplifier that controls the armature current. A position decoder contains digital integrated circuits which receive the signals from the armature position sensors and generate the driving signals for the power commutator in the proper sequence. These units drive motors with stall currents up to about 400 mA.

  15. On the Commutativity of a Certain Class of Toeplitz Operators

    Directory of Open Access Journals (Sweden)

    Louhichi Issam

    2014-01-01

    Full Text Available One of the major goals in the theory of Toeplitz operators on the Bergman space over the unit disk D in the complex place C is to completely describe the commutant of a given Toeplitz operator, that is, the set of all Toeplitz operators that commute with it. Here we shall study the commutants of a certain class of quasihomogeneous Toeplitz operators defined on the harmonic Bergman space.

  16. Associations between active commuting and physical and mental wellbeing.

    OpenAIRE

    Humphreys, DK; Goodman, A.; Ogilvie, D

    2013-01-01

    OBJECTIVE: To examine whether a relationship exists between active commuting and physical and mental wellbeing. METHOD: In 2009, cross-sectional postal questionnaire data were collected from a sample of working adults (aged 16 and over) in the Commuting and Health in Cambridge study. Travel behaviour and physical activity were ascertained using the Recent Physical Activity Questionnaire (RPAQ) and a seven-day travel-to-work recall instrument from which weekly time spent in active commuting (w...

  17. Non-commutative computer algebra and molecular computing

    Directory of Open Access Journals (Sweden)

    Svetlana Cojocaru

    2001-12-01

    Full Text Available Non-commutative calculations are considered from the molecular computing point of view. The main idea is that one can get more advantage in using molecular computing for non-commutative computer algebra compared with a commutative one. The restrictions, connected with the coefficient handling in Grobner basis calculations are investigated. Semigroup and group cases are considered as more appropriate. SAGBI basis constructions and possible implementations are discussed.

  18. A review of non-commutative gauge theories

    Indian Academy of Sciences (India)

    N G Deshpande

    2003-02-01

    Construction of quantum field theory based on operators that are functions of non-commutative space-time operators is reviewed. Examples of 4 theory and QED are then discussed. Problems of extending the theories to () gauge theories and arbitrary charges in QED are considered. Construction of standard model on non-commutative space is then briefly discussed. The phenomenological implications are then considered. Limits on non-commutativity from atomic physics as well as accelerator experiments are presented.

  19. Supersymmetric Quantum Mechanics on Non-Commutative Plane

    CERN Document Server

    Harikumar, E; Khare, A

    2004-01-01

    We study the Pauli equation on non-commutative plane. It is shown that the Supersymmetry algebra holds to all orders in the non-commutative parameter $\\theta$ in case the gyro-magnetic ratio $g$ is 2. Using Seiberg-Witten map, the first order in $\\theta$ correction to the spectrum is obtained in the case of uniform magnetic field. We find that the eigenstates in the non-commutative case are identical to the commutative case provided the magnetic field $B$ is everywhere replaced by $B(1+B\\theta)$.

  20. Supersymmetric quantum mechanics on non-commutative plane

    Energy Technology Data Exchange (ETDEWEB)

    Harikumar, E.; Kumar, V. Sunil; Khare, Avinash

    2004-06-10

    We study the Pauli equation on non-commutative plane. It is shown that the supersymmetry algebra holds to all orders in the non-commutative parameter {theta} in case the gyro-magnetic ratio g is 2. Using Seiberg-Witten map, the first order in {theta} correction to the spectrum is obtained in the case of uniform magnetic field. We find that the eigenstates in the non-commutative case are identical to the commutative case provided the magnetic field B is everywhere replaced by B(1+B{theta})

  1. Current commutator anomalies and chiral anomalies in the canonical formalism

    International Nuclear Information System (INIS)

    Without recourse to the Bjorken-Johnson-Low (BJL) method, current-current and current-electric-field commutator anomalies are evaluated in chiral gauge theories in two- and four-dimensional spacetime with the help of a gauge covariant regularization method. The results are consistent with previous analyses through the BJL method, and partially confirmed Faddeev's conjecture on the commutator anomalies of the Gauss law constraint operators within the canonical formalism. The chiral anomalies of the current divergence are derived from these commutator anomalies in the Weyl gauge where current-electric-field commutator anomalies play important roles

  2. Geometry, commutation relations and the quantum fictitious force

    DEFF Research Database (Denmark)

    Botero, J.; Cirone, M.A.; Dahl, Jens Peder;

    2003-01-01

    We express the commutation relation between the operators of the momentum and the radial unit vectors in D dimensions in differential and integral form. We connect this commutator with the quantum fictitious potential emerging in the radial Schrodinger equation of an s-wave.......We express the commutation relation between the operators of the momentum and the radial unit vectors in D dimensions in differential and integral form. We connect this commutator with the quantum fictitious potential emerging in the radial Schrodinger equation of an s-wave....

  3. Self-commutating converters for high power applications

    CERN Document Server

    Arrillaga, Jos; Watson, Neville R; Murray, Nicholas J

    2010-01-01

    For very high voltage or very high current applications, the power industry still relies on thyristor-based Line Commutated Conversion (LCC), which limits the power controllability to two quadrant operation. However, the ratings of self-commutating switches such as the Insulated-Gate Bipolar Transistor (IGBT) and Integrated Gate-Commutated Thyristor (IGCT), are reaching levels that make the technology possible for very high power applications. This unique book reviews the present state and future prospects of self-commutating static power converters for applications requiring either ultr

  4. Modeling the Distribution Characteristics of Urban Public Bicycle Rental Duration

    Directory of Open Access Journals (Sweden)

    Shuichao Zhang

    2016-01-01

    Full Text Available In order to model the distribution characteristics of public bicycle rental durations, individual journey data for three cities in China (Ningbo, Hangzhou, and Beijing, for weekdays, was obtained. The distribution curves for public bicycle rental duration in the three cities were found to be extremely similar, with small differences among the weekdays. The basic parameters such as the average rental duration, the rental duration corresponding to the maximum rental frequency, and the rental duration corresponding to 75% degree were then calculated. On this basis, the radioactive decay law from physics was used to establish a theoretical model for the relationship between rental frequency and rental duration. The data on public bicycle rental duration in Ningbo, Hangzhou, and Beijing were used to test the model and produce a corrected theoretical model. The results indicate that the relationship between rental frequency and rental duration obeys the decay law. The study results provide important theoretical support for the rental station planning of bicycle sharing systems, as well as the allocation, operation, and dispatch of public bicycles.

  5. Heterogeneous cellular automata model for straight-through bicycle traffic at signalized intersection

    Science.gov (United States)

    Ren, Gang; Jiang, Hang; Chen, Jingxu; Huang, Zhengfeng; Lu, Lili

    2016-06-01

    This paper presents a cellular automata (CA) model to elucidate the straight-through movements of the heterogeneous bicycle traffic at signalized intersection. The CA model, via simulation, particularly exposits the dispersion phenomenon existing in the straight-through bicycle traffic. The nonlane-based cycling behavior and diverse bicycle properties are also incorporated in the CA model. A series of simulations are conducted to reveal the travel process, bicycles interaction and influence of the dispersion phenomenon. The simulation results show that the dispersion phenomenon significantly results in more bicycles interactions in terms of spilling maneuvers and overtaking maneuvers during the straight-through movements. Meanwhile, the dispersion phenomenon could contribute to the efficiency of the bicycle traffic, and straight-through bicycles need less time to depart the intersection under the circumstance of dispersion phenomenon. The simulation results are able to provide specific guideline for reasonably utilizing the dispersion phenomenon to improve the operational efficiency of straight-through bicycle traffic.

  6. Associations between a walkability index and bicycle use in Denmark

    DEFF Research Database (Denmark)

    Madsen, T.; Christiansen, L.; Nielsen, Thomas Alexander Sick;

    2012-01-01

    /day, and important health benefits can accrue from regular commuting cycling. Studies have shown a positive correlation between walkability attributes of neighborhood environments (street connectivity, and use mix, residential density, retail floor area ratio) and cycling. Results from Australia...

  7. Commutative Γ-rings do not model all commutative ring spectra

    OpenAIRE

    Lawson, Tyler

    2009-01-01

    We show that the free E∞-algebra on a zero-cell cannot be modeled by a commutative Γ-ring. The proof shows that Dyer-Lashof operations of positive degree must vanish on the zero'th homology of such an object.

  8. Non-commutative model of quark interactions

    International Nuclear Information System (INIS)

    A non-commutative model of quark interactions with the generalized O(2.6) symmetry in quantum phase space is considered. The model is based on the Snyder-Yang algebra, which includes in the relativistically invariant way two parameters μc and λc with dimensionality of mass and length. The equations of motion obtained in the framework of the model contain the rising potentials which provide the confinement of color particles. The values of the parameters μc and λc, as well as the masses of constituent and current quarks are estimated

  9. Borchers' commutation relations and modular symmetries

    CERN Document Server

    Kuckert, B

    1995-01-01

    Recently Borchers has shown that in a theory of local observables, certain unitary and antiunitary operators, which are obtained from an elementary construction suggested by Bisognano and Wichmann, commute with the translation operators like Lorentz boosts and \\pct-operators, respectively. We conclude from this that as soon as the operators considered implement {\\em any} symmetry, this symmetry can be fixed up to at most some translation. As a symmetry, we admit any unitary or antiunitary operator under whose adjoint action any algebra of local observables is mapped onto an algebra which can be localized somewhere in Minkowski space.

  10. The quaternionic commutator bracket and its implications

    CERN Document Server

    Arbab, Arbab I

    2014-01-01

    A quaternionic commutator bracket for position and momentum shows that the quaternionic wave function, \\emph{viz.} $\\widetilde{\\psi}=(\\frac{i}{c}\\,\\psi_0\\,,\\vec{\\psi})$, represents a state of a particle with orbital angular momentum, $L=3\\,\\hbar$, resulting from the internal structure of the particle. This angular momentum can be attributed to spin of the particle. The vector $\\vec{\\psi}$, points along the direction of $\\vec{L}$. When a charged particle is placed in an electromagnetic fields the interaction energy reveals that the magnetic moments interact with the electric and magnetic fields giving rise to terms similar to Aharonov-Bohm and Aharonov-Casher effects.

  11. Non-commutative tools for topological insulators

    Science.gov (United States)

    Prodan, Emil

    2010-06-01

    This paper reviews several analytic tools for the field of topological insulators, developed with the aid of non-commutative calculus and geometry. The set of tools includes bulk topological invariants defined directly in the thermodynamic limit and in the presence of disorder, whose robustness is shown to have nontrivial physical consequences for the bulk states. The set of tools also includes a general relation between the current of an observable and its edge index, a relation that can be used to investigate the robustness of the edge states against disorder. The paper focuses on the motivations behind creating such tools and on how to use them.

  12. Bispectral algebras of commuting ordinary differential operators

    CERN Document Server

    Bakalov, B N; Yakimov, M T

    1997-01-01

    We develop a systematic way for constructing bispectral algebras of commuting ordinary differential operators of any rank N. It enables us to obtain all previously known classes or examples of bispectral operators. The suggested method is completely algorithmic, which allows us to present explicitly new examples. We conjecture that the class built in the present paper exhausts all bispectral scalar operators. This paper is the third of a series of papers (hep-th/9510211, q-alg/9602010, q-alg/9602012) on the bispectral problem.

  13. Restrictions on commutativity ratios in finite groups

    Directory of Open Access Journals (Sweden)

    Robert Heffernan

    2014-12-01

    Full Text Available We consider two commutativity ratios $Pr(G$ and $f(G$ in a finite group $G$ and examine the properties of $G$ when these ratios are `large'. We show that if $Pr(G > frac{7}{24}$, then $G$ is metabelian and we give threshold results in the cases where $G$ is insoluble and $G'$ is nilpotent. We also show that if $f(G > frac{1}{2}$, then $f(G = frac{n+1}{2n}$, for some natural number $n$.

  14. Star products from commutative string theory

    Indian Academy of Sciences (India)

    Sunil Mukhi

    2002-01-01

    A boundary-state computation is performed to obtain derivative corrections to the Chern–Simons coupling between a -brane and the RR gauge potential -3. We work to quadratic order in the gauge field strength , but all orders in derivatives. In a certain limit, which requires the presence of a constant -field background, it is found that these corrections neatly sum up into the *2 product of (commutative) gauge fields. The result is in agreement with a recent prediction using noncommutativity

  15. Remarks on the New High-Efficiency Motor for an Electrical Bicycle

    Science.gov (United States)

    Kousaka, Takuji; Hasimoto, Naohide; Abe, Minoru

    There have been numerous theoretical and experimental investigations of the electrical bicycle, electrical vehicle, and so on. In this paper, we consider the new d-c compound motor for the electrical bicycle. This improvement maybe take positive advantage of compound moter in the electrical bicycle. As an illustrative example, we show the experimental results on the level ground. The experiments show that the proposed method is more higher efficiency for the electrical bicycle than conventional method.

  16. Investigation with Bluetooth Sensors of Bicycle Travel Time Estimation on a Short Corridor

    OpenAIRE

    Zhenyu Mei; Dianhai Wang; Jun De Chen

    2012-01-01

    Accurate travel time information acquisition is essential to the effective planning and management of bicycle travel conditions. Traditionally, video camera data have been used as the primary source for measuring the quality of bicycle travel time. This paper deals with an investigation of bicycle travel time estimation on a short corridor, using Bluetooth sensors, based on field survey of travel time at one arterial road in Hangzhou. Usually bicycle travel time estimates with Bluetooth senso...

  17. Influences of infrastructure and attitudes to health on value of travel time savings in bicycle journeys

    OpenAIRE

    Björklund, Gunilla; Mortazavi , Reza

    2013-01-01

    In this paper we investigate how attitudes to health and exercise in connection with cycling influence the estimation of values of travel time savings in different kinds of bicycle environments (mixed traffic, bicycle lane in the road way, bicycle path next to the road, and bicycle path not in connection with the road). The results, based on two Swedish stated choice studies, suggest that the values of travel time savings are lower when cycling in better conditions. Surprisingly, the responde...

  18. Bicycle helmet use and non-use – recently published research

    OpenAIRE

    Uibel Stefanie; Müller Daniel; Klingelhoefer Doris; Groneberg David A

    2012-01-01

    Abstract Bicycle traumata are very common and especially neurologic complications lead to disability and death in all stages of the life. This review assembles the most recent findings concerning research in the field of bicycle traumata combined with the factor of bicycle helmet use. The area of bicycle trauma research is by nature multidisciplinary and relevant not only for physicians but also for experts with educational, engineering, judicial, rehabilitative or public health functions. Du...

  19. Bicycling injury hospitalisation rates in Canadian jurisdictions: analyses examining associations with helmet legislation and mode share

    OpenAIRE

    Teschke, Kay; Koehoorn, Mieke; Shen, Hui; Dennis, Jessica

    2015-01-01

    Objectives The purpose of this study was to calculate exposure-based bicycling hospitalisation rates in Canadian jurisdictions with different helmet legislation and bicycling mode shares, and to examine whether the rates were related to these differences. Methods Administrative data on hospital stays for bicycling injuries to 10 body region groups and national survey data on bicycling trips were used to calculate hospitalisation rates. Rates were calculated for 44 sex, age and jurisdiction st...

  20. Using magnetorheological fluids in an innovative hybrid bicycle damper

    Science.gov (United States)

    Shiao, Y. J.; Nguyen, T. S.

    2015-12-01

    Magnetorheological fluids are capable of changing their viscosity quickly. This can provide good controllability and fast dynamic response. A conventional passive suspension system with air spring or hydraulic damper has simple design and financial benefit for bicycles, but its operation is uncontrollable and non-adaptive. This paper presented a semi-active hybrid bicycle suspension system which combines conventional air spring and a new magnetorheological damping brake together to reduce vibration of a bicycle. A multi-layer magnetorheological brake and linkage mechanism are connected to bike fork to form the adaptive damping part of the innovative hybrid suspension system. The simulation results proved that the semi-active suspension system can reduce bike vibration effectively.

  1. Synthesis of bicyclic alkaloids from the iridoid antirrhinoside

    DEFF Research Database (Denmark)

    Frederiksen, Signe Maria

    The present thesis describes the isolation of the iridoid glucoside antirrhinoside from Antirrhinum majus, and the approaches made towards its transformation into analogues of biologically active compounds, with special interest in syntheses of bicyclic alkaloids.A synthetic piperidine monoterpene...... alkaloids. The corresponding ditosyl derivative was treated with benzylamine to afford a bicyclic N-benzylated pyrrolidine. An alternative starting material was prepared from 5,6:4',6'-di-O-isopropylidene antirrhinoside by reduction with lithium aluminum hydride. Subsequent ozonolysis and sodium borohydride...... gave the expected triol. The corresponding ditosyl derivative was treated with benzylamine or 2-methoxy-benzylamine to afford bicyclic pyrrolidines in 54-66% yield. The isopropylidene protection was removed and the unprotected pyrrolidine was acylated with benzoyl chloride to afford a potential...

  2. Predicting Public Bicycle Adoption Using the Technology Acceptance Model

    Directory of Open Access Journals (Sweden)

    Benjamin T. Hazen

    2015-10-01

    Full Text Available Bicycle sharing programs provide a sustainable mode of urban transportation. Although cities across the globe have developed these systems for their citizens and visitors, usage rates are not as high as anticipated. This research uses the technology acceptance model as the basis to understand one’s intention to adopt bicycle sharing programs. Using survey data derived from 421 participants in Beijing, China, the proposed covariance-based structural equation model consisting of perceived quality, perceived convenience, and perceived value is found to predict 50.5% of the variance in adoption intention. The findings of this research contribute to theory and practice in the burgeoning literature on public bicycle systems and sustainable urban transportation by offering a theoretical lens through which to consider system adoption, and providing information to practitioners as to what factors might contribute most to adoption.

  3. Bicycle Training for Youth with Down Syndrome and Autism Spectrum Disorders

    Science.gov (United States)

    MacDonald, Megan; Esposito, Phil; Hauck, Janet; Jeong, Irully; Hornyak, Joseph; Argento, Angela; Ulrich, Dale A.

    2012-01-01

    Children with Down syndrome (DS) and autism spectrum disorders (ASD) frequently have difficulty riding a two-wheel bicycle. The purpose of this study was to investigate an intervention using an adapted bicycle and individualized instruction to teach 71 youth to ride a standard two-wheel bicycle. Youth with DS (n = 30) and ASD (n = 41) between the…

  4. A City Plans for Bicycles: A Case Study of Olympia, Washington.

    Science.gov (United States)

    Litman, Todd

    1990-01-01

    Discusses community planning for bicycling programs with emphasis on safety education for children and adults, enforcement of bicycle laws, engineering improvements, and special events. Describes how Olympia improved existing bicycling facilities and summarizes planning, communication, engineering, and policy issues addressed. (SV)

  5. Bicycle cycles and mobility patterns - Exploring and characterizing data from a community bicycle program

    CERN Document Server

    Kaltenbrunner, Andreas; Grivolla, Jens; Codina, Joan; Banchs, Rafael

    2008-01-01

    This paper provides an analysis of human mobility data in an urban area using the amount of available bikes in the stations of the community bicycle program Bicing in Barcelona. The data was obtained by periodic mining of a KML-file accessible through the Bicing website. Although in principle very noisy, after some preprocessing and filtering steps the data allows to detect temporal patterns in mobility as well as identify residential, university, business and leisure areas of the city. The results lead to a proposal for an improvement of the bicing website, including a prediction of the number of available bikes in a certain station within the next minutes/hours. Furthermore a model for identifying the most probable routes between stations is briefly sketched.

