As múltiplas funções da agricultura familiar: um estudo no assentamento Monte Alegre, região de Araraquara (SP).

A partir da emergência da ideia de sustentabilidade, a agricultura adquiriu novas conotações, associadas não apenas ao aspecto produtivo, mas também à conservação dos recursos naturais e dos territórios rurais, em um reconhecimento de sua multifuncionalidade. Com base nesta noção, que valoriza as funções socioambientais desempenhadas pelas famílias rurais e pelas agriculturas praticadas, o presente artigo analisa um assentamento rural no estado de São Paulo, buscando identificar quais são e de que forma se expressam as funções para além da produção neste território particular. Por meio de uma metodologia de cunho quali-quantitativo, observou-se que, no assentamento em foco, a agricultura encerra em si questões de coesão territorial, manutenção da segurança alimentar, conservação da agrobiodiversidade e de fomento a outras atividades produtivas, sendo o elemento central da reconstrução de um modo de vida rural neste ambiente

Search for composite and exotic fermions at LEP 2

A search for unstable heavy fermions with the DELPHI detector at LEP is reported. Sequential and non-canonical leptons, as well as excited leptons and quarks, are considered. The data analysed correspond to an integrated luminosity of about 48 pb^{-1} at an e^+e^- centre-of-mass energy of 183 GeV and about 20 pb^{-1} equally shared between the centre-of-mass energies of 172 GeV and 161 GeV. The search for pair-produced new leptons establishes 95% confidence level mass limits in the region between 70 GeV/c^2 and 90 GeV/c^2, depending on the channel. The search for singly produced excited leptons and quarks establishes upper limits on the ratio of the coupling of the excited fermio

Search for charginos in e+e- interactions at sqrt(s) = 189 GeV

An update of the searches for charginos and gravitinos is presented, based on a data sample corresponding to the 158 pb^{-1} recorded by the DELPHI detector in 1998, at a centre-of-mass energy of 189 GeV. No evidence for a signal was found. The lower mass limits are 4-5 GeV/c^2 higher than those obtained at a centre-of-mass energy of 183 GeV. The (\mu,M_2) MSSM domain excluded by combining the chargino searches with neutralino searches at the Z resonance implies a limit on the mass of the lightest neutralino which, for a heavy sneutrino, is constrained to be above 31.0 GeV/c^2 for tan(beta) \geq 1.Comment: 22 pages, 8 figure

Search for lightest neutralino and stau pair production in light gravitino scenarios with stau NLSP

Promptly decaying lightest neutralinos and long-lived staus are searched for in the context of light gravitino scenarios. It is assumed that the stau is the next to lightest supersymmetric particle (NLSP) and that the lightest neutralino is the next to NLSP (NNLSP). Data collected with the Delphi detector at centre-of-mass energies from 161 to 183 \GeV are analysed. No evidence of the production of these particles is found. Hence, lower mass limits for both kinds of particles are set at 95% C.L.. The mass of gaugino-like neutralinos is found to be greater than 71.5 GeV/c^2. In the search for long-lived stau, masses less than 70.0 to 77.5 \GeVcc are excluded for gravitino masses from 10 to 150 \eVcc . Combining this search with the searches for stable heavy leptons and Minimal Supersymmetric Standard Model staus a lower limit of 68.5 \GeVcc may be set for the stau mas

Hadronization properties of b quarks compared to light quarks in e+e- -> q qbar from 183 to 200 GeV

The DELPHI detector at LEP has collected 54 pb^{-1} of data at a centre-of-mass energy around 183 GeV during 1997, 158 pb^{-1} around 189 GeV during 1998, and 187 pb^{-1} between 192 and 200 GeV during 1999. These data were used to measure the average charged particle multiplicity in e+e- -> b bbar events, _{bb}, and the difference delta_{bl} between _{bb} and the multiplicity, _{ll}, in generic light quark (u,d,s) events: delta_{bl}(183 GeV) = 4.55 +/- 1.31 (stat) +/- 0.73 (syst) delta_{bl}(189 GeV) = 4.43 +/- 0.85 (stat) +/- 0.61 (syst) delta_{bl}(200 GeV) = 3.39 +/- 0.89 (stat) +/- 1.01 (syst). This result is consistent with QCD predictions, while it is inconsistent with calculations assuming that the multiplicity accompanying the decay of a heavy quark is independent of the mass of the quark itself.Comment: 13 pages, 2 figure

