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1
Yakovenko, V. M. "The influence of deluvial processes on macro- and micromorphology of ravined forest soil." Fundamental and Applied Soil Science 15, no. 3-4 (2014): 74–88. http://dx.doi.org/10.15421/041419.
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The paper presents the results of studying the effect of deluvial processes on the formation of macro- and micromorphological properties of forest soils on the example of ravined biogeocenoses of Dnieper Prysamarya. Ravined forest biogeocenoses have a long history of development associated with the evolution of land cover in Postpleistocene epoch. One of the factors of soil formation in ravines is deluvial process as a natural phenomenon typical for the landscapes of the present steppes. Ravined forest soils in the catena in the upper reaches of the ravine Glyboky have been studied. They are situated on the upland part of the watershed-gulch landscape in 2 km tonorth of the Andreevka village Novomoskovsk district Dnepropetrovsk region. The methods of macromorphological and micromorphological study of genetic profiles of soils have been used. It is established that ravined forest ecosystems are subjected to intensive influence of deluvial processes, whereby, morphogenesis of ravined soil has a complex peculiar character, which results to theformation of specific morphological properties. It is revealed that the source rock for the forest chernozem on the slopes and formeadow-forest soils of the thalweg are loamy humus deluvial deposits, unlike the ordinary chernozem near the ravines formed on loess rocks. Modern deluvial deposits are the materialof surface horizons of chernozems adjacent to ravine territories. Ravines act as storage ofhumus material of steppe chernozem rendered by adjacent areas. The peculiarities of the morphological structure of the profiles of the soils indicate the intensity of involvement of deluvial material in the processes forest chernozem formation. The different effects of slope processes on the structure of the investigated soil catenahave been revealed. Ordinary chernozem near forest edges have signs of erosion of the surface horizons, while the forest soils of slopes and thalweg are characterized by superpower profile. It is found that the profile of the thalweg and forest soils tends to develop, increasing its power in the two lateral directions: down – thanks to the vertical flow of substances (lessivage, intensive movement of soil invertebrates, the development of the root system); up – the deposition of lessivage material. Deluvial processes connected with lessivage ones as theytransport the new mass of finely divided material into the body of forest soil.
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Ramirez-Herranz, Myriam, Rodrigo S. Rios, Renzo Vargas-Rodriguez, Jose-Enrique Novoa-Jerez, and Francisco A. Squeo. "The importance of scale-dependent ravine characteristics on breeding-site selection by the Burrowing Parrot, Cyanoliseus patagonus." PeerJ 5 (April 26, 2017): e3182. http://dx.doi.org/10.7717/peerj.3182.
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In birds, the environmental variables and intrinsic characteristics of the nest have important fitness consequences through its influence on the selection of nesting sites. However, the extent to which these variables interact with variables that operate at the landscape scale, and whether there is a hierarchy among the different scales that influences nest-site selection, is unknown. This interaction could be crucial in burrowing birds, which depend heavily on the availability of suitable nesting locations. One representative of this group is the burrowing parrot, Cyanoliseus patagonus that breeds on specific ravines and forms large breeding colonies. At a particular site, breeding aggregations require the concentration of adequate environmental elements for cavity nesting, which are provided by within ravine characteristics. Therefore, intrinsic ravine characteristics should be more important in determining nest site selection compared to landscape level characteristics. Here, we assess this hypothesis by comparing the importance of ravine characteristics operating at different scales on nest-site selection and their interrelation with reproductive success. We quantified 12 characteristics of 105 ravines in their reproductive habitat. For each ravine we quantified morphological variables, distance to resources and disturbance as well as nest number and egg production in order to compare selected and non-selected ravines and determine the interrelationship among variables in explaining ravine differences. In addition, the number of nests and egg production for each reproductive ravine was related to ravine characteristics to assess their relation to reproductive success. We found significant differences between non-reproductive and reproductive ravines in both intrinsic and extrinsic characteristics. The multidimensional environmental gradient of variation between ravines, however, shows that differences are mainly related to intrinsic morphological characteristics followed by extrinsic variables associated to human disturbance. Likewise, within reproductive ravines, intrinsic characteristics are more strongly related to the number of nests. The probability of producing eggs, however, was related only to distance to roads and human settlements. Patterns suggest that C. patagonus mainly selects nesting sites based on intrinsic morphological characteristics of ravines. Scale differences in the importance of ravine characteristics could be a consequence of the particular orography of the breeding habitat. The arrangement of resources is associated to the location of the gullies rather than to individual ravines, determining the spatial availability and disposition of resources and disturbances. Thus, nest selection is influenced by intrinsic characteristics that maximize the fitness of individuals. Scaling in nest-selection is discussed under an optimality approach that partitions patch selection based on foraging theory.
