Azimuthal asymmetries in QCD hard scattering: infrared safe but divergent

We consider high-mass systems of two or more particles that are produced by QCD hard scattering in hadronic collisions. We examine the azimuthal correlations between the system and one of its particles. We point out that the perturbative QCD computation of such azimuthal correlations and asymmetries can lead to divergent results at fixed perturbative orders. The fixed-order divergences affect basic (and infrared safe) quantities such as the total cross section at fixed (and arbitrary) values of the azimuthal-correlation angle $\varphi$. Examples of processes with fixed-order divergences are heavy-quark pair production, associated production of vector bosons and jets, dijet and diboson production. A noticeable exception is the production of high-mass lepton pairs through the Drell--Yan mechanism of quark-antiquark annihilation. However, even in the Drell--Yan process, fixed-order divergences arise in the computation of QED radiative corrections. We specify general conditions that produce the divergences by discussing their physical origin in fixed-order computations. We show lowest-order illustrative results for $\cos(n\varphi)$ asymmetries (with $n=1,2,4,6$) in top-quark pair production and associated production of a vector boson and a jet at the LHC. The divergences are removed by a proper all-order resummation procedure of the perturbative contributions. Resummation leads to azimuthal asymmetries that are finite and computable. We present first quantitative results of such a resummed computation for the $\cos(2\varphi)$ asymmetry in top-quark pair production at the LHC.Comment: 43 pages, 5 eps figure

Enzyme activities in brown forest soils after introduction of Bacillus thuringiensis-based bioinsecticides

Much attention in the complex of forest pest control methods nowadays is devoted to the application of biological preparations, especially to bacterial formulations produced on the base of Bacillus thuringiensis (BT) that in addition to their high biological effectiveness against injurious insects are safe for man, homoiоtherms, beneficial insects and fish. As is known only 20-40% of sprayed preparation influences directly on pests while its 60-80% by different ways eventually penetrates into the soil. Taking into account also the fact that usage norm of commercial bacterial preparations makes up to 1-3 kg ha^-1^ and that preparation powder contains 45-100 billion viable spores g^-1^ it becomes evident that as a result of spraying huge quantity of bacterial stimulants introduces into the forest soils. In this connection a goal was set to determine the impact of some separately applied domestic insecticides of BT species (BT кб-1, BT кб-2, BT(SAR)-49, BT(SAR)-54, BT(SAR)-86, BT subsp. thuringiensis) introduced into the brown forest soils after spraying on soil enzymatic activity (invertase, urease) defining its fertility. Studies were conducted in 2010 under laboratory conditions. The results obtained indicate that in soils sprayed and non-sprayed by bioinsecticides the activities of invertase and urease undergo to changes from May to August. Maximal activities in soils were registered in June (25.641mg C~6~H~12~O~6~ g^-1^ for invertase and 12.254 mg NH~3~ g^-1^ for urease) and minimal – in May (20.643 mg C~6~H~12~O~6~ g^-1^ for invertase) and in August (9.297 mg NH~3~ g^-1^ for urease) at the average for all variants. By statistical analysis of study results it has been established that there aren’t any significant differences between indices of enzyme activities in sprayed and non-sprayed by biopesticides soils. Study results have led us to the assumption that tested insecticides don’t influence adversely on enzyme activities of brown forest soils and can be widely used in the field of plant protection

Armenia in Public Perceptions: The Case of Armenian Youth

This article is informed by a trip to Armenia and fieldwork in the capital city of Yerevan. Based on findings and evidence from fifty interviews conducted in Armenia and the diaspora, in conjunction with mobility research analysis, this paper explores the changes Armenian society has undergone since the 1990s and how shifts in world politics reflect on the country's reconnection with its European bonds. The general question is whether the new generation of Armenians identifies itself more closely with Russian or European society. To arrive at an answer, the article elaborates on Armenia's relations with Russia and the European Union, revealing the key factors that influence the orientation of Armenian society in contemporary history. The article, therefore, aims to contribute to understandings of past and present Armenian society, and the factors that affect and determine their cultural identity and foreign policy choice, as well as their sense of belonging

