31 research outputs found

    Сравнителен анализ на аграрната политика на България и Виетнам

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    This book is a first attempt to make a comprehensive comparative analysis of agricultural policies in Bulgaria and Vietnam. Twenty year experience in reforming the agrarian sectors in both countries gives an extraordinary opportunity to (re)assess agrarian policies, their impacts and perspectives, and rethink advantages and disadvantages of specific models for modernization of agriculture. The analyses comprises the evolution and importance of agriculture in Bulgaria and Vietnam, the pace and progress of land reforms and restructuring of farms, policies of state support and regulations of agriculture, policies associated with trade regime and international trade with agrarian and food products. Finally, an assessment is made on possibilities to improve competitiveness of agriculture in both countries

    Сравнителен анализ на аграрната политика на България и Виетнам

    Get PDF
    This book is a first attempt to make a comprehensive comparative analysis of agricultural policies in Bulgaria and Vietnam. Twenty year experience in reforming the agrarian sectors in both countries gives an extraordinary opportunity to (re)assess agrarian policies, their impacts and perspectives, and rethink advantages and disadvantages of specific models for modernization of agriculture. The analyses comprises the evolution and importance of agriculture in Bulgaria and Vietnam, the pace and progress of land reforms and restructuring of farms, policies of state support and regulations of agriculture, policies associated with trade regime and international trade with agrarian and food products. Finally, an assessment is made on possibilities to improve competitiveness of agriculture in both countries

    A normal gem-dimethyl effect in the base-catalyzed cyclization of -( p-nitrophenyl)hydantoic acids: evidence for hindered proton transfer in the permethylated esters †

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    The cyclization of hydantoic acids 2-UA and 3-UA -kinetics, solvent kinetic isotope effects (SKIE) and buffer catalysis -were studied in an attempt to explain the disappearance of the gem-dimethyl effect (GDME) in the specific base-catalyzed cyclization of hydantoic esters. pH-Rate profiles for both acids (after correction for ionization and for reversibility at high pH) show two regions of unit slope corresponding to different mechanisms. For 2-UA at high pH and 3-UA at lower pH the mechanism is considered to involve rate-determining attack by the ureido anion on the neutral carboxy group, consistent with the observed inverse SKIE. The normal GDME of 15 provides strong evidence that anomalies observed with the esters do indeed result from steric hindrance to proton transfer. The change to rate determining departure of OH Ϫ with 2-UA is caused at low pH by acid catalysis of the reversion of the tetrahedral intermediate (T Ϫ ) to reactants, while with 3-UA at high pH this takes place through T 2Ϫ . The GDME favours attack on the carboxylate anion but makes ring opening more difficult, thus decreasing acid inhibition. The observed β = 0.44 for general base catalysis of the cyclization of 2-UA is consistent with concerted deprotonation and attack of the ureido group. With 3-UA two simultaneous general base-catalyzed reactions take place: slow deprotonation of the ureido group (β = 1.0) and attack of the ureide anion on the carboxy anion aided by the buffer conjugate acid. The estimated GDME is 2800 for the equilibrium between acid anion and hydantoin, ‡ but only 45 and 15 for catalysis by H 3 O ϩ and OH Ϫ , respectively: both reactions are presumed to go through early transition states. A convenient way to accelerate the bioorganic reactions of small molecules is to introduce steric strain into the substrate. In cyclization reactions this is readily done by introducing substituents into the interconnecting chain: the resulting increase in rate defines the gem-dimethyl effect (GDME). 1 However, in a recent study 2,3 of catalytic mechanisms for the ring closure of hydantoic esters, we found no GDME for the base-catalyzed reaction. We concluded that the rate determining step had changed, for the most heavily substituted compounds, from the formation of the tetrahedral intermediate to its breakdown, because of steric hindrance in proton transfer to the leaving ethoxy group. In the tetrahedral intermediate, T Ϫ , the two methyl groups screen one side and the N-aryl substituent the other, while R (ethyl was studied) in its least hindered conformation blocks easy access of a general acid. If this analysis is correct, and the effect depends on steric hindrance in proton † Pseudo-first-order rate constants are available as supplementary data. For direct electronic access see http://www.rsc.org/suppdata/p2/b0/ b002276o ‡ The IUPAC name for hydantoin is imidazolidine-2,4-dione. transfer to the developing ethoxide by its ethyl group, it should be reduced or removed if a smaller group replaces ethyl. We have tested this proposition by studying the cyclization of the hydantoic acids shown in Scheme 1. We find that hydantoic acids 2 and 3 undergo base-catalyzed ring closure more slowly than the esters when the pH is higher than the pK of the COOH group; and that the results confirm our prediction. The hydroxide-catalyzed cyclization of the fully methylated acid 3-UA shows a normal GDME, and the solvent kinetic isotope effects (SKIE) suggest that acids 2-UA and 3-UA are cyclized by the same mechanism. Experimental Materials Inorganic reagents and buffer components were of analytical Scheme

    Calibration of the CMS Drift Tube Chambers and Measurement of the Drift Velocity with Cosmic Rays

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    CMS physics technical design report : Addendum on high density QCD with heavy ions

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    Aligning the CMS Muon Chambers with the Muon Alignment System during an Extended Cosmic Ray Run

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    Alignment of the CMS muon system with cosmic-ray and beam-halo muons