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Sayan, Erdinç. "A MORE DEVASTATING VERSION OF THE RAVEN PARADOX." Think 19, no. 54 (2019): 21–24. http://dx.doi.org/10.1017/s1477175619000356.
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Hempel's famous Raven Paradox derives from Nicod's criteria for confirmation and the Equivalence Condition, the unintuitive conclusion that things like white roses, green T-shirts and ice cubes confirm the raven hypothesis ‘All ravens are black.’ By a small rearrangement of the Equivalence Condition, I show that we can also derive the conclusion, which sounds even more intuitively intolerable, that observation of black ravens fails to confirm the raven hypothesis. We are left with the contradictory result that black ravens both confirm and do not confirm the raven hypothesis.
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Sabirzyanov, Almaz, Mikhail Panasyuk, Nikolai Trofimov, and Svetlana Sochneva. "GIS-technology and data of earth remote sensing to identify and predict ravine erosion development." BIO Web of Conferences 27 (2020): 00113. http://dx.doi.org/10.1051/bioconf/20202700113.
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This article discusses the study of the process of ravine erosion using geoinformation technologies and Earth remote sensing data. Ravine erosion, which develops on the territory of the Verkhneuslonsky municipal region of the Republic of Tatarstan, is considered as a multifactorial process. The possibility of using freely available data to study the factors affecting ravine erosion is evaluated. It is shown that in modern conditions of increased anthropogenic environmental impact, especially in areas heavily divided by ravines, the use of GIS technology is sufficient in order to monitor and quickly respond to negative erosion processes occurring on agricultural lands.
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Škiljan, Dubravko. "Predsokratiki in jezik." Keria: Studia Latina et Graeca 2, no. 2 (2000): 73. http://dx.doi.org/10.4312/keria.2.2.73-96.
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Pri predsokratskih filozofih je moč sledi zanimanja za jezikoslovje opazovati na štirih ravneh: raven jezikovne rabe, raven eksplicitnih opažanj o jeziku, raven jezikoslovnih teorij in nuce in raven epistemoloških konstrukcij.
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Zawadzka, Dorota, and Grzegorz Zawadzki. "Synanthropisation And Synurbisation Of Raven Corvus Corax In Poland: A Review." International Studies on Sparrows 38, no. 1 (2014): 11–16. http://dx.doi.org/10.1515/isspar-2015-0025.
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Abstract The Raven Corvus corax is one of the oldest synanthropic bird species. Historical development of human settlements and cities was the reason of occupancy by ravens neighborhood of villages and town. Nowadays, suburban areas are, among forest and rural areas, habitats used by Ravens. Since end of middle ages Ravens began breeding in interior of towns in the Great Britain. During 20th century Raven occupied several big cities of Europe and North America. In Poland, the first attempts of colonization of cities took place in the 1950s in Warsaw and Kraków. During next decades Raven came back from centrum of cities and began colonized suburban zone, mainly big forests within the border of towns. Untilnow, Raven in Poland nest only in suburban zones. Observations of non-breeding pairs inside of cities are still rare. The biggest population in cities do not exceed 20 breeding pairs.
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Howe, Kristy B., and Peter S. Coates. "Observations of Territorial Breeding Common Ravens Caching Eggs of Greater Sage-Grouse." Journal of Fish and Wildlife Management 6, no. 1 (2015): 187–90. http://dx.doi.org/10.3996/042014-jfwm-030.
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AbstractPrevious investigations using continuous video monitoring of greater sage-grouse Centrocercus urophasianus nests have unambiguously identified common ravens Corvus corax as an important egg predator within the western United States. The quantity of greater sage-grouse eggs an individual common raven consumes during the nesting period and the extent to which common ravens actively hunt greater sage-grouse nests are largely unknown. However, some evidence suggests that territorial breeding common ravens, rather than nonbreeding transients, are most likely responsible for nest depredations. We describe greater sage-grouse egg depredation observations obtained opportunistically from three common raven nests located in Idaho and Nevada where depredated greater sage-grouse eggs were found at or in the immediate vicinity of the nest site, including the caching of eggs in nearby rock crevices. We opportunistically monitored these nests by counting and removing depredated eggs and shell fragments from the nest sites during each visit to determine the extent to which the common raven pairs preyed on greater sage-grouse eggs. To our knowledge, our observations represent the first evidence that breeding, territorial pairs of common ravens cache greater sage-grouse eggs and are capable of depredating multiple greater sage-grouse nests.
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Zmiievska, Kristina, and Artur Zmiievskyi. "Study of the ravine-gully system of the city of Dnipro with the aim of returning them territories to the urban infrastructure." E3S Web of Conferences 109 (2019): 00129. http://dx.doi.org/10.1051/e3sconf/201910900129.