  6. Efficiency of Choice Set Generation Methods for Bicycle Routes

    DEFF Research Database (Denmark)

    Halldórsdóttir, Katrín; Rieser-Schüssler, Nadine; W. Axhausen, Kay;

    behaviour, observed choices and alternatives composing the choice set of each cyclist are necessary. However, generating the alternative choice sets can prove challenging. This paper analyses the efficiency of various choice set generation methods for bicycle routes in order to contribute to our...... might produce inconsistent estimates. There have been some studies on bicycle route choice set generation reported in the literature, whereof few studies focussed on route choice models for bicyclist estimated from GPS observations. Menghini et al. [3] successfully applied a Breadth First Search on Link...

  7. Experimental and mathematical car-bicycle collision simulations.

    OpenAIRE

    Huybers, J.J.W. & Janssen, E.G.

    1988-01-01

    The results of 35 mathematical simulations will be used to get a better insight in car-bicycle collisions. This information will be used later on to formulate hypotheses to be tested in an accident investigation project. In this paper special attention is given to the influence of the shape of the car and the dimensions of the bicycle/cyclist on the severity of the impacts. It is known that the speed of the car at impact is an important parameter in the resulting injury severity of the cyclis...

  8. Reducing employee travelling time through smart commuting

    Science.gov (United States)

    Rahman, A. N. N. A.; Yusoff, Z. M.; Aziz, I. S.; Omar, D.

    2014-02-01

    Extremely congested roads will definitely delay the arrival time of each trip.This certainly impacted the journey of employees. Tardiness at the workplace has become a perturbing issue for companies where traffic jams are the most common worker excuses. A depressing consequence on daily life and productivity of the employee occurs. The issues of commuting distance between workplace and resident area become the core point of this research. This research will emphasize the use of Geographical Information System (GIS) technique to explore the distance parameter to the employment area and will focus on the accessibility pattern of low-cost housing. The research methodology consists of interview sessions and a questionnaire to residents of low-cost housing areas in Melaka Tengah District in Malaysia. The combination of these processes will show the criteria from the selected parameter for each respondent from their resident area to the employment area. This will further help in the recommendation of several options for a better commute or improvement to the existing routes and public transportations system. Thus enhancing quality of life for employees and helping to reduce stress, decrease lateness, absenteeism and improving productivity in workplace.

  9. Shock Waves and Commutation Speed of Memristors

    Science.gov (United States)

    Tang, Shao; Tesler, Federico; Marlasca, Fernando Gomez; Levy, Pablo; Dobrosavljević, V.; Rozenberg, Marcelo

    2016-01-01

    Progress of silicon-based technology is nearing its physical limit, as the minimum feature size of components is reaching a mere 10 nm. The resistive switching behavior of transition metal oxides and the associated memristor device is emerging as a competitive technology for next-generation electronics. Significant progress has already been made in the past decade, and devices are beginning to hit the market; however, this progress has mainly been the result of empirical trial and error. Hence, gaining theoretical insight is of the essence. In the present work, we report the striking result of a connection between the resistive switching and shock-wave formation, a classic topic of nonlinear dynamics. We argue that the profile of oxygen vacancies that migrate during the commutation forms a shock wave that propagates through a highly resistive region of the device. We validate the scenario by means of model simulations and experiments in a manganese-oxide-based memristor device, and we extend our theory to the case of binary oxides. The shock-wave scenario brings unprecedented physical insight and enables us to rationalize the process of oxygen-vacancy-driven resistive change with direct implications for a key technological aspect—the commutation speed.

  10. Reducing employee travelling time through smart commuting

    International Nuclear Information System (INIS)

    Extremely congested roads will definitely delay the arrival time of each trip.This certainly impacted the journey of employees. Tardiness at the workplace has become a perturbing issue for companies where traffic jams are the most common worker excuses. A depressing consequence on daily life and productivity of the employee occurs. The issues of commuting distance between workplace and resident area become the core point of this research. This research will emphasize the use of Geographical Information System (GIS) technique to explore the distance parameter to the employment area and will focus on the accessibility pattern of low-cost housing. The research methodology consists of interview sessions and a questionnaire to residents of low-cost housing areas in Melaka Tengah District in Malaysia. The combination of these processes will show the criteria from the selected parameter for each respondent from their resident area to the employment area. This will further help in the recommendation of several options for a better commute or improvement to the existing routes and public transportations system. Thus enhancing quality of life for employees and helping to reduce stress, decrease lateness, absenteeism and improving productivity in workplace

  11. Parabosonic string and space-time non-commutativity

    Energy Technology Data Exchange (ETDEWEB)

    Seridi, M. A.; Belaloui, N. [Laboratoire de Physique Mathematique et Subatomique, Universite Mentouri Constantine (Algeria)

    2012-06-27

    We investigate the para-quantum extension of the bosonic strings in a non-commutative space-time. We calculate the trilinear relations between the mass-center variables and the modes and we derive the Virasoro algebra where a new anomaly term due to the non-commutativity is obtained.

  12. Lying-Over Theorem on Left Commutative Rngs

    OpenAIRE

    Liu, Keqin

    2005-01-01

    We introduce the notion of a graded integral element, prove the counterpart of the lying-over theorem on commutative algebra in the context of left commutative rngs, and use the Hu-Liu product to select a class of noncommutative rings.

  13. Translation-invariant models for non-commutative gauge fields

    International Nuclear Information System (INIS)

    Motivated by the recent construction of a translation-invariant renormalizable non-commutative model for a scalar field, we introduce models for non-commutative U(1) gauge fields along the same lines. More precisely, we include some extra terms into the action with the aim of getting rid of the UV/IR mixing. (fast track communication)

  14. An improved 4-step commutation method application for matrix converter

    DEFF Research Database (Denmark)

    Guo, Yu; Guo, Yougui; Deng, Wenlang;

    2014-01-01

    A novel four-step commutation method is proposed for matrix converter cell, 3 phase inputs to 1 phase output in this paper, which is obtained on the analysis of published commutation methods for matrix converter. The first and fourth step can be shorter than the second or third one. The discussed...

  15. On the commutators of singular integrals related to block spaces

    OpenAIRE

    Lu, Shanzhen; Wu, Hoxiong

    2004-01-01

    In this paper, the commutators of singular integrals with rough kernels are considered. By the method of block decomposition for kernel function and Fourier transform estimates, some new results about the $L^p(\\rz)$ boundedness for these commutators are obtained.

  16. Newton's second law in a non-commutative space

    International Nuclear Information System (INIS)

    In this Letter we show that corrections to Newton's second law appear if we assume a symplectic structure consistent with the commutation rules of the non-commutative quantum mechanics. For central field we find that the correction term breaks the rotational symmetry. For the Kepler problem, this term is similar to a Coriolis force

  17. Homogeneous Buchberger algorithms and Sullivant's computational commutative algebra challenge

    DEFF Research Database (Denmark)

    Lauritzen, Niels

    2005-01-01

    We give a variant of the homogeneous Buchberger algorithm for positively graded lattice ideals. Using this algorithm we solve the Sullivant computational commutative algebra challenge.......We give a variant of the homogeneous Buchberger algorithm for positively graded lattice ideals. Using this algorithm we solve the Sullivant computational commutative algebra challenge....

  18. Inflation on a non-commutative space-time

    Science.gov (United States)

    Calmet, Xavier; Fritz, Christopher

    2015-07-01

    We study inflation on a non-commutative space-time within the framework of enveloping algebra approach which allows for a consistent formulation of general relativity and of the standard model of particle physics. We show that within this framework, the effects of the non-commutativity of spacetime are very subtle. The dominant effect comes from contributions to the process of structure formation. We describe the bound relevant to this class of non-commutative theories and derive the tightest bound to date of the value of the non-commutative scale within this framework. Assuming that inflation took place, we get a model independent bound on the scale of space-time non-commutativity of the order of 19 TeV.

  19. Non-commutative geometry on quantum phase-space

    International Nuclear Information System (INIS)

    A non-commutative analogue of the classical differential forms is constructed on the phase-space of an arbitrary quantum system. The non-commutative forms are universal and are related to the quantum mechanical dynamics in the same way as the classical forms are related to classical dynamics. They are constructed by applying the Weyl-Wigner symbol map to the differential envelope of the linear operators on the quantum mechanical Hilbert space. This leads to a representation of the non-commutative forms considered by A. Connes in terms of multiscalar functions on the classical phase-space. In an appropriate coincidence limit they define a quantum deformation of the classical tensor fields and both commutative and non-commutative forms can be studied in a unified framework. We interprete the quantum differential forms in physical terms and comment on possible applications. (orig.)

  20. Inflation on a non-commutative space–time

    Directory of Open Access Journals (Sweden)

    Xavier Calmet

    2015-07-01

    Full Text Available We study inflation on a non-commutative space–time within the framework of enveloping algebra approach which allows for a consistent formulation of general relativity and of the standard model of particle physics. We show that within this framework, the effects of the non-commutativity of spacetime are very subtle. The dominant effect comes from contributions to the process of structure formation. We describe the bound relevant to this class of non-commutative theories and derive the tightest bound to date of the value of the non-commutative scale within this framework. Assuming that inflation took place, we get a model independent bound on the scale of space–time non-commutativity of the order of 19 TeV.

  1. Inflation on a non-commutative space–time

    International Nuclear Information System (INIS)

    We study inflation on a non-commutative space–time within the framework of enveloping algebra approach which allows for a consistent formulation of general relativity and of the standard model of particle physics. We show that within this framework, the effects of the non-commutativity of spacetime are very subtle. The dominant effect comes from contributions to the process of structure formation. We describe the bound relevant to this class of non-commutative theories and derive the tightest bound to date of the value of the non-commutative scale within this framework. Assuming that inflation took place, we get a model independent bound on the scale of space–time non-commutativity of the order of 19 TeV

  2. Inflation on a non-commutative space–time

    Energy Technology Data Exchange (ETDEWEB)

    Calmet, Xavier, E-mail: x.calmet@sussex.ac.uk; Fritz, Christopher, E-mail: c.fritz@sussex.ac.uk

    2015-07-30

    We study inflation on a non-commutative space–time within the framework of enveloping algebra approach which allows for a consistent formulation of general relativity and of the standard model of particle physics. We show that within this framework, the effects of the non-commutativity of spacetime are very subtle. The dominant effect comes from contributions to the process of structure formation. We describe the bound relevant to this class of non-commutative theories and derive the tightest bound to date of the value of the non-commutative scale within this framework. Assuming that inflation took place, we get a model independent bound on the scale of space–time non-commutativity of the order of 19 TeV.

  3. Almost Commuting Unitary Matrices Related to Time Reversal

    Science.gov (United States)

    Loring, Terry A.; Sørensen, Adam P. W.

    2013-11-01

    The behavior of fermionic systems depends on the geometry of the system and the symmetry class of the Hamiltonian and observables. Almost commuting matrices arise from band-projected position observables in such systems. One expects the mathematical behavior of almost commuting Hermitian matrices to depend on two factors. One factor will be the approximate polynomial relations satisfied by the matrices. The other factor is what algebra the matrices are in, either for , or , the algebra of quaternions. There are potential obstructions keeping k-tuples of almost commuting operators from being close to a commuting k-tuple.We consider two-dimensional geometries and so this obstruction lives in . This obstruction corresponds to either the Chern number or spin Chern number in physics. We show that if this obstruction is the trivial element in K-theory then the approximation by commuting matrices is possible.

  4. Experimental and mathematical car-bicycle collision simulations.

    NARCIS (Netherlands)

    Huybers, J.J.W. & Janssen, E.G.

    1988-01-01

    The results of 35 mathematical simulations will be used to get a better insight in car-bicycle collisions. This information will be used later on to formulate hypotheses to be tested in an accident investigation project. In this paper special attention is given to the influence of the shape of the

  5. Traffic Education for Montana Elementary Schools: Bicycle Safety 1974.

    Science.gov (United States)

    Montana State Office of the Superintendent of Public Instruction, Helena.

    Designed to fit into existing curricula, the loose-leaf guide includes instructional aids, resources, and units for grades K-6. Each grade is presented separately, but with informative introductory material duplicated in each. For all grades, materials include information sheets for instructors about bicycles and traffic safety, and a list of…

  6. Arizona Traffic Safety Education, K-8. Bicycle Safety, Grade 2.

    Science.gov (United States)

    Mesa Public Schools, AZ.

    One in a series designed to assist Arizona elementary and junior high school teachers in developing children's traffic safety skills, this curriculum guide contains ten lessons on bicycles for use in grade 2. Introductory information provided for the teacher includes basic highway safety concepts, stressing communication methods for highway users,…

  7. Mapping Bicycle Crash Risk Patterns on the Local Scale

    Directory of Open Access Journals (Sweden)

    Martin Loidl

    2016-09-01

    Full Text Available Currently, mainly aggregated statistics are used for bicycle crash risk calculations. Thus, the understanding of spatial patterns at local scale levels remains vague. Using an agent-based flow model and a bicycle crash database covering 10 continuous years of observation allows us to calculate and map the crash risk on various spatial scales for the city of Salzburg (Austria. In doing so, we directly account for the spatial heterogeneity of crash occurrences. Additionally, we provide a measure for the statistical robustness on the level of single reference units and consider modifiable areal unit problem (MAUP effects in our analysis. This study is the first of its kind. The results facilitate a better understanding of spatial patterns of bicycle crash rates on the local scale. This is especially important for cities that strive to improve the safety situation for bicyclists in order to address prevailing safety concerns that keep people from using the bicycle as a utilitarian mode of (urban transport.

  8. Consumers’ preferences for “bicycle poultry” in Benin

    DEFF Research Database (Denmark)

    Sodjinou, Epiphane; Henningsen, Arne; Koudande, Delphin O.;

    Village poultry, also termed "bicycle poultry," is produced in scavenging farming systems and is a chewy meat with a low fat content, and constitutes an important source of meat in many African countries. This study investigates consumers’ preferences regarding the physical traits of these birds...

  9. Utilizing the Bicycle for Non-Traditional Activities

    Science.gov (United States)

    Maina, Michael P.; Maina, Julie Schlegel; Sebek, Ludek; Hoffmanova, Jana; Kane, Jennifer Jackson

    2012-01-01

    This article examines the bicycle as not simply a means of transportation or as an exercise device, but rather as a vehicle for teambuilding and problem solving activities within a physical education curriculum. The activities described in this article focus on bike-centered initiatives that foster creative problem solving. They have universal…

  10. Synthesis and anticonvulsant activity of novel bicyclic acidic amino acids

    DEFF Research Database (Denmark)

    Conti, Paola; De Amici, Marco; Joppolo Di Ventimiglia, Samuele;

    2003-01-01

    Bicyclic acidic amino acids (+/-)-6 and (+/-)-7, which are conformationally constrained homologues of glutamic acid, were prepared via a strategy based on a 1,3-dipolar cycloaddition. The new amino acids were tested toward ionotropic and metabotropic glutamate receptor subtypes; both of them...

  11. Bicyclic graphs with exactly two main signless Laplacian eigenvalues

    CERN Document Server

    Huang, He

    2012-01-01

    A signless Laplacian eigenvalue of a graph $G$ is called a main signless Laplacian eigenvalue if it has an eigenvector the sum of whose entries is not equal to zero. In this paper, all connected bicyclic graphs with exactly two main eigenvalues are determined.

  12. "Walking" Along a Free Rotating Bicycle Wheel (Round and Round)

    CERN Document Server

    Guemez, Julio

    2016-01-01

    We describe the kinematics, dynamics and also some energetic issues related to the Marta mouse motion when she walks on top of a horizontal bicycle wheel, which is free to rotate like a merry-to-go round, as presented recently by Paul Hewitt in the Figuring Physics section of this magazine.

  13. Consumers’ preferences for “bicycle poultry” in Benin

    DEFF Research Database (Denmark)

    Sodjinou, Epiphane; Henningsen, Arne; Koudande, Delphin O.;

    2015-01-01

    Village poultry, also termed "bicycle poultry," is produced in scavenging farming systems and is a chewy meat with a low fat content, and constitutes an important source of meat in many African countries. This study investigates consumers’ preferences regarding the physical traits of these birds...

  14. Bicycle sharing system: role, effects and application to Plymouth

    OpenAIRE

    Wiersma, Bouke

    2010-01-01

    Abstract This thesis investigates the role and effects of a bicycle sharing system, and studies the feasi-bility of such a system in Plymouth. The research consists of a literature review, policy dis-cussion, case studies, and a detailed assessment of t

  15. A Formal Synthesis of ( + )-Cassiol Exploiting Meyers' Bicyclic Lactam Methodology

    Institute of Scientific and Technical Information of China (English)

    SHEN,Xin(沈鑫); WU,Yi-Kang(伍贻康); ZHANG,Fan(张帆)

    2002-01-01

    A formal synthesis of ( + )-cassiol using (1S,2S)-2-amino-1-(4- nitrophenyl)-1,3-propanediol as chiral auxiliary is reported.The quaternary chiral center in the molecule was constructed by sequential alkylation of a bicyclic lactam (prepared from the aforementioned auxiliary and 5-oxo-heptanlic acid) with methyl iodide and benzyloxymethyl chloride.

  16. Commuting patterns of workers in a village of Barddhaman district, West Bengal

    Directory of Open Access Journals (Sweden)

    Bhaswati Mondal

    2015-06-01

    Full Text Available Commuting helps to keep balance between residence and workplace of workers. With growing accessibility and connectivity, the importance of commuting is increasing all over the world. It is becoming a major substitute to migration. In commute-studies, commute-pattern is an important chapter. It highlights commuters’ directions of movement, distance they cover, modes of transport they use, the time they take to commute, etc. Unlike the urban-based commute pattern, commute pattern in rural areas are relatively an under-researched issue. In fact, traditionally rural people are thought to carry a sedentary lifestyle. Using primary data, this study aims to explore the commute patterns of rural workers located in the village of Gandharbapur of Barddhaman district of West Bengal, India. All the commuters were found to be engaged in non-farm work. Commuters stem from two major groups. One group of commuters is accumulated farm-income induced. They possess sufficient agricultural land. Investing their surplus farm-income, they have established non-farm works. The second group of commuters is poverty-driven. They are landless poor or are marginal farmers and to escape poverty, they have slipped into these works. Located beyond the suburban area (Memari being the nearest town, most commuters commute to nearby rural areas. Due to non-availability of public transport, women commute less than men do. Regular-paid government employees commute longer than other workers commute. The article concludes with a summary of findings and recommendations for further research.