Performance Analysis Of An Wavelength/code-routed Burst Switched Network

This paper analysis the use of hybrid technology of wavelength division multiplexing and optical code division multiplexing (WDM/OCDM) for optical burst switching (OBS) with two-way reservation scheme. The architecture of WDM/OCDM edge router that utilizes fast circuit switching by dynamically assigning and releasing virtual optical code/wavelength path channels (VOCP/VWP) over bufferless optical core is describe. We derived expressions for burst blocking probability for the edge router and analyzed the behavior of the network in function the traffic load and latency. The main results show that are decreasing the burst blocking probability and network latency when increase the number of codes per wavelength. © 2005 IEEE.263266Yoo, M., Qiao, C., Dixit, S., Qos Performance of Optical Burst Switching in IP-Over-WDM Networks (2000) IEEE J. Select Areas in Commun, 18 (10), pp. 2062-2071. , OctoberBattestilli, T., Perros, H., An Introduction to Optical Burst Switching (2003) IEEE Optical Commun, pp. 510-515. , AugustRosberg, Z., Vu, H., Zukerman, M., White, J., Performance Analyses of Optical Burst-Switching Networks (2003) IEEE J. Select Areas in Commun, 21 (7), pp. 1187-1197. , SeptemberZalesky, A., Wong, E., Zukerman, M., Vu, H., Tucker, R., Performance Analysis of an OBS Edge Router (2002) IEEE Photon. Technol. Lett, 16 (2), pp. 695-697. , FebruaryDuser, M., Beyvel, P., Analysis of Dynamically Wavelength-Routed Optical Burst Switched Network Architecture (2002) J. Lightwave Technol, 20 (4), pp. 574-585. , AprilSotobayashi, H., Chujo, W., Kitayama, K., Transparent Virtual Optical Code/Wavelength Path Network (2002) IEEE IEEE J. Select Areas in Commun, 8 (3), pp. 699-704. , May/JuneWen, Y.G., Zhang, Y., Chen, L.K., On Architecture and Limitation of Optical Multiprotocol Label Switching (MPLS) Networks Using Optical-Orthogonal-Code (OOC)/Wavelength Label (2002) Optical Fiber Technology, 8, pp. 43-70Kitayama, K., Murata, M., Versatile Optical Code-Based MPLS for Circuit, Burst and Packet Switchings (2003) J. Lightwave Technol, 21 (11), pp. 2573-2764. , NovemberDetti, A., Eramo, V., Listanti, M., Performance evalution of a new techniquefor ip support in a wdm optical network: Optical composite burst switching (OCBS) (2002) J. Lightwave Technol, 20 (2), pp. 154-165. , FebruaryZalesky, A., Wong, E., Zukerman, M., Vu, H., Tucker, R., Performance Analysis of an OBS Edge Router (2004) IEEE Photon. Technol. Lett, 16 (2), pp. 695-697. , FebruaryZukerman, M., Wong, E., Rosberg, Z., Lee, G., Vu, H., On Teletraffic Applications to OBS (2004) IEEE Commun. Lett, 8 (2), pp. 116-118. , Februar