THE GOAL AND ISSUES OF THE FORMAL DESCRIPTION OF ARMENIAN VOCABULARY AND CREATION OF THE ELECTRONIC DATABASE

The article is devoted to the goals and issues of formal description of Armenian word formation. Although recently formal description of the language has become more practical, it should be noted that the full formal description of the Armenian language has not been done yet. The author of the article states that the formal description of the Armenian vocabulary will enable to reveal as the regular structures, as well as the variative forms, deflections, and irregularities with frequency data with their automatic analysis and the possibility of derivation. It has an informative value, it can clarify and explain many problems in Armenian linguistics, and also can give much material for the further researches of Armenian grammar.The article is devoted to the goals and issues of formal description of Armenian word formation. Although recently formal description of the language has become more practical, it should be noted that the full formal description of the Armenian language has not been done yet. The author of the article states that the formal description of the Armenian vocabulary will enable to reveal as the regular structures, as well as the variative forms, deflections, and irregularities with frequency data with their automatic analysis and the possibility of derivation. It has an informative value, it can clarify and explain many problems in Armenian linguistics, and also can give much material for the further researches of Armenian grammar

The genus Crataegus (Rosaceae) in Armenia (an updated review)

The Rosaceae family plays a leading role in the dendroflora of Armenia. The Pyrus, Sorbus, Crataegus, Cotoneaster, Rubus and Rosa genera representing the family are of great importance in Armenia in the formation of various plant coexistences. With its species composition and taxonomic diversity, Crataegus is one of the largest genera in the Rosaceae family. Growing in Armenia in low, medium and high mountain zones, Crataegus has a great role in the formation of dendroflora: they are an important element of a number of forest coexistences, form a sub-forest with other representatives of dendroflora, grow in arid sparse forests, scrub, shoreline areas of mountain rivers. Crataegus is a valuable plant resource. Some species produce tasty and nutritious fruits that are rich in sugars, organic acids, mineral salts and vitamins. Since ancient times, the people of Armenia have used it in food and folk medicine, for example there is a decoction of hawthorn root and bark dyed threads. Currently, Crataegus has great economic importance. Drought-resistant and frost-resistant species are used as grafts for obtaining high-value varieties of apple, pear, and quince, decorative species are suitable for greening cities and settlements, creating living fences. Furniture and carpentry tools are made from its hard and strong natural wood. Due to their hardiness, some species of Crataegus are promising for the creation of arid arboretums in the lower and middle mountain zones of Armenia. In Armenia the genus Crataegus is represented by 23 species belonging to three sections: Crataegus, Pentagynae C. K. Schneid. and Azaroli Loud. Species C. ulotricha Pojark. ex Gladkova, C. razdanica Pojark. ex Sargsyan, C. gabrielianae Pojark. ex Sargsyan, C. susanykleinae Gabrieljan et Sargsyan and C. gregorianii Gabrielian et Sargsyan are endemic to Armenia. An updated key is provided to identify species based on new data. Altitudinal and geographical distribution of species, habitat, flowering and fruiting time are given

Home or away? Pathways to employment for the highly qualified in Armenia after the velvet revolution

In this article, we take a look at transitions to employment in Armenia for the highly qualified, focusing on students and graduates. Theoretically, we acknowledge the importance of insights from prior research, including the idea of the transition-to-work as a journey, with our research questions aimed at highlighting specific challenges facing Armenian youth following spatialized and sedentary transition pathways; moving abroad for work and entering the local labour market respectively. As evidence, we make use of interviews conducted with 51 young Armenians in the months that followed the Velvet Revolution of 2018. Discussion highlights factors that inhibit highly qualified youth from finding jobs at home, including perceptions of corruption in the workplace, difficulties associated with entering foreign labour markets and the salience of recent political events.info:eu-repo/semantics/acceptedVersio

Student and Graduate Mobility in Armenia

Focuses on mobility in a relatively understudied, but nonetheless important region. Recognises the contribution made by the highly qualified to constructing spatialized education and work pathways alongside the role played by institutions. Expands the parameters of existing debate on student and graduate mobility beyond the confines of Europe and intra-European circulation.info:eu-repo/semantics/acceptedVersio