  17. Satisfaction with transport and enjoyment of the commute by commuting mode in inner Sydney.

    Science.gov (United States)

    Rissel, Chris; Crane, Melanie; Wen, Li Ming; Greaves, Stephen; Standen, Chris

    2016-04-01

    Issue addressed Travel satisfaction has become an increasingly popular construct for the assessment and monitoring of transport systems and services. However, satisfaction may not adequately assess emotion or mood towards walking and cycling, especially when infrastructure is biased towards motor vehicle modes. In this exploratory study we sought to examine the associations of both satisfaction with transport and enjoyment from the commute to work or study by commute mode in an Australian inner city context where transport mode choices are readily available. Methods As part of the Sydney Transport and Health Study, 675 baseline study participants (2013) were invited to complete an online questionnaire in September/October 2014 and 512 did so (76% response rate). Participants who did not travel to work were removed from analyses, giving complete data for 473. Participants provided data on usual travel mode to work or study, satisfaction with transport, enjoyment from their commute, and demographics and neighbourhood factors. Results The main mode of travel to work or study in this inner city sample was public transport (41%), followed by motor vehicle (27%), walking (21%) and cycling (10%). Most participants were satisfied with their transport (82%), with little variation by mode. Walkers (49%) and cyclists (52%) reported far higher levels of enjoyment from their commute than car drivers (14%) or public transport users (10%), with an adjusted odds ratio of 6.18 (95% confidence interval 3.10-12.29, Pactive travel. So what? Focusing on 'enjoyment' associated with walking or cycling to work may be a positive motivator to encourage active travel. PMID:26650670

  18. Commuting involutions and degenerations of isotropy representations

    CERN Document Server

    Panyushev, Dmitri I

    2011-01-01

    Let $\\sigma_1$ and $\\sigma_2$ be commuting involutions of a semisimple algebraic group $G$. This yields a $Z_2\\times Z_2$-grading of $\\g=\\Lie(G)$, $\\g=\\bigoplus_{i,j=0,1}\\g_{ij}$, and we study invariant-theoretic aspects of this decomposition. Let $\\g$ be the $Z_2$-contraction of $\\g$ determined by $\\sigma_1$. Then both $\\sigma_2$ and $\\sigma_3:=\\sigma_1\\sigma_2$ remain involutions of the non-reductive Lie algebra $\\g$. The isotropy representations related to $(\\g, \\sigma_2)$ and $(\\g, \\sigma_3)$ are degenerations of the isotropy representations related to $(\\g, {\\sigma_2})$ and $(\\g, {\\sigma_3})$, respectively. We show that these degenerated isotropy representations retain many good properties. For instance, they always have a generic stabiliser and their algebras of invariants are often polynomial. We also develop some theory on Cartan subspaces for various $Z_2$-gradings associated with the $Z_2\\times Z_2$-grading of $\\g$.

  19. A non-commuting stabilizer formalism

    Energy Technology Data Exchange (ETDEWEB)

    Ni, Xiaotong; Van den Nest, Maarten [Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Str. 1, 85748 Garching (Germany); Buerschaper, Oliver [Perimeter Institute for Theoretical Physics, 31 Caroline Street North, Waterloo, Ontario N2L 2Y5 (Canada); Dahlem Center for Complex Quantum Systems, Freie Universität Berlin, Arnimallee 14, 14195 Berlin (Germany)

    2015-05-15

    We propose a non-commutative extension of the Pauli stabilizer formalism. The aim is to describe a class of many-body quantum states which is richer than the standard Pauli stabilizer states. In our framework, stabilizer operators are tensor products of single-qubit operators drawn from the group 〈αI, X, S〉, where α = e{sup iπ/4} and S = diag(1, i). We provide techniques to efficiently compute various properties related to bipartite entanglement, expectation values of local observables, preparation by means of quantum circuits, parent Hamiltonians, etc. We also highlight significant differences compared to the Pauli stabilizer formalism. In particular, we give examples of states in our formalism which cannot arise in the Pauli stabilizer formalism, such as topological models that support non-Abelian anyons.

  20. Electronically commutated dc motors for electric vehicles

    Science.gov (United States)

    Maslowski, E. A.

    1981-01-01

    A motor development program to explore the feasibility of electronically commutated dc motors (also known as brushless) for electric cars is described. Two different design concepts and a number of design variations based on these concepts are discussed. One design concept is based on a permanent magnet, medium speed, machine rated at 7000 to 9000 rpm, and powered via a transistor inverter power conditioner. The other concept is based on a permanent magnet, high speed, machine rated at 22,000 to 26,000 rpm, and powered via a thyristor inverter power conditioner. Test results are presented for a medium speed motor and a high speed motor each of which have been fabricated using samarium cobalt permanent magnet material.

  1. Bicycle injuries: a matter of mechanism and age.

    Science.gov (United States)

    Siman-Tov, Maya; Jaffe, Dena H; Peleg, Kobi

    2012-01-01

    Bicycle riding is a popular form of recreation with positive health and environmental effects. These road users are vulnerable to serious injuries, especially when motor vehicles are involved. The goal of this study was to characterize cyclist-related injuries according to motor vehicle involvement for adults versus children. A retrospective study was carried out using data from 11 trauma centers in the Israeli National Trauma Registry (2001-2007). Injuries were classified according to whether a motor vehicle was involved, and differences in injury characteristics were assessed for adults (18+ years) versus children (1-17 years). A total of 5529 patients were hospitalized for bicycle injuries, of whom 1765 were adults and 3764 were children. Thirty percent (n=1662) of all bicycle injuries involved motor vehicles, although the rate of injuries resulting in hospitalization was 37% among adults and 27% among children. Injury characteristics and hospital resource utilization differed substantially by age group. Cyclists struck by a motor vehicle presented with more severe injuries requiring more hospital resources and resulting in poorer outcomes than those not involved with motor vehicles. The interaction effect between motor vehicle involvement and age was significant for torso injuries and need for medical imaging. We found that injury characteristics, hospital resource utilization and health-related outcomes for bicycle injuries are highly dependent on patient's age and mechanism of injury. Effect modification of motor vehicle involvement by age may in part reflect physicians' attitudes toward pediatric imaging. The risks identified in this study should be used for preparedness and management of trauma hospitalizations from bicycle injuries. PMID:22062347

  2. The role of multilevel factors in geographic differences in bicycle crash risk: a prospective cohort study

    Science.gov (United States)

    2013-01-01

    Background Regular cycling plays an important role in increasing physical activity levels but raises safety concerns for many people. While cyclists bear a higher risk of injury than most other types of road users, the risk differs geographically. Auckland, New Zealand’s largest urban region, has a higher injury risk than the rest of the country. This paper identified underlying factors at individual, neighbourhood and environmental levels and assessed their relative contribution to this risk differential. Methods The Taupo Bicycle Study involved 2590 adult cyclists recruited in 2006 and followed over a median period of 4.6 years through linkage to four national databases. The Auckland participants were compared with others in terms of baseline characteristics, crash outcomes and perceptions about environmental determinants of cycling. Cox regression modelling for repeated events was performed with multivariate adjustments. Results Of the 2554 participants whose addresses could be mapped, 919 (36%) resided in Auckland. The Auckland participants were less likely to be Māori but more likely to be socioeconomically advantaged and reside in an urban area. They were less likely to cycle for commuting and off-road but more likely to cycle in the dark and in a bunch, use a road bike and use lights in the dark. They had a higher risk of on-road crashes (hazard ratio: 1.47; 95% CI: 1.22, 1.76), of which 53% (95% CI: 20%, 72%) was explained by baseline differences, particularly related to cycling off-road, in the dark and in a bunch and residing in urban areas. They were more concerned about traffic volume, speed and drivers’ behaviour. Conclusions The excess crash risk in Auckland was explained by cycling patterns, urban residence and factors associated with the region’s car-dominated transport environment. PMID:24321134

  3. Resolution of stringy singularities by non-commutative algebras

    International Nuclear Information System (INIS)

    In this paper we propose a unified approach to (topological) string theory on certain singular spaces in their large volume limit. The approach exploits the non-commutative structure of D-branes, so the space is described by an algebraic geometry of non-commutative rings. The paper is devoted to the study of examples of these algebras. In our study there is an auxiliary commutative algebraic geometry of the center of the (local) algebras which plays an important role as the target space geometry where closed strings propagate. The singularities that are resolved will be the singularities of this auxiliary geometry. The singularities are resolved by the non-commutative algebra if the local non-commutative rings are regular. This definition guarantees that D-branes have a well defined K-theory class. Homological factors also play an important role. They describe the intersection theory of D-branes and lead to a formal definition of local quivers at singularities, which can be computed explicitly for many types of singularities. These results can be interpreted in terms of the derived category of coherent sheaves over the non-commutative rings, giving a non-commutative version of recent work by M. Douglas. We also describe global features like the Betti numbers of compact singular Calabi-Yau threefolds via global holomorphic sections of cyclic homology classes. (author)

  4. A characterization of semiprojectivity for commutative C*-algebras

    OpenAIRE

    Sørensen, Adam P. W.; Thiel, Hannes

    2011-01-01

    Given a compact, metric space X, we show that the commutative C*-algebra C(X) is semiprojective if and only if X is an absolute neighborhood retract of dimension at most one. This confirms a conjecture of Blackadar. Generalizing to the non-unital setting, we derive a characterization of semiprojectivity for separable, commutative C*-algebras. As further application of our findings we verify two conjectures of Loring and Blackadar in the commutative case, and we give a partial answer to the qu...

  5. Non-Commutative Geometry and Twisted Conformal Symmetry

    OpenAIRE

    Matlock, Peter

    2005-01-01

    The twist-deformed conformal algebra is constructed as a Hopf algebra with twisted co-product. This allows for the definition of conformal symmetry in a non-commutative background geometry. The twisted co-product is reviewed for the Poincar\\'e algebra and the construction is then extended to the full conformal algebra. It is demonstrated that conformal invariance need not be viewed as incompatible with non-commutative geometry; the non-commutativity of the coordinates appears as a consequence...

  6. A combinatorial non-commutative Hopf algebra of graphs

    OpenAIRE

    Tanasa, Adrian; Duchamp, Gerard; Foissy, Loïc; Hoang-Nghia, Nguyen; Manchon, Dominique

    2013-01-01

    A non-commutative, planar, Hopf algebra of planar rooted trees was defined independently by one of the authors in Foissy (2002) and by R. Holtkamp in Holtkamp (2003). In this paper we propose such a non-commutative Hopf algebra for graphs. In order to define a non-commutative product we use a quantum field theoretical (QFT) idea, namely the one of introducing discrete scales on each edge of the graph (which, within the QFT framework, corresponds to energy scales of the associated propagators)...

  7. Commutative subalgebras of the algebra of smooth operators

    OpenAIRE

    Ciaś, Tomasz

    2015-01-01

    We consider the Fr\\'echet ${}^*$-algebra $L(s',s)$ of the so-called smooth operators, i.e. continuous linear operators from the dual $s'$ of the space $s$ of rapidly decreasing sequences into $s$. This algebra is a non-commutative analogue of the algebra $s$. We characterize all closed commutative ${}^*$-subalgebras of $L(s',s)$ which are at the same time isomorphic to closed ${}^*$-subalgebras of $s$ and we provide an example of a closed commutative ${}^*$-subalgebra of $L(s',s)$ which canno...

  8. Subgroup s-commutativity degree of finite groups

    CERN Document Server

    Otera, Daniele Ettore

    2010-01-01

    In a recent contribution, Tarnauceanu has introduced the subgroup commutativity degree of a finite group, adapting to the context of the lattice theory some ideas and some techniques, which were known by the studies of Lescot on the commutativity degree. This new notion allows us to detect how a group is far from having all subgroups which are permutable. In the present paper we investigate a probability, which generalizes the subgroup commutativity degree, and find some numerical restrictions on groups which are rich in S-permutable subgroups in the sense of Kegel.

  9. Introduction to Dubois-Violette's non-commutative differential geometry

    International Nuclear Information System (INIS)

    In this work, one presents a detailed review of Dubois-Violette et al. approach to non-commutative differential calculus. The non-commutative differential geometry of matrix algebras and the non-commutative Poisson structures are treated in some details. We also present the analog of the Maxwell's theory and the new models of Yang-Mills-Higgs theories that can be constructed in this framework. In particular, some simple models are compared with the standard model. Finally, we discuss some perspectives and open questions. (author). 32 refs

  10. Non-Commutative Geometry, Categories and Quantum Physics

    CERN Document Server

    Bertozzini, Paolo; Lewkeeratiyutkul, Wicharn

    2008-01-01

    After an introduction to some basic issues in non-commutative geometry (Gel'fand duality, spectral triples), we present a "panoramic view" of the status of our current research program on the use of categorical methods in the setting of A.Connes' non-commutative geometry: morphisms/categories of spectral triples, categorification of Gel'fand duality. We conclude with a summary of the expected applications of "categorical non-commutative geometry" to structural questions in relativistic quantum physics: (hyper)covariance, quantum space-time, (algebraic) quantum gravity.

  11. Mechanism For Adjustment Of Commutation Of Brushless Motor

    Science.gov (United States)

    Schaefer, Richard E.

    1995-01-01

    Mechanism enables adjustment of angular position of set of Hall-effect devices that sense instantaneous shaft angle of brushless dc motor. Outputs of sensors fed to commutation circuitry. Measurement of shaft angle essential for commutation; that is, application of voltage to stator windings must be synchronized with shaft angle. To obtain correct angle measurement for commutation, Hall-effect angle sensors positioned at proper reference angle. The present mechanism accelerates adjustment procedure and makes it possible to obtain more accurate indication of minimum-current position because it provides for adjustment while motor running.

  12. Non-Commutative Mechanics in Mathematical & in Condensed Matter Physics

    Directory of Open Access Journals (Sweden)

    Peter A. Horváthy

    2006-12-01

    Full Text Available Non-commutative structures were introduced, independently and around the same time, in mathematical and in condensed matter physics (see Table 1. Souriau's construction applied to the two-parameter central extension of the planar Galilei group leads to the ''exotic'' particle, which has non-commuting position coordinates. A Berry-phase argument applied to the Bloch electron yields in turn a semiclassical model that has been used to explain the anomalous/spin/optical Hall effects. The non-commutative parameter is momentum-dependent in this case, and can take the form of a monopole in momentum space.

  13. The shear viscosity of the non-commutative plasma

    OpenAIRE

    Landsteiner, Karl; Mas, Javier

    2007-01-01

    We compute the shear viscosity of the non-commutative N=4 super Yang-Mills quantum field theory at strong coupling using the dual supergravity background. Special interest derives from the fact that the background presents an intrinsic anisotropy in space through the distinction of commutative and non-commutative directions. Despite this anisotropy the analysis exhibits the ubiquitous result \\eta/s = 1/4\\pi for two different shear channels. In order to derive this result, we show that the bou...

  14. Generalized Uncertainty Relation in the Non-commutative Quantum Mechanics

    Science.gov (United States)

    Chung, Won Sang

    2016-06-01

    In this paper the non-commutative quantum mechanics (NCQM) with the generalized uncertainty relations {Δ } x1 {Δ } x2 ≥ {θ}/{2}, {Δ} p1 {Δ } p2 ≥ {bar{θ}}/{2}, {Δ } xi {Δ } pi ≥ {hbar _{eff}}/{2} is discussed. Four each uncertainty relation, wave functions saturating each uncertainty relation are explicitly constructed. The unitary operators relating the non-commutative position and momentum operators to the commutative position and momentum operators are also investigated. We also discuss the uncertainty relation related to the harmonic oscillator.

  15. The Commuting Graph of the Symmetric Inverse Semigroup

    OpenAIRE

    Araújo, João; Bentz, Wolfram; Konieczny, Janusz

    2012-01-01

    The commuting graph of a finite non-commutative semigroup $S$, denoted $\\cg(S)$, is a simple graph whose vertices are the non-central elements of $S$ and two distinct vertices $x,y$ are adjacent if $xy=yx$. Let $\\mi(X)$ be the symmetric inverse semigroup of partial injective transformations on a finite set $X$. The semigroup $\\mi(X)$ has the symmetric group $\\sym(X)$ of permutations on $X$ as its group of units. In 1989, Burns and Goldsmith determined the clique number of the commuting graph ...

  16. Emergent Classicality via Commuting Position and Momentum Operators

    OpenAIRE

    Halliwell, J. J.

    2009-01-01

    Any account of the emergence of classicality from quantum theory must address the fact that the quantum operators representing positions and momenta do not commute, whereas their classical counterparts suffer no such restrictions. To address this, we revive an old idea of von Neumann, and seek a pair of commuting operators $X,P$ which are, in a specific sense, "close" to the canonical non-commuting position and momentum operators, $x,p$. The construction of such operators is related to the pr...

  17. Gauge transformation and symmetries of the commutative multicomponent BKP hierarchy

    Science.gov (United States)

    Li, Chuanzhong

    2016-01-01

    In this paper, we defined a new multi-component B type Kadomtsev-Petviashvili (BKP) hierarchy that takes values in a commutative subalgebra of {gl}(N,{{C}}). After this, we give the gauge transformation of this commutative multicomponent BKP (CMBKP) hierarchy. Meanwhile, we construct a new constrained CMBKP hierarchy that contains some new integrable systems, including coupled KdV equations under a certain reduction. After this, the quantum torus symmetry and quantum torus constraint on the tau function of the commutative multi-component BKP hierarchy will be constructed.

  18. 14 CFR 23.574 - Metallic damage tolerance and fatigue evaluation of commuter category airplanes.

    Science.gov (United States)

    2010-01-01

    ... evaluation of commuter category airplanes. 23.574 Section 23.574 Aeronautics and Space FEDERAL AVIATION... COMMUTER CATEGORY AIRPLANES Structure Fatigue Evaluation § 23.574 Metallic damage tolerance and fatigue evaluation of commuter category airplanes. For commuter category airplanes— (a) Metallic damage tolerance....

  19. 14 CFR 298.52 - Air taxi operations by commuter air carriers.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Air taxi operations by commuter air... (AVIATION PROCEEDINGS) ECONOMIC REGULATIONS EXEMPTIONS FOR AIR TAXI AND COMMUTER AIR CARRIER OPERATIONS Commuter Air Carrier Authorizations § 298.52 Air taxi operations by commuter air carriers. (a) A...

  20. A Smartphone Intervention for Cycle Commuting

    Directory of Open Access Journals (Sweden)

    Yun-Maw Cheng

    2014-11-01

    Full Text Available For those who new to cycling to and from work, how do you inspire yourself to keep up with it? Previous research has identified that having a partner is crucial to create and maintain a new habit. However, the rapidly changing work dynamics pose a challenge on this basis. Frequently failing to show up at the appointed or expected time can cause the motivation breakdown. In this paper, we introduce BikeTogether, a smartphone app that encourages and supports its users to cycle home with each other over the Internet. The app employs the metaphor of a bicycle flashlight to represent closeness, leading, and following between two sides. The cycling performance is also recorded so the users can track how they are doing over time. 10 participants were instructed and randomly paired to take a two-phases test ride on different routes. Results indicated that the app can help create the sense of being with each other while cycling and promote not only accompanied but competing ride. In addition, the outcome of the desirability towards the app implies a higher chance it will lead to a behavior change. This provides a new way that we can commit to remain encouraged.

