194 research outputs found
Risk Management of IT Projects: The Essence and Features of the Application of the PMBoK and AGILE Approaches
Recently, the relevance of risk management of IT projects has increased significantly, which is associated with their rapid development and a high level of uncertainty in the external environment. The purpose of the study is to determine the features of risk management of IT projects on the basis of modern theory and practice of project management. The paper analyzes the essence of the concept of «IT project», as well as identifies its features, including: non-standard life cycle; mobility and ambiguity of some areas in the IT field; high level of uniqueness of the project; dependence on other IT projects and technologies; low level of project expertise due to the uniqueness of the technologies on which the project is based; high level of project complexity and uncertainty. The essence of the concept of «IT project risk» is also defined, the main types of risks are characterized. The features of using the PMBoK (Project Management Body of Knowledge) methodology in project risk management are analyzed. A characterization of the stages of risk management in IT projects based on the PMBoK approach is provided, including: risk planning; risk identification; qualitative and quantitative risk assessment; planning a risk response strategy; monitoring and control of risks. It is determined that risk management of IT projects using the PMBoK approach has significant shortcomings if used in conditions of a high level of uncertainty and novelty of the project. The article also provides a characterization of flexible risk management of an IT project based on the Agile methodology, which in turn is based on an iterative approach, continuous risk assessment and the development of measures for their adaptation. A comparative characterization of the approaches of PMBoK and Agile to risk management of IT projects is provided: their strengths, weaknesses, and areas of application are identified. It is noted that the choice between PMBoK and Agile approaches should be based on the specific needs of the project and the organizational context. PMBoK will be appropriate for large, long-term projects, as well as in situations where predictability, adherence to the plan are crucial, while Agile is best suited for innovative projects that are implemented in an uncertain or dynamic environment and require flexibility, quick adaptation, and customer focus. A significant number of project managers in the IT field prefer a hybrid approach that combines the strengths of both methodologies
Inventing a herbal tradition: The complex roots of the current popularity of Epilobium angustifolium in Eastern Europe
Ethnopharmacological relevance: Currently various scientific and popular sources provide a wide spectrum of ethnopharmacological information on many plants, yet the sources of that information, as well as the information itself, are often not clear, potentially resulting in the erroneous use of plants among lay people or even in official medicine. Our field studies in seven countries on the Eastern edge of Europe have revealed an unusual increase in the medicinal use of Epilobium angustifolium L., especially in Estonia, where the majority of uses were specifically related to “men's problems”. The aim of the current work is: to understand the recent and sudden increase in the interest in the use of E. angustifolium in Estonia; to evaluate the extent of documented traditional use of E. angustifolium among sources of knowledge considered traditional; to track different sources describing (or attributed as describing) the benefits of E. angustifolium; and to detect direct and indirect influences of the written sources on the currently documented local uses of E. angustifolium on the Eastern edge of Europe. Materials and methods: In this study we used a variety of methods: semi-structured interviews with 599 people in 7 countries, historical data analysis and historical ethnopharmacological source analysis. We researched historical and archival sources, and academic and popular literature published on the medicinal use of E. angustifolium in the regions of our field sites as well as internationally, paying close attention to the literature that might have directly or indirectly contributed to the popularity of E. angustifolium at different times in history. Results: Our results show that the sudden and recent popularity in the medical use of E. angustifolium in Estonia has been caused by local popular authors with academic medical backgrounds, relying simultaneously on “western” and Russian sources. While Russian sources have propagated (partially unpublished) results from the 1930s, “western” sources are scientific insights derived from the popularization of other Epilobium species by Austrian herbalist Maria Treben. The information Treben disseminated could have been originated from a previous peak in popularity of E. angustifolium in USA in the second half of the 19th century, caused in turn by misinterpretation of ancient herbals. The traditional uses of E. angustifolium were related to wounds and skin diseases, fever, pain (headache, sore throat, childbirth), and abdominal-related problems (constipation, stomach ache) and intestinal bleeding. Few more uses were based on the similarity principle. The main theme, however, is the fragmentation of use and its lack of consistency apart from wounds and skin diseases. Conclusions: Historical ethnobotanical investigations could help to avoid creating repeating waves of popularity of plants that have already been tried for certain diseases and later abandoned as not fully effective. There is, of course, a chance that E. angustifolium could also finally be proven to be clinically safe and cost-effective for treating benign prostatic hyperplasia, but this has not yet happened despite recent intensive research. Documented traditional use would suggest investigating the dermatological, intestinal anti-hemorrhagic and pain inhibiting properties of this plant, if any
RESEARCH OF FATTY ACIDS OF THE SPREADING BEDSTRAW (ASPERULA HUMIFUSA (M.B.) BESS.)
