The γ∗p\gamma^* p total cross section and elastic diffraction

The empirical scaling law, wherein the total photoabsorption cross section depends on the single variable $\eta=(Q^2 + m^2_0)/\Lambda^2 (W^2)$, provides empirical evidence for saturation in the sense of $\sigma_{\gamma^* p} (W^2, Q^2) / \sigma_{\gamma p} (W^2) \to 1$ for $W^2 \to \infty$ at fixed $Q^2$. The total photoabsorption cross section is related to elastic diffraction in terms of a sum rule. The excess of diffractive production over the elastic component is due to inelastic diffraction that contains the production of hadronic states of higher spins. Motivated by the diffractive mass spectrum, the generalized vector dominance/color dipole picture (GVD/CDP) is extended to successfully describe the DIS data in the full region of $x \le 0.1$, all $Q^2 \ge 0$, where the diffractive two-gluon-exchange mechanism dominates.Comment: 4 pages, Latex using espcrc2.sty, 1 figure using 1 eps file. Presented at QCD2002, Montpellier, France, July 200

EXPERIMENTAL STUDI OF CHRONIC EXPOSURE TO SMALL DOSES OF DDT AND γ–HCH IN THE SOLUTION OF HONEY ON THE ORGAN-ISM WHITE MICE

Досліджено вплив мікродоз хлорорганічних пестицидів (γ–ГХЦГ та ДДТ) у розчині меду, за умови їх хронічного надхо-дження як окремо, так і у поєднанні, на організм білих мишей,. Перша дослідна група отримувала розчин меду з вмістом ГХЦГ (γ–ізомеру) з концентрацією 3,0 мкг/кг; друга дослідна група отримувала розчин меду з вмістом ДДТ з концентраці-єю 3,0 мкг/кг; третя дослідна група отримувала розчин меду з поєднаним вмістом ГХЦГ (γ–ізомеру) та ДДТ у загальній концентрації 6,0 мкг/кг (3,0 мкг/кг кожного пестициду). Встановлено деструктивний вплив цих пестицидів на макро та мікроструктуру паренхіматозних органів дослідних тварин. В результаті розтину піддослідних мишей встановлено, що найбільш виразними патологоанатомічними та гістологічними змінами характеризувалась третя група гризунів (які отримували під час досліду ДДТ та γ–ГХЦГ у концентрації 6,0 мкг/кг). Гістологічне дослідження виявило загальний гемо-сидероз паренхіматозних органів всіх дослідних груп тварин, а також початкову стадію зернистої дистрофії епітелію ниркових канальців та розвиток гідропічної дистрофії печінки. Результатами дослідження доведено, що мікродози пести-цидів, навіть ті, які не перевищують ГДК, в умовах хронічного потрапляння до щоденного раціону, пригнічують життєво важливі функції організму. Хронічне потрапляння декількох видів пестицидів одночасно до раціону посилює їх негативний вплив на організм тварин.Исследовано влияние микродоз хлорорганических пестицидов (γ–ГХЦГ и ДДТ) в растворе меда, при условии их хронического поступления на организм белых мышей, как отдельно, как и в сочетании. Первая опытная группа получала раствор меда с содержанием ГХЦГ (γ–изомера) с концентрацией 3,0 мкг/кг; вторая опытная группа получала раствор меда с содержанием ДДТ с концентрацией 3,0 мкг/кг; третья опытная группа получала раствор меда с содержанием ГХЦГ (γ–изомера) и ДДТ в общей концентрации 6,0 мкг/кг (3,0 мкг/кг каждого пестицида). Установлено деструктивное влияние этих пестицидов на макро и микроструктуру паренхиматозных органов подопытных животных. В результате вскрытия подопытных мышей установлено, что наиболее выразительными патологоанатомическими и гистологическими изменениями характеризовалась третья группа грызунов (которые получали во время опыта ДДТ и γ–ГХЦГ в концентра-ции 6,0 мкг/кг). Гистологическое исследование выявило общий гемосидероз паренхиматозных органов всех исследовательс-ких групп животных, а также начальную стадию зернистой дистрофии эпителия почечных канальцев и развитие гидро-пической дистрофии печени. Результатами исследования доказано, что микродозы пестицидов, даже те, которые не превышают ПДК, в условиях хронического попадания в ежедневный рацион, подавляют жизненно важные функции органи-зма. Хроническое поступление нескольких видов пестицидов одновременно в рацион усиливает их негативное влияние на организм животных.The aim of study was to investigate the combined effects of pesticides HCH (γ–isomer) and DDT on the body of white mice under conditions of daily intake in the diet along with a solution of honey. Pesticides for animals given a 2% solution of honey and water. It was formed four groups, one control and three research, which was given daily 2% solution of honey with the addition of pesticides. The control group received a solution of honey without pesticides. The first treatment group received a solution of honey containing HCH (γ–isomer) with a concentration of 3.0 mg / kg; second experimental group received a solution of honey containing DDT concentration of 3.0 mg / kg; third treatment group received a solution of honey combined with content HCH (γ–isomer) and the total DDT concentrations of 6.0 mg / kg (3.0 mg / kg of each pesticide). The control and experimental group of animals received normal diet. Each group formed of ten mice of both sexes, aged 5–6 weeks. The experiment was carried out for 90 days. On the 90 th day the animals were slaughtered for pathological studies. As a result of studies found that chronic organochlorine pesticides getting to the daily diet of animals has a destructive impact on their internal organs compared to controls. Analyzing the data section of experimental mice, we concluded that the most pronounced pathological changes characterized by a third group of rodents (treated during the experiment DDT and γ–HCH concentration of 6.0 mg / kg). Namely, liver enlargement, changing its color to gray. Reduced density of the parenchyma. These changes are characteristic of protein malnutrition (granular and hyaline drip distrofiya) and the initial stages of lipophanerosis. In carrying out histological study found significant accumulation of hemosiderin in the parenchymal and interstitial tissue of the lungs, liver and spleen. These changes were common to all research groups treated with pesticides in the diet. In the liver of some animals we found the initial stage of granular and lipophanerosis. In the kidneys decrease was observed capsules Shymlanskу–Bowman (in some cases, its extinction) and the development of granular dystrophy. Lung and spleen did not suffer microscopic changes except hemosiderosis. Heart in animals as the control and experimental groups were without pathological changes. Considering we found pathological and histological changes, we can conclude that small doses of pesticides, even those that do not exceed the MPC, in terms of falling into chronic daily diet have a detrimental effect to the body of animals. This makes the feasibility of a more thorough veterinary control of animal products and vegetable content of organochlorine pesticides