  1. Chest Traumas due to Bicycle accident in Childhood

    Directory of Open Access Journals (Sweden)

    Ufuk Cobanoglu

    2011-09-01

    Full Text Available Aim:Childhood injuries are the leading cause of death in children and result in significant healthcare utilization. Trauma is the second most common cause of mortality in children aged 1-4 years and leading cause of death in children older than 4 years. Thoracic injury is the second most leading cause of death in traumatized children. Multisystemic injury is found in more than 50% of children with thoracic injuries most of which are secondary to blunt traumas. We planned this study to evaluate thorax trauma cases secondary to bicycle driving in childhood and to draw attention to the importance of the regulation of traffic rules, the education of bicycle drivers.Material and Methods:  A retrospective evaluation was performed in 17 pediatric patients admitted to the Department of Thoracic Surgery during 2006-2010 with a diagnosis of chest trauma due to bicycle driving. For every patient, a pediatric trauma score (PTS was calculated. Descriptive statistics were performed for PTS. Results; Eleven (64.70% cases were injured due to the tricycle accidents and six cases 6 (35.29% were injured due to the two-wheeled bicycle accidents. The most frequent thoracic pathologies included pulmonary contusion (41.2% and chest wall contusion (29.41%. Extrathoracic injuries were seen in 35.29%, the extremities (17.64% and abdomino pelvic (11.76% being the most commonly involved. Treatment consisted of symptomatic treatment in 12 patients (70.58%, tube thoracostomy in 2 patients (11.76%, and thoracotomy in 1 patient (5.9%. The morbidity was seen in 3 patients (17.64%. The mortality rate was 5.9% (n:1. The mean PTS of the cases who had additional system injuries were significantly worse than the cases who had isolated chest traumas Conclusions: The pediatric thorax has a greater cartilage content and incomplete ossification of the ribs. Due to the pliability of the pediatric rib cage and mediastinal mobility, significant intrathoracic injury may exist in the

  2. Personal and behavioral factors associated with bicycling in adults from Curitiba, Parana State, Brazil

    Directory of Open Access Journals (Sweden)

    Marilson Kienteka

    2014-01-01

    Full Text Available Bicycling is an important form of physical activity that can promote health benefits. The objective of this study was to analyze the association between personal and behavioral aspects in transportation bicycling and leisure time bicycling in adults. Data was drawn from a household survey involving 677 adults (53.1% female in Curitiba, Paraná State, Brazil. The prevalence of bicycling was 11.2% for transportation and 16.7% for leisure. The frequency of leisure time bicycling was higher among men (PR = 2.08; p < 0.001, young people < 30 and adults aged between 30 and 39.9, bicycle owners (PR = 8.76; p < 0.001 and among the physically active. Transportation bicycling occurred more frequently among men (PR = 3.63; p < 0.001, individuals aged 30 to 39.9, those with a low socioeconomic status (PR = 5.00; p = 0.006, bicycle owners (PR = 10.2; p < 0.001 and individuals with a negative perception of their quality of life. The prevalence of bicycling is low in Curitiba considering its potential as a means of physical activity. Personal and behavioral factors were associated with each form of bicycling.

  3. The fastest bicycle in the world; how a team of Delft students is building a bicycle to break the world speed record

    NARCIS (Netherlands)

    Annega, G.

    2011-01-01

    The Netherlands is a country known for its extensive use of bicycles as a means of everyday transport. However, while it has existed for about two centuries, todays bicycles only differ from those of the 19th century in relatively small details. Human Power Team Delft is building a whole new type of

  4. On the renormalization of non-commutative field theories

    Energy Technology Data Exchange (ETDEWEB)

    Blaschke, Daniel N. [University of Vienna, Faculty of Physics, Vienna (Austria); Garschall, Thomas; Heindl, Franz; Schweda, Manfred [Vienna University of Technology, Institute for Theoretical Physics, Vienna (Austria); Gieres, Francois [Universite de Lyon, Universite Lyon 1 and CNRS/IN2P3, Institut de Physique Nucleaire, Bat. P. Dirac, Villeurbanne (France); Wohlgenannt, Michael [University of Vienna, Faculty of Physics, Vienna (Austria); Austro-Ukrainian Institute for Science and Technology, Vienna (Austria)

    2013-01-15

    This paper addresses three topics concerning the quantization of non-commutative field theories (as defined in terms of the Moyal star product involving a constant tensor describing the non-commutativity of coordinates in Euclidean space). To start with, we discuss the Quantum Action Principle and provide evidence for its validity for non-commutative quantum field theories by showing that the equation of motion considered as insertion in the generating functional Z {sup c} [j ] of connected Green functions makes sense (at least at one-loop level). Second, we consider the generalization of the BPHZ renormalization scheme to non-commutative field theories and apply it to the case of a self-interacting real scalar field: Explicit computations are performed at one-loop order and the generalization to higher loops is commented upon. Finally, we discuss the renormalizability of various models for a self-interacting complex scalar field by using the approach of algebraic renormalization. (orig.)

  5. On the renormalization of non-commutative field theories

    International Nuclear Information System (INIS)

    This paper addresses three topics concerning the quantization of non-commutative field theories (as defined in terms of the Moyal star product involving a constant tensor describing the non-commutativity of coordinates in Euclidean space). To start with, we discuss the Quantum Action Principle and provide evidence for its validity for non-commutative quantum field theories by showing that the equation of motion considered as insertion in the generating functional Z c [j ] of connected Green functions makes sense (at least at one-loop level). Second, we consider the generalization of the BPHZ renormalization scheme to non-commutative field theories and apply it to the case of a self-interacting real scalar field: Explicit computations are performed at one-loop order and the generalization to higher loops is commented upon. Finally, we discuss the renormalizability of various models for a self-interacting complex scalar field by using the approach of algebraic renormalization. (orig.)

  6. Strong Planck constraints on braneworld and non-commutative inflation

    Energy Technology Data Exchange (ETDEWEB)

    Calcagni, Gianluca [Instituto de Estructura de la Materia, CSIC, Serrano 121, 28006 Madrid (Spain); Kuroyanagi, Sachiko; Ohashi, Junko; Tsujikawa, Shinji, E-mail: calcagni@iem.cfmac.csic.es, E-mail: skuro@rs.tus.ac.jp, E-mail: j1211703@ed.tus.ac.jp, E-mail: shinji@rs.kagu.tus.ac.jp [Department of Physics, Faculty of Science, Tokyo University of Science, 1-3, Kagurazaka, Shinjuku-ku, Tokyo 162-8601 (Japan)

    2014-03-01

    We place observational likelihood constraints on braneworld and non-commutative inflation for a number of inflaton potentials, using Planck, WMAP polarization and BAO data. Both braneworld and non-commutative scenarios of the kind considered here are limited by the most recent data even more severely than standard general-relativity models. At more than 95 % confidence level, the monomial potential V(φ)∝φ{sup p} is ruled out for p ≥ 2 in the Randall-Sundrum (RS) braneworld cosmology and, for p > 0, also in the high-curvature limit of the Gauss-Bonnet (GB) braneworld and in the infrared limit of non-commutative inflation, due to a large scalar spectral index. Some parameter values for natural inflation, small-varying inflaton models and Starobinsky inflation are allowed in all scenarios, although some tuning is required for natural inflation in a non-commutative spacetime.

  7. On a classification of irreducible almost commutative geometries

    International Nuclear Information System (INIS)

    We classify all irreducible, almost commutative geometries whose spectral action is dynamically nondegenerate. Heavy use is made of Krajewski's diagrammatic language. The motivation for our definition of dynamical nondegeneracy stems from particle physics where the fermion masses are nondegenerate

  8. Strong Planck constraints on braneworld and non-commutative inflation

    International Nuclear Information System (INIS)

    We place observational likelihood constraints on braneworld and non-commutative inflation for a number of inflaton potentials, using Planck, WMAP polarization and BAO data. Both braneworld and non-commutative scenarios of the kind considered here are limited by the most recent data even more severely than standard general-relativity models. At more than 95 % confidence level, the monomial potential V(φ)∝φp is ruled out for p ≥ 2 in the Randall-Sundrum (RS) braneworld cosmology and, for p > 0, also in the high-curvature limit of the Gauss-Bonnet (GB) braneworld and in the infrared limit of non-commutative inflation, due to a large scalar spectral index. Some parameter values for natural inflation, small-varying inflaton models and Starobinsky inflation are allowed in all scenarios, although some tuning is required for natural inflation in a non-commutative spacetime

  9. Commutators, paraproducts and BMO in non-homogeneous martingale settings

    CERN Document Server

    Treil, Sergei

    2010-01-01

    In this paper we investigate the relations between (martingale) BMO spaces, paraproducts and commutators in non-homogeneous martingale settings. Some new, and one might add unexpected, results are obtained. Some alternative proof of known results are also presented.

  10. The shear viscosity of the non-commutative plasma

    International Nuclear Information System (INIS)

    We compute the shear viscosity of the non-commutative N = 4 super Yang-Mills quantum field theory at strong coupling using the dual supergravity background. Special interest derives from the fact that the background presents an intrinsic anisotropy in space through the distinction of commutative and non-commutative directions. Despite this anisotropy the analysis exhibits the ubiquitous result η/s = 1/4π for two different shear channels. In order to derive this result, we show that the boundary energy momentum tensor must couple to the open string metric. As a byproduct we compute the renormalised holographic energy momentum tensor and show that it coincides with one in the commutative theory

  11. The shear viscosity of the non-commutative plasma

    CERN Document Server

    Landsteiner, Karl

    2007-01-01

    We compute the shear viscosity of the non-commutative N=4 super Yang-Mills quantum field theory at strong coupling using the dual supergravity background. Special interest derives from the fact that the background presents an intrinsic anisotropy in space through the distinction of commutative and non-commutative directions. Despite this anisotropy the analysis exhibits the ubiquitous result \\eta/s = 1/4\\pi for two different shear channels. In order to derive this result, we show that the boundary energy momentum tensor must couple to the open string metric. As a byproduct we compute the renormalised holographic energy momentum tensor and show that it coincides with one in the commutative theory.

  12. Commutative algebra with a view toward algebraic geometry

    CERN Document Server

    Eisenbud, David

    1995-01-01

    Commutative Algebra is best understood with knowledge of the geometric ideas that have played a great role in its formation, in short, with a view towards algebraic geometry. The author presents a comprehensive view of commutative algebra, from basics, such as localization and primary decomposition, through dimension theory, differentials, homological methods, free resolutions and duality, emphasizing the origins of the ideas and their connections with other parts of mathematics. Many exercises illustrate and sharpen the theory and extended exercises give the reader an active part in complementing the material presented in the text. One novel feature is a chapter devoted to a quick but thorough treatment of Grobner basis theory and the constructive methods in commutative algebra and algebraic geometry that flow from it. Applications of the theory and even suggestions for computer algebra projects are included. This book will appeal to readers from beginners to advanced students of commutative algebra or algeb...

  13. Non-commutative spacetime in very special relativity

    International Nuclear Information System (INIS)

    The purpose of Very Special Relativity is to show that the ISIM(2) subgroup of the Poincare group is sufficient to describe the spacetime symmetries of the so far observed physical phenomena. A deformation of such group, called DISIMb(2), was later introduced. In the present work, we present a novel non-commutative spacetime structure, underlying the DISIMb(2), that allows us to construct explicitly the generators of the group. Exploiting the Darboux map technique, we then construct a point particle Lagrangian that lives in the non-commutative phase space proposed by us. -- Highlights: → We propose a non-commutative phase space that enjoys the symmetries of deformed VSR. → We find a Darboux map relating non-commutative variables to canonical ones. → We use this map to construct a particle Lagrangian compatible with our phase space. → The Lagrangian so obtained is of Finsler type.

  14. Commutative curvature operators over four-dimensional generalized symmetric

    Directory of Open Access Journals (Sweden)

    Ali Haji-Badali

    2014-12-01

    Full Text Available Commutative properties of four-dimensional generalized symmetric pseudo-Riemannian manifolds were considered. Specially, in this paper, we studied Skew-Tsankov and Jacobi-Tsankov conditions in 4-dimensional pseudo-Riemannian generalized symmetric manifolds.

  15. COMMUTATION TIME ESTIMATOR FOR PM BLDC MOTOR TORQUE SIGNATURE ENHANCEMENT

    Directory of Open Access Journals (Sweden)

    WAEL A. SALAH

    2014-12-01

    Full Text Available This paper presents the development of the commutation time estimator (CTE for PM BLDC motor drives. The proposed scheme is aimed to enhance motor output torque by minimizing the generated torque ripples. The torque ripples originating from commutation instances cause spikes and dips in the motor output torque. The motor output torque could be enhanced by mitigating the phase current mismatch rate during phase current commutation period. This rate could be almost matched by introducing the commutation time estimator (CTE in order to control the rate of the energized phase current to be matched with the de-energized phase rate. Results obtained have validated and verified the proposed CTE effectiveness with a 50% average reduction of the generated torque ripples in PM BLDC motor.

  16. On the road : Social aspects of commuting long distances to work

    OpenAIRE

    Sandow, Erika

    2011-01-01

    With its point of departure of increasing numbers of people being engaged in commuting, the aim of this thesis is to reveal prerequisites for and consequences of long-distance commuting in Sweden for the individual and his or her partner. Special attention has been given to prerequisites for long-distance commuting in sparsely populated areas, and to social consequences related to long-distance commuting in terms of gender differences in commuting patterns, earnings and separation. The thesis...

  17. Classical limits of quantum mechanics on a non-commutative configuration space

    CERN Document Server

    Benatti, Fabio

    2013-01-01

    We consider a model of non-commutative Quantum Mechanics given by two harmonic oscillators over a non-commutative two dimensional configuration space. We study possible ways of removing the non-commutativity based on the classical limit context known as anti-Wick quantization. We show that removal of non-commutativity from the configuration space and from the canonical operators are not commuting operations.

  18. Active commuting of the inhabitants of Liberec city in low and high walkability areas

    OpenAIRE

    Lukáš Rubín; Josef Mitáš; Jan Dygrýn; Jiří Šmída; Lukáš Gábor; Adam Pátek

    2015-01-01

    Background: Active commuting in terms of everyday transport to school or work can have a significant effect on physical activity. Active commuting can be influenced by the environment, and examples from abroad show that current environmental changes tend mostly to promote passive forms of commuting. A similar situation of decreasing active commuting might be expected in the Czech Republic. However, little information has been published to date about the issue of active commuting among the inh...

  19. A Homemade Autosampler/Injector Commutator for Flow Injection Analysis

    Science.gov (United States)

    de Figueiredo, Eduardo Costa; de Souza, Leandro Ruela; de Magalhães, Cristiana Schmidt; Wisniewski, Célio

    2006-01-01

    An autosampler/injector commutator for flow injection analysis (FIA) was constructed with electronic components of used equipments. The apparatus is controlled by commercially available multifunctional interface (PCL711B) connected to a personal computer, and the software was written in Visual Basic language. The system was applied to water analysis and it presented satisfactory results. The low cost and simplicity are the principal characteristics of the autosampler/injector commutator. PMID:17671617

  20. Non-commutativity, teleology and GRB time delay

    Energy Technology Data Exchange (ETDEWEB)

    Li Miao, E-mail: mli@itp.ac.c [Kavli Institute for Theoretical Physics China, Key Laboratory of Frontiers in Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing 100190 (China); Pang Yi, E-mail: yipang@itp.ac.c [Kavli Institute for Theoretical Physics China, Key Laboratory of Frontiers in Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing 100190 (China); Wang Yi, E-mail: wangyi@itp.ac.c [Kavli Institute for Theoretical Physics China, Key Laboratory of Frontiers in Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing 100190 (China)

    2010-01-04

    We propose a model in which an energy-dependent time delay of a photon originates from space-time non-commutativity, the time delay is due to a non-commutative coupling between dilaton and photon. We predict that in our model, high energy photons with different momentum can either be delayed or superluminal, this may be related to a possible time delay reported by the Fermi LAT and Fermi GBM Collaborations.

  1. Non-commutativity, teleology and GRB time delay

    Science.gov (United States)

    Li, Miao; Pang, Yi; Wang, Yi

    2010-01-01

    We propose a model in which an energy-dependent time delay of a photon originates from space-time non-commutativity, the time delay is due to a non-commutative coupling between dilaton and photon. We predict that in our model, high energy photons with different momentum can either be delayed or superluminal, this may be related to a possible time delay reported by the Fermi LAT and Fermi GBM Collaborations.

  2. Commutators in real interpolation with quasi-power parameters

    Directory of Open Access Journals (Sweden)

    Ming Fan

    2002-01-01

    Full Text Available The basic higher order commutator theorem is formulated for the real interpolation methods associated with the quasi-power parameters, that is, the function spaces on which Hardy inequalities are valid. This theorem unifies and extends various results given by Cwikel, Jawerth, Milman, Rochberg, and others, and incorporates some results of Kalton to the context of commutator estimates for the real interpolation methods.

  3. COMMUTE MAPPING AND TRAVELING MEANS FOR CAR SHARING INDICATION

    OpenAIRE

    Cristiane Gonçalves Machado; Sergio Augusto Rodrigues

    2014-01-01

    The growth of urban centers in a disorderly manner has brought damage to the population concerning urban mobility. Public transportation is not considered as an efficient solution and looking for more comfort, many people have chosen to use their private cars for commuting which worsens the conditions of traffic and pollution. This paper aimed to evaluate locomotion means used by a group of employees in Botucatu, SP, Brazil, checking whether possible difficulties in commut...

  4. Monocentric and Polycentric Density Functions and Their Required Commutes

    OpenAIRE

    Song, Shunfeng

    1992-01-01

    This paper examines the relationship between urban structure and commuting behavior. Analyzing the 1980 journey-to-work data for the Los Angeles region, this paper has shown that polycentric density functions fit the actual urban structure better than the conventional monocentric model. This finding indicates the preeminence of accessibility to major employment centers in location choices. This paper also estimates commute flows implied by the polycentric and monocentric functions. I...

  5. A commutativity theorem for left s-unital rings

    Directory of Open Access Journals (Sweden)

    Hamza A. S. Abujabal

    1990-12-01

    Full Text Available In this paper we generalize some well-known commutativity theorems for associative rings as follows: Let R be a left s-unital ring. If there exist nonnegative integers m>1, k≥0, and n≥0 such that for any x, y in R, [xky−xnym,x]=0, then R is commutative.

  6. Trace Dynamics and a non-commutative special relativity

    Energy Technology Data Exchange (ETDEWEB)

    Lochan, Kinjalk, E-mail: kinjalk@tifr.res.in [Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400 005 (India); Singh, T.P., E-mail: tpsingh@tifr.res.in [Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400 005 (India)

    2011-10-17

    Trace Dynamics is a classical dynamical theory of non-commuting matrices in which cyclic permutation inside a trace is used to define the derivative with respect to an operator. We use the methods of Trace Dynamics to construct a non-commutative special relativity. We define a line-element using the Trace over space-time coordinates which are assumed to be operators. The line-element is shown to be invariant under standard Lorentz transformations, and is used to construct a non-commutative relativistic dynamics. The eventual motivation for constructing such a non-commutative relativity is to relate the statistical thermodynamics of this classical theory to quantum mechanics. -- Highlights: → Classical time is external to quantum mechanics. → This implies need for a formulation of quantum theory without classical time. → A starting point could be a non-commutative special relativity. → Such a relativity is developed here using the theory of Trace Dynamics. → A line-element is defined using the Trace over non-commuting space-time operators.

  7. Two-parameter Non-commutative Central Limit Theorem

    CERN Document Server

    Blitvić, Natasha

    2012-01-01

    The non-commutative Central Limit Theorem (CLT) introduced by Speicher in 1992 states that given almost any sequence of non-commutative random variables that commute or anti-commute pair-wise, the *-moments of the normalized partial sum S_N=(b_1+...+ b_N)/\\sqrt{N} are given by a Wick-type formula refined to count the number of crossings in the underlying pair-partitions. When coupled with explicit matrix models, the theorem yields random matrix models for creation and annihilation operators on the q-Fock space of Bozejko and Speicher. In this paper, we derive a non-commutative CLT when the pair-wise commutation coefficients are real numbers (as opposed to signs). The statistics of the limiting random variable are a second-parameter refinement of those above, jointly indexing the number of crossings and nestings in the underlying pair-partitions. Coupled with analogous matrix constructions, the theorem yields random matrix models for creation and annihilation operators on the recently introduced (q,t)-Fock spa...