Examination of qualitative composition and quantitative content of fatty acids of the spreading bedstraw (Asperula humifusa (M.B.) Bess.) was carried out by the chromato-mass spectrometry method. As a result of the research 16 fatty acids, including 9 saturated (37,45% of all fatty acids) and 7 non-saturated (62,55%) have been revealed. Dominating components are palmitic, linoleic, oleic and linolenic acids
Multiplicity dependence of light (anti-)nuclei production in p–Pb collisions at sNN=5.02 TeV
The measurement of the deuteron and anti-deuteron production in the rapidity range −1 < y < 0 as a function of transverse momentum and event multiplicity in p–Pb collisions at √sNN = 5.02 TeV is presented. (Anti-)deuterons are identified via their specific energy loss dE/dx and via their time-of- flight. Their production in p–Pb collisions is compared to pp and Pb–Pb collisions and is discussed within the context of thermal and coalescence models. The ratio of integrated yields of deuterons to protons (d/p) shows a significant increase as a function of the charged-particle multiplicity of the event starting from values similar to those observed in pp collisions at low multiplicities and approaching those observed in Pb–Pb collisions at high multiplicities. The mean transverse particle momenta are extracted from the deuteron spectra and the values are similar to those obtained for p and particles. Thus, deuteron spectra do not follow mass ordering. This behaviour is in contrast to the trend observed for non-composite particles in p–Pb collisions. In addition, the production of the rare 3He and 3He nuclei has been studied. The spectrum corresponding to all non-single diffractive p-Pb collisions is obtained in the rapidity window −1 < y < 0 and the pT-integrated yield dN/dy is extracted. It is found that the yields of protons, deuterons, and 3He, normalised by the spin degeneracy factor, follow an exponential decrease with mass number
Measurement of electrons from semileptonic heavy-flavour hadron decays at midrapidity in pp and Pb–Pb collisions at √sNN = 5.02 TeV
The differential invariant yield as a function of transverse momentum (pT) of electrons from semileptonic heavy-flavour hadron decays was measured at midrapidity in central (0–10%), semi-central (30–50%) and peripheral (60–80%) lead–lead (Pb–Pb) collisions at √sNN = 5.02 TeV in the pT intervals 0.5–26 GeV/c (0–10% and 30–50%) and 0.5–10 GeV/c (60–80%). The production cross section in proton–proton (pp) collisions at √s = 5.02 TeV was measured as well in 0.5 < pT < 10 GeV/c and it lies close to the upper band of perturbative QCD calculation uncertainties up to pT = 5 GeV/c and close to the mean value for larger pT. The modification of the electron yield with respect to what is expected for an incoherent superposition of nucleon–nucleon collisions is evaluated by measuring the nuclear modification factor RAA. The measurement of the RAA in different centrality classes allows in-medium energy loss of charm and beauty quarks to be investigated. The RAA shows a suppression with respect to unity at intermediate pT, which increases while moving towards more central collisions. Moreover, the measured RAA is sensitive to the modification of the parton distribution functions (PDF) in nuclei, like nuclear shadowing, which causes a suppression of the heavy-quark production at low pT in heavy-ion collisions at LHC
Study of the - interaction with femtoscopy correlations in pp and p-Pb collisions at the LHCC
This work presents new constraints on the existence and the binding energy of a possible - bound state, the H-dibaryon, derived from - femtoscopic measurements by the ALICE collaboration. The results are obtained from a new measurement using the femtoscopy technique in pp collisions at TeV and p-Pb collisions at TeV, combined with previously published results from pp collisions at TeV. The - scattering parameter space, spanned by the inverse scattering length and the effective range , is constrained by comparing the measured - correlation function with calculations obtained within the Lednicky model. The data are compatible with hypernuclei results and lattice computations, both predicting a shallow attractive interaction, and permit to test different theoretical approaches describing the - interaction. The region in the plane which would accommodate a - bound state is substantially restricted compared to previous studies. The binding energy of the possible - bound state is estimated within an effective-range expansion approach and is found to be MeV.This work presents new constraints on the existence and the binding energy of a possible Λ–Λ bound state, the H-dibaryon, derived from Λ–Λ femtoscopic measurements by the ALICE collaboration. The results are obtained from a new measurement using the femtoscopy technique in Image 1 collisions at s=13 TeV and p–Pb collisions at sNN=5.02 TeV, combined with previously published results from Image 1 