Archived Issues
2023
Ecosystem transformation Volume 6 No 1 (2023)
- Ekaterina V. Koval , Svetlana Yu. Ogorodnikova Treatment of seeds with cyanobacterial biofilm to increase plant resistance to methylphosphonate pollution 3–11 PDF
- Irina K. Evstigneeva , Irina N. Tankovskaya The ecological structure of the macroalgal community in western Crimea 12–24 PDF
- Oksana V. Yusupova , Larisa M. Abramova , Yury P. Gorichev Characteristics of coenopopulations of European feather grass Stipa pennata L. in the South Ural State Nature Reserve 25–38 PDF
- Alexey S. Sazhnev, Nikolay M. Ermakov , Evgeniy N. Kondratyev Beetles (Coleoptera) from the burrows of the great gerbil Rhombomys opimus (Lichtenstein, 1823) (Mammalia: Muridae) in the southern Turkmenistan 39–50 PDF
- Liubov’ V. Malovichko , Nadezhda Ya. Poddubnaya , Dmitry V. Kulakov Ecology and reproductive biology of the European Roller Coracias garrulus L., 1758 in Stavropol Region 51–71 PDF
- Elena V. Ulrich , Anna S. Barkova Use of flocculants for wastewater treatment 168–187 PDF
Ecosystem Transformation Volume 6, NO 2 (2023)
- Dulmazhab Yu. Tsyrenova The microstructure of the root of Euryale ferox Salisb. (Nymphaeaceae) from the Russian Far East 3–8 PDF
- Elena A. Voronina, Anastasia E. Lakhtina, Viktoriya V. Proskurina Monitoring of invasions of family Percidae in the Volga-Caspian fishery basin 9–18 PDF
- Ivan V. Semadeni Spatial distribution and photosynthetic activity of phytoplankton in the Rybinsk Reservoir in the summer period of 2018–2020 19–32 PDF
- Natalya V. Ivanova, Aleksandr V. Lebedev , Maхim P. Shashkov Evaluation of the quality of automatic tree detection using photogrammetric canopy height models and orthomosaic 33–48 PDF
- Inna A. Dubrovina Features of profile distribution and nutrient stocks in drained peat soils 49–63 PDF
- Maria V. Nosova , Valentina P. Seredina , Sergey A. Stovbunik Assessment of soil changes causing contamination with crude oil and mineralized liquids in the Middle Ob region (Western Siberia) 64–73 PDF
- Еlena V. Dubinina , Roman A. Fedorov , Viktoriya V. Petrova , Alexey A. Shabunov In memory of Nelli M. Radchenko (May 28, 1942–October 08, 2012) 74–86 PDF
Ecosystem Transformation Volume 6, No 3 (2023)
- Alla N. Krasnova, Tatyana N. Polshina Morphostructural malformations of graceful cattail Typha laxmannii Lepech. (Typhaceae) in the Don River delta 3–9 PDF
- Stanislav K. Korb The first attempt to study the habitat-related distribution of the owlet moths (Lepidoptera: Noctuoidea) in the mountains of Central Asia using low-power UV-sources 10–21 PDF
- Inga I. Zinicovscaia, Konstantin N. Vergel, Andrey I. Safonov, Nikita S. Yushin, Aleksandra V. Kravtsova, Omari Chaligava Using moss Ceratodon purpureus (Hedw.) Brid for assessing the technogenic pollution (Ni, Zn, Mn, Al, Se, Cs, La, and Sm) of transformed ecotopes of Donbass 22–38 PDF
- Svetlana M. Zhdanova, Mikhail I. Malin Features of under-ice zooplankton in Lake Pleshcheyevo (Yaroslavl Region, Russia) 39–52 PDF
- Elena A. Dzhayani, Elena A. Shashulovskaya Interannual dynamics of the Ural River phytoplankton and different-type stretches of the Iriklinsky reservoir in spring 53–85 PDF
- Darina V. Garina Influence of chronic intake of small doses of mercury on some biochemical parameters of lipid and protein metabolism in goldfish Carassius auratus (L., 1758) 86–104 PDF
- N.I. Ermolaeva Tolerance limits and ecological optima of mass zooplankton species of lakes in the south of Western Siberia* 105–119 PDF