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The article provides an analysis of the state of individual fragments of a ravine-gully system in the right-bank part of the city of Dnepr and its impact on the urban infrastructure. Examples of the successful use and construction of ravines with buildings and structures are considered. According to the results of the survey by the method of the natural impulse electromagnetic field of the Earth, a map-scheme of the flux density of the natural impulse electromagnetic field of the Earth was constructed in the area adjacent to the Monument of Glory, showing the presence of a previously covered ravine. The deformation processes that are observed on the eastern side of the Monastyrska gully are analyzed. Methods for strengthening landslide-prone slopes are considered.
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Pani, Padmini. "Ravine Erosion and Livelihoods in Semi-arid India: Implications for Socioeconomic Development." Journal of Asian and African Studies 53, no. 3 (2017): 437–54. http://dx.doi.org/10.1177/0021909616689798.
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The ravines found along the Chambal River are among the most severe types of gully erosion found in semi-arid India. This paper estimates the extent and areal expansion of ravines over 40 years in the Lower Chambal Valley and provides a classification scheme to understand ravine characteristics in the region. To examine the implications of ravines on socioeconomic development and livelihoods of the people in the area, a mixed method approach has been followed. A combination of spatial and statistical tests has been run to examine the overall status of land degradation and its impact in the area concerned. Village-level socioeconomic data have been integrated with physical and environmental parameters in a GIS environment, which has been supplemented with findings from a qualitative survey in a few villages of the study region. The results show that there is a positive and significant relationship between indices of natural resources availability and socioeconomic development. A majority of villages within ravines were found to be very poor in development. In this fragile environment, people’s livelihoods are being adversely affected because of land degradation.
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Vancatova, M. A., and T. Klima. "The spontaneous tool use by raven in a zoo." Experimental Psychology (Russia) 12, no. 3 (2019): 135–41. http://dx.doi.org/10.17759/exppsy.2019120310.
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Ravens are known for their ability to use tools, both in captivity and in natural conditions. This activity is connected mainly to nourishment-related or aggressive behaviour. At Košice Zoo, we carried out an observation of raven tool use behaviour, with the observation focused on contact with a human, that can be interpreted as social behaviour within the context of interspecies communication. In all observed cases (54) of raven tool use, this type of behaviour only manifested itself in an adult male. The raven was inclined to mostly choose longer tools for an attack. In roughly the same measure, the raven uses a new tool, or uses the same tool repeatedly. Concerning the working of the tool, a tool that has not been worked on predominates significantly in this case. In the case of working the tool, the male raven nibbles or shortens the sticks with his beak. A human in and of himself does not represent danger to ravens in a zoo, because the birds are in daily contact with zookeepers. In the given situation, it seems that male raven was aiming to establish contact with a visitor. The entire situation is more reminiscent of a game, rather than the protection of the nest. The whole situation of using the tool was spontaneous and in no case was prepared in advance or otherwise induced experimentally.
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Segura, Amalia, and Pelayo Acevedo. "Influence of Habitat and Food Resource Availability on Common Raven Nest Site Selection and Reproductive Success in Mediterranean Forests." Birds 2, no. 3 (2021): 302–13. http://dx.doi.org/10.3390/birds2030022.
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Bird nest selection in forests can be influenced by the composition of key structural elements and resources. This has important consequences in terms of species population dynamics since it can determine reproduction success. Here, we assessed Common raven nest-site selection and reproductive success, and how these might be determined by foraging behavior and habitat structure. A previously documented breeding raven population that exerts high predation pressure on young Spur-thighed tortoises (Testudo graeca) in a Mediterranean forest was monitored. Generalized linear mixed models were performed to determine the singularities of the trees with nests and the drivers of reproductive success of breeding pairs of ravens. The results showed a high density of breeding pairs in the study area (0.8 pairs/km2), which selected taller trees in areas with higher bare ground cover and a high density of tortoises for nesting. Nests were spatially aggregated; breeding pairs occupied smaller territories and intraspecific competition seemed relaxed, reflecting the abundance of food resources. Most breeding pairs occasionally predated on young tortoises. Tortoises seem to play a part in raven reproductive success in our study area, which might be associated with the availability/catchability of young tortoises. The study illustrates that Spur-thighed tortoise distribution and abundance plays a role in the breeding behavior of ravens and is mediated by habitat structure. Understanding the drivers of nest-site selection and the breeding behavior of ravens is pivotal to implementing appropriate habitat management and conservation strategies across their distribution range, particularly in areas where ravens potentially affect threatened species.
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Харченко, Nikolay Kharchenko, Харченко, Nikolay Kharchenko, Ахтырцев, and Anatoliy Akhtyrtsev. "Reclamation role of oak forests of Central forest steppe." Forestry Engineering Journal 4, no. 1 (2014): 40–47. http://dx.doi.org/10.12737/3344.