collisions at s=7 TeV. The Λ–Λ scattering parameter space, spanned by the inverse scattering length f0−1 and the effective range d0 , is constrained by comparing the measured Λ–Λ correlation function with calculations obtained within the Lednický model. The data are compatible with hypernuclei results and lattice computations, both predicting a shallow attractive interaction, and permit to test different theoretical approaches describing the Λ–Λ interaction. The region in the (f0−1,d0) plane which would accommodate a Λ–Λ bound state is substantially restricted compared to previous studies. The binding energy of the possible Λ–Λ bound state is estimated within an effective-range expansion approach and is found to be BΛΛ=3.2−2.4+1.6(stat)−1.0+1.8(syst) MeV.This work presents new constraints on the existence and the binding energy of a possible - bound state, the H-dibaryon, derived from - femtoscopic measurements by the ALICE collaboration. The results are obtained from a new measurement using the femtoscopy technique in pp collisions at TeV and p-Pb collisions at TeV, combined with previously published results from p-Pb collisions at TeV. The - scattering parameter space, spanned by the inverse scattering length and the effective range , is constrained by comparing the measured - correlation function with calculations obtained within the Lednicky model. The data are compatible with hypernuclei results and lattice computations, both predicting a shallow attractive interaction, and permit to test different theoretical approaches describing the - interaction. The region in the plane which would accommodate a - bound state is substantially restricted compared to previous studies. The binding energy of the possible - bound state is estimated within an effective-range expansion approach and is found to be MeV
Global polarization of Λ and Λ hyperons in Pb-Pb collisions at √ s N N = 2.76 and 5.02 TeV
The global polarization of Λ and Λ hyperons is measured for Pb-Pb collisions at √sNN = 2.76 and 5.02 TeV recorded with the ALICE at the Large Hadron Collider (LHC). The results are reported differentially as a function of collision centrality and hyperon’s transverse momentum (pT ) for the range of centrality 5–50%, 0.5 < pT < 5 GeV/c, and rapidity |y| < 0.5. The hyperon global polarization averaged for Pb-Pb collisions at √sNN = 2.76 and 5.02 TeV is found to be consistent with zero, ⟨PH⟩(%)≈0.01±0.06(stat.)±0.03(syst.)
in the collision centrality range 15–50%, where the largest signal is expected. The results are compatible with
expectations based on an extrapolation from measurements at lower collision energies at the Relativistic Heavy
Ion Collider, hydrodynamical model calculations, and empirical estimates based on collision energy dependence
of directed flow, all of which predict the global polarization values at LHC energies of the order of 0.01%
Production of (anti-)3He and (anti-)3H in p–Pb collisions at √sNN = 5.02 TeV
The transverse momentum (pT) differential yields of (anti-)3He and (anti-)3H measured in p-Pb collisions at sNN−−−√ = 5.02 TeV with ALICE at the LHC are presented. The ratios of the pT-integrated yields of (anti-)3He and (anti-)3H to the proton yields are reported, as well as the pT dependence of the coalescence parameters B3 for (anti-)3He and (anti-)3H. For (anti-)3He, the results obtained in four classes of the mean charged-particle multiplicity density are also discussed. These results are compared to predictions from a canonical statistical hadronization model and coalescence approaches. An upper limit on the total yield of 4He¯ is determined
Measurement of dielectron production in central Pb–Pb collisions at √sNN = 2.76 TeV
The first measurement of dielectron (e+e−) production in central (0−10%) Pb-Pb collisions at sNN−−−√ = 2.76 TeV at the LHC is presented. The dielectron invariant-mass spectrum is compared to the expected contributions from hadron decays in the invariant-mass range 0<mee<3.5 GeV/c2. The ratio of data and the cocktail of hadronic contributions without vacuum ρ0 is measured in the invariant-mass range 0.15<mee<0.7 GeV/c2, where an excess of dielectrons is observed in other experiments, and its value is 1.40±0.28 (stat.)±0.08 (syst.)±0.27 (cocktail). The dielectron spectrum measured in the invariant mass range 0<mee<1 GeV/c2 is consistent with the predictions from two theoretical model calculations that include thermal dielectron production from both partonic and hadronic phases with in-medium broadened ρ0 meson. The fraction of direct virtual photons over inclusive virtual photons is extracted for dielectron pairs with invariant mass 0.1<mee<0.3 GeV/c2, and in the transverse-momentum intervals 1<pT,ee<2 GeV/c and 2<pT,ee<4 GeV/c. The measured fraction of virtual direct photons is consistent with the measurement of real direct photons by ALICE and with the expectations from previous dielectron measurements at RHIC within the experimental uncertainties
- …