Search results

Filter

Filetype

Your search for "*" yielded 530930 hits

Nambu-Jona-Lasinio-like models and the low-energy effective action of QCD

We present a derivation of the low-energy effective action of an extended Nambu-Jona-Lasinio (ENJL) model to O(p4) in the chiral counting. Two alternative scenarios are considered on how the ENJL model could originate as a low-energy approximation to QCD. The low-energy effective lagrangian we derive includes the usual pseudoscalar Goldstone modes, as well as the lower scalar, vector and axial-vec

Hadronic matrix elements and the 0 mass difference

We estimate the 0 electromagnetic mass difference within the 1/N expansion approach to hadronic matrix elements. Perturbative QCD and a truncated meson theory describe the high- and low-photon-loop-momentum contributions, respectively. The matching between these complementary pictures for strong interactions is discussed.

Synthesis, characterisation and crystal structures of the palladium(II) phosphite complexes cis-[PdI2{cis-(iPr2PO)2C 6H10}] and trans-[Pd2I4{cis-(iPr2PO) 2C6H10}2]

Treatment of 2 equiv. of a mixture of the diphosphite cis, trans-1,3-(iPr2PO)2C6H 10 with [Pd(CO2CF3)2] and sequential addition of an excess of NaI gives the binuclear 16-atom ring chelate complex trans-[Pd2I4{cis-(iPr2PO) 2C6H10}2] (1) and the mononuclear complex cis-[PdI2{cis-(iPr2PO)2C 6H10}] (2) exclusively. NMR spectroscopy and X-ray crystallography have unambiguously determined the structure

Comprehensive echocardiographic imaging of atrioventricular valves in children with atrioventricular septal defect : Accuracy of 2D and 3D imaging and reasons for disagreement

OBJECTIVE: To compare the accuracy and reasons for disagreement of two-dimensional (2D) and three-dimensional (3D) echocardiography findings in the assessment of the atrioventricular valve complex in patients with atrioventricular septal defect. METHODS: A total of 20 children (mean age 8 months) with atrioventricular septal defect were enrolled prospectively into this study. The accuracy of and t

Directed motion emerging from two coupled random processes: translocation of a chain through a membrane nanopore driven by binding proteins

We investigate the translocation of a stiff polymer consisting of M monomersthrough a nanopore in a membrane, in the presence of binding particles(chaperones) that bind onto the polymer, and partially prevent backsliding ofthe polymer through the pore. The process is characterized by the rates: kfor the polymer to make a diffusive jump through the pore, q for unbinding ofa chaperone, and the rate

Binding dynamics of single-stranded DNA binding proteins to fluctuating bubbles in breathing DNA

We investigate the dynamics of a single local denaturation zone in a DNA molecule, a so-called DNA bubble, in the presence of single-stranded DNA binding proteins (SSBs). In particular, we develop a dynamical description of the process in terms of a two-dimensional master equation for the time evolution of the probability distribution of having a bubble of size m with n bound SSBs, for the case wh

Simulation based investigation of achieving low temperature combustion with methanol in a direct injected compression ignition engine

Low temperature combustion concepts used in compression ignition engines have shown to be able to produce simultaneous reduction of oxides of nitrogen and soot as well as generating higher gross indicated efficiencies compared to conventional diesel combustion. This is achieved by a combination of premixing, dilution and optimization of combustion phasing. Low temperature combustion can be comple

Comparison of kinetic mechanisms for numerical simulation of methanol combustion in dici heavy-duty engine

The combustion process in a homogeneous charge compression ignition (HCCI) engine is mainly governed by ignition wave propagation. The in-cylinder pressure, heat release rate, and the emission characteristics are thus largely driven by the chemical kinetics of the fuel. As a result, CFD simulation of such combustion process is very sensitive to the employed reaction mechanism, which model the real

Geochemical composition of Baltic benthic foraminifera collected and cultured over a large salinity gradient.

Some of the most significant challenges in paleoclimate research arise from the need to both understand and reduce the uncertainty associated with proxies for climate reconstructions. These challenges were further highlighted in connection with the IODP Exp.347 Baltic Sea Paleoenvironment. We have investigated temperature and salinity proxies through a combination of field-and culture-based benthi

Skjutvapens- och explosionsvåld

Det skjutvapenrelaterade våldet i Sverige har ökat kraftigt sedan 1990-talet, och trots att hela Sverige är drabbat sticker Region Skåne och då främst Malmö ut. Även om en stor del av skottlossningarna riktas mot byggnader och fordon dör och skadas årligen ett tiotal personer i staden. Även explosionsvåldet har ökat både i landet och i Malmö och det kan vara ett tecken på ett trendbrott inom den gGun-related violence in Sweden has increased dramatically since the 1990s, and while the entire country has been affected, the Skåne region and Malmö in particular stand out. Although many of the shootings are directed at buildings and vehicles, more than ten people are killed and injured in the city every year. Violence caused by explosives has also increased both in Malmö and in the country as a

Two-pion production in photon-photon collisions

We calculate within chiral perturbation theory the cross section for γγ→π0π0 and γγ→π+π- to next-to-leading order. The first process only depends on the one-loop contributions and forms a test of chiral perturbation theory. We also calculate the pion electromagnetic form factor and compare it to recent data.

Corrections to the Weiss-Zumino term in chiral perturbation theory

All the terms needed to cancel the divergences appearing in one-loop calculations involving the Wess-Zumino term are obtained. We apply this result to the Pγγ and PPPγ vertices, fixing the finite part of the coefficients of the O(p6) terms in the lagrangian with vector meson contributions. In all the cases the corrections improve the agreement between the theoretical predictions and experimental d

On the tensor formulation of effective vector lagrangians and duality transformations

Using two different methods inspired by duality transformations we present the equivalence between effective Lagrangians for massive vector mesons using a vector field and an antisymmetric tensor field. This completes the list of explicit field transformations between the various effective Lagrangian methods to describe massive vector and axial vector mesons. Our method automatically generates the