Massive Stars as Major Factories of Galactic Cosmic Rays

The identification of major contributors to the locally observed fluxes of Cosmic Rays (CRs) is a prime objective towards the resolution of the long-standing enigma of CRs. We report on a compelling similarity of the energy and radial distributions of multi-TeV CRs extracted from observations of very high energy (VHE) $\gamma$-rays towards the Galactic Center (GC) and two prominent clusters of young massive stars, Cyg~OB2 and Westerlund~1. This resemblance we interpret as a hint that CRs responsible for the diffuse VHE $\gamma$-ray emission from the GC are accelerated by the ultracompact stellar clusters located in the heart of GC. The derived $1/r$ decrement of the CR density with the distance from a star cluster is a distinct signature of continuous, over a few million years, CR injection into the interstellar medium. The lack of brightening of the $\gamma$-ray images toward the stellar clusters excludes the leptonic origin of $\gamma$-radiation. The hard, $\propto E^{-2.3}$ type power-law energy spectra of parent protons continues up to $\sim$ 1 PeV. The efficiency of conversion of kinetic energy of stellar winds to CRs can be as high as 10 percent implying that the young massive stars may operate as proton PeVatrons with a dominant contribution to the flux of highest energy galactic CRs.Comment: minor revisions have been applied to address the referees' comments, conclusion unchange

Cluster Analysis for Diminishing Heterogeneous Opinions of Service Quality Public Transport Passengers

[EN] One of the principal measures that public transport administrations are following for reaching a sustainable transportation in the cities consists on attract a higher number of citizens towards the use of public transport modes, by offering high quality services. Collecting users opinions is the best way of detecting where the service is failing and which aspects are been provided successfully. The main problem that has to be faced for analyzing service quality is the subjective nature of its measurement, offering heterogeneous assessments among passengers about the service. Stratifying the sample of users on segments of passengers which have more uniform opinions about the service can help to reduce this heterogeneity. This stratification usually is conducted based on the social and demographic characteristics of the passengers. However, there are more advance techniques that permits to identify more homogeneous groups of users. One of these techniques is the Cluster Analysis, which is a data mining technique that can be used for segmenting the sample of passengers on groups that share some common characteristics, and that have more homogeneous perceptions about the service. This technique has been applied in other fields of transport engineering but it has never been applied for searching homogeneous groups of users with regards to service quality evaluation in a public transport service. For this reason, the aim of this work is to find groups of passengers that perceive the quality of the service in a more homogeneous way, and to apply to this clusters a suitable statistic technique that permit us to discover which are the variables that more influence the passengers¿ overall evaluation about the service. The comparison among the results of each cluster will show considerable differences among them and also with the results obtained using the global sample.This study is sponsored by the Consejería de Innovación, Ciencia y Economía of the Junta de Andalucía (Spain) through the Excellence Research Project denominated Q-METROBUS-Quality of service indicator for METROpolitan public BUS transport services . The authors also acknowledge the Granada Consorcio de Transportes for making the data set available for this study. Likewise, Griselda López wishes to express her acknowledgement to the regional ministry of Economy, Innovation and Science of the regional government of Andalusia (Spain) for their scholarship to train teachers and researchers in Deficit AreasDe Oña, R.; López-Maldonado, G.; Díez De Los Ríos, F.; De Oña, J. (2014). Cluster Analysis for Diminishing Heterogeneous Opinions of Service Quality Public Transport Passengers. Procedia - Social and Behavioral Sciences. 162:459-466. https://doi.org/10.1016/j.sbspro.2014.12.227S45946616

Is it possible to attract private vehicle users towards public transport? Understanding the key role of service quality, satisfaction and involvement on behavioral intentions