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Arena and ravine oak forests make up a single, suitable for each stage of development of forest steppe spatial structure of forests. According to the domestic foresters role of oak forests in the forest is much more important than their productivity. Forest cover of the region must correspond to its network of gullies and ravines. Current state of gullies and gully systems, direction climatic changes indicate the formation of favorable conditions for their natural overgrowth with trees and shrubs, which leads to stabilization of forest-steppe landscapes.
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Sze, Arthur. "Ravine." Massachusetts Review 59, no. 4 (2018): 643. http://dx.doi.org/10.1353/mar.2018.0098.
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Lill, Alan, and Emma Hales. "Behavioural and Ecological Keys to Urban Colonization by Little Ravens ()." Open Ornithology Journal 8, no. 1 (2015): 22–31. http://dx.doi.org/10.2174/1874453201508010022.
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Avian urban colonization is thought to be facilitated by a capacity for innovative feeding, ecological generalism and social foraging. However, the relative importance in exploiting urban resources and avoiding urban predators of being inherently ‘pre-adapted’ to the urban environment or adjusting to it through phenotypic plasticity requires more examination. These issues were explored in a native ‘urban adapter’, the Little raven Corvus mellori, by comparing its foraging ecology, group size and nest site use in Melbourne, Australia, and the surrounding exurban environment. Urban individuals manipulated human food waste and gleaned from sealed surfaces more than exurban conspecifics (suggesting behavioural flexibility), but foraging behaviour and substrate use were broadly similar in both environments (suggesting ‘preadaptation’). Little ravens foraged close to conspecifics and heterospecifics more frequently in the urban than the exurban environment, but some potential dietary competitors rarely foraged near urban Little ravens, possibly indicating some niche partitioning. Mean urban rate of agonistic interaction with other bird species was low (0.023 interactions per foraging raven observed). Although displacement of a raven >10 m occurred in 61-70% of such interactions, the displaced individual usually rapidly resumed foraging nearby. Thus aggressive, interspecific interference competition for food appeared limited. Large groups of Little ravens were twice as common in the exurban as the urban environment, which was inconsistent with the hypothesis that social foraging facilitated urban colonization. Nest tree type (predominantly eucalypts), size and isolation were similar in urban and exurban environments, but urban nests were significantly more concealed. We suggest that ‘preadaptation’, behavioural innovation and a relative lack of significant, interspecific food competition have contributed to urban colonization by Little ravens.
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Restani, Marco, John M. Marzluff, and Richard E. Yates. "Effects of Anthropogenic Food Sources on Movements, Survivorship, and Sociality of Common Ravens in the Arctic." Condor 103, no. 2 (2001): 399–404. http://dx.doi.org/10.1093/condor/103.2.399.
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Abstract We investigated survivorship, movements, and sociality of Common Ravens (Corvus corax) exploiting concentrated food resources at a landfill in Greenland. From 1992–1995 we banded 383 ravens: 365 were captured at the landfill and 18 were banded in nearby nests. Thirty-nine ravens were recovered, most by shooting (87%). Mean number of days survived post-banding (494 ± 97) did not differ among age groups, but a higher proportion of juveniles was recovered. Ravens migrated west and south to the coast during winter. No difference existed among age groups in mean distance between locations of banding and recovery (151 ± 31 km). Number of ravens congregating at the landfill declined during the study, coinciding with a decrease in the local human population. Harsh winter climate, limited ice-free land, and abundant human refuse influenced raven use of the wilderness landscape by facilitating the formation of large, nomadic foraging groups.
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E.A., Gurbanov, Verdiev S.B., and Gazieva P.CH. "The intensity of gully erosion on the tertiary plateau under arid conditions of the Republic of Azerbaijan." Ekologiya i stroitelstvo 4 (2017): 8–15. http://dx.doi.org/10.35688/2413-8452-2017-04-002.
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Found that gully erosion covers the entire area of the study land. On 68.3% of the area the dissection is 2.0...7.0 km/km2 and density of gullies in some places reaches up to 15.5 pieces/km2. The average annual growth of ravines in length is 0,34...7.48 m, a maximum width is 0.20...2.48 m, depth – 0,10...Of 1.16 m. The intensity of development of gullies is influenced by their catchment area. Of the 79 gully systems that have a small catchment area from 0.02 to 0.47 km2, only 4 has the degree of dissection is less than 1.0 km/km2 and in 36 gully systems – 5.0...7.5 km/km2, a 12-year – from 7.5 to 10.0 km/km2, 4 ravines – from 10.0 to 15.0, and the one ravine system has more than 15 km/km2. The degree of dismemberment of individual gully systems is dependent on their catchment area, which is associated with the conditions of their stay.
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Whisson, Desley A., Michael A. Weston, and Kelly Shannon. "Home range, habitat use and movements by the little raven (Corvus mellori) in a coastal peri-urban landscape." Wildlife Research 42, no. 6 (2015): 500. http://dx.doi.org/10.1071/wr15039.
