802 research outputs found
How Banks Construct and Manage Risk: A Sociological Study of Small Firm Lending in Britain and Germany
This paper analyses the role of banks in financing SMEs in Britain and Germany. It applies a sociological institutionalist approach to understand how banks construct and manage risk, relating to SME business. The empirical analysis is based on the results of a comparative survey of a sample of British and German banks and also refers to statistical material produced by the banks themselves. The paper concludes that, even though bank- firm relations are still deeply embedded in national institutional frameworks, some tendencies towards convergence can also be observed, particularly among commercial banks from the two countries. These flow from both internationalisation and from the political influence of the EU.Bank Lending; SMEs; Britain; Germany
Two regularizations - two different models of Nambu-Jona-Lasinio
Two variants of the Nambu--Jona-Lasinio model -- the model with 4-dimensional
cutoff and the model with dimensionally-analytical regularization -- are
systematically compared. It is shown that they are, in essence, two different
models of light-quark interaction. In the mean-field approximation the
distinction becomes apparent in a behavior of scalar amplitude near the
threshold. For 4-dimensional cutoff the pole term can be extracted, which
corresponds to sigma-meson. For dimensionally-analytical regularization the
singularity of the scalar amplitude is not pole, and this singularity is quite
disappeared at some value of the regularization parameter.
Still more essential distinction of these models exists in the
next-to-leading order of mean-field expansion. The calculations of meson
contributions in the quark chiral condensate and in the dynamical quark mass
demonstrate, that these contributions though their relatively smallness can
destabilize the Nambu--Jona-Lasinio model with 4-dimensional cutoff. On the
contrary, the Nambu--Jona-Lasinio model with dimensionally-analytical
regularization is stabilized with the next-to-leading order, i.e. the value of
the regularization parameter shifts to the stability region, where these
contributions decrease.Comment: 14 pages; Journal version; parameter fixing procedure is modifie
Short-lived brominated hydrocarbons – observations in the source regions and the tropical tropopause layer
We conducted measurements of the five important short-lived organic bromine species in the marine boundary layer (MBL). Measurements were made in the Northern Hemisphere mid-latitudes (Sylt Island, North Sea) in June 2009 and in the tropical Western Pacific during the TransBrom ship campaign in October 2009. For the one-week time series on Sylt Island, mean mixing ratios of CHBr3, CH2Br2, CHBr2Cl and CH2BrCl were 2.0, 1.1, 0.2, 0.1 ppt, respectively. We found maxima of 5.8 and 1.6 ppt for the two main components CHBr3 and CH2Br2. Along the cruise track in the Western Pacific (between 41° N and 13° S) we measured mean mixing ratios of 0.9, 0.9, 0.2, 0.1 and 0.1 ppt for CHBr3, CH2Br2, CHBrCl2, CHBr2Cl and CH2BrCl. Air samples with coastal influence showed considerably higher mixing ratios than the samples with open ocean origin. Correlation analyses of the two data sets yielded strong linear relationships between the mixing ratios of four of the five species (except for CH2BrCl). Using a combined data set from the two campaigns and a comparison with the results from two former studies, rough estimates of the molar emission ratios between the correlated substances were: 9/1/0.35/0.35 for CHBr3/CH2Br2/CHBrCl2/CHBr2Cl. Additional measurements were made in the tropical tropopause layer (TTL) above Teresina (Brazil, 5° S) in June 2008, using balloon-borne cryogenic whole air sampling technique. Near the level of zero clear-sky net radiative heating (LZRH) at 14.8 km about 2.25 ppt organic bromine was bound to the five short-lived species, making up 13% of total organic bromine (17.82 ppt). CH2Br2 (1.45 ppt) and CHBr3 (0.56 ppt) accounted for 90% of the budget of short-lived compounds in that region. Near the tropopause (at 17.5 km) organic bromine from these substances was reduced to 1.35 ppt, with 1.07 and 0.12 ppt attributed to CH2Br2 and CHBr3, respectively
Sub-Doppler supersonic jet spectra of the coupled 6a10 and 6b10 vibronic bands of the S1(1B2u) ← S0(1A1g) transition in monodeuterobenzene and their rovibrational analysis
Photophysiological state of natural phytoplankton communities in the South China Sea and Sulu Sea
In recent years, an increasing number of studies on phytoplankton in the tropical South China Sea (SCS) and Sulu Sea (SS) have been conducted. However, still little is known about the photophysiological state of natural phytoplankton communities under varying environmental conditions. This study investigates the photophysiological state of natural phytoplankton communities in the southern SCS and SS based on high horizontal and vertical resolution field observations collected during the SHIVA (Stratosphere ozone: Halogens in a Varying Atmosphere) cruise (SO 218) in November 2011 on board RV Sonne. At the surface, pigment results revealed that total chlorophyll a (TChl a ) concentrations at all offshore stations were low at the surface and were generally dominated by cyanobacteria. Enhanced concentrations of TChl a were only observed below the upper mixed layer and above the euphotic depth with haptophytes, prochlorophytes and prasinophytes contributing most of the biomass. At stations close to the coast and river outflows, surface phytoplankton blooms (between 1 to 2.2 mg m−3) dominated by diatoms were observed. Overall, the study region exhibited strong nitrate + nitrite (NOx, 2 μmol L−1) were observed in conjunction with increased TChl a and diatoms concentrations. Surface NOx concentrations were observed to correlate positively with temperature (τ = 0.22, p 0.4
Soft Photons from Off-shell Particles in a Hot Plasma
Considering the propagation of off-shell particles in the framework of
thermal field theory, we present the general formalism for the calculation of
the production rate of soft photons and dileptons from a hot plasma. This
approach is illustrated with an electrodynamic plasma. The photon production
rate from strongly interacting quarks in the quark-gluon plasma, which might be
formed in ultrarelativistic heavy ion collisions, is calculated in the
previously unaccessible regime of photon energies of the order of the plasma