This paper contributes to the public transport literature by ascertaining the role of involvement upon the service quality-satisfaction-behavioral intentions paradigm from the point of view of private vehicle users. This is the first study that provides a comprehensive understanding of this framework based on the private vehicle users’ perspective. The added value of this research is that, by using a structural equation modeling approach, it provides a comparison of alternative models and uses data from different samples collected in five large metropolitan areas (Berlin, Lisbon, London, Madrid and Rome) for modeling validation. In addition, a SEM-MIMIC approach was applied for controlling the heterogeneity of data due to specific characteristics of the interviewee (territorial setting, place of residence, demographic and socio-economic characteristics and travel related variables). The findings show that involvement is a full mediator between satisfaction and behavioral intentions, and that satisfaction is a full mediator between service quality and involvement. Furthermore, the SEM-MIMIC results revealed that the four latent factors investigated (service quality, satisfaction, involvement and behavioral intentions) dealt with highly heterogenous data. However, the most important finding is that private vehicle users’ involvement is the factor that contributes most to their behavioral intentions towards public transport. Hence, public transport managers might benefit from these outcomes when establishing detailed policies and specific guidelines for public transport systems to engage private vehicle users in a higher degree of usage of public transport services.Spanish Government TRA2015-66235-

Transit service quality analysis using cluster analysis and decision trees: a step forward to personalized marketing in public transportation