  8. Trace Dynamics and a non-commutative special relativity

    International Nuclear Information System (INIS)

    Trace Dynamics is a classical dynamical theory of non-commuting matrices in which cyclic permutation inside a trace is used to define the derivative with respect to an operator. We use the methods of Trace Dynamics to construct a non-commutative special relativity. We define a line-element using the Trace over space-time coordinates which are assumed to be operators. The line-element is shown to be invariant under standard Lorentz transformations, and is used to construct a non-commutative relativistic dynamics. The eventual motivation for constructing such a non-commutative relativity is to relate the statistical thermodynamics of this classical theory to quantum mechanics. -- Highlights: → Classical time is external to quantum mechanics. → This implies need for a formulation of quantum theory without classical time. → A starting point could be a non-commutative special relativity. → Such a relativity is developed here using the theory of Trace Dynamics. → A line-element is defined using the Trace over non-commuting space-time operators.

  9. [Electrically assisted bicycles: health enhancement or "green" gadget?].

    Science.gov (United States)

    Welker, J; Cornuz, J; Gojanovic, B

    2012-07-25

    Electrically assisted bicycles (EAB) are flourishing in cities throughout the world and capitalize on ecological and practical advantages, helping in the fight against pollution, CO2 emissions and traffic jam. Human power is necessary to activate the electrical support, so that it equals to a moderate intensity physical activity (> 3 MET), or a vigorous one on hilly courses (>6 MET). The ecological benefits are obvious and transportation departments tend to support citizens who purchase one. EAB offer increased mobility at speeds of 15 to 25 km/h depending on hills and fitness of the rider, but could cause more accidents. EAB is linked to a real physical activity beneficial for health, but potentially more dangerous than a traditional bicycle. PMID:22913003

  10. Cellular automata simulation of traffic including cars and bicycles

    Science.gov (United States)

    Vasic, Jelena; Ruskin, Heather J.

    2012-04-01

    As 'greening' of all aspects of human activity becomes mainstream, transportation science is also increasingly focused around sustainability. Modal co-existence between motorised and non-motorised traffic on urban networks is, in this context, of particular interest for traffic flow modelling. The main modelling problems here are posed by the heterogeneity of vehicles, including size and dynamics, and by the complex interactions at intersections. Herein we address these with a novel technique, based on one-dimensional cellular automata components, for modelling network infrastructure and its occupancy by vehicles. We use this modelling approach, together with a corresponding vehicle behaviour model, to simulate combined car and bicycle traffic for two elemental scenarios-examples of components that would be used in the building of an arbitrary network. Results of simulations performed on these scenarios, (i) a stretch of road and (ii) an intersection causing conflict between cars and bicycles sharing a lane, are presented and analysed.

  11. A system for quantifying the cooling effectiveness of bicycle helmets.

    Science.gov (United States)

    Reid, J; Wang, E L

    2000-08-01

    This article describes the design and development of a system that is capable of quantifying the thermal comfort of bicycle helmets. The motivation for the development of the system stems from the desire both to increase helmet use and to provide the designer with a quantitative method of evaluating the thermal comfort of a helmet. The system consists of a heated mannequin head form, a heated reference sphere, a small wind tunnel, and a data acquisition system. Both the head form and the reference sphere were instrumented with thermocouples. The system is capable of simulating riding speeds ranging from 4.5-15.5 m/s. A cooling effectiveness, C1, that is independent of both ambient conditions and wind velocity is defined as a measure of how well the helmet ventilates as compared to the reference sphere. The system was validated by testing six commercially available bicycle helmets manufactured between approximately 1992 and 1998. PMID:11036573

  12. Simultaneous optimization of transit network and public bicycle station network

    Institute of Scientific and Technical Information of China (English)

    刘洋; 朱宁; 马寿峰

    2015-01-01

    The traditional manner to design public transportation system is to sequentially design the transit network and public bicycle network. A new public transportation system design problem that simultaneously considers both bus network design and public bicycle network design is proposed. The chemical reaction optimization (CRO) is designed to solve the problem. A shortcoming of CRO is that, when the two-molecule collisions take place, the molecules are randomly picked from the container. Hence, we improve CRO by employing different mating strategies. The computational results confirm the benefits of the mating strategies. Numerical experiments are conducted on the Sioux-Falls network. A comparison with the traditional sequential modeling framework indicates that the proposed approach has a better performance and is more robust. The practical applicability of the approach is proved by employing a real size network.

  13. Methodology for a global bicycle real world accidents reconstruction

    OpenAIRE

    Bourdet, Nicolas; Deck, Caroline; Serre, Thierry; Perrin, Christophe; LLARI, Maxime; Willinger, Rémy

    2012-01-01

    The use of the bicycle on a large scale encouraged in the context to develop an eco friendly environment is facing today on a range of barriers. One of these barriers identified by researchers and governments is observed to include ‘road safety’. Hence, it is necessary to set up a protection system for bicyclists especially for the cephalic segment. Currently only few studies are available concerning the head impact loading in case of real accidents. Therefore, the objective of th...

  14. In-depth real-world bicycle accident reconstructions

    OpenAIRE

    Bourdet, Nicolas; Deck, Caroline; Serre, Thierry; Perrin, Christophe; LLARI, Maxime; Willinger, Rémy

    2013-01-01

    Use of bicycles on a large scale, encouraged in the context to develop an eco-friendly environment, is facing today a range of barriers. One of these barriers identified by researchers and governments is observed to include ‘road safety’. Hence, it is necessary to set up a protection system for bicyclists especially for the cephalic segment. Currently only few studies are available concerning the head impact loading in case of real accidents. Therefore, the objective of this work ...

  15. Optimization of electric bicycle for youths with disabilities

    OpenAIRE

    Blumenstein, Tobias; Zeitlmann, Hilar; Alves-Pinto, Ana; Turova, Varvara; Lampe, Renée

    2014-01-01

    Cerebral palsy is a group of neurodevelopmental disorders that affect a person’s ability to move and to maintain balance and posture. People with cerebral palsy have also perception and space orientation deficits so that special assistance devices should be developed to compensate these handicaps. The objective was to optimize an adapted electric bicycle (E-bike) for youths with neurodevelopmental disorders. An adapted E-bike was provided with ultrasonic sensors that measure distances to obje...

  16. Interventions in Bicycle Infrastructure, Lessons from Dutch and Danish Cases

    OpenAIRE

    Van Goeverden, K.; Nielsen, Thomas Alexander Sick; Harder, Henrik; van Nes, Rob

    2015-01-01

    Today the interest in cycling is increasing worldwide and in many countries authorities are faced with the question how cycling can be promoted efficiently. In the Netherlands and Denmark, this question came up already in the 1970s when the downsides of the rapidly increasing motorisation became evident. At the time, in both countries large scale interventions in bicycle infrastructure were introduced and evaluated extensively in order to create knowledge on efficient promoting of cycling in ...

  17. Mobile cockpit system for enhanced electric bicycle use

    OpenAIRE

    João C. Ferreira; Monteiro, Vítor Duarte Fernandes; Afonso, José A.; Afonso, João L.

    2015-01-01

    This paper presents the project of a Mobile Cockpit System (MCS) for smartphones, which provides assistance to Electric Bicycle (EB) cyclists in Smart Cities’ environment. The presented system introduces a mobile application (MCS App) with the goal to provide useful personalized information to the cyclist related with the EB’s use, including EB range prediction considering the intended path, management of the cycling effort performed by the cyclist, handling of the battery charging process an...

  18. Capacity analysis of actions to increase safety of bicycle traffic

    OpenAIRE

    Stavrević, Igor

    2012-01-01

    The thesis speaks about modern editing methods of bicycle traffic in urban areas. It contains comparison of four foreign design manuals for planning and editing cyclist areas in cities. Those are Dutch, German, Canadian and design manual of the United States of America. The comparison is done upon different situations, which could appear in process of editing cyclist friendly infrastructure. Therefore the comparison is done upon situations like crossing of the side road, turning left and righ...

  19. Harvesting Energy from the Counterbalancing (Weaving) Movement in Bicycle Riding

    OpenAIRE

    Shashank Priya; Jeongjin Yeo; Yoonseok Yang

    2012-01-01

    Bicycles are known to be rich source of kinetic energy, some of which is available for harvesting during speedy and balanced maneuvers by the user. A conventional dynamo attached to the rim can generate a large amount of output power at an expense of extra energy input from the user. However, when applying energy conversion technology to human powered equipments, it is important to minimize the increase in extra muscular activity and to maximize the efficiency of human movements. This study p...

  20. Built Environment Influences on Healthy Transportation Choices: Bicycling versus Driving

    OpenAIRE

    Winters, Meghan; Brauer, Michael; Setton, Eleanor M.; Teschke, Kay

    2010-01-01

    A growing body of evidence links the built environment to physical activity levels, health outcomes, and transportation behaviors. However, little of this research has focused on cycling, a sustainable transportation option with great potential for growth in North America. This study examines associations between decisions to bicycle (versus drive) and the built environment, with explicit consideration of three different spatial zones that may be relevant in travel behavior: trip origins, tri...

  1. Measuring dynamic loads on a foldable city bicycle:

    OpenAIRE

    Boltežar, Miha; Pirnat, Miha; Savšek, Zdenko

    2011-01-01

    Strain gauges have been used to measure dynamic loads on a foldable bicycle while it is being ridden. Eight full, Wheatstone-bridge measuring points were used to measure the forces on the front and rear wheels, the handlebars, the seat and the pedals. These bridges were positioned at special measuring parts that simplified the measurements. Some of the measuring problems that were successfully resolved are described. The measuring took place on public roads where real-life data was gathered f...

  2. The value of time and external benefits in bicycle appraisal

    OpenAIRE

    Börjesson, Maria; ELIASSON, Jonas

    2011-01-01

    We estimate the value of time savings, different cycling environments and additional benefits in cost-benefit analysis of cycling investments. Cyclists’ value of travel time savings turns out to be high, considerably higher than the value of time savings on alternative modes. Cyclists also value other improvements highly, such as separated bicycle lanes. As to additional benefits of cycling improvements in the form of health and reduced car traffic, our results do not support the notion that ...

  3. Formation and Properties of a Bicyclic Silylated Digermene

    OpenAIRE

    Hlina, Johann; Baumgartner, Judith; Marschner, Christoph; Albers, Lena; Müller, Thomas; Jouikov, Viatcheslav V

    2014-01-01

    In the presence of PMe3 or N-heterocyclic carbenes, the reaction of oligosilanylene dianions with GeCl2⋅dioxane gives germylene–base adducts. After base abstraction, the free germylenes can dimerize by formation of a digermene. An electrochemical and theoretical study of a bicyclic tetrasilylated digermene revealed formation of a comparably stable radical anion and a more reactive radical cation, which were characterized further by UV/Vis and ESR spectroscopy.

  4. Grand unification in non-commutative geometry

    International Nuclear Information System (INIS)

    The formalism of non-commutative geometry of A. Connes is used to construct unified models in particle physics. The physical space-time is taken to be a product of a continuous four-manifold by a discrete set of points. The basic algebra is chosen to be an algebra of matrix-valued functions, and the symmetry-breaking mechanism is coded into a generalized Dirac operator. The formalism is then applied to three examples. In the first example the discrete space consists of two points, and the two algebras are taken respectively to be those of 2x2 and 1x1 matrices. With the Dirac operator containing the vacuum breaking SU(2)xU(1) to U(1), the model is shown to correspond to the standard model. In the second example the discrete space has three points, two of the algebras are identical and consist of 5x5 complex matrices, and the third algebra consists of functions. With an appropriate Dirac operator this model is almost identical to the minimal SU(5) model of Georgi and Glashow. The third and final example is the left-right symmetric model SU(2)LxSU(2)RxU(1)B-L. (orig.)

  5. Tensor products of commutative Banach algebras

    Directory of Open Access Journals (Sweden)

    Shobha Madan

    1982-09-01

    Full Text Available Let A1, A2 be commutative semisimple Banach algebras and A1⊗∂A2 be their projective tensor product. We prove that, if A1⊗∂A2 is a group algebra (measure algebra of a locally compact abelian group, then so are A1 and A2. As a consequence, we prove that, if G is a locally compact abelian group and A is a comutative semi-simple Banach algebra, then the Banach algebra L1(G,A of A-valued Bochner integrable functions on G is a group algebra if and only if A is a group algebra. Furthermore, if A has the Radon-Nikodym property, then the Banach algebra M(G,A of A-valued regular Borel measures of bounded variation on G is a measure algebra only if A is a measure algebra.

  6. Non-commutative representation for quantum systems on Lie groups

    Energy Technology Data Exchange (ETDEWEB)

    Raasakka, Matti Tapio

    2014-01-27

    The topic of this thesis is a new representation for quantum systems on weakly exponential Lie groups in terms of a non-commutative algebra of functions, the associated non-commutative harmonic analysis, and some of its applications to specific physical systems. In the first part of the thesis, after a review of the necessary mathematical background, we introduce a {sup *}-algebra that is interpreted as the quantization of the canonical Poisson structure of the cotangent bundle over a Lie group. From the physics point of view, this represents the algebra of quantum observables of a physical system, whose configuration space is a Lie group. We then show that this quantum algebra can be represented either as operators acting on functions on the group, the usual group representation, or (under suitable conditions) as elements of a completion of the universal enveloping algebra of the Lie group, the algebra representation. We further apply the methods of deformation quantization to obtain a representation of the same algebra in terms of a non-commutative algebra of functions on a Euclidean space, which we call the non-commutative representation of the original quantum algebra. The non-commutative space that arises from the construction may be interpreted as the quantum momentum space of the physical system. We derive the transform between the group representation and the non-commutative representation that generalizes in a natural way the usual Fourier transform, and discuss key properties of this new non-commutative harmonic analysis. Finally, we exhibit the explicit forms of the non-commutative Fourier transform for three elementary Lie groups: R{sup d}, U(1) and SU(2). In the second part of the thesis, we consider application of the non-commutative representation and harmonic analysis to physics. First, we apply the formalism to quantum mechanics of a point particle on a Lie group. We define the dual non-commutative momentum representation, and derive the phase

  7. Non-commutative representation for quantum systems on Lie groups

    International Nuclear Information System (INIS)

    The topic of this thesis is a new representation for quantum systems on weakly exponential Lie groups in terms of a non-commutative algebra of functions, the associated non-commutative harmonic analysis, and some of its applications to specific physical systems. In the first part of the thesis, after a review of the necessary mathematical background, we introduce a *-algebra that is interpreted as the quantization of the canonical Poisson structure of the cotangent bundle over a Lie group. From the physics point of view, this represents the algebra of quantum observables of a physical system, whose configuration space is a Lie group. We then show that this quantum algebra can be represented either as operators acting on functions on the group, the usual group representation, or (under suitable conditions) as elements of a completion of the universal enveloping algebra of the Lie group, the algebra representation. We further apply the methods of deformation quantization to obtain a representation of the same algebra in terms of a non-commutative algebra of functions on a Euclidean space, which we call the non-commutative representation of the original quantum algebra. The non-commutative space that arises from the construction may be interpreted as the quantum momentum space of the physical system. We derive the transform between the group representation and the non-commutative representation that generalizes in a natural way the usual Fourier transform, and discuss key properties of this new non-commutative harmonic analysis. Finally, we exhibit the explicit forms of the non-commutative Fourier transform for three elementary Lie groups: Rd, U(1) and SU(2). In the second part of the thesis, we consider application of the non-commutative representation and harmonic analysis to physics. First, we apply the formalism to quantum mechanics of a point particle on a Lie group. We define the dual non-commutative momentum representation, and derive the phase space path

  8. Design Analysis And Applications Of A Regenerative Bicycle Ergometer

    Directory of Open Access Journals (Sweden)

    Chukwuneke J. L.

    2015-08-01

    Full Text Available Man needs to do some form of physical work in other to remain healthy this work is similar to the work done by any machine or equipment and thus should be channeled to give useful output but rather it is usually dissipated into the environment in form of heat. The regenerative bicycle ergometer takes advantage of the greater power generated by the limbs and arms thus conserves converts and stores the energy dissipated by the rider with an ideal mechanical advantage of 7.6 it strategically uses simple mechanisms to magnify its work and then converts this mechanical energy into electrical energy by the use of a dynamo with a speed ratio of 108.5 and a transmission efficiency of 89 the rider pedals 27rpm to obtain the dynamos rated input of 2600rpm giving an output of 12.6volts. The regenerative bicycle ergometer is designed and constructed to perform all the core functions of a bicycle ergometer having an allowable load of 116.5kg and a maximum resistance of 65.33N which is equivalent to a mass of 6.66kg. The energy converted is stored in a 12volts battery making its use flexible clean and meeting the energy demands of man.

  9. Electric motor assisted bicycle as an aerobic exercise machine.

    Science.gov (United States)

    Nagata, T; Okada, S; Makikawa, M

    2012-01-01

    The goal of this study is to maintain a continuous level of exercise intensity around the aerobic threshold (AT) during riding on an electric motor assisted bicycle using a new control system of electrical motor assistance which uses the efficient pedaling rate of popular bicycles. Five male subjects participated in the experiment, and the oxygen uptake was measured during cycling exercise using this new pedaling rate control system of electrical motor assistance, which could maintain the pedaling rate within a specific range, similar to that in previous type of electrically assisted bicycles. Results showed that this new pedaling rate control system at 65 rpm ensured continuous aerobic exercise intensity around the AT in two subjects, and this intensity level was higher than that observed in previous type. However, certain subjects were unable to maintain the expected exercise intensity because of their particular cycling preferences such as the pedaling rate. It is necessary to adjust the specific pedaling rate range of the electrical motor assist control according to the preferred pedaling rate, so that this system becomes applicable to anyone who want continuous aerobic exercise. PMID:23366293

  10. Harvesting Energy from the Counterbalancing (Weaving) Movement in Bicycle Riding

    Science.gov (United States)

    Yang, Yoonseok; Yeo, Jeongjin; Priya, Shashank

    2012-01-01

    Bicycles are known to be rich source of kinetic energy, some of which is available for harvesting during speedy and balanced maneuvers by the user. A conventional dynamo attached to the rim can generate a large amount of output power at an expense of extra energy input from the user. However, when applying energy conversion technology to human powered equipments, it is important to minimize the increase in extra muscular activity and to maximize the efficiency of human movements. This study proposes a novel energy harvesting methodology that utilizes lateral oscillation of bicycle frame (weaving) caused by user weight shifting movements in order to increase the pedaling force in uphill riding or during quick speed-up. Based on the 3D motion analysis, we designed and implemented the prototype of an electro-dynamic energy harvester that can be mounted on the bicycle's handlebar to collect energy from the side-to-side movement. The harvester was found to generate substantial electric output power of 6.6 mW from normal road riding. It was able to generate power even during uphill riding which has never been shown with other approaches. Moreover, harvesting of energy from weaving motion seems to increase the economy of cycling by helping efficient usage of human power. PMID:23112598

  11. Finite element analysis of advanced bicycle precision brake disk forming technology

    Directory of Open Access Journals (Sweden)

    Chen Dyi-Cheng

    2015-01-01

    Full Text Available In recent years, the bicycle has become an environmentally friendly transportation. The bicycle can be divided into mountain bicycle and highway bicycle. Safe driving is the prior consideration. The bicycle braking system can be divided into oil pressure disk brakes and mechanical disk brakes. The brake disk system is one indispensable component of the safe system. In accordance to overall weight consideration of the bike, the brake disk should also focus on the lightweight design. This paper discussed an innovative brake disk forming technology for 6061 aluminum alloy by the rigid-plastic finite element analysis. The simulation parameters include geometric shapes of the brake disk and mold, die temperature, and friction factors. The stress and strain in forming, brake deformation and vibration modal analysis of brake disk in riding were studied. The paper is expected to offer some precision bicycle brake disk manufacture knowledge for industry.