Analysis Of Hybrid Wdm/ocdm Networks With All-optical Code Converters

In this work, optical networks using the hybrid technology of wavelength division multiplexing and optical code division multiplexing (WDM/OCDM) with all-optical code converters are investigated. Expressions to show the code converter node performance including the effects of polarization mode dispersion (PMD) are derived. The main results show that the effects of PMD can decrease the code converter performance. It is also investigated a simple analytical formalism to solve the problem of optimal code converter placement. This formalism shows the network performance when the code converter are optimally/uniformly distributed in the network. © 2005 IEEE.172175Ram Murthy, C.S., Gurusamy, M., (2002) WDM Optical Networks: Concepts, Design, and Algorithms, , Prentice Hall: Upper Saddle RiverBanerjee, A., Generalized Multiprotocol Label Switching: An Overview of Routing and Management Enhancements (2001) IEEE Commun. Mag, pp. 144-150. , JanuarySotobayashi, H., Chujo, W., Kitayama, K., Transparent Virtual Optical Code/Wavelength Path Network (2002) IEEE J. Select Areas in Commun, 8 (3), pp. 699-704. , May/JuneKitayama, K., Murata, M., Versatile Optical Code-Based MPLS for Circuit, Burst and Packet Switchings (2003) J. Lightwave Technol, 21 (11), pp. 2573-2764. , NovemberMurata, M., Kitayama, K., A Perspective on Photonic Mutiprotocol Label Switching (2001) IEEE Network, 15 (4), pp. 56-63. , Jul-AugWen, Y.G., Zhang, Y., Chen, L.K., On Architecture and Limitation of Optical Multiprotocol Label Switching (MPLS) Networks Using Optical-Orthogonal-Code (OOC)/Wavelength Label (2002) Optical Fiber Technology, 8, pp. 43-70Kitayama, K., Code Division Multiplexing Lightwave Networks Based upon Optical Code Conversion (1998) IEEE J. Select Areas in Commun, 16 (7), pp. 1309-1319. , SeptemberSubramaniam, S., Azizoglu, M., Somani, A., On Optimal Converter Placement in Wavelength-Routed Networks (1999) IEEE/ACM Trans. Networking, 7 (5), pp. 754-766. , OctoberStrand, J., Chiu, A.L., Tkach, R., Issues For Routing In The Optical Layer (2001) IEEE Commun. Mag, pp. 81-87. , FebruaryChung, F., Salehi, J., Wei, V., Optical Orthogonal Codes: Design, Analysis, and Applications (1989) IEEE Trans on Information Theory, 35 (3), pp. 595-604. , MayWen, Y.G., Chen, L.K., Ho, K.P., Tong, F., All-Optical Code Converter Scheme for OCDM Routing Networks (2000) ECOC'2000, pp. 1088-1090. , paper P4.5, ppWen, Y.G., Chen, L.K., Ho, K.P., Tong, F., Fundamental Limitation and Optimization on Optical Code Conversion for WDM Packet Switching Networks (2001) Proc OFC'01, , paper TuVS-

Effects Of Multiple Access Interference And Pmd On Optical Code Lightpaths

In this work we investigate the effects of multiple access interference (MAI) and polarization mode dispersion (PMD) in optical code division multiplexing (OCDM) lightpaths. These paths are determined by the data encoding with non-coherent optical orthogonal codes (OOC), using a sequence inversion keying (SIK) optical correlator system. Our results show the impact of MAI effects and PMD constraint on the packet error rate, which depends on OOC parameters like weight and length. These parameters in turn depend on MAI and PMD effects. The results obtained can be used as input parameters for the design of OOC in virtual code/ wavelength path (VOCP/ VWP) routed networks.Kitayama, K., Murata, M., Versatile optical code-based MPLS for circuit, burst and packet switchings (2003) J. Lightwave Technol, 21 (11), pp. 2573-2764. , NovMurata, M., Kitayama, K., A perspective on photonic mutiprotocol label switching (2001) IEEE Network, 15 (4), pp. 56-63. , Jul-AugMutafungwa, E., Halme, S., Analysis of the blocking performance of hybrid OCDM-WDM transport Networks (2002) Microwave and Opt Tech. Lett, 34 (1). , JulyWen, Y.G., Zhang, Y., Chen, L.K., On architecture and limitation of optical Multiprotocol Label Switching (MPLS) networks using Optical-Orthogonal-Code (OOC)/wavelength label (2002) Opt. Fiber Technol, 8, pp. 43-70Huang, S., Baba, K., Murata, M., Kitayama, K., Variable-bandwidth optical paths: Comparison between optical code-labeled path and OCDM path (2006) J. Lightwave Technol, 24 (10), pp. 3563-3573. , OctDurand, F.R., Lima, M., César, A., Moschim, E., Impact of PMD on hybrid WDM/OCDM networks (2005) IEEE Photon Techno Letters, 17 (12), pp. 2787-2789. , DecChung, F., Salehi, J., Wei, V., Optical orthogonal codes: Design, analysis, and applications (1989) IEEE Trans on Information Theory, 35 (3), pp. 595-604. , MayF. R. Durand, F. R. Barbosa, M. F. Abbade, E. Moschim, Performance Analysis of an Optical Code/ Wavelength Path Routed Burst Switched Network, submitted to J. Opt. Network., Nov. 2006Strand, J., Chiu, A.L., Tkach, R.I., Issues for routing in the optical layer (2001) IEEE Com. Mag, pp. 81-87. , FebRobertazzi, T., (2000) Computers Networks And Systems: Queueing Theory And Performance Evaluation, p. 284. , Springer-Verlag, Berli