- Marina V. Sirotina , Lyudmila V. Muradova, Anna S. Dyukova, Tatyana L. Sokolova Assessing the environmental status of the Zeya River by the state of aquatic communities at the construction site of the Amur Gas Chemical Complex 120–141 PDF
ECOSYSTEM TRANSFORMATION VOLUME 6, NO 4 (2023)
- Dumnich N. V. , Konovalov A.F. Preface 3-4 PDF
- Konovalov A.F., Borisov M. Ya, Tropin N.Yu., Ugryumova E.V., Ignashev A.A., Neporotovskii S.A., Popeta E.S., Shilova A.E., Dumnich N. V. The current state of fishery in water bodies of the Vologda Oblast and its impact on commercial stocks of aquatic biological resources 5-32 PDF
- Lobunicheva E.V., Makarenkova N.N., Filonenko I.V., Ivicheva K.N., Litvin A.I., Dumnich N. V. Modern state of plankton and benthos of large fishery water bodies in Vologda region 33-63 PDF
- Borisov M. Ya, Konovalov A.F., Dumnich N. V. , Stepanov M.V., Chechulinskaya A.A. Current state and development of aquaculture in Vologda Oblast 64-78 PDF
- Ignashev A.A., Shcherbakova V.D., Borisov M. Ya, Barmintseva A.E., Dumnich N. V. , Mugue N.S. Population-genetic structure of the sterlet Acipenser ruthenus L., 1758 in the Mologa River during its re-acclimatization 79-95 PDF
- Borisov M. Ya, Ivanova E.S., Tropin N.Yu., Shilova A.E., Ugryumova E.V., Bazhenova D.E. Assessing the consumptive safety of fish with different mercury content in its muscles (water bodies of Vologda Oblast as a case study) 96-118 PDF
- Lobunicheva E.V., Makarenkova N.N., Ivicheva K.N., Filonenko I.V., Litvin A.I., Popeta E.S., Dumnich N. V. Assessing the ecological state of a small river in the urbanized area in terms of phytoplankton, zooplankton and zoobenthos characteristics (the Sodema River of Vologda Oblast as a case study) 119-140 PDF
- Kartanovich A.V., Belicheva L.A., Guzhieva A.V. State of Lake Onega fish community under fishery pressure 141-154 PDF
2022
Ecosystem transformation Volume 5 No 1 (2022)
- Lyudmila A. Fedyaeva, Roman A. Fedyaev Zooplankton of macrophyte thickets of different types in kultuk zone of the Volga River Delta in the spring-summer period 3-18 PDF
- Vera V. Gridneva, Basil N. Yakimov Transformation of hemiboreal ornithocenoses in modern forest management 19–26 PDF
- Valeria A. Gashek, Valeriy D. Zakharov Long-term dynamics of avifauna and bird population of Chelyabinsk International Airport Balandino, Russia 27–49 PDF
- Natalia S. Kolesova , Olga M. Balukova The role of photography as a form of visual content in the popularization of the fauna of the Vologda Region 50-58 PDF
- Natalia S. Kolesova , Alexey A. Shabunov Faunistic and ecological features of the order Lagomorpha in the Vologda Region, Russia 59-71 PDF
Ecosystem transformation Volume 5 No 2 (2022)
- Eduard I. Mirnenko Taxonomic diversity of phytoplankton of the Kalmius River and its reservoirs 3–13 PDF
- Olga Yu. Derevenskaya Zooplankton of small shallow lakes after eco-rehabilitation activities 14-25 PDF
- Olga N. Vdovina, Dmitry M. Bezmaternykh, Evgeniya N. Krylova Restoration of macrozoobenthos after dredging on Lake Manzherokskoe (Republic of Altai, Russia) 26-34 PDF
- Alexey S. Sazhnev, Aleksandr V. Artemyev, Aleksandr V. Matyukhin Beetles (Coleoptera) in nests of the European pied flycatcher Ficedula hypoleuca (Pallas, 1764) in the southeast of the Ladoga area (Republic of Karelia) 35–41 PDF
- Yulia V. Zagurskaya Study isssues of invasive species of the genus Solidago 42–54 PDF
Ecosystem transformation Volume 5 No 3 (2022)
- Anna S. Olkova The procedure for selecting bioassays for different types of pollution 3–13 PDF
