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The Maxwell-Dirac system describes the interaction of an electron with its own electromagnetic field. We prove the existence of soliton-like solutions of Maxwell-Dirac in (3+1)-Minkowski space-time. The solutions obtained are regular, stationary in time, and localized in space. They are found by a variational method, as critical points of an energy functional. This functional is strongly indefinite and presents a lack of compactness. We also find soliton-like solutions for the Klein-Gordon-Dirac system, arising in the Yukawa model.

OBJECTIVES: To examine the value of uterine artery Dopp-ler at 11-14 weeks of gestation in the identification of wom-en at risk of developing pre-eclampsia and fetal growth re-striction. METHODS: Uterine artery Doppler was carried out at 11-14 weeks in 187 ...

OBJECTIVES: To examine the value of uterine artery Dopp-ler at 11-14 weeks of gestation in the identification of wom-en at risk of developing pre-eclampsia and fetal growth re-striction. METHODS: Uterine artery Doppler was carried out at 11-14 weeks in 187 ...

The Dirac–Fock equations are the relativistic analogue of the well-known Hartree–Fock equations. They are used in computational chemistry, and yield results on the inner-shell electrons of heavy atoms that are in very good agreement with experimental data. By a variational method, we prove the existence of infinitely many solutions of the Dirac–Fock equations “without projector”, for Coulomb systems of electrons in atoms, ions or molecules, with Z≤ 124, N≤ 41, N≤ Z. Here, Z is the sum of the nuclear charges in the molecule, N is the number of electrons.

OBJECTIVES: To examine the value of uterine artery Dopp-ler at 11-14 weeks of gestation in the identification of wom-en at risk of developing pre-eclampsia and fetal growth re-striction. METHODS: Uterine artery Doppler was carried out at 11-14 weeks in 187 ...

OBJECTIVES: To examine the value of uterine artery Dopp-ler at 11-14 weeks of gestation in the identification of wom-en at risk of developing pre-eclampsia and fetal growth re-striction. METHODS: Uterine artery Doppler was carried out at 11-14 weeks in 187 ...

OBJECTIVES: To examine the value of uterine artery Dopp-ler at 11-14 weeks of gestation in the identification of wom-en at risk of developing pre-eclampsia and fetal growth re-striction. METHODS: Uterine artery Doppler was carried out at 11-14 weeks in 187 ...

OBJECTIVES: To examine the value of uterine artery Dopp-ler at 11-14 weeks of gestation in the identification of wom-en at risk of developing pre-eclampsia and fetal growth re-striction. METHODS: Uterine artery Doppler was carried out at 11-14 weeks in 187 ...

OBJECTIVES: To examine the value of uterine artery Dopp-ler at 11-14 weeks of gestation in the identification of wom-en at risk of developing pre-eclampsia and fetal growth re-striction. METHODS: Uterine artery Doppler was carried out at 11-14 weeks in 187 ...

Oxalates in plant material can be methylated directly to from dimethyl oxalate. After addition of water and chloroform, the volatile compoun is extracted into the organic phase and analysed quantitatively by gas chromatography.Some forms of oxalates are difficult to methylise, and this is apparent when 20% boron trifluoride-methanol is used as the methylating reagent. The use of 7% hydrochloric acid-methanol improved methylation, but the best result was obtained by repacing the acid catalyst with sulphuric acid and increasing the acid concentration up to 30%. Using this reagent, recovery from spiked samples was satisfactory (ranging from 92 to 105%), and precision of the method was good (Relative Standard Deviation (RSD) 1.3% at a total oxalate content of 1.95%).

OBJECTIVES: To examine the value of uterine artery Dopp-ler at 11-14 weeks of gestation in the identification of wom-en at risk of developing pre-eclampsia and fetal growth re-striction. METHODS: Uterine artery Doppler was carried out at 11-14 weeks in 187 ...

OBJECTIVES: To examine the value of uterine artery Dopp-ler at 11-14 weeks of gestation in the identification of wom-en at risk of developing pre-eclampsia and fetal growth re-striction. METHODS: Uterine artery Doppler was carried out at 11-14 weeks in 187 ...

OBJECTIVES: To examine the value of uterine artery Dopp-ler at 11-14 weeks of gestation in the identification of wom-en at risk of developing pre-eclampsia and fetal growth re-striction. METHODS: Uterine artery Doppler was carried out at 11-14 weeks in 187 ...

OBJECTIVES: To examine the value of uterine artery Dopp-ler at 11-14 weeks of gestation in the identification of wom-en at risk of developing pre-eclampsia and fetal growth re-striction. METHODS: Uterine artery Doppler was carried out at 11-14 weeks in 187 ...

OBJECTIVES: To examine the value of uterine artery Dopp-ler at 11-14 weeks of gestation in the identification of wom-en at risk of developing pre-eclampsia and fetal growth re-striction. METHODS: Uterine artery Doppler was carried out at 11-14 weeks in 187 ...