Performance Evaluation Of Advanced Wdm Networks With Optical Codes And Photonic Switching

We propose and evaluate performance of an innovative hybrid technology using wavelength and optical code division multiplexing (WDM/OCDM) for optical burst switching (OBS) advanced WDM networks. An architecture for the edge routers with fast optical circuit switching and virtual optical code/wavelength paths (VOCP/VWP) is described. We consider burst blocking probability (BBP) as a function of traffic load and various delays. Simulation results indicate that increasing the number of optical codes per wavelength considerably decreases BBP and latency, and also increases network throughput. © 2007 IEEE.187190Jue, J.P., Vokkarane, V.M., (2005) Optical Burst Switched Networks, Springer Science, , Boston, cBattestilli, T., Perros, H., An Introduction to Optical Burst Switching, IEEE (2003) Optical Comm, pp. 510-515Duser, M., Beyvel, P., Analysis of Dynamically Wavelength-Routed OBS Network Architecture (2002) J. Lightwave Tech, 20 (4), pp. 574-585Sotobayashi, H., Chujo, W., Kitayama, K., Transparent Virtual Optical Code/Wavelength Path Network (2002) IEEE J. Select. Top. Quantum Electron, 8 (3), pp. 699-704Wen, Y.G., Zhang, Y., Chen, L.K., On Architecture and Limitation of Optical Multiprotocol Label Switching (MPLS) Networks Using Optical-Orthogonal-Code/Wavelength Label (2002) Optical Fiber Technology, 8, pp. 43-70Durand, F., Lima, M., César, A., Moschim, E., Impact of PMD on Hybrid WDM/OCDM Networks (2005) IEEE Photon. Tech. Lett, 17 (12), pp. 2787-2789Tarhuni, N., Korhonen, T., Mutafungwa, E., Elmusrati, M., Multiclass Optical Orthogonal Codes for Multiservice Optical CDMA Networks (2006) J. Lightwave Tech, 24 (2), pp. 694-704Durand, F., Abbade, M.L.F., Moschim, E., Performance Analysis of an Wavelength/Code Burst Switched Edge Router (2006) International Conference on Telecommunication, , ICT, Madeira, Portugal, MayZukerman, M., Wong, E., Rosberg, Z., Lee, G., Vu, H., On Teletraffic Applications to OBS (2004) IEEE Comm. Letters, 8 (2), pp. 116-118Zalesky, Wong, E., Zukerman, M., Vu, H., Tucker, R., Performance Analysis of an OBS Edge Router (2004) IEEE Photon. Tech. Lett, 16 (2), pp. 695-697Durand, F.R., Rudge Barbosa, F., Abbade, M.F., Moschim, E., Effects of Multiple Access Interference and PMD on Optical Code Lightpaths (2007) IEEE Sarnoff 2007 Symposium, , paper S-13-2, Princeton NJ, USA, Apri