- Maria A. Galkina, Viktoria N. Zelenkova, Andrey Yu. Kurskoy, Mikhail Yu. Tretyakov, Valeriy K. Tokhtar, Yuliya K. Vinogradova Polymorphism of alien Erigeron canadensis L. (Asteraceae) along the Trans-Siberian Railway 14–20 PDF
- Nadezhda Yu. Terpugova, Maria P. Grushko, Nadezhda N. Fedorova, Viktoria V. Volodina Revisiting the morphofunctional state of the organs of wels catfish (Silurus glanis L.) 21–28 PDF
- Valeria A. Gashek, Valeriy D. Zakharov, Boris V. Krasutskiy Features of the fauna and summer bird population of the Ashinsky natural biological reserve (Chelyabinsk region) 29–44 PDF
- Vyacheslav O. Bizborodov, Victoria D. Petishkina, Vasiliy Yu. Tsygankov Trace element composition of commercial fish of the Amur River Basin: A review 45–54 PDF
Ecosystem transformation Volume 5 No 4 (2022)
- Vladimir V. Chemposov , Nadezhda K. Chirikova Comparative characteristics of the chemical composition of Veronica incana L. (Plantaginaceae) in Yakutia 3-6 PDF
- Ekaterina E. Vorobyeva , Natalya V. Fotina , Lyudmila K. Asyakina , Mariya A. Osintseva , Alexandr Yu. Prosekov Chemical and sanitary assessment of coal spoil heaps in the south of the Kuznetsk Basin 7-20 PDF
- Evgeny A. Belyakov , Svetlana A. Nikolaenko , Valeriy A. Glazunov , Aleksandr G. Lapirov Distribution, ecology and biology of Sparganium hyperboreum (Typhaceae) in Western Siberia 21-33 PDF
- Alexey L. Sirotin , Marina V. Sirotina The structure of zooplankton community in different biotopes of small rivers in the Kologrivsky cluster of the Natural State Reserve “Kologrivsky Forest” 37-47 PDF
- Nikita O. Yablokov , Nadezhda I. Kislitsina Morphoecological characteristics and feeding of wild rainbow trout Oncorhynchus mykiss (Walbaum, 1792) inhabiting the Krasnoyarsk Reservoir 48-56 PDF
- Nickolay V. Sedikhin Individual variability of dewlap and antlers of the European elk Alces alces (L., 1758) on the territory of the Leningrad Province (Russia) according to observations with camera traps mounted nearby artificial salt licks 57-70 PDF
2021
Ecosystem transformation Volume 4 No 1 (2021)
- Aleksandr A. Protasov Paradigm shift in technical hydrobiology: from local impact, to a new techno-ecosystem concept for thermal and nuclear plant water 3–9 PDF
- Alexey V. Kutuzov Search for the waterfalls in Ethiopia using remote sensing data 10–19 PDF
- Sergey F. Komulaynen, Igor A. Baryshev, Alexandra N. Kruglova, Yulia L. Slastina, Alexandr V. Ryzhakov, Kseniya M. Nikerova Response of communities of water organisms to anthropogenic changes in mineralization small steam (White Sea basin, Republic of Karelia, Russia) 20–34 PDF
- Anzhelika A. Malashchuk, Dmitriy A. Philippov Post-pyrogenic dynamics of the vegetation cover of the Barskoe raised bog (Vologda Region, Russia) 35–52. PDF
- Irina Yu. Lychkovskaya To the study of hemipteran assemblages (Insecta: Heteroptera) of aquatic and near-aquatic biotopes of the Meshchera National Park 53–60 PDF
Ecosystem transformation Volume 4 No 2 (2021)
- Alexandr A. Prokin, Dmitry G. Seleznev, Alexander I. Tsvetkov Influence of environmental factors on the interannual variability of macrozoobenthos of the floodplain lakes 3-15 PDF
- Sergey F. Komulaynen, Igor A. Baryshev, Alexandra N. Kruglova, Yulia L. Slastina, Maksim S. Potakhin, Nataliya E. Galakhina, Kseniya M. Nikerova The Lake Pizanets (Republic of Karelia, Russia) – a new site for establishingthe protected area 16-27 PDF
- Elena G. Krylova, Alexander V. Tikhonov, Eduard V. Garin Floristic diversity in the small riverswith different morphology in the zoneaffected by backwater of a lowland reservoir 28-40 PDF