  12. The impact of transportation infrastructure on bicycling injuries and crashes: a review of the literature

    OpenAIRE

    Cripton Peter A; Teschke Kay; Harris M.; Reynolds Conor CO; Winters Meghan

    2009-01-01

    Abstract Background Bicycling has the potential to improve fitness, diminish obesity, and reduce noise, air pollution, and greenhouse gases associated with travel. However, bicyclists incur a higher risk of injuries requiring hospitalization than motor vehicle occupants. Therefore, understanding ways of making bicycling safer and increasing rates of bicycling are important to improving population health. There is a growing body of research examining transportation infrastructure and the risk ...

  13. Automated Analysis Methods for the Assessment of Bicycle Infrastructure and Demand

    OpenAIRE

    Pashkevich, Anton

    2013-01-01

    A first phase of the research activity has been related to the study of the state of art of the infrastructures for cycling, bicycle use and methods for evaluation. In this part, the candidate has studied the "bicycle system" in countries with high bicycle use and in particular in the Netherlands. Has been carried out an evaluation of the questionnaires of the survey conducted within the European project BICY on mobility in general in 13 cities of the participating countries. The questionn...

  14. A Modified Cellular Automaton Approach for Mixed Bicycle Traffic Flow Modeling

    OpenAIRE

    Xiaonian Shan; Zhibin Li; Xiaohong Chen; Jianhong Ye

    2015-01-01

    Several previous studies have used the Cellular Automaton (CA) for the modeling of bicycle traffic flow. However, previous CA models have several limitations, resulting in differences between the simulated and the observed traffic flow features. The primary objective of this study is to propose a modified CA model for simulating the characteristics of mixed bicycle traffic flow. Field data were collected on physically separated bicycle path in Shanghai, China, and were used to calibrate the C...

  15. Conversion Of An Ordinary N Bicycle Into An Electric Bike And Related Research

    OpenAIRE

    Marius Janavičius

    2014-01-01

    An electric bicycle as a transport and leisure vehicle is expected to have a promising future. Currently, he market offers a great choice of factory electric bicycles and conversion kits to remake an ordinary bicycle into an electric bike. Also, the increasing number of electric vehicles is determined by the reduction in costs for manufacturing of batteries and an evolution in battery technology. This article presents the implementation of an electric bike by selecting the “Golden Motor Techn...

  16. "The Mechanisms. Light and Miraculous": The Convivial Bicycle in Literature and Film

    OpenAIRE

    Guevara, J. Josh

    2012-01-01

    This dissertation explores the prevalent representation of the bicycle as a liberatory figure in theoretical texts, novels, films, and poetry. Because the bicycle confers unexpected creativity and autonomy, it alters definitions of technology, modernity, and identity. Chapter one recuperates and employs Ivan Illich's concept of conviviality in order to re-examine the inheritance of the project of modernity and question the definition of technology in the twenty-first century bicycle epoch. Fo...

  17. Hangzhou Public Bicycle: Understanding Early Adoption and Behavioral Response to Bikesharing in Hangzhou, China

    OpenAIRE

    Shaheen, Susan

    2011-01-01

    Over the past 20 years, China has experienced a steady decline in bicycle use. To address this trend, China's central and local government for urban transportation created the "Public Transit Priority" to encourage public transport initiatives. As part of this effort, the Hangzhou government launched “Hangzhou Public Bicycle” in 2008. This service allows members to access a shared fleet of bicycles. As of March 2011, it operated 60,600 bicycles with 2,416 fixed stations in eight core district...

  18. Spatial analysis of dynamic movements of Vélo'v, Lyon's shared bicycle program

    OpenAIRE

    Borgnat, Pierre; Fleury, Eric; Robardet, Céline; Scherrer, Antoine

    2009-01-01

    Public transportation systems like Lyon's bicycle community sharing program can be considered as a complex system composed of interconnected stations that exchange bicycles. Such system generates digital footprints that reveals the activity in the city over time and space and make possible their analyze. In this paper, the analysis deals with the spatial understanding and visualization of bicycle trips. We first study the activity in each station separately and then identify the main characte...

  19. Shared Bicycles in a City: A Signal Processing and Data Analysis Perspective

    OpenAIRE

    Borgnat, Pierre; Robardet, Céline; Rouquier, Jean-Baptiste; Abry, Patrice; Fleury, Eric; Flandrin, Patrick

    2011-01-01

    Community shared bicycle systems, such as the Vélo'v program launched in Lyon in May 2005, are public transportation programs that can be studied as a complex system composed of interconnected stations that exchange bicycles. They generate digital footprints that reveal the activity in the city over time and space, making possible a quantitative analysis of movements using bicycles in the city. A careful study relying on nonstationary statistical modeling and data mining allows us to first mo...

  20. Envisioning Competence: Learning, Problem Solving, and Children at Work in the Exploratory Bicycle Shop

    OpenAIRE

    Hammond, Charles Florian

    2010-01-01

    This study examines the conceptual learning and cognitive processes of schoolchildren engaged in problem solving activities in a non-school, workplace setting known as the exploratory bicycle shop. The exploratory bike shop is a commercial bicycle shop: a) that has been adapted for combined retail and educational purposes and b) where middle-school and high-school age students participate as bicycle mechanics explorers or, more formally, as apprentices. It provides a multi-generational, econo...

  1. Improving Bicyclic Peptide Phage Display and Development of Sortase A Inhibitors

    OpenAIRE

    Rentero Rebollo, Inmaculada

    2014-01-01

    Bicyclic peptide ligands are promising molecules for the development of new therapeutics. They combine advantages from large protein therapeutics and small molecule drugs. Large combinatorial libraries of bicyclic peptides can be generated and screened by phage display using a recently developed strategy. Potent and selective bicyclic peptide inhibitors against several therapeutic targets have already been developed and their therapeutic potential is currently being evaluated in animal models...

  2. Compositions comprising a polypeptide having cellulolytic enhancing activity and a bicycle compound and uses thereof

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Feng; Sweeney, Matthew; Quinlan, Jason

    2015-06-16

    The present invention relates to compositions comprising: a polypeptide having cellulolytic enhancing activity and a bicyclic compound. The present invention also relates to methods of using the compositions.

  3. Bicycle helmets are highly effective at preventing head injury during head impact: head-form accelerations and injury criteria for helmeted and unhelmeted impacts.

    Science.gov (United States)

    Cripton, Peter A; Dressler, Daniel M; Stuart, Cameron A; Dennison, Christopher R; Richards, Darrin

    2014-09-01

    Cycling is a popular form of recreation and method of commuting with clear health benefits. However, cycling is not without risk. In Canada, cycling injuries are more common than in any other summer sport; and according to the US National Highway and Traffic Safety Administration, 52,000 cyclists were injured in the US in 2010. Head injuries account for approximately two-thirds of hospital admissions and three-quarters of fatal injuries among injured cyclists. In many jurisdictions and across all age levels, helmets have been adopted to mitigate risk of serious head injuries among cyclists and the majority of epidemiological literature suggests that helmets effectively reduce risk of injury. Critics have raised questions over the actual efficacy of helmets by pointing to weaknesses in existing helmet epidemiology including selection bias and lack of appropriate control for the type of impact sustained by the cyclist and the severity of the head impact. These criticisms demonstrate the difficulty in conducting epidemiology studies that will be regarded as definitive and the need for complementary biomechanical studies where confounding factors can be adequately controlled. In the bicycle helmet context, there is a paucity of biomechanical data comparing helmeted to unhelmeted head impacts and, to our knowledge, there is no data of this type available with contemporary helmets. In this research, our objective was to perform biomechanical testing of paired helmeted and unhelmeted head impacts using a validated anthropomorphic test headform and a range of drop heights between 0.5m and 3.0m, while measuring headform acceleration and Head Injury Criterion (HIC). In the 2m (6.3m/s) drops, the middle of our drop height range, the helmet reduced peak accelerations from 824g (unhelmeted) to 181g (helmeted) and HIC was reduced from 9667 (unhelmeted) to 1250 (helmeted). At realistic impact speeds of 5.4m/s (1.5m drop) and 6.3m/s (2.0m drop), bicycle helmets changed the

  4. Active commuting to school: How far is too far?

    LENUS (Irish Health Repository)

    Nelson, Norah M

    2008-01-01

    ABSTRACT: BACKGROUND: Walking and cycling to school provide a convenient opportunity to incorporate physical activity into an adolescent\\'s daily routine. School proximity to residential homes has been identified as an important determinant of active commuting among children. The purpose of this study is to identify if distance is a barrier to active commuting among adolescents, and if there is a criterion distance above which adolescents choose not to walk or cycle. METHODS: Data was collected in 2003-05 from a cross-sectional cohort of 15-17 yr old adolescents in 61 post primary schools in Ireland. Participants self-reported distance, mode of transport to school and barriers to active commuting. Trained researchers took physical measurements of height and weight. The relation between mode of transport, gender and population density was examined. Distance was entered into a bivariate logistic regression model to predict mode choice, controlling for gender, population density socio-economic status and school clusters. RESULTS: Of the 4013 adolescents who participated (48.1% female, mean age 16.02 +\\/- 0.661), one third walked or cycled to school. A higher proportion of males than females commuted actively (41.0 vs. 33.8%, chi2 (1) = 22.21, p < 0.001, r = -0.074). Adolescents living in more densely populated areas had greater odds of active commuting than those in the most sparsely populated areas (chi2 (df = 3) = 839.64, p < 0.001). In each density category, active commuters travelled shorter distances to school. After controlling for gender and population density, a 1-mile increase in distance decreased the odds of active commuting by 71% (chi2 (df = 1) = 2591.86, p < 0.001). The majority of walkers lived within 1.5 miles and cyclists within 2.5 miles. Over 90% of adolescents who perceived distance as a barrier to active commuting lived further than 2.5 miles from school. CONCLUSION: Distance is an important perceived barrier to active commuting and a predictor

  5. Geometric properties of commutative subalgebras of partial differential operators

    Science.gov (United States)

    Zheglov, A. B.; Kurke, H.

    2015-05-01

    We investigate further algebro-geometric properties of commutative rings of partial differential operators, continuing our research started in previous articles. In particular, we start to explore the simplest and also certain known examples of quantum algebraically completely integrable systems from the point of view of a recent generalization of Sato's theory, developed by the first author. We give a complete characterization of the spectral data for a class of 'trivial' commutative algebras and strengthen geometric properties known earlier for a class of known examples. We also define a kind of restriction map from the moduli space of coherent sheaves with fixed Hilbert polynomial on a surface to an analogous moduli space on a divisor (both the surface and the divisor are part of the spectral data). We give several explicit examples of spectral data and corresponding algebras of commuting (completed) operators, producing as a by-product interesting examples of surfaces that are not isomorphic to spectral surfaces of any (maximal) commutative ring of partial differential operators of rank one. Finally, we prove that any commutative ring of partial differential operators whose normalization is isomorphic to the ring of polynomials k \\lbrack u,t \\rbrack is a Darboux transformation of a ring of operators with constant coefficients. Bibliography: 39 titles.

  6. The Commuting Graph of the Symmetric Inverse Semigroup

    CERN Document Server

    Araújo, João; Konieczny, Janusz

    2012-01-01

    The commuting graph of a finite non-commutative semigroup $S$, denoted $\\cg(S)$, is a simple graph whose vertices are the non-central elements of $S$ and two distinct vertices $x,y$ are adjacent if $xy=yx$. Let $\\mi(X)$ be the symmetric inverse semigroup of partial injective transformations on a finite set $X$. The semigroup $\\mi(X)$ has the symmetric group $\\sym(X)$ of permutations on $X$ as its group of units. In 1989, Burns and Goldsmith determined the clique number of the commuting graph of $\\sym(X)$. In 2008, Iranmanesh and Jafarzadeh found an upper bound of the diameter of $\\cg(\\sym(X))$, and in 2011, Dol\\u{z}an and Oblak claimed (but their proof has a GAP) that this upper bound is in fact the exact value. The goal of this paper is to begin the study of the commuting graph of the symmetric inverse semigroup $\\mi(X)$. We calculate the clique number of $\\cg(\\mi(X))$, the diameters of the commuting graphs of the proper ideals of $\\mi(X)$, and the diameter of $\\cg(\\mi(X))$ when $|X|$ is even or a power of a...

  7. QPFT operator algebras and commutative exterior differential calculus

    International Nuclear Information System (INIS)

    The reduction of the structure theory of the operator algebras of quantum projective (sl(2, C)-invariant) field theory (QPFT operator algebras) to a commutative exterior differential calculus by means of the operation of renormalization of a pointwise product of operator fields is described. In the first section, the author introduces the concept of the operator algebra of quantum field theory and describes the operation of the renormalization of a pointwise product of operator fields. The second section is devoted to a brief exposition of the fundamentals of the structure theory of QPT operator algebras. The third section is devoted to commutative exterior differential calculus. In the fourth section, the author establishes the connection between the renormalized pointwise product of operator fields in QPFT operator algebras and the commutative exterior differential calculus. 5 refs

  8. Modelling the relation between income and commuting distance

    DEFF Research Database (Denmark)

    Carra, Giulia; Mulalic, Ismir; Fosgerau, Mogens;

    2016-01-01

    We discuss the distribution of commuting distances and its relation to income. Using data from Denmark, the UK and the USA, we show that the commuting distance is (i) broadly distributed with a slow decaying tail that can be fitted by a power law with exponent γ ≈ 3 and (ii) an average growing...... slowly as a power law with an exponent less than one that depends on the country considered. The classical theory for job search is based on the idea that workers evaluate the wage of potential jobs as they arrive sequentially through time, and extending this model with space, we obtain predictions that...... skills of the worker and decreases with the wage. The predicted distribution of commuting distances decays as 1/r3 and is independent of the distribution of the quality of jobs. We find our alternative model to be in agreement with our data. This type of approach opens new perspectives for the modelling...

  9. Large N limit of non-commutative gauge theories

    International Nuclear Information System (INIS)

    Using the correspondence between gauge theories and string theory in curved backgrounds, we investigate aspects of the large N limit of non-commutative gauge theories by considering gravity solutions with B fields. We argue that the total number of physical degrees of freedom at any given scale coincides with the commutative case. We then compute a two-point correlation function involving momentum components in the directions of the B-field. In the infrared regime it reproduces the usual behavior of the commutative gauge theory (i.e. of the form k4 log k2). In the UV regime, we find that the two-point function decays exponentially with the momentum. A calculation of Wilson lines suggests that strings cannot be localized near the boundary. We also find string configurations that are localized in a finite region of the radial direction. These are worldsheet instantons. (author)

  10. Modes and Moods of Mobility: Tourists and Commuters

    Directory of Open Access Journals (Sweden)

    Orvar Löfgren

    2015-06-01

    Full Text Available What can we learn from comparing different modes and moods of travel, among, for example, tourists and commuters? This paper contrasts these two very different kinds of mobility, and the ways in which they organise both motion and emotion. It is not only a question about how people interact with various systems of transport, but also how materialities and affects work together. An important topic is the question of how people acquire travelling skills. How do they learn to be a tourist or a commuter, to handle a train ride, navigate a transit space, or interact with strangers? A good reason to contrast commuters and tourists is also because they have often been studied within very different research paradigms. How can these different research traditions be put into a dialogue with each other, and help to develop methods for capturing the often elusive ways in which motion and emotion work together?

  11. Optimization of polynomials in non-commuting variables

    CERN Document Server

    Burgdorf, Sabine; Povh, Janez

    2016-01-01

    This book presents recent results on positivity and optimization of polynomials in non-commuting variables. Researchers in non-commutative algebraic geometry, control theory, system engineering, optimization, quantum physics and information science will find the unified notation and mixture of algebraic geometry and mathematical programming useful. Theoretical results are matched with algorithmic considerations; several examples and information on how to use NCSOStools open source package to obtain the results provided. Results are presented on detecting the eigenvalue and trace positivity of polynomials in non-commuting variables using Newton chip method and Newton cyclic chip method, relaxations for constrained and unconstrained optimization problems, semidefinite programming formulations of the relaxations and finite convergence of the hierarchies of these relaxations, and the practical efficiency of algorithms.

  12. Canonical approach to the closed string non-commutativity

    Directory of Open Access Journals (Sweden)

    Davidović Ljubica

    2014-01-01

    Full Text Available We consider the propagation of the closed bosonic string in the weakly curved background. We show that the closed string non-commutativity is essentially connected to the T-duality and nontrivial background. From the T-duality transformation laws, connecting the canonical variables of the original and T-dual theory, we find the structure of the Poisson brackets in the T-dual space corresponding to the fundamental Poisson brackets in the original theory. We find that the commutative original theory is equivalent to the non-commutative T-dual theory, in which Poisson brackets close on winding and momenta numbers and the coefficients are proportional to the background fluxes. [Projekat Ministarstva nauke Republike Srbije, br. 171031

  13. COMMUTE MAPPING AND TRAVELING MEANS FOR CAR SHARING INDICATION

    Directory of Open Access Journals (Sweden)

    Cristiane Gonçalves Machado

    2014-04-01

    Full Text Available The growth of urban centers in a disorderly manner has brought damage to the population concerning urban mobility. Public transportation is not considered as an efficient solution and looking for more comfort, many people have chosen to use their private cars for commuting which worsens the conditions of traffic and pollution. This paper aimed to evaluate locomotion means used by a group of employees in Botucatu, SP, Brazil, checking whether possible difficulties in commuting can affect the daily lives of these people. A structured questionnaire was used for collecting data which were analyzed using descriptive statistical techniques. Mapping of each employee´s origin place to workplace was performed through Google Maps. Results showed that bus is the most used means of transportation and users spend more time in commuting as well as suffer stress and tiredness after the route.

  14. Monopoles and dyons in non-commutative geometry

    International Nuclear Information System (INIS)

    Taking advantage of the equivalence between supersymmetric Yang-Mills theory on non-commutative spaces and the field theory limit of D3-branes in the background of NSNS 2-form field, we investigate the static properties of magnetic monopoles and dyons using brane construction techniques. When parallel D3-branes are separated by turning on a Higgs vacuum expectation value, D-strings will stretch between them at an angle which depends on the value of the background 2-form potential. These states preserve half of the supersymmetries and have the same masses as their commutative counterparts in the field theory limit. We also find stable (p,q)-dyons and string junctions. We find that they do not preserve any supersymmetry but have the same masses as their commutative counterparts. In the field theory limit, the (p,q)-dyons and the string junctions restore 1/2 and 1/4 of the 16 supersymmetries, respectively. (author)

  15. Using an experimental bicycle seat to reduce perineal numbness.

    Science.gov (United States)

    Taylor, Kenneth S; Richburg, Allen; Wallis, David; Bracker, Mark

    2002-05-01

    Researchers evaluated the effectiveness of an experimental seat that was designed to prevent perineal numbness and possibly erectile dysfunction in male bicyclists. A trial of the device among 15 experienced cyclists measured perineal sensation after a 1-hour stationary cycling session on a standard seat followed several days later by the same exercise protocol on the experimental bike seat. Cyclists reported more numbness with the standard seat than with the experimental seat (79% vs 14%). Sensory testing found greater hypoesthesia with the standard seat. Innovations in bicycle seat design may decrease or eliminate perineal numbness. PMID:20086525

  16. Design Analysis And Applications Of A Regenerative Bicycle Ergometer

    OpenAIRE

    Chukwuneke J. L.; Ugwuegbu D. C.; Sinebe J. E.; Enyi L. C.