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    This is the Pre-print version of the Article. The official published version of the Paper can be accessed from the link below - Copyright @ 2010 IOPThe CMS muon system has been aligned using cosmic-ray muons collected in 2008 and beam-halo muons from the 2008 LHC circulating beam tests. After alignment, the resolution of the most sensitive coordinate is 80 microns for the relative positions of superlayers in the same barrel chamber and 270 microns for the relative positions of endcap chambers in the same ring structure. The resolution on the position of the central barrel chambers relative to the tracker is comprised between two extreme estimates, 200 and 700 microns, provided by two complementary studies. With minor modifications, the alignment procedures can be applied using muons from LHC collisions, leading to additional significant improvements.This work is supported by FMSR (Austria); FNRS and FWO (Belgium); CNPq, CAPES, FAPERJ, and FAPESP (Brazil); MES (Bulgaria); CERN; CAS, MoST, and NSFC (China); COLCIENCIAS (Colombia); MSES (Croatia); RPF (Cyprus); Academy of Sciences and NICPB (Estonia); Academy of Finland, ME, and HIP (Finland); CEA and CNRS/IN2P3 (France); BMBF, DFG, and HGF (Germany); GSRT (Greece); OTKA and NKTH (Hungary); DAE and DST (India); IPM (Iran); SFI (Ireland); INFN (Italy); NRF (Korea); LAS (Lithuania); CINVESTAV, CONACYT, SEP, and UASLP-FAI (Mexico); PAEC (Pakistan); SCSR (Poland); FCT (Portugal); JINR(Armenia, Belarus, Georgia, Ukraine, Uzbekistan); MST and MAE (Russia); MSTDS (Serbia); MICINN and CPAN (Spain); Swiss Funding Agencies (Switzerland); NSC (Taipei); TUBITAK and TAEK (Turkey); STFC (United Kingdom); DOE and NSF (USA)

    Alignment of the CMS muon system with cosmic-ray and beam-halo muons

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    This is the Pre-print version of the Article. The official published version of the Paper can be accessed from the link below - Copyright @ 2010 IOPThe CMS muon system has been aligned using cosmic-ray muons collected in 2008 and beam-halo muons from the 2008 LHC circulating beam tests. After alignment, the resolution of the most sensitive coordinate is 80 microns for the relative positions of superlayers in the same barrel chamber and 270 microns for the relative positions of endcap chambers in the same ring structure. The resolution on the position of the central barrel chambers relative to the tracker is comprised between two extreme estimates, 200 and 700 microns, provided by two complementary studies. With minor modifications, the alignment procedures can be applied using muons from LHC collisions, leading to additional significant improvements.This work is supported by FMSR (Austria); FNRS and FWO (Belgium); CNPq, CAPES, FAPERJ, and FAPESP (Brazil); MES (Bulgaria); CERN; CAS, MoST, and NSFC (China); COLCIENCIAS (Colombia); MSES (Croatia); RPF (Cyprus); Academy of Sciences and NICPB (Estonia); Academy of Finland, ME, and HIP (Finland); CEA and CNRS/IN2P3 (France); BMBF, DFG, and HGF (Germany); GSRT (Greece); OTKA and NKTH (Hungary); DAE and DST (India); IPM (Iran); SFI (Ireland); INFN (Italy); NRF (Korea); LAS (Lithuania); CINVESTAV, CONACYT, SEP, and UASLP-FAI (Mexico); PAEC (Pakistan); SCSR (Poland); FCT (Portugal); JINR(Armenia, Belarus, Georgia, Ukraine, Uzbekistan); MST and MAE (Russia); MSTDS (Serbia); MICINN and CPAN (Spain); Swiss Funding Agencies (Switzerland); NSC (Taipei); TUBITAK and TAEK (Turkey); STFC (United Kingdom); DOE and NSF (USA)

    Precise mapping of the magnetic field in the CMS barrel yoke using cosmic rays

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    This is the Pre-print version of the Article. The official published version can be accessed from the link below - Copyright @ 2010 IOPThe CMS detector is designed around a large 4 T superconducting solenoid, enclosed in a 12 000-tonne steel return yoke. A detailed map of the magnetic field is required for the accurate simulation and reconstruction of physics events in the CMS detector, not only in the inner tracking region inside the solenoid but also in the large and complex structure of the steel yoke, which is instrumented with muon chambers. Using a large sample of cosmic muon events collected by CMS in 2008, the field in the steel of the barrel yoke has been determined with a precision of 3 to 8% depending on the location.This work is supported by FMSR (Austria); FNRS and FWO (Belgium); CNPq, CAPES, FAPERJ, and FAPESP (Brazil); MES (Bulgaria); CERN; CAS, MoST, and NSFC (China); COLCIENCIAS (Colombia); MSES (Croatia); RPF (Cyprus); Academy of Sciences and NICPB (Estonia); Academy of Finland, ME, and HIP (Finland); CEA and CNRS/IN2P3 (France); BMBF, DFG, and HGF (Germany); GSRT (Greece); OTKA and NKTH (Hungary); DAE and DST (India); IPM (Iran); SFI (Ireland); INFN (Italy); NRF (Korea); LAS (Lithuania); CINVESTAV, CONACYT, SEP, and UASLP-FAI (Mexico); PAEC (Pakistan); SCSR (Poland); FCT (Portugal); JINR (Armenia, Belarus, Georgia, Ukraine, Uzbekistan); MST and MAE (Russia); MSTDS (Serbia); MICINN and CPAN (Spain); Swiss Funding Agencies (Switzerland); NSC (Taipei); TUBITAK and TAEK (Turkey); STFC (United Kingdom); DOE and NSF (USA)
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