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Context In peri-urban environments, high availability of anthropogenic resources may result in relatively high abundances of some species, with potentially negative implications for other native biota. Effective management of such impacts requires understanding of the spatial ecology of problem species. However, home range and habitat use have not been described for the little raven (Corvus mellori), a superabundant native predator that occurs in urban and natural habitats, including those where threatened shorebirds breed. Aims The aim of this study was to provide basic information on little raven home range, habitat use and movements in a coastal peri-urban landscape. Methods Between October 2011 and January 2012 we radio-tracked 20 little ravens captured in a coastal wetland (near Melbourne, Australia). Key results Little ravens were highly mobile, moving up to 9.9 km in an hour (median = 2 km), and had large ranges: Minimum Convex Polygons were 1664–9989 ha (median = 3362 ha). Although most birds used both anthropogenic and natural habitats, some birds strongly selected for coastal wetland habitat. Birds used multiple roosts during the study period, most of which occurred in grassland (58.7%) or urban (22.3%) areas. Movement of up to 8.3 km (median = 2.2 km) between roosts during the night was also detected. Conclusions Ravens were highly mobile and used large home ranges and a variety of habitats, with habitat preferences varying between birds. Implications Considering the large home ranges and inter-individual variation in habitat preferences of little raven populations, localised management to reduce their impacts on breeding shorebirds is unlikely to be successful.
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Król, Karol, and Józef Hernik. "Crows and Ravens as Indicators of Socioeconomic and Cultural Changes in Urban Areas." Sustainability 12, no. 24 (2020): 10231. http://dx.doi.org/10.3390/su122410231.
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Crows and ravens are deeply symbolic. They have featured in myriads of myths and legends. They have been perceived as ominous, totemic, but also smart and intelligent birds by various peoples around the world. They have heralded bad luck and evoked negative associations. How are they perceived today, in the time of the Internet, mobile devices, and popular culture? Is the young generation familiar with the legends, tales, or beliefs related to these birds? The purpose of this paper was to determine the place of the crow and raven in the consciousness of young generations, referred to as Generation Y and Generation Z. The authors proposed that young people, Generations Y and Z, were not familiar with the symbolism of crows and ravens, attached no weight to them, and failed to appreciate their past cultural roles. The survey involved respondents aged 60 and over as well. Both online surveys and direct, in-depth, structured interviews were employed. It was demonstrated that the crow and raven are ominous birds that herald bad luck and evoke negative associations and feelings in the consciousness of young generations. The perception of crows and ravens by the younger generation stems mostly from popular culture and the appearance and behavior of the birds. The ways in which crows and ravens are represented in popular culture and perceived by the public may directly affect their fate in areas with human presence.
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Gorban, V. A. "Soil natural radioactivity of northern variant ravine biogeocenoses of Ukrainian steppe zone." Питання степового лісознавства та лісової рекультивації земель 49 (October 25, 2020): 58–66. http://dx.doi.org/10.15421/442005.
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Ravine biogeocenoses in the steppe zone of Ukraine are a unique natural phenomenon. Under these natural forests for many millennia formed a specific kind of soil – forest chernozems, which differ in a number of ways from the zonal chernozems. Today in the scientific literature you can find information about such properties of these soils as organic matter, structural and aggregate composition, lessivage, micromorphological features. However, the natural radioactivity of forest chernozems remains virtually unexplored. Our work is devoted to the establishment of the peculiarities of the natural radioactivity of the soils of ravine biogeocenoses. The soils of the Hlyboky ravine, which according to the classification of O.L. Belgard belongs to the northern version of the ravines of the steppe zone of Ukraine. As a result of the performed researches it is established that the surface horizons of chernozems of forest southern and northern exposures of the ravine differ in reduced values of ashing coefficient, which indicates an increased content of organic matter in them compared to other horizons of the studied soils. Eluvial horizons are characterized by reduced values of natural radioactivity compared to illuvial, which indicates increased sorption by small particle size fractions of radioactive elements compared to larger fractions. The maximum values of natural radioactivity were found in the lower genetic horizons of the studied soils. This indicates that the source of radioactive elements is the parent rock from which the soil was formed. Organic substances and their ability to bind radioactive elements are characterized by a smaller contribution to the natural radioactivity of soils compared to small particle size fractions and parent rock. The distribution of natural radioactivity values by soil profile is determined by the peculiarities of soil genesis of each individual soil type and to some extent can reflect them.
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Ciach, Michał, Dominik Wikar, and Małgorzata Bylicka. "Density and Flock Size of the Raven (Corvus corax) In the Orawa - Nowy Targ Basin During Non-Breeding Season." Ring 28, no. 2 (2006): 119–25. http://dx.doi.org/10.2478/v10050-008-0033-y.