    2015-01-01

    Man needs to do some form of physical work in other to remain healthy this work is similar to the work done by any machine or equipment and thus should be channeled to give useful output but rather it is usually dissipated into the environment in form of heat. The regenerative bicycle ergometer takes advantage of the greater power generated by the limbs and arms thus conserves converts and stores the energy dissipated by the rider with an ideal mechanical advantage of 7.6 it strategically use...

  17. 16 CFR Figure 8 to Part 1512 - Reflectorized Bicycle Wheel Rim Abrasion Test Device

    Science.gov (United States)

    2010-01-01

    ... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Reflectorized Bicycle Wheel Rim Abrasion Test Device 8 Figure 8 to Part 1512 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION FEDERAL...—Reflectorized Bicycle Wheel Rim Abrasion Test Device EC03OC91.074...

  18. 77 FR 60050 - Special Regulations; Areas of the National Park System, Saguaro National Park, Bicycling

    Science.gov (United States)

    2012-10-02

    ... Hope Camp Trail as a bicycle route within Saguaro National Park (77 FR 12761). The proposed rule was..., and mountain bicycles (no motorized vehicles). I have hiked on this trail, as well as helping to work... NPS rangers and volunteers will patrol these trails and enforce NPS regulations. 5. Comment: I find...

  19. Use of Adapted Bicycles on the Learning of Conventional Cycling by Children with Mental Retardation

    Science.gov (United States)

    Burt, Tammy L.; Porretta, David L.; Klein, Richard E.

    2007-01-01

    This study investigated the use of adapted bicycles on the acquisition, maintenance, and generalization of conventional cycling by seven children with mild mental retardation. Feedback was used in addition to the adapted bicycles and consisted of pedal rate, head position, and steering participation. A multiple probe design was used. Participants…

  20. Pedal On! Mini-Units and Learning Activities on Bicycles for Grades 6 through 9.

    Science.gov (United States)

    Finn, Peter; And Others

    One of a series of eleven curriculum manuals which cover the four transportation topics of public transportation, transportation and the environment, transportation safety, and bicycles for elementary, secondary and adult levels, this manual covers the topic of bicycling for grades 6-9. The manual contains forty-seven learning activities grouped…

  1. Pedal On! Mini-Units and Learning Activities on Bicycling for Grades 9 through 12.

    Science.gov (United States)

    Finn, Peter; And Others

    One of a series of eleven curriculum manuals which cover the four transportation topics of public transportation, transportation and the environment, transportation safety, and bicycles for elementary, secondary, and adult levels, this manual covers bicycling for grades 9-12. It contains forty-four learning activities grouped into eight…

  2. Advocating Green Transport and Promoting Healthy Urban Development: Strategies for Bicycle Transport Development in Jinan

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    <正>As a green transport means,the bicycle has a history of over two hundred years.Since the 1970s,due to the inf luence of energy crisis and the consciousness of environment protection,the bicycle has regained its popularity in the public for its

  3. The Dutch Reference Study: Cases of interventions in bicycle infrastructure reviewed in the framework of Bikeability

    NARCIS (Netherlands)

    Van Goeverden, C.D.; Godefrooij, T.

    2011-01-01

    The Netherlands have a tradition of high bicycle usage and a long history of research on effective policies for promoting cycling. Findings in Dutch studies can be useful in the Danish Bikeability-project that has the objective to increase the level of knowledge in relation to bicycle based transpor

  4. 77 FR 12761 - Special Regulations; Areas of the National Park System, Saguaro National Park, Bicycle Route

    Science.gov (United States)

    2012-03-02

    ...The National Park Service (NPS) is proposing to designate the Hope Camp Trail as a bicycle route within Saguaro National Park (Park). The National Park Service general regulation at 36 CFR 4.30(b) requires promulgation of a special regulation to designate bicycle routes outside of developed areas and special use...

  5. [A specific sign of the injury inflicted by the front wheel of a bicycle].

    Science.gov (United States)

    Leonov, S V; Pinchuk, P V; Molchanov, D V

    2016-01-01

    The authors report the results of the comprehensive forensic medical expertise of the injury inflicted by the front wheel of a bicycle that revealed a new specific sign of the contact between the protruding part of the wheel of the bicycle (the brake disk) and the pedestrian's body. PMID:27070037

  6. Getting Bicycles on Trains - Inter-modal Transport Developments in Denmark

    DEFF Research Database (Denmark)

    Jørgensen, Ulrik; Pedersen, Bjørn Brix

    2001-01-01

    The combined use of bicycles and trains has been favored in contemporary public transport policies in Denmark. Although bicycling has played a major role in Danish personal transportation in more than hundred years, the attitude from public transport authorities towards supporting bicyclists has...

  7. Modelling mode choice in short trips - shifting from car to bicycle

    DEFF Research Database (Denmark)

    Halldórsdóttir, Katrín; Christensen, Linda; Jensen, Thomas Christian;

    2011-01-01

    relevance of the cost for short trips. Expectedly, the selection of bicycle as mode for short trips is positively related to owning a bicycle and negatively linked to owning one or more cars. Urban density has also positive correlation with the selection of sustainable transport modes....

  8. Safety effects of permanent running lights for bicycles: A controlled experiment.

    Science.gov (United States)

    Madsen, J C O; Andersen, T; Lahrmann, H S

    2013-01-01

    Making the use of daytime running lights mandatory for motor vehicles is generally documented to have had a positive impact upon traffic safety. Improving traffic safety for bicyclists is a focal point in the road traffic safety work in Denmark. In 2004 and 2005 a controlled experiment including 3845 cyclists was carried out in Odense, Denmark in order to examine, if permanent running lights mounted to bicycles would improve traffic safety for cyclists. The permanent running lights were mounted to 1845 bicycles and the accident rate was recorded through 12 months for this treatment group and 2000 other bicyclists, the latter serving as a control group without bicycle running lights. The safety effect of the running lights is analysed by comparing incidence rates - number of bicycle accidents recorded per man-month - for the treatment group and the control group. The incidence rate, including all recorded bicycle accidents with personal injury to the participating cyclist, is 19% lower for cyclists with permanent running lights mounted; indicating that the permanent bicycle running light significantly improves traffic safety for cyclists. The study shows that use of permanent bicycle running lights reduces the occurrence of multiparty accidents involving cyclists significantly. In the study the bicycle accidents were recorded trough self-reporting on the Internet. Possible shortcomings and problems related to this accident recording are discussed and analysed. PMID:22884376

  9. A non-commutative framework for topological insulators

    Science.gov (United States)

    Bourne, C.; Carey, A. L.; Rennie, A.

    2016-04-01

    We study topological insulators, regarded as physical systems giving rise to topological invariants determined by symmetries both linear and anti-linear. Our perspective is that of non-commutative index theory of operator algebras. In particular, we formulate the index problems using Kasparov theory, both complex and real. We show that the periodic table of topological insulators and superconductors can be realized as a real or complex index pairing of a Kasparov module capturing internal symmetries of the Hamiltonian with a spectral triple encoding the geometry of the sample’s (possibly non-commutative) Brillouin zone.

  10. Modular Theory, Non-Commutative Geometry and Quantum Gravity

    Directory of Open Access Journals (Sweden)

    Wicharn Lewkeeratiyutkul

    2010-08-01

    Full Text Available This paper contains the first written exposition of some ideas (announced in a previous survey on an approach to quantum gravity based on Tomita-Takesaki modular theory and A. Connes non-commutative geometry aiming at the reconstruction of spectral geometries from an operational formalism of states and categories of observables in a covariant theory. Care has been taken to provide a coverage of the relevant background on modular theory, its applications in non-commutative geometry and physics and to the detailed discussion of the main foundational issues raised by the proposal.

  11. The commutativity of quantized first- and higher-order Hamiltonians

    International Nuclear Information System (INIS)

    The key point of the Hamiltonian formalism of Toda molecules is the commutativity of the Hamiltonians (tr yk, tr yl)=0, where y in GL(n) and (,) is a Poisson bracket associated with the classical r-matrix. To quantize the Toda molecule, we have to consider the q-analogue of the above formula. In this paper, we show the commutativity of the quantized first- and higher-order Hamiltonians (trq Xm, trq X)=0, where X is a matrix of quantum group GLq(n). (author)

  12. Decreasing the commutation failure frequency in HVDC transmission systems

    DEFF Research Database (Denmark)

    Hansen (retired June, 2000), Arne; Havemann (retired June, 2000), Henrik

    2000-01-01

    In this paper we show how a fairly large proportion of those commutation failures that are due to single-phased short circuits to earth can be avoided. In a control circuit based on a digital signal processor (DSP) it is possible, with instantaneous results, to switch from a normal control strategy...... with equidistant firing pulses to a strategy that takes into consideration the potentially dangerous voltage changes on the supply lines, If the supply voltages are monitored continuously, it is possible to calculate the necessity of advancing the firing pulses to avoid commutation failures. In the...

  13. Constraining non-commutative space-time from GW150914

    CERN Document Server

    Kobakhidze, Archil; Manning, Adrian

    2016-01-01

    The gravitational wave signal GW150914, recently detected by LIGO and Virgo collaborations, is used to place a bound on the scale of quantum fuzziness of non-commutative space-time. We show that the leading non-commutative correction to the phase of the gravitational waves produced by a binary system appears at the 2nd order of the post- Newtonian expansion. This correction is proportional to $\\Lambda^2 \\equiv |\\theta^{0i}|^2/(l_P t_P)^2$, where $\\theta^{\\mu \

  14. The impact of pecuniary costs on commuting flows

    OpenAIRE

    McArthur, David Philip; Kleppe, Gisle; Thorsen, Inge; Ubøe, Jan

    2010-01-01

    In many cases fjords cause disconnections in the road network, calling for the service of ferries. The construction of bridges or subsea tunnels may, however, substitute the ferries, often financed by toll charges. In this paper we use data on commuting flows from a Norwegian region with a high number of ferry connections and/or tunnels and bridges. Based on a doubly-constrained gravity-based model specification we focus on how commuting flows respond to varying toll charges and ferry prices....

  15. Bispectral commuting difference operators for multivariable Askey-Wilson polynomials

    OpenAIRE

    Iliev, Plamen

    2008-01-01

    We construct a commutative algebra A_z, generated by d algebraically independent q-difference operators acting on variables z_1, z_2,..., z_d, which is diagonalized by the multivariable Askey-Wilson polynomials P_n(z) considered by Gasper and Rahman [6]. Iterating Sears' transformation formula, we show that the polynomials P_n(z) possess a certain duality between z and n. Analytic continuation allows us to obtain another commutative algebra A_n, generated by d algebraically independent differ...

  16. Commuting, CO2 and the location of offices

    OpenAIRE

    P. Wyatt

    2009-01-01

    This paper investigates the extent to which office activity contributes to travel-related CO2 emission. Using ‘end-user’ figures[1], travel accounts for 32% of UK CO2 emission (Commission for Integrated Transport, 2007) and commuting and business travel accounts for a fifth of transport-related CO2 emissions, equating to 6.4% of total UK emissions (Building Research Establishment, 2000). Figures from the Department for Transport (2006) report that 70% of commuting trips were made by car, acco...

  17. A characterization of semiprojectivity for commutative C*-algebras

    DEFF Research Database (Denmark)

    Sørensen, Adam Peder Wie; Theil, Hannes

    2012-01-01

    Given a compact metric space X, we show that the commutative C*-algebra C(X) is semiprojective if and only if X is an absolute neighbourhood retract of dimension at most 1. This confirms a conjecture of Blackadar. Generalizing to the non-unital setting, we derive a characterization of semiproject......Given a compact metric space X, we show that the commutative C*-algebra C(X) is semiprojective if and only if X is an absolute neighbourhood retract of dimension at most 1. This confirms a conjecture of Blackadar. Generalizing to the non-unital setting, we derive a characterization of...

  18. Changes to urban form and commuting patterns: trends in two Danish city regions

    DEFF Research Database (Denmark)

    Nielsen, Thomas Alexander Sick

    2015-01-01

    This paper compares indicators of polycentricity in a monocentric (MUR) and a polycentric urban region (PUR) in Denmark at two points in time (1982 and 2002). It describes how population, jobs and commuting indicators of polycentricity develop and interact over time. Both the MUR and the PUR tend...... towards more balanced development. The increasing size of the main node in the PUR is the only deviation from the general trend. The general tendency towards a more polycentric regional structure was most marked in changing interaction and commuting patterns. Inter-urban commuting increased, while intra......-urban commuting decreased, leading to dispersion of commuters and a rapid increase in commuting across the region. Commuting distances were shortest in the polycentric region, but it also had the highest growth rates. In both regions, the balancing trend leads to a dispersal of commuting demand over an...

  19. Multiple commutation relations in the models with gl(2|1) symmetry

    CERN Document Server

    Slavnov, N A

    2016-01-01

    We consider quantum integrable models with $\\mathfrak{gl}(2|1)$ symmetry. We derive a set of multiple commutation relations between the monodromy matrix entries. These multiple commutation relations allow us to obtain different representations for Bethe vectors.

  20. Can You Ride a Bicycle? The Ability to Ride a Bicycle Prevents Reduced Social Function in Older Adults With Mobility Limitation

    Directory of Open Access Journals (Sweden)

    Ryota Sakura

    2016-06-01

    Full Text Available Background: The health benefits of bicycling in older adults with mobility limitation (ML are unclear. We investigated ML and functional capacity of older cyclists by evaluating their instrumental activities of daily living (IADL, intellectual activity, and social function. Methods: On the basis of interviews, 614 community-dwelling older adults (after excluding 63 participants who never cycled were classified as cyclists with ML, cyclists without ML, non-cyclists with ML (who ceased bicycling due to physical difficulties, or non-cyclists without ML (who ceased bicycling for other reasons. A cyclist was defined as a person who cycled at least a few times per month, and ML was defined as difficulty walking 1 km or climbing stairs without using a handrail. Functional capacity and physical ability were evaluated by standardized tests. Results: Regular cycling was documented in 399 participants, and 74 of them (18.5% had ML; among non-cyclists, 49 had ML, and 166 did not. Logistic regression analysis for evaluating the relationship between bicycling and functional capacity revealed that non-cyclists with ML were more likely to have reduced IADL and social function compared to cyclists with ML. However, logistic regression analysis also revealed that the risk of bicycle-related falls was significantly associated with ML among older cyclists. Conclusions: The ability and opportunity to bicycle may prevent reduced IADL and social function in older adults with ML, although older adults with ML have a higher risk of falls during bicycling. It is important to develop a safe environment for bicycling for older adults.

  1. Vision-Based Bicycle Detection Using Multiscale Block Local Binary Pattern

    Directory of Open Access Journals (Sweden)

    Hongyu Hu

    2014-01-01

    Full Text Available Bicycle traffic has heavy proportion among all travel modes in some developing countries, which is crucial for urban traffic control and management as well as facility design. This paper proposes a real-time multiple bicycle detection algorithm based on video. At first, an effective feature called multiscale block local binary pattern (MBLBP is extracted for representing the moving object, which is a well-classified feature to distinguish between bicycles and nonbicycles; then, a cascaded bicycle classifier trained by AdaBoost algorithm is proposed, which has a good computation efficiency. Finally, the method is tested with video sequence captured from the real-world traffic scenario. The bicycles in the test scenario are successfully detected.

  2. The spatio-temporal Development of Copenhagen's bicycle infrastructure 1912-2013

    DEFF Research Database (Denmark)

    Carstensen, Trine Agervig; Olafsson, Anton Stahl; Bech, Nynne Marie;

    2015-01-01

    Cycling plays an important role in low-carbon transitions. Around the globe, cities are constructing bicycle infrastructure. The city of Copenhagen has a bicycle-friendly infrastructure celebrated for its fine-meshed network. This study documents the spatio-temporal development of Copenhagen......’s bicycle infrastructure and explores how the development corresponds to other processes of urban transformation. The study builds on historical maps of bicycle infrastructure that are digitised into geographical information, which allows for a comprehensive analysis of the formation of the network. In...... search for identifying drivers, the study analyses the city’s spatial growth pattern, migration pattern, development of road network and changes in the transport culture. Analyses reveal that the bicycle infrastructure expanded at a relatively constant pace during distinct periods of urban transformation...

  3. On the continuity of the commutative limit of the 4d N=4 non-commutative super Yang-Mills theory

    CERN Document Server

    Hanada, Masanori

    2014-01-01

    We study the commutative limit of the non-commutative maximally supersymmetric Yang-Mills theory in four dimensions (N=4 SYM). The commutative limits of non-commutative spaces are important in particular in the applications of non-commutative spaces for regularisation of supersymmetric theories (such as the use of non-commutative spaces as alternatives to lattices for supersymmetric gauge theories and interpretations of some matrix models as regularised supermembrane or superstring theories), which in turn can play a prominent role in the study of quantum gravity via the gauge/gravity duality. In general, the commutative limits are known to be singular and non-smooth due to UV/IR mixing effects. We give a direct proof that UV effects do not break the continuity of the commutative limit of the non-commutative N=4 SYM to all order in perturbation theory, including non-planar contributions. This is achieved by establishing the uniform convergence (with respect to the non-commutative parameter) of momentum integr...

  4. "The Backward-bending Commute times of Married Women with Household Responsibility"

    OpenAIRE

    Shinichiro Iwata; Keiko Tamada

    2008-01-01

    Though the existing literature provides evidence that married women choose short commutes because of low wages and household responsibilities, this theoretical paper shows that wives employed in highly paid positions also undertake short commutes and endogenously choose longer times for housework. In contrast, middle-class wives choose long commutes and undertake limited household chores. The results suggest that the commute times of wives follow a backward-bending pattern and there is a trad...

  5. Hopf algebra structure of generalized quasi-symmetric functions in partially commutative variables

    OpenAIRE

    Doliwa, Adam

    2016-01-01

    We introduce a generalization of the Hopf algebra of quasi-symmetric functions in terms of power series in partially commutative variables. This is the graded dual of the Hopf algebra of coloured non-commutative symmetric functions described as a subalgebra of the Hopf algebra of rooted ordered coloured trees. In the Appendix we discuss the role of partial commutativity in derivation of Weyl commutation relations.

  6. Finite Cohen-Macaulay type and smooth non-commutative schemes

    OpenAIRE

    Jorgensen, Peter

    2005-01-01

    A commutative local Cohen-Macaulay ring R of finite Cohen-Macaulay type is known to be an isolated singularity; that is, Spec(R)-m is smooth. This paper proves a non-commutative analogue. Namely, if A is a (non-commutative) graded AS Cohen-Macaulay algebra which is FBN and has finite Cohen-Macaulay type, then the non-commutative projective scheme determined by A is smooth.