temperature within an effective field theory incorporating dynamical chiral
symmetry breaking.Comment: 8 pages in RevTeX format, 3 figures uuencoded postscript added. Also
available by anonymous ftp at ftp://tpri6c.gsi.de/pub/phenning/qh95ga
Modelling marine emissions and atmospheric distributions of halocarbons and dimethyl sulfide: the influence of prescribed water concentration vs. prescribed emissions
Marine-produced short-lived trace gases such as dibromomethane (CH2Br2), bromoform (CHBr3), methyliodide (CH3I) and dimethyl sulfide (DMS) significantly impact tropospheric and stratospheric chemistry. Describing their marine emissions in atmospheric chemistry models as accurately as possible is necessary to quantify their impact on ozone depletion and Earth's radiative budget. So far, marine emissions of trace gases have mainly been prescribed from emission climatologies, thus lacking the interaction between the actual state of the atmosphere and the ocean. Here we present simulations with the chemistry climate model EMAC (ECHAM5/MESSy Atmospheric Chemistry) with online calculation of emissions based on surface water concentrations, in contrast to directly prescribed emissions. Considering the actual state of the model atmosphere results in a concentration gradient consistent with model real-time conditions at the ocean surface and in the atmosphere, which determine the direction and magnitude of the computed flux. This method has a number of conceptual and practical benefits, as the modelled emission can respond consistently to changes in sea surface temperature, surface wind speed, sea ice cover and especially atmospheric mixing ratio. This online calculation could enhance, dampen or even invert the fluxes (i.e. deposition instead of emissions) of very short-lived substances (VSLS). We show that differences between prescribing emissions and prescribing concentrations (−28 % for CH2Br2 to +11 % for CHBr3) result mainly from consideration of the actual, time-varying state of the atmosphere. The absolute magnitude of the differences depends mainly on the surface ocean saturation of each particular gas. Comparison to observations from aircraft, ships and ground stations reveals that computing the air–sea flux interactively leads in most of the cases to more accurate atmospheric mixing ratios in the model compared to the computation from prescribed emissions. Calculating emissions online also enables effective testing of different air–sea transfer velocity (k) parameterizations, which was performed here for eight different parameterizations. The testing of these different k values is of special interest for DMS, as recently published parameterizations derived by direct flux measurements using eddy covariance measurements suggest decreasing k values at high wind speeds or a linear relationship with wind speed. Implementing these parameterizations reduces discrepancies in modelled DMS atmospheric mixing ratios and observations by a factor of 1.5 compared to parameterizations with a quadratic or cubic relationship to wind spee
Sources of short-lived bromocarbons in the Iberian upwelling system
Seawater concentrations of the four brominated trace gases dibromomethane (CH2Br2), bromodichloromethane (CHBrCl2), dibromochloromethane (CHBr2Cl) and bromoform (CHBr3) were measured at different depths of the water column in the Iberian upwelling off Portugal during summer 2007. Bromocarbon concentrations showed elevated values in recently upwelled and aged upwelled waters (mean values of 30 pmol L−1 for CHBr3), while values in the open ocean were significantly lower (7.4 pmol L−1 for CHBr3). Correlations with biological variables and marker pigments indicated that phytoplankton could be identified as a weak bromocarbon source in the open ocean. In upwelled water masses along the coast, halocarbons were not correlated to Chl-a, indicating an external source, overlapping the possible internal production by phytoplankton. We showed that the tidal frequency had a significant influence on halocarbon concentrations in the upwelling and we linked those findings to a strong intertidal coastal source, as well as to a transport of those halocarbon enriched coastal waters by westward surface upwelling currents. Coastal sources and transport can be accounted for maximum values of up to 185.1 pmol L−1 CHBr3 in the upwelling.
Comparison with other productive marine areas revealed that the Iberian upwelling had stronger halocarbon sources than the phytoplankton dominated sources in the Mauritanian upwelling. However, the concentrations off the Iberian Peninsula were still much lower than those of coastal macroalgal influenced waters or those of polar regions dominated by cold water adapted diatom
Thermal and Nonthermal Pion Enhancements with Chiral Symmetry Restoration
The pion production by sigma decay and its relation with chiral symmetry
restoration in a hot and dense matter are investigated in the framework of the
Nambu-Jona-Lasinio model. The decay rate for the process sigma -> 2pion to the
lowest order in a 1/N_c expansion is calculated as a function of temperature T
and chemical potential mu. The thermal and nonthermal enhancements of pions
generated by the decay before and after the freeze-out present only in the
crossover region of the chiral symmetry transition. The strongest nonthermal
enhancement is located in the vicinity of the endpoint of the first-order
transition.Comment: Latex2e, 12 pages, 8 Postscript figures, submitted to Phys. Rev.
1/N_c- expansion of the quark condensate at finite temperature
Previously the quark and meson properties in a many quark system at finite
temperature have been studied within effective QCD approaches in the Hartree
approximation. In the present paper we consider the influence of the mesonic
correlations on the quark self-energy and on the quark propagator within a
systematic - expansion. Using a general separable ansatz for the
nonlocal interaction, we derive a selfconsistent equation for the
correction to the quark propagator. For a separable model with cut-off
formfactor, we obtain a decrease of the condensate of the order of 20\% at zero
temperature. A lowering the critical temperature for the onset of the chiral
restoration transition due to the inclusion of mesonic correlations is obtained
what seems to be closer to the results from lattice calculations.Comment: 19 pages, REVTeX, 5 figure
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