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Density and Flock Size of the Raven (Corvus corax) In the Orawa - Nowy Targ Basin During Non-Breeding Season During the 2002/2003-2004/2005 non-breeding seasons the density of the Raven in the open habitats of the Orawa - Nowy Targ Basin was studied by line transect method. The results were analysed in four periods (autumn, early winter, winter and early spring). The median density of Ravens did not differ significantly between individual periods and was respectively: 3.5, 3.8, 4.8 and 3.8 indiv. / 10 km. Number of birds during particular controls varied from 1.0 to 24.8 indiv. / 10 km. However, while excluding flocks, the median density of single individuals and pairs of the Raven was considerably lower and in subsequent periods reached respectively: 2.2, 2.4, 2.2 and 1.7 indiv. / 10 km. Flock size did not differ significantly between individual periods. Single individuals and, less often, groups of two birds were recorded mostly. Small (3-5 indiv.) and medium (6-15 indiv.) flocks were recorded rarely and large flocks (16 indiv. and above) - only exceptionally. The high density and strong fluctuations of abundance of Ravens were determined by flocks presence, which was probably linked to irregular occurrence of food resources.
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Gėgžnienė, D. "RAVENO PROGRESYVINIŲ MATRICŲ METODIKOS TAIKYMAS ABITURIENTŲ MĄSTYMO SUGEBĖJIMAMS TIRTI." Psichologija 4 (December 23, 2015): 29–40. http://dx.doi.org/10.15388/psichol.1983.4.9136.
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Šiame straipsnyje apžvelgiami Lietuvos TSR abiturientų intelektualiniai gebėjimai, naudojant Raveno metodiką ir sudarant standartines normas. Buvo ištirti 576 17-20 metų amžiaus abiturientai ir skirtingų Lietuvos miestų ir rajonų centrų ir kaimų. Gautos normos ir kiti rezultatai buvo palyginti su gautaisiais J. C. Raven, A. Toim ir A. Lunge.
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Hernández-Ojeda, María. "The Ravine." Review: Literature and Arts of the Americas 43, no. 2 (2010): 266–67. http://dx.doi.org/10.1080/08905762.2010.514417.
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Klochenko, P. D., Z. N. Gorbunova, T. F. Shevchenko, and T. V. Vitovetska. "INORGANIC AND ORGANIC SUBSTANCES IN WATER BODIES OF THE “OLEKSANDRIYA” DENDROLOGICAL PARK (THE TOWN OF BILA TSERKVA)." Hydrology, hydrochemistry and hydroecology, no. 1 (56) (2020): 48–55. http://dx.doi.org/10.17721/2306-5680.2020.1.5.
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The content of inorganic nitrogen and phosphorus compounds, chloride, organic matter, and dissolved oxygen was studied in 11 ponds of the “Oleksandriya” Dendrological Park. Samples were taken in summer 2016–2018 in the cascade of ponds located in the Western, Middle, and Eastern ravines of the park. The obtained data suggest that the studied ponds are significantly polluted by inorganic and organic substances, the amount of which remains still very high. The ponds of the Western ravine are characterized by the highest content of inorganic nitrogen compounds and chloride.Thus, in particular, the concentration of ammonium in the Poterchata pond accounted for 103.00–160.00 mg N/L, in the Rusalka pond – 64.00–89.50 mg N/L, in the Vodyanyk pond – 28.00–43.00 mg N/L, whereas in the Skelny pond – 12.00–38.50 mg N/L. The concentration of nitrite in the studied ponds accounted for respectively 1.130–2.213 mg N/L, 1.538–1.950 mg N/L, 0.988–1.388 mg N/L, and 0.730–1.288 mg N/L. The concentration of nitrate was also rather high. Thus, in the Poterchata pond it was 52.00–81.25 mg N/L, in the Rusalka pond – 48.00–73.75 mg N/L, in the Vodyayk pond – 21.50–38.75 mg N/L, whereas in the Skelny pond – 14.50–27.50 mg N/L. The concentration of chloride in the studied ponds accounted for respectively 690.9–795.7 mg/L, 553.8–580.5 mg/L, 283.5–308.4 mg/L, and 274.5–287.1 mg/L. The highest concentration of inorganic phosphorus (0.470 mg/L) was observed in one of the ponds of the Middle ravine. The highest values of dichromate oxidizablity (97.0 and 81.0 mg O/L) were registered in the first two ponds of the Western ravine, which is indicative of their essential contamination by organic matter. The lowest concentration of the dissolved oxygen (3.8 mg/L) was observed in the ponds of the Middle ravine. The complex of measurements aimed at the improvement of the state of the ponds of the “Oleksandriya” Dendrological Park should be elaborated and realized. In particular, it is essential to reveal the main source of the pollution of the ponds of the Western ravine by inorganic nitrogen compounds and chloride, and also to keep them clear of pollutants.