- Artiom M. Ostrovsky First results of the study of obligatorily myrmecophilous aphids (Hemiptera: Sternorrhyncha: Aphididae) of south-eastern Belarus 41-47 PDF
- Nataliya V. Polyakova, Aleksandr V. Kucheryavyy, Ekaterina A. Movchan The European river lamprey Lampetra fluviatilis (L., 1758) (Petromyzontidae) as a component of the Neva Bay bottom coenoses 48-56 PDF
Ecosystem transformation Volume 4 No 3 (2021)
- Lilit G. Stepanyan, Evelina Kh. Ghukasyan Nutrient enrichment and its effect on the phytoplankton community of Hrazdan River in the Yerevan District, Republic of Armenia 3–12 PDF
- Margarita A. Gvozdareva Quantitative indicators and trophic structure of zooplankton in different types of shallow water zone in Meshinsky Bay (Kuibyshev Reservoir) 13–26 PDF
- Mikhail I. Malin, Svetlana M. Zhdanova, Dmitriy B. Kosolapov, Inga P. Malina, Natalya G. Kosolapova, Rimma Z. Sabitova, Alexander V. Krylov Unusual vertical distribution of zooplankton and fish in the pelagic zone of Lake Sevan during summer stratification 27–41 PDF
- Alexandra P. Strelnikova, Nadezhda A. Berezina Diversity of food spectra of vendace in the water bodies of Eurasia 42–56 PDF
- Stanislav K. Korb Butterflies (Lepidoptera: Hesperioidea and Papilionoidea) of the Moldo-Too Range (Inner Tien-Shan): faunistic analysis and vertical distribution 57–67 PDF
- Corrigendum 68 PDF
Ecosystem transformation Volume 4 No 4 (2021)
- Alexey S. Sazhnev, Dmitry V. Vlasov, Aleksander A. Rusinov, Viktor D. Titov Harmonia axyridis (Pallas, 1773) (Coleoptera: Coccinellidae) – expansion to the north: first records of invasion species in Yaroslavl and Novgorod Regions 3-6 PDF
- Ekaterina V. Tkacheva , Maria A. Galkina, Aleksandra V. Stogova Spoil heaps in Safonovo, Smolensk region: changes in vegetation cover 20 years later 7-17 PDF
- Zalimkhan M. Yusupov , Konstantin I. Shorenko Fauna and ecological features of ants (Hymenoptera, Formicidae) in the southeast of the Crimean Peninsula 18-23 PDF
- Marine R. Dallakyan , Vardan L. Asatryan Studying macrozoobenthos community and assessing the ecological status of the Tandzut River for improving hydrobiological monitoring system in Armenia 24-31 PDF
- Stanislav K. Korb Dynamics of gamma diversity and abundance of diurnal butterflies (Lepidoptera, Papilionoformes) in the Nizhny Novgorod Region (Russia) under anthropogenic changes in landscapes over the last hundred years 32-41 PDF
2020
Ecosystem transformation Volume 3 No 1 (2020)
- Elena G. Krylova The effect of heavy metal salt anions on their toxicity to higher aquatic plants 3–10 PDF
- Mariya T. Syarki, Yuliya Yu. Fomina Current state of zooplankton of Lake Munozero (Republic of Karelia, Russia) 11–18 PDF
- Darya I. Lebedeva, Galina A. Yakovleva, Dmitry O. Zaytsev, Bud Mėndsaĭkhan Trematode Metacercariae in the eyes of fish from reservoirs of Mongolia 19–26 PDF
- Elena S. Krivina, Natalia G. Tarasova The taxonomic and ecological-floristic characteristics of the phytoplankton of a technogenic reservoir after the cessation of industrial exploitation by the example of Lake Shlamonakopitelnoe (Samara Region, Russia) 27–39 PDF
- Tatyana N. Novoselova, Anzhelika A. Sylaieva, Yuliya F. Gromova, Tanita I. Menshova, Irina A. Morozovskaya, Aleksandr A. Protasov Technoecosystem of the cooling pond of the South Ukrainian Nuclear Power Plant: group dynamics and transformation 40–54 PDF
Ecosystem transformation Volume 3 No 2 (2020)
- Kristina I. Prokina Heterotrophic flagellates from the saline lakes of the Crimean Peninsula 3-10 PDF