  7. "Estimation of Fatigue Cost of Commuting Congestion and Optimal Congestion Fare" (in Japanese)

    OpenAIRE

    Hisaki Yamaga; Tatsuo Hatta

    2000-01-01

    This paper has three aims. First, we estimate a hedonic housing rent function along the Chuo Line in Tokyo with (i) commuting time distance and (ii) congestion degree as explanatory variables. Second, from the hedonic rent function thus estimated, we measure time cost and fatigue cost of commuting in terms of Equivalent Variation. We show that the fatigue cost of commuting is 5-29% of total commuting cost. Third, from the fatigue cost thus estimated, we measure marginal external congestion co...

  8. Upper bound of the time-space non-commutative parameter from gravitational quantum well experiment

    International Nuclear Information System (INIS)

    Starting from a field theoretic description of the gravitational well problem in a canonical non-commutative spacetime, we have studied the effect of time-space non-commutativity in the gravitational well scenario. The corresponding first quantized theory reveals a spectrum with leading order perturbation term of non-commutative origin. GRANIT experimental data are used to estimate an upper bound on the time-space non-commutative parameter

  9. Bicycle Riding: Impact on Lower Urinary Tract Symptoms and Erectile Function in Healthy Men

    Science.gov (United States)

    Baek, Seok; Lee, Sun Young; Kim, Jong Min; Shin, Esther; Kam, Sin

    2011-01-01

    Purpose Recently, reports in the mass media have implicated that bicycle riding increases the risk of erectile dysfunction and prostatic diseases. So, we evaluate the impact of bicycle riding on erectile function and lower urinary tract symptoms (LUTS) in healthy general men. Methods From 26 June 2010 to 20 July 2010, we investigate degree of LUTS (voiding and storage symptoms), using International Continence Society-male Questionnaire (ICS-mQ) and erectile function using International Index of Erectile Function-5 Questionnaire (IIEF-5) in 5 work places (personnel of public office, hospital, university, etc.) of which bicycle riding club members were doing active club activities. Respondents, who participated in club activities for 6 months and longer, were classified as the bicycle club (142 men; age, 44.02±8.56). Ones who do not ride bicycles were classified as the control group (83 men; age, 42.13±7.85). People who were having the history of urological and other chronic diseases (diabetes, vascular disease, heart disease, etc) were excluded from both groups. Results Bicycle club is not significantly associated with increased prevalence of LUTS (bicycle club, 2.1 to 57.7% control, 4.8 to 73.5%) and erectile dysfunction (bicycle club, 46.1% control, 55.4%). The total mean score (storage/voiding/erectile function) of bicycle club (13.93±1.95/11.14±3.49/20.46±5.30) were not significantly different from control (14.35±2.49/11.52±3.38/20.40±4.07) (P=0.190 to 0.968). Conclusions These results suggested that bicycle riding as exercise or hobby has no negative effect on LUTS and erectile function in healthy general men, although this research data were limited to the questionnaire analysis. PMID:21811700

  10. Harvesting Energy from the Counterbalancing (Weaving Movement in Bicycle Riding

    Directory of Open Access Journals (Sweden)

    Shashank Priya

    2012-07-01

    Full Text Available Bicycles are known to be rich source of kinetic energy, some of which is available for harvesting during speedy and balanced maneuvers by the user. A conventional dynamo attached to the rim can generate a large amount of output power at an expense of extra energy input from the user. However, when applying energy conversion technology to human powered equipments, it is important to minimize the increase in extra muscular activity and to maximize the efficiency of human movements. This study proposes a novel energy harvesting methodology that utilizes lateral oscillation of bicycle frame (weaving caused by user weight shifting movements in order to increase the pedaling force in uphill riding or during quick speed-up. Based on the 3D motion analysis, we designed and implemented the prototype of an electro-dynamic energy harvester that can be mounted on the bicycle’s handlebar to collect energy from the side-to-side movement. The harvester was found to generate substantial electric output power of 6.6 mW from normal road riding. It was able to generate power even during uphill riding which has never been shown with other approaches. Moreover, harvesting of energy from weaving motion seems to increase the economy of cycling by helping efficient usage of human power.

  11. The influence of body mass in endurance bicycling.

    Science.gov (United States)

    Swain, D P

    1994-01-01

    Bicycling is a complex sport in which an athlete's energy cost is related to two principal forces: air resistance when traveling on flat terrain, and gravity when traveling uphill. Both wind tunnel data and physiological measurements suggest that air resistance scales as body mass to about the 1/3 power. Thus, large cyclists have only slightly greater frontal drags than small cyclists. If expressed relative to body mass, the frontal drag of small cyclists is considerably greater than that of large cyclists. The difference in frontal drag (energy cost) is not made up for by the advantage to small cyclists in relative VO2max (energy supply), since the mass exponent for drag (1/3) is closer to zero than that for VO2max (2/3). Thus, small cyclists should be at a disadvantage in flat time trials, which field data support. The energy cost of riding uphill slightly favors the large cyclist, because the weight of the bicycle represents a relatively smaller load than it does to a small cyclist. The mass exponent is 0.79. Since this exponent is greater than that for VO2max, the small cyclists have an advantage in climbing, which is supported by field data. PMID:8133740

  12. Non-commutative stochastic distributions and applications to linear systems theory

    OpenAIRE

    Alpay, Daniel; Salomon, Guy

    2012-01-01

    In this paper, we introduce a non-commutative space of stochastic distributions, which contains the non-commutative white noise space, and forms, together with a natural multiplication, a topological algebra. A special inequality which holds in this space allows to characterize its invertible elements and to develop an appropriate framework of non-commutative stochastic linear systems.

  13. Understanding What Influences Successful Black Commuter Students' Engagement in College: An Exploratory Study

    Science.gov (United States)

    Yearwood, Trina Lynn

    2011-01-01

    Although Black commuter students are disadvantaged when it comes to higher education, research on the success of Black commuter students in college is very rare. Existing research on Black and commuter students primarily concentrate on negative statistics such as stagnant college completion rates, departure, and lack of engagement. The purpose of…

  14. The Z→γγ,gg decays in the non-commutative standard model

    International Nuclear Information System (INIS)

    On non-commutative spacetime, the standard model (SM) allows new, usually SM forbidden, triple gauge boson interactions to occur. In this letter we propose the SM strictly forbidden Z→γγ and Z→gg decay modes coming from the gauge sector of the non-commutative standard model (NCSM) as a place where non-commutativity could be experimentally discovered. (orig.)

  15. Long-Distance Relationships in Dual-Career Commuter Couples: A Review of Counseling Issues.

    Science.gov (United States)

    Rhodes, Angel R.

    2002-01-01

    The dual-career commuter couple is an alternative family configuration that continues to grow in number. Reviews the literature on dual-career commuter couples that has been published since 1982. Addresses the counseling issues of marital and family characteristics, commuting characteristics, and decision-making styles. Counseling implications and…

  16. 20 CFR 704.102 - Commutation of payments to aliens and nonresidents.

    Science.gov (United States)

    2010-04-01

    ... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false Commutation of payments to aliens and... LHWCA EXTENSIONS Defense Base Act § 704.102 Commutation of payments to aliens and nonresidents. Authority to commute payments to aliens and nonnationals who are not residents of the United States...

  17. 76 FR 57924 - Transportation for Individuals With Disabilities at Intercity, Commuter, and High Speed Passenger...

    Science.gov (United States)

    2011-09-19

    ... station-based lifts. On commuter, intercity, or high-speed rail lines or systems in which track passing... serves new or altered stations on the line or system. For example, if a new commuter or high-speed rail..., Commuter, and High Speed Passenger Railroad Station Platforms; Miscellaneous Amendments AGENCY: Office...

  18. On the Need for Separate Commuter Programs: San Diego State Looks at Its Students.

    Science.gov (United States)

    McCully, Barbie

    1980-01-01

    A self-assessment of commuter student programs and services at San Diego State University (SDSU) indicated that the university was doing well in meeting the needs of this population. For many years, most of the students at SDSU have been commuter students. Services and programs that were developed were created with the commuter student in mind.…

  19. Active commuting and habit strength: an interactive and discriminant analyses approach

    NARCIS (Netherlands)

    G.-J. de Bruijn; B. Gardner

    2011-01-01

    Purpose. Habits may be a mechanism linking environmental variables with active commuting. This study investigated the role of habit strength in the explanation of active commuting across profiles based on current active commuting, motivation, and habit strength within the framework of the theory of

  20. A perspective on non-commutative quantum gravity

    Science.gov (United States)

    Martins, Rachel A. D.

    2015-06-01

    In this paper, we present some of the concepts underlying a program of non-commutative quantum gravity and recall some of the results. This program includes a novel approach to spectral triple categorification and also a precise connection between Fell bundles and Connes' non-commutative geometry. Motivated by topics in quantization of the non-commutative standard model and introduction of algebraic techniques and concepts into quantum gravity (following for example Crane, Baez and Barrett), we define spectral C*-categories, which are deformed spectral triples in a sense made precise. This definition gives to representations of a C*-category on a small category of Hilbert spaces and bounded linear maps, the interpretation of a topological quantum field theory. The construction passes two mandatory tests: (i) there is a classical limit theorem reproducing a Riemannian spin manifold manifesting Connes' and Schücker's non-commutative counterpart of Einstein's equivalence principle, and (ii) there is consistency with the experimental fermion mass matrix. We also present an algebra invariant taking the form of a partition function arising from a C*-bundle dynamical system in connection with C*-subalgebra theory.

  1. Commutative post-Lie algebra structures on Lie algebras

    OpenAIRE

    Burde, Dietrich; Moens, Wolfgang Alexander

    2015-01-01

    We show that any CPA-structure (commutative post-Lie algebra structure) on a perfect Lie algebra is trivial. Furthermore we give a general decomposition of inner CPA-structures, and classify all CPA-structures on parabolic subalgebras of simple Lie algebras.

  2. Lattices of Annihilators in Commutative Algebras Over Fields

    Directory of Open Access Journals (Sweden)

    Jastrzebska M.

    2015-12-01

    Full Text Available Let K be any field and L be any lattice. In this note we show that L is a sublattice of annihilators in an associative and commutative K-algebra. If L is finite, then our algebra will be finite dimensional over K.

  3. Homotopy commutative algebra and 2-nilpotent Lie algebra

    OpenAIRE

    Dubois-Violette, Michel; Popov, Todor

    2012-01-01

    The homotopy transfer theorem due to Tornike Kadeishvili induces the structure of a homotopy commutative algebra, or $C_{\\infty}$-algebra, on the cohomology of the free 2-nilpotent Lie algebra. The latter $C_{\\infty}$-algebra is shown to be generated in degree one by the binary and the ternary operations.

  4. On a Classification of Irreducible Almost Commutative Geometries

    OpenAIRE

    Iochum, Bruno; Schucker, Thomas; Stephan, Christoph

    2003-01-01

    We classify all irreducible, almost commutative geometries whose spectral action is dynamically non-degenerate. Heavy use is made of Krajewski's diagrammatic language. The motivation for our definition of dynamical non-degeneracy stems from particle physics where the fermion masses are non-degenerate.

  5. Gauge Theories on Open Lie Algebra Non-Commutative Spaces

    CERN Document Server

    Agarwal, A

    2003-01-01

    It is shown that non-commutative spaces, which are quotients of associative algebras by ideals generated by non-linear relations of a particular type, admit extremely simple formulae for deformed or star products. Explicit construction of these star products is carried out. Quantum gauge theories are formulated on these spaces, and the Seiberg-Witten map is worked out in detail.

  6. Gauge Theories on Open Lie Algebra Non-Commutative Spaces

    OpenAIRE

    A. Agarwal; Akant, L.

    2002-01-01

    It is shown that non-commutative spaces, which are quotients of associative algebras by ideals generated by non-linear relations of a particular type, admit extremely simple formulae for deformed or star products. Explicit construction of these star products is carried out. Quantum gauge theories are formulated on these spaces, and the Seiberg-Witten map is worked out in detail.

  7. A multipurpose switched reluctance motor with a series commutation buffer

    Directory of Open Access Journals (Sweden)

    L.A. Vasil'ev

    2014-06-01

    Full Text Available In this paper, a power-supply circuit for a multipurpose switched reluctance motor with a series commutation buffer is presented. It is shown that a series buffer improves output characteristics of multipurpose switched reluctance motors under supply from a single-phase circuit and also lifts necessity of switching capacitors according to the motor power supply modes.

  8. Exploratory mapping of commuter flows in England and Wales

    DEFF Research Database (Denmark)

    Nielsen, Thomas Alexander Sick; Hovgesen, Henrik Harder; Lassen, Claus

    2005-01-01

    Birmingham. These are chosen for their size and differences in regional context. In the general analysis – at the country-wide scale - special emphasis is put on deriving a representation of the scale and the corridors of interaction from the relatively disaggregate data. A map of commuter flows in England...

  9. On some classes of unbounded commutants of unbounded operator families

    International Nuclear Information System (INIS)

    We consider some classes of unbounded commutants and bicommutants and we investigate their behaviour with respect to the quasi weak* topology which seems to play here the role of the weak topology for bounded operators. In particular we give some sufficient conditions in order that the bicommutants be the quasi weak* closure of the original set of operators. (author)

  10. Generic simplicity of certain families of almost commutative algebras

    CERN Document Server

    Tikaradze, Akaki

    2011-01-01

    We discuss generic simplicity and Bernstein's inequality for families of almost commutative algebras. We also relate completions of infinitesimal Hecke algebras of sl_2 to noncommutative deformations of Kleinian singularities of type D of Crawley-Boevey and Holland. As a consequence, we show an analogue of Bernstein's inequality and simplicity of generic maximal primitive quotients of these algebras.

  11. Device-Independent Quantum Key Distribution with Commuting Measurements

    CERN Document Server

    Hänggi, Esther

    2010-01-01

    We consider quantum key distribution in the device-independent scenario, i.e., where the legitimate parties do not know (or trust) the exact specification of their apparatus. We show how secure key distribution can be realized against the most general attacks by a quantum adversary under the condition that measurements on different subsystems by the honest parties commute.

  12. The non-commutative geometry of string field theory

    International Nuclear Information System (INIS)

    We analyse the geometry of string field theory in exactly the same way as one would analyse the geometry of Yang-Mills theory. We find that a version of non-commutative geometry, where the differential forms are considered as infinite matrices, seems to provide a suitable context for studying string field theory. (author)

  13. Procreating Tiles of Double Commutative-Step Digraphs

    Institute of Scientific and Technical Information of China (English)

    Jian-qin Zhou

    2008-01-01

    Double commutative-step digraph generalizes the double-loop digraph. A double commutative-step digraph can be represented by an L-shaped tile, which periodically tessellates the plane. Given an initial tile L(l, h,x, y), Agniló et al. define a discrete iteration L(p) = L(l + 2p, h + 2p, x + p, y + p),p = 0, 1, 2,…, over L-shapes (equivalently over double commutative-step digraphs), and obtain an orbit generated by L(l, h, x, y),which is said to be a procreating k-tight tile if L(p)(p= 0, 1, 2,… ) are all k-tight tiles. They classify the set of L-shaped tiles by its behavior under the above-mentioned discrete dynamics and obtain some procreating tiles of double commutative-step digraphs. In this work, with an approach proposed by Li and Xu et al., we define some new discrete iteration over L-shapes and classify the set of tiles by the procreating condition. We also propose some approaches to find infinite families of realizable k-tight tiles starting from any realizable k-tight L-shaped tile L(l, h, x, y), 0≤|y - x|≤ 2k + 2. As an example, we present an infinite family of 3-tight optimal double-loop networks to illustrate our approaches.

  14. A commuting network model: going to the bulk

    CERN Document Server

    Gargiulo, Floriana; Huet, Sylvie; Espinosa, Omar Baqueiro

    2011-01-01

    The influence of commuting in socio-economic dynamics increases constantly. Analysing and modelling the networks formed by commuters to help decision-making regarding the land-use has become crucial. This paper presents a simple spatial interaction simulated model with only one parameter. The proposed algorithm considers each individual who wants to commute, starting from their living place to all their workplaces. It decides where the location of the workplace following the classical rule inspired from the gravity law consisting in a compromise between the job offers and the distance to the jobs. The further away the job offer is, the more important it must be in order to be considered. Inversely, only the quantity of offers is important for the decision when these offers are close. The paper also presents a comparative analysis of the structure of the commuting networks of the four European regions to which we apply our model. The model is calibrated and validated on these regions. Results from the analysis...

  15. Regenerative Snubber For GTO-Commutated SCR Inverter

    Science.gov (United States)

    Rippel, Wally E.; Edwards, Dean B.

    1992-01-01

    Proposed regenerative snubbing circuit substituted for dissipative snubbing circuit in inverter based on silicon controlled rectifiers (SCR's) commutated by gate-turn-off thyristor (GTO). Intended to reduce loss of power that occurs in dissipative snubber. Principal criteria in design: low cost, simplicity, and reliability.

  16. Seasonal and socio-demographic determinants of school commuting

    DEFF Research Database (Denmark)

    Bjørkelund Børrestad, Line Anita; Andersen, Lars Bo; Bere, Elling

    2011-01-01

    OBJECTIVE: To report prevalence of commuting to school in Norway with regard to season, gender, parental education level, ethnicity and distance to school. METHODS: Cross-sectional questionnaire data from the Fruits and Vegetables Make the Marks project collected in 2008, including 1,339 ten to t...

  17. Phase space quantization, non-commutativity and the gravitational field

    CERN Document Server

    Chatzistavrakidis, Athanasios

    2014-01-01

    In this paper we study the structure of the phase space in non-commutative geometry in the presence of a non-trivial frame. Our basic assumptions are that the underlying space is a symplectic and parallelizable manifold. Furthermore, we assume the validity of the Leibniz rule and the Jacobi identities. We consider non-commutative spaces due to the quantization of the symplectic structure and determine the momentum operators that guarantee a set of canonical commutation relations, appropriately extended to include the non-trivial frame. We stress the important role of left vs. right acting operators and of symplectic duality. This enables us to write down the form of the full phase space algebra on these non-commutative spaces, both in the non-compact and in the compact case. We test our results against the class of 4D and 6D symplectic nilmanifolds, thus presenting a large set of non-trivial examples that realize the general formalism.

  18. Weak estimates for commutators of fractional integral operators

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    By introducing a kind of maximal operator of the fractional order associated with the mean Luxemburg norm and using the technique of the sharp function,the weak type LlogL estimates for the commutators of the fractional integral operator and the related maximal operator are established.

  19. The Business Case for Commuter Benefits at Colleges and Universities

    Science.gov (United States)

    Klavon, Patty

    2005-01-01

    Transportation and parking-related issues are common challenges for many colleges and universities today. Most institutions have far fewer parking spaces than they do commuters, and constructing and maintaining new parking facilities can cost hundreds of thousands of dollars. In this article, an Environmental Protection Agency representative…

  20. Groups of automorphisms of the canonical commutation and anticommutation relations

    International Nuclear Information System (INIS)

    Observables of supersymmetric quantum mechanics are coded by taking the antisymmetric tensor product with anticommuting parameters. Next we define superunitary transformations, which mix bosonic and fermionic degrees of freedom, in order to construct automorphisms of the canonical (anti-) commutation relations. Conversely, every automorphism of the C(A)CR is implemented by an essentially unique superunitary transformation. 12 refs. (Author)