[EN] A transit service quality study based on cluster analysis was performed to extract detailed customer profiles sharing similar appraisals concerning the service. This approach made it possible to detect specific requirements and needs regarding the quality of service and to personalize the marketing strategy. Data from various customer satisfaction surveys conducted by the Transport Consortium of Granada (Spain) were analyzed to distinguish these groups; a decision tree methodology was used to identify the most important service quality attributes influencing passengers overall evaluations. Cluster analysis identified four groups of passengers. Comparisons using decision trees among the overall sample of all users and the different groups of passengers identified by cluster analysis led to the discovery of differences in the key attributes encompassed by perceived quality.The authors also acknowledge the Granada Consorcio de Transportes for making the data set available for this study. Griselda Lopez wishes to express her acknowledgement to the regional ministry of Economy, Innovation and Science of the regional government of Andalusia (Spain) for their scholarship to train teachers and researchers in Deficit Areas. Rocio de Ona wishes to express her acknowledgement to the regional ministry of Economy, Innovation and Science of the regional government of Andalusia (Spain) for the Excellence Research Project denominated "Q-METROBUS-Quality of service indicator for METROpolitan public BUS transport services'', co-funded with Feder.De Oña, J.; De Oña, R.; López-Maldonado, G. (2015). Transit service quality analysis using cluster analysis and decision trees: a step forward to personalized marketing in public transportation. Transportation. 43(5):725-747. https://doi.org/10.1007/s11116-015-9615-0S725747435Abou Zeid, M., Ben-Akiva, M.: A model of travel happiness and mode switching, in choice modelling: the state-of-the-art and the state-of-practice. In: Hess S., Daly A. (eds.) Proceedings from the Inaugural International Choice Modelling Conference, pp. 289–307. Emerald Group Publishing Limited (2010)Akaike, H.: Factor analysis and AIC. Psychome 52, 317–332 (1987)Breiman, L., Friedman, J., Olshen, R., Stone, C.: Classification and Regression Trees. Chapman and Hall, Belmont, CA (1984)Chang, L.Y., Wang, H.W.: Analisys of traffic injury severity: an application of non-parametric classification tree techniques. Accid. Anal. Prev. 38, 1019–1027 (2006)Cheung, K.-W., Kwok, J., Law, M.H., Tsui, K.-C.: Mining customer product ratings for personalized marketing. Decis. Support Syst. 35, 231–243 (2003)De Oña, J., de Oña, R., Calvo, F.J.: A classification tree approach to identify key factors of transit service quality. Expert Syst. Appl. 39, 11164–11171 (2012)De Oña, R., de Oña, J.: Analyzing transit service quality evolution using decision trees and gender segmentation. WIT Trans Built Environ 130, 611–621 (2013)De Oña, J., de Oña, R., Eboli, L., Mazzulla, G.: Perceived service quality in bus transit service: a structural equation approach. Transp. Policy 29, 219–226 (2013a)De Oña, J., López, G., Mujalli, R.O., Calvo, F.J.: Analysis of traffic accidents on rural highways using Latent Class Clustering and Bayesian Networks. Accid. Anal. Prev. 51, 1–10 (2013b)De Oña, J., de Oña, R., Eboli, L., Mazzulla, G.: Heterogeneity in perceptions of service quality among groups of railway passengers. Int J Sustain Transp 9(8), 612–626 (2014a)De Oña, R., Eboli, L., Mazzulla, G.: Key factors affecting rail service quality. A decision tree approach. Transport 29(1), 75–83 (2014b)De Oña, J., de Oña, R., Garrido, C.: Extracting importance of attributes from customer satisfaction surveys with data mining: decision trees and neural networks. In: Proceedings of the Transportation Research Board 94th Annual Meeting, Washington, DC, 11–15 Jan 2015Dell’Olio, L., Ibeas, A., Cecín, P.: Modelling user perception of bus transit quality. Transp. Policy 17(6), 388–397 (2010)Dell’Olio, L., Ibeas, A., Cecín, P.: The quality of service desired by public transport users. Transp. Policy 18(1), 217–227 (2011)Depaire, B., Wets, G., Vanhoof, K.: Traffic accident segmentation by means of latent class clustering. Accid. Anal. Prev. 40(4), 1257–1266 (2008)Duarte, A., Garcia, C., Giannarakis, G., Limão, S., Litinas, N., Polydoropoulou, A.: New approaches in transport planing: happiness and transport economics. Netnomics. Economic Research and Electronic Networking, Springer Netherlands, 1385–9587 (Print) 1573–7071 (Online) (2008)Eboli, L., Mazzulla, G.: Service quality attributes affecting customer satisfaction for bus transit. J Public Transp 10(3), 21–34 (2007)Eboli, L., Mazzulla, G.: Willingness-to-pay of public transport users for improvement in service quality. Eur Transp 38, 107–118 (2008)Eboli, L., Mazzulla, G.: How to capture the passengers’ point of view on a transit service through rating and choice options. Transp Rev 30, 435–450 (2010)Eboli, L., Mazzulla, G.: Performance indicators for an objective measure of public transport service quality. Eur Transp 51, 1–21 (2012)Ettema, D., Garling, T., Eriksson, L., Friman, M., Olsson, L.E., Fujii, S.: Satisfaction with travel and subjective well-being (SWB): development and tests of a measurement tool. Transp. Res. Part F 14, 167–175 (2011)Fraley, C., Raftery, A.E.: How many clusters? Which clustering method? Answers via model-based cluster analysis. Comput J 41, 578–588 (1998)Gärling, T., Fujii, S.: Travel behavior modification: theories, methods, and programs. In: Kitamura, R., Yoshi, T., Yamamoto, T. (eds.), The Expanding Sphere of Travel Behavior Research. IATBR, 97–128 (2009)Garrido, C., de Oña, R., de Oña, J.: Neural networks for analysing service quality in public transportation. Expert Syst. Appl. 4, 6830–6838 (2014)Hair Jr, J.F., Anderson, R.E., Tatham, R.L., Black, W.C.: Multivariate Data Analysis. Prentice Hall, Englewood Cliffs, NJ (1998)Hensher, D.A., Stopher, P., Bullock, P.: Service quality: developing a service quality index in the provision of commercial bus contracts. Transp. Res. Part A 37, 499–517 (2003)Hensher, D.A., Mulley, C., Yahya, N.: Passenger experience with quality-enhanced bus service: the tyne and wear ‘superoute’ services. Transportation 37(2), 239–256 (2010)INPHORMM: Case Studies of Transport Information and Publicity/Marketing Campaigns to Reduce Car Use and Promote Cycling, Walking and Public Transport. INPHORMM Deliverable D2 to the European Commission. Transport Studies Group. University of Westminster, and Partners, London (1998)Irfan Syed, M., Mui, H.K.D., Shahbaz, S.: Service quality in rail transport of Pakistan: a passenger perspective? In: Paper presented at the 3rd SAICON: International Conference on Management, Business Ethics and Economics (ICMBEE), Lahore, Pakistan, 28–29 Dec 2011Karlaftis, M., Tarko, A.: Heterogeneity considerations in accident modeling. Accid. Anal. Prev. 30(4), 425–433 (1998)Kashani, A.T., Mohaymany, A.S.: Analysis of the traffic injury severity on two-lane, two-way rural roads based on classification tree models. Saf. Sci. 49, 1314–1320 (2011)Ma, J., Kockelman, K.: Crash frequency and severity modeling using clustered data from Washington state. In: IEEE Intelligent Transportation Systems Conference, Toronto, Canadá (2006)Magidson, J., Vermunt, J.K.: Latent class models for clustering: a comparison with K-means. Can J Mark Res 20, 37–44 (2002)Mahmoud, M., Hine, J.: Using AHP to measure the perception gap between current and potential users of bus services. Transp Plan Technol 36(1), 4–23 (2013)McLachlan, G.J., Peel, D.: Finite Mixture Models. Wiley, New York (2000)Ory, D.T., Mokhtarian, P.L.: When is getting there half of the fun? Modelling the liking for travel. Transp. Res. Part A 39(2–3), 97–123 (2005)Outwater, M.L., Castleberry, S., Shiftan, Y., Ben-Akiva, M., Zhou, Y.S., Kuppam, A.: Attitudinal market segmentation approach to mode choice and ridership forecasting: structural equation modeling. Transp. Res. Rec. 1854, 32–42 (2003)Paquette, J., Bellavance, F., Cordeau, J., Laporte, G.: Measuring quality of service in dial-a-ride operations: the case of a canadian city. Transportation 39(3), 539–564 (2012)Parkan, C.: Measuring the operational performance of a public transit company. Int J Oper Prod Manag 22(6), 693–720 (2002)Raftery, A.E.: A note on Bayes factors for log-linear contingency table models with vague prior information. J. Roy. Stat. Soc. B 48, 249–250 (1986)Redman, L., Friman, M., Gärling, T., Hartig, T.: Quality attributes of public transport that attract car users: a research review. Transp. Policy 25, 119–127 (2013)Rietveld, P.: Six reasons why supply oriented indicators systematically overestimate service quality in public transport. Transp Rev 25(3), 319–328 (2005)Sanjust, B., Meloni, I., Spissu, E.: An impact assessment of a travel behavior change program: a case study of a light rail service in Cagliari, Italy. Case study of transport policy. ( http://dx.doi.org/10.1016/j.cstp.2014.04.002 ) (2014, in press)Sepúlveda, R.A.: Contribuciones al Análisis de Clases latentes en Presencia de Dependencia Local. Thesis, University of Salamanca (2004)TAPESTRY: Best Practice Guidelines (Deliverable 5). Report to the European Commission (DGTREN) Travel and Transport Research, Nottingham and Partners (2003)Vermunt, J.K., Magidson, J.: Latent GOLD 4.0 user’s guide. Statistical Innovations Inc., Belmont, MA (2005)Vesanen, J.: What is personalization? A conceptual framework. Eur. J. Mark. 41(5/6), 409–418 (2007)Xie, C., Lu, J., Parkany, E.: Work travel mode choice modelling with data mining. Transp. Res. Rec. 1854, 03–4338 (2003