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Kelly, John P., Katherine L. Etienne, and Jennifer E. Roth. "Factors Influencing the Nest Predatory Behaviors of Common Ravens in Heronries." Condor 107, no. 2 (2005): 402–15. http://dx.doi.org/10.1093/condor/107.2.402.
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AbstractAn investigation of nest predation and associated foraging behaviors by resident Common Ravens (Corvus corax) indicated that occupation of heronries, predation of Great Egret (Ardea alba) nests, duration of patrol flights, landing rates, and number of interactions with ardeids varied with the productivity of resident ravens. Annual increases in raven predatory behaviors were consistent with increases in foraging experience for a few to several years after ravens became resident at colony sites. However, overall nest predation did not increase at three sites from 1999–2004, and at one of these sites, predation did not differ from levels measured before ravens were resident, suggesting that ravens may have interfered with the nest predatory activities of other species. Ravens at one colony site obtained most or all of their energy needs from the heronry. Predation of Great Egret nestlings was most likely 14–29 days after first hatch, when parental attendance begins to decline. Regional monitoring of heronries in the San Francisco Bay area, California, indicated highly variable rates of nest predation by Common Ravens and a low overall presence of ravens, even though ravens occurred throughout the region. Implications for conservation include the potential value of manipulating raven reproduction to limit nest predation, exclusion of other nest predators by resident ravens, annual increases in nest predatory behaviors, and the importance of regional monitoring to substantiate concerns about raven predation.Factores que Influencian las Conductas de Corvus corax como Depredadores de Nidos en Colonias de GarzasResumen. Una investigación de la depredación de nidos y de las conductas asociadas de cuervos de la especie Corvus corax indicaron que la ocupación de colonias de garzas, la depredación de los nidos de Ardea alba, la duración de los vuelos de patrullaje, las tasas de aterrizaje y el número de interacciones con ardeidos varió con la productividad de los cuervos residentes. Los incrementos anuales de las conductas depredadoras de los cuervos fueron consistentes con los aumentos en la experiencia de forrajeo de unos pocos a varios años, a partir de que los cuervos se incorporaron como residentes en las colonias. Sin embargo, la depredación global de nidos no incrementó en los tres sitios entre 1999 y 2004, y en uno de los sitios la depredación no varió con relación a los niveles medidos antes de que los cuervos fueran residentes, lo que sugiere que los cuervos pueden haber interferido con las actividades de depredación de nidos de otras especies. Los cuervos de una colonia obtuvieron la mayoría o todas sus necesidades energéticas de las colonias de garzas. La depredación de los pichones fue más probable entre los 14 y los 29 días luego de la primera eclosión, cuando la asistencia de los padres comienza a disminuir. El monitoreo regional de las garzas en el área de la bahía de San Francisco, California, indicó la existencia de tasas de depredación de nidos por parte de C. corax altamente variables y una presencia general baja de cuervos, aunque estas aves estuvieron presentes en toda la región. Las implicancias para la conservación incluyen el valor potencial de manipular la reproducción de C. corax para limitar la depredación de nidos, la exclusión de otros depredadores de nidos por parte de cuervos residentes, incrementos anuales en comportamientos de depredación de nidos y la importancia del monitoreo regional para verificar las preocupaciones sobre la depredación de nidos.
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Werner, F. A., J. Homeier, M. Oesker, and J. Boy. "Epiphytic biomass of a tropical montane forest varies with topography." Journal of Tropical Ecology 28, no. 1 (2011): 23–31. http://dx.doi.org/10.1017/s0266467411000526.
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Abstract:The spatial heterogeneity of tropical forest epiphytes has rarely been quantified in terms of biomass. In particular, the effect of topographic variation on epiphyte biomass is poorly known, although forests on ridges and ravines can differ drastically in stature and exposure. In an Ecuadorian lower montane forest we quantified epiphytic biomass along two gradients: (1) the twig–branch–trunk trajectory, and (2) the ridge–ravine gradient. Twenty-one trees were sampled in each of three forest types (ridge, slope, ravine positions). Their epiphytic biomass was extrapolated to stand level based on basal area–epiphyte load relationships, with tree basal areas taken from six plots of 400 m2 each per forest type. Our results document the successional addition and partial replacement of lichens by bryophytes, angiosperms and finally dead organic matter along the twig–branch–trunk trajectory. Despite having the highest tree basal area, total epiphytic biomass (mean ± SD) of ravine forest was significantly lower (2.6 ± 0.7 Mg ha−1) than in mid-slope forest (6.3 ± 1.1 Mg ha−1) and ridge forest (4.4 ± 1.6 Mg ha−1), whereas maximum bryophyte water storage capacity was significantly higher. We attribute this pattern to differences in forest dynamics, stand structure and microclimate. Although our study could not differentiate between direct effects of slope position (nutrient availability, mesoclimate) and indirect effects (stand structure and dynamics), it provides evidence that fine-scale topography needs to be taken into account when extrapolating epiphytic biomass and related matter fluxes from stand-level data to the regional scale.