Heavy Quark Mass Effects in Deep Inelastic Scattering and Global QCD Analysis

A new implementation of the general PQCD formalism of Collins, including heavy quark mass effects, is described. Important features that contribute to the accuracy and efficiency of the calculation of both neutral current (NC) and charged current (CC) processess are explicitly discussed. This new implementation is applied to the global analysis of the full HERA I data sets on NC and CC cross sections, with correlated systematic errors, in conjunction with the usual fixed-target and hadron collider data sets. By using a variety of parametrizations to explore the parton parameter space, robust new parton distribution function (PDF) sets (CTEQ6.5) are obtained. The new quark distributions are consistently higher in the region x ~ 10^{-3} than previous ones, with important implications on hadron collider phenomenology, especially at the LHC. The uncertainties of the parton distributions are reassessed and are compared to the previous ones. A new set of CTEQ6.5 eigenvector PDFs that encapsulates these uncertainties is also presented.Comment: 32 pages, 12 figures; updated, Publication Versio

Determination of the longitudinal structure function FLF_{L} at HERA

Recent results from the HERA experiment H1 on the longitudinal stucture function $F_{L}$ of the proton are presented. They include proton structure function analyses with particular emphasis on those kinematic regions which are sensitive to $F_{L}$. All results can be consistently described within the framework of perturbative QCD.Comment: 16 pages, 11 figures (requires iopart, iopams and epsfig); Talk presented in the Intern. Workshop on New Trends in HERA Physics 2001, 17-22 June 2001, Ringberg Castle, Tegernsee, Germany; To appear in the Proceeding

Fractal Inspired Models of Quark and Gluon Distributions and Longitudinal Structure Function FL(x, Q2) at small x

In recent years, Fractal Inspired Models of quark and gluon densities at small x have been proposed. In this paper, we investigate longitudinal structure function F-L (x, Q2) within this approach. We make predictions using the QCD based approximate relation between the longitudinal structure function and the gluon density. As the Altarelli-Martinelli equation for the longitudinal structure function cannot be applied to Model I due to the presence of a singularity in the Bjorken x-space we consider Model II only. The qualitative feature of the prediction of Model II is found to be compatible with the QCD expectation.Comment: 11 pages, 4 figures, Accepted for publication on 10-07-2010 in Indian Journal of Physic

Small x behavior of the slope dlnF_2/dln(1/x) in the framework of perturbative QCD

Using an analytical parameterization for the behavior of the x slope of the structure function F_2 at small x in perturbative QCD, at the leading twist approximation of the Wilson operator product expansion, and applying a flat initial condition in the DGLAP evolution equations, we found very good agreement with new precise deep inelastic scattering experimental data from HERA.Comment: 13 pages, 3 figures, late