Analysis of transit quality of service through segmentation and classification tree techniques

Perceptions about the quality of service are very different among public transport (PT) users. Users’ perceptions are heterogeneous for many reasons: the qualitative aspects of PT service, users’ socio-economic characteristics, and the diversity of tastes and attitudes towards PT. By analysing different groups of users who share a common characteristic (e.g. socio-economic or travel behaviour), it is possible to homogenise user opinions about the quality of service. This paper studies quality as perceived by users of the metropolitan transit system of Granada (Spain) through a classification tree technique (classification and regression trees (CART)) based on five market segmentations (gender, age, frequency of use, reason for travelling, and type of ticket). CART is a non-parametric method that has a number of advantages compared to other methods that require a predefined underlying relationship between dependent and independent variables. The study is based on data gathered in several customer satisfaction surveys (non-research-oriented) conducted in the Granada metropolitan transit system. The models' outcomes show that some attributes are very important for almost all the market segments (punctuality and information), while others are not very relevant for any of the segments – most notably fare, despite the fact that fare was stated as very important by most of the passengers during the interviewConserjería de Innovación, Ciencia y Economía of the Junta de Andalucía (Spain) through the Excellence Research Project denominated “Q-METROBUS-Quality of service indicator for METROpolitan public BUS transport services”

Time-dependent modeling of TeV-detected, young pulsar wind nebulae

The increasing sensitivity of instruments at X-ray and TeV energies have revealed a large number of nebulae associated with bright pulsars. Despite this large data set, the observed pulsar wind nebulae (PWNe) do not show a uniform behavior and the main parameters driving features like luminosity, magnetization, and others are still not fully understood. To evaluate the possible existence of common evolutive trends and to link the characteristics of the nebula emission with those of the powering pulsar, we selected a sub-set of 10 TeV detections which are likely ascribed to young PWNe and model the spectral energy distribution with a time-dependent description of the nebulae's electron population. In 9 of these cases, a detailed PWNe model, using up-to-date multiwavelength information, is presented. The best-fit parameters of these nebula are discussed, together with the pulsar characteristics. We conclude that TeV PWNe are particle-dominated objects with large multiplicities, in general far from magnetic equipartition, and that relatively large photon field enhancements are required to explain the high level of Comptonized photons observed. We do not find significant correlations between the efficiencies of emission at different frequencies and the magnetization. The injection parameters do not appear to be particularly correlated with the pulsar properties either. We find that a normalized comparison of the SEDs (e.g., with the corresponding spin-down flux) at the same age significantly reduces the spectral distributions dispersion.Comment: 38 pages, 20 figures, 8 tables. Accepted for publication in the Journal of High Energy Astrophysics (JHEAp

Valuation and location of the grass for the goat ranching at typical forest of Tolox municipality. (Sierra de las Nieves)

El objetivo de este trabajo es conocer si los montes de propios del municipio de Tolox poseen aptitudes para acoger más aprovechamiento ganadero del que soportan a día de hoy considerando este como una actividad económica rentable y sostenible dentro de un espacio natural protegido (parque natural sierra de las Nieves) y enmarcado en la política comunitaria de la Agenda Territorial Europea 2020. Para ello se parte de un análisis geográfico regional e interescalar de la zona de estudio (parque natural-municipio de Tolox-explotación del ganadero entrevistado) y de un conocimiento cualitativo (mediante entrevista) del aprovechamiento caprino para conocer las necesidades palatables del ganado caprino y como es su manejo a lo largo del año. Esta información, que incluye los recorridos del ganado, se ha aplicado a la realización de un inventario de transecto, basado, a su vez, en criterios que permitan extrapolar sus resultados al resto de la superficie de montes de propios. Por último, se han aplicado técnicas desarrolladas en Sistemas de Información Geográfica (SIG), para comparar la vegetación existente en esta zona con la del conjunto de los montes de propios del municipio de Tolox, viendo como existen lugares dentro de estos en los que a día de hoy no se está realizando un aprovechamiento ganadero pero son susceptibles de ello y podría ser una actividad capaz de generar empleo de modo sostenible dentro de un espacio natural protegido

The effects of magnetic field, age, and intrinsic luminosity on Crab-like pulsar wind nebulae

We investigate the time-dependent behavior of Crab-like pulsar wind nebulae (PWNe) generating a set of models using 4 different initial spin-down luminosities ($L_0 =\{1,0.1,0.01,0.001\} \times L_{0, {\rm Crab}}$), 8 values of magnetic fraction ($\eta =$ 0.001, 0.01, 0.03, 0.1, 0.5, 0.9, 0.99, and 0.999, i.e., from fully particle dominated to fully magnetically dominated nebulae), and 3 distinctive ages: 940, 3000, and 9000 years. We find that the self-synchrotron Compton (SSC) contribution is irrelevant for $L_{SD}$=0.1, 1, and 10% of the Crab power, disregarding the age and the magnetic fraction. SSC only becomes relevant for highly energetic ($\sim 70$ of the Crab), particle dominated nebulae at low ages (of less than a few kyr), located in a FIR background with relatively low energy density. Since no pulsar other than Crab is known to have these features, these results clarify why the Crab Nebula, and only it, is SSC dominated. No young PWN would be detectable at TeV energies if the pulsar's spin-down power is 0.1% Crab or lower. For 1% of the Crab spin-down, only particle dominated nebulae can be detected by H.E.S.S.-like telescopes when young enough (with details depending on the precise injection and environmental parameters). Above 10% of the Crab's power, all PWNe are detectable by H.E.S.S.-like telescopes if they are particle dominated, no matter the age. The impact of the magnetic fraction on the final SED is varied and important, generating order of magnitude variations in the luminosity output for systems that are otherwise the same (equal $P$, $\dot P$, injection, and environment).Comment: Accepted for publication in MNRA