- Artiom M. Ostrovsky On the fauna of false scorpions (Arachnida: Pseudoscorpiones) of south-eastern Belarus 11-21 PDF
- Alexey S. Sazhnev Beetles of the family Heteroceridae (Insecta: Coleoptera) in extreme environments 22-31 PDF
- Olga S. Noskova, Nadezhda E. Kolesova, Sergey A. Baranov Seasonal and interannual dynamics of the bird population of the Nizhny Novgorod International Airport 32-48 PDF
- Maria A. Belova, Alyona A. Zudilova, Dmitry S. Kopylov To shred roughly or to grind? On the methods of sample preparation of the keratinous material for stable hydrogen isotope analysis 49-57 PDF
Ecosystem transformation Volume 3 No 3 (2020)
- Andrei N. Sharov, Alekxei V. Tolstikov Hydrological and biological regimes of lakes of East Antarctica 3-11 PDF
- Elena S. Krivina Analysis of phytoplankton of a small water body in the zone of influence of a large industrial center by the example of the Lake Vos’merka (Samara Region, Russia) 12-33 PDF
- Irina I. Rudneva, Viktor V. Chaban, Miroslava A. Golub, Valentin G. Shayda, Anton V. Shcerba Influence of hydrometeorological factors on the ecological state of the hypersaline lake Saki (Crimea) in 2017–2018 34-47 PDF
- Roza A. Lozhkina, Irina I. Tomilina, Maria V. Gapeeva Long-term dynamics of the water quality in the Rybinsk reservoir according to biotesting 48-61 PDF
- Maria A. Galkina, Yuliya K. Vinogradova Hybridogenic activity of Solidago L. in North-Eastern Europe 62-69 PDF
Ecosystem transformation Volume 3 No 4 (2020)
- Kristina B. Mikhailova, Sergey G. Mikhalap The dynamics of overgrowing of spawning areas of Lake Pskov, using the example of Anokhovo Bay 3-14 PDF
- Evgeny A. Belyakov , Ekaterina G. Sakharova, Alexandra S. Sokolova The current state and dynamics of the flora of several small lakes of the Yaroslavl Region, Russia 15-40 PDF
- Darya S. Kiseleva Phenological phenomena in the life of plants in Zhiguli Nature Reserve in the changing climate (using the example of Laser trilobum and Euphorbia zhiguliensis) 41–50 PDF
- Daria M. Martynova, Yury V. Ivankovich Response of planktonic copepods of the White Sea to the water salinity changes in acute and chronic experiments 51-64 PDF
- Elena Yu. Ivancheva, Victor P. Ivanchev, Irina Yu. Lychkovskaya Dynamics of the fish population of the high floodplain lake of the Oka River basin by the example of the Lake Erus, Ryazan Oblast, Russia 65-73 PDF
- Corridendum to "Influence of hydrometeorological factors on the ecological state of the hypersaline lake Saki (Crimea) in 2017– 2018" 74 PDF
2019
Ecosystem transformation Volume 2 No 1 (2019)
- Alexander V. Krylov, Bud Mėndsaĭkhan, Chananbaatar Ayushsuren, Alexander I. Tsvetkov Zooplankton of the channel zone of reservoirs of the arid zone: effects of level regime and meteorological conditions 3–17 PDF
- Yuri G. Udodenko, Viktor T. Komov, Yuliya S. Gorbunova, Tatyana A. Devyatova Effect of forest fire on mercury content in soddy podburs of typical forest-steppe environments (Voronezh region, Russia) 18–27 PDF
- Kristina B. Mikhailova, Sergey G. Mikhalap Long-term dynamics of the area overgrown by helophytic vegetation in Lake Pskov 28–34 PDF
- Dmitriy M. Palatov, Agniya M. Sokolova Stygobiotic faunal elements in spring assemblages of West Transcaucasia 35–43 PDF
- Victor P. Ivanchev, Dmitriy D. Pavlov, Olesya R. Kutuzova Dynamics of colonial settlements of grey heron (Ardea cinerea L.) and great egret (Ardea alba L.) and stages of great egret expansion on the territory of Ryazan and Yaroslavl regions 44–50 PDF
Ecosystem transformation Volume 2 No 2 (2019)
