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I Hristova

Publications and source records attributed to I Hristova.

5 recordsLinked to original sources
PubMed2006

Double-hadron leptoproduction in the nuclear medium.

The first measurements of double-hadron production in deep-inelastic scattering within the nuclear medium were made with the HERMES spectrometer at DESY HERA using a 27.6 GeV positron beam. By comparing data for deuterium, nitrogen, krypton, and xenon nuclei, the influence of the nuclear medium on the ratio of double-hadron to single-hadron yields was investigated. Nuclear effects on the additional hadron are clearly observed, but with little or no difference among nitrogen, krypton, or xenon, and with smaller magnitude than effects seen on previously measured single-hadron multiplicities. The data are compared with models based on partonic energy loss or prehadronic scattering and with a model based on a purely absorptive treatment of the final-state interactions. Thus, the double-hadron ratio provides an additional tool for studying modifications of hadronization in nuclear matter.

Journal Article↗
PubMed2006

Correlation between cognitive P300 changes and the grade of closed head injury.

OBJECTIVE: To investigate the use of auditory oddball cognitive P300 changes in an attempt to find out the correlation between the grade and consequences of closed head injury. MATERIALS AND METHODS: Twenty patients with cerebral concussion (mean age 38.5 +/- 10.5 years) and twenty patients with cerebral contusion (mean age 35.5 +/- 9.8 years) underwent auditory oddball P300 investigation within 0.5 - 28 months after the incident. CT was performed in all of patients before P300 testing. The control group consisted of 30 healthy persons, age and sex matched to the study cohort. RESULTS: All of the patients with concussion showed normal results in P300. Sixteen cases with contusion (80%, CI 62.5-97.3%, p < 0.05) revealed abnormal P300 (latency more than 360 msec and absent P300 response in 4 cases). CONCLUSION: Years after the head injury, cognitive P300 changes make cerebral contusion objective.

Adolescent↗
PubMed2005

Single-spin asymmetries in semi-inclusive deep-inelastic scattering on a transversely polarized hydrogen target.

Single-spin asymmetries for semi-inclusive electroproduction of charged pions in deep-inelastic scattering of positrons are measured for the first time with transverse target polarization. The asymmetry depends on the azimuthal angles of both the pion (phi) and the target spin axis (phi(S)) about the virtual-photon direction and relative to the lepton scattering plane. The extracted Fourier component sin((phi+phi(S))(pi)(UT) is a signal of the previously unmeasured quark transversity distribution, in conjunction with the Collins fragmentation function, also unknown. The component sin((phi-phi(S)(pi)(UT) arises from a correlation between the transverse polarization of the target nucleon and the intrinsic transverse momentum of quarks, as represented by the previously unmeasured Sivers distribution function. Evidence for both signals is observed, but the Sivers asymmetry may be affected by exclusive vector meson production.

Journal Article↗
PubMed1994

Nephrogenic diabetes insipidus--prodromal phase of multiple myeloma.

We report on a 65-year-old female patient with an A-kappa multiple myeloma diagnosed on the grounds of bone pain, anemia and extremely elevated erythrocyte sedimentation rate (ESR). Eight years prior to admission to the Clinic of Haematology the patient started to excrete a considerable amount of urine (4-6 liters per 24 hrs) with low specific gravity and to experience hardly controllable thirst. The disorder was specified in a specialised endocrinologic clinic as diabetes inspidus with ambiguous aetiology. The administered treatment with adiuretin had a small effect. A course of cyclophosphamide and glucocorticosteroids was started after myeloma was diagnosed--this had a considerable effect on the polyuria and polydipsia; the specific gravity of the urine increased. This effect, as well as the proven light chain proteinuria in the patient, leads to the interpretation of the early complaints of the patient as onset of the underlying disease in the form of nephrogenic diabetes insipidus--a rare light chain tubular syndrome.

Aged↗