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Werlang, Mauro Kumpfer. "Monitoramento de voçorocas em solos podzóllcos da região de Rondonópolls-MT." Ciência e Natura 22, no. 22 (2000): 177. http://dx.doi.org/10.5902/2179460x27119.
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The objective of this paper is to present the ravine and voçorocas in monitorings done in podzolic soils in the region of Rondonópolis - Mato Grosso - Brazil. The ravines and voçorocas were monitored in an area of 25.500 m2 in the county of Rondonópolis , in a section of concave slope with approximately 23% of declivity. This declivity can be found in a ramp of 174 meters located on the left bank of the Jurigue River. The work was done in a period of one year, covering a dry period and a rainy. It presents considerations related to the physical atmosphere of the region and of the area. These considerations observed aspects, such as: geology, geomorphology, vegetation and climate.
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Zhilin, M., V. Ruev, and A. Simonenko. "MULTILAYER CAVE SITES IN RAVINES CHERKEZ-KERMEN AND ZAMIL IN THE CRIMEA." Scientific Notes of V.I. Vernadsky Crimean Federal University. Historical science 6 (72), no. 3 (2020): 149–66. http://dx.doi.org/10.37279/2413-1741-2020-6-3-149-166.
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The article sums up available data about excavations of multilayer cave sites in ravines Zamil and The sites Zamil-Koba 1and 2 were discovered and excavated by D. A. Krainov in 1935–1937. The former yielded two cultural layers dated to the Early and Late Mesolithic, and the latter yielded besides these two also layers dated to the Neolithic, Early Bronze Age, Early Iron Age and Middle Ages. Excavations of ZamilKoba 3 site carried out in 2020 yielded two cultural layers dated to the Late Mesolithic and Middle Ages. Directions of future multidisciplinary research of multilayer cave sites in the Zamil ravine are outlined.Cherkez-Kermen in the South-Western Crimea. The latter were excavated in the late 19th century.
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Vázquez, Rosario, Lucia Capra, and Velio Coviello. "Factors controlling erosion/deposition phenomena related to lahars at Volcán de Colima, Mexico." Natural Hazards and Earth System Sciences 16, no. 8 (2016): 1881–95. http://dx.doi.org/10.5194/nhess-16-1881-2016.
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Abstract. One of the most common phenomena at Volcán de Colima is the annual development of lahars that runs mainly through the southern ravines of the edifice. Since 2011 the study and the monitoring of these flows and of the associated rainfall has been achieved by means of an instrumented station located along the Montegrande ravine, together with the systematic surveying of cross-topographic profiles of the main channel. From these, we present the comparison of the morphological changes experimented by this ravine during the 2013, 2014 and 2015 rainy seasons. The erosion/deposition effects of 11 lahars that occurred during this period of time were quantified by means of the topographic profiles taken at the beginning and at the end of the rainy seasons and before and after the major lahar event of 11 June 2013. We identified (i) an erosive zone between 2100 and 1950 m a.s.l., 8° in slope, with an annual erosional rate of 10.3 % mainly due to the narrowness of the channel and to its high slope angle and (ii) an erosive-depositional zone, between 1900 and 1700 m a.s.l., ( ∼ 8 % erosion and ∼ 16 % deposition), characterized by a wider channel that decreases in slope angle (4°). Based on these observations, the major factors controlling the erosion/deposition rates in the Montegrande ravine are the morphology of the gully (i.e., channel bed slope and the cross section width) and the joint effect of sediment availability and accumulated rainfall. On the distal reach of the ravine, the erosion/deposition processes tend to be promoted preferentially one over the other, mostly depending on the width of the active channel. Only for extraordinary rainfall events are the largest lahars mostly erosive all along the ravine up to the distal fan where the deposition takes place. In addition, as well as the morphological characteristics of the ravine, the flow depth is a critical factor in controlling erosion, as deeper flows will promote erosion against deposition. Finally, by comparing rainfalls associated with lahars that originated after the last main eruptive episode that occurred in 2004–2005, we observed that higher accumulated rainfall was needed to trigger lahars in the 2013 and 2014 seasons, which points to a progressive stabilization of the volcano slope during a post-eruptive period. These results can be used as a tool to foresee the channel response to future volcanic activity, to improve the input parameters for lahar modeling and to better constrain the hazard zonation at Volcán de Colima.
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Driver, Jonathan C. "Raven Skeletons from Paleoindian