- Lilit G. Stepanyan, Evelina Kh. Ghukasyan The abundance and seasonal dynamics of phytoplankton community of the middle course part of Hrazdan River in 2018 3–11 PDF
- Maria A. Galkina, Yuliya K. Vinogradova Invasive taxa of the genus Solidago L. in the vicinity of the city of Pskov 12–18 PDF
- Artiom M. Ostrovsky On the fauna of woodlice (Crustacea: Isopoda: Oniscidea) of south-eastern Belarus 19–28 PDF
- Alexey S. Sazhnev, Aleksandr V. Matyukhin Cases of unintentional phoresy of beetles (Insecta: Coleoptera) on birds 29–33 PDF
- Vera A. Gremyachikh, Roza A. Lozhkina, Viktor T. Komov Spatial-temporal variability of mercury content in the river perch Perca fluviatilis Linnaeus, 1758 (Perciformes: Percidae) of the Rybinsk Reservoir at the turn of the XX–XXI centuries 34–44 PDF
Ecosystem transformation Volume 2 No 3 (2019)
- Alexandr A. Prokin, Alexander I. Tsvetkov, Dmitry G. Seleznev, Alexey S. Sazhnev Macroinvertebrates of fluctuating lakes in Mongolia 3–15 PDF
- Irina I. Rudneva, Valentin G. Shayda Bioassay of the estuary waters of the Chernaya River (Bay of Sevastopol, Black Sea) using the brine shrimp Artemia (Crustacea: Brachiopoda) 16–23 PDF
- Evelina Kh. Ghukasyan, Hranush F. Melkonyan, Lilit G. Stepanyan, Norik S. Badalyan The features of narrow-clawed crayfish (Pontastacus leptodactylus Eschscholtz, 1823) population development in Lake Sevan during 1996–2018 24–31 PDF
- Stanislav A. Kutenkov, Dmitriy A. Philippov The structure and dynamics of the vegetation of Gladkoe Mire in the upper reaches of the sinking Uzhla River (Vologda Region) 32–46 PDF
- Natalia S. Shevchenko, Irina V. Chalova The first data on the study of the influence of waste products of semiaquatic birds on planktonic crustaceans and fish (laboratory experiments) 47–51 PDF
- Resolution of the Round Table “State and the rational use of water resources in the Upper Volga” 52–54 PDF
Ecosystem transformation Volume 2 No 4 (2019)
2018
Ecosystem transformation Volume 1 No 1 (2018)
- Alexander V. Krylov Editorial 3-4 PDF
- Alexander V. Krylov, Bud Mėndsaĭkhan, Chananbaatar Ayushsuren, Alexander I. Tsvetkov Zooplankton of the coastal areas of reservoirs of the arid zone: effects of level regime and meteorological conditions 5–23 PDF
- Alexey V. Kutuzov The use of modern and archive remote sensing data for GIS monitoring of riparian ecosystems 24–28 PDF
- Evgeny A. Belyakov , Dmitriy A. Philippov The effect of changes in environmental conditions on the morphology of Sparganium natans L. (Typhaceae) in the taiga zone of European Russia 29–41 PDF
- Vasiliy B. Kolesnikov Faunistic review of oribatid mites (Acari: Oribatida) from Voronezh state nature biosphere reserve 42–48 PDF
- Alexey S. Sazhnev On the position of Heteroceridae (Insecta: Coleoptera) in food webs in riparian communities 49–56 PDF
Ecosystem transformation Volume 1 No 2 (2018)
- Anna V. Cherevichko Zooplankton and trophic status of Peipsi-Pihkva Lake 3–10 PDF
- Ekaterina G. Pryanichnikova, Alexander I. Tsvetkov Main characteristics of the Lake Pleshcheyevo population of Dreissena polymorpha (Bivalvia, Dreissenidae) 11–18 PDF
- Svetlana M. Zhdanova Veliger larvae of Dreissena (Bivalvia, Dreissenidae) in the zooplankton of Lake Pleshcheyevo (Yaroslavl Region, Russia) 19–29 PDF
- Elena Yu. Ivancheva, Victor P. Ivanchev, Irina Yu. Lychkovskaya Results and perspectives of fish population studies in the central lake-river system of the Meschera lowland 30–45 PDF
- Kseniya A. Solovyova, Olga S. Noskova Dynamics of summer bird population in coniferous-deciduous forests of Seryozha River valley at the beginning of 21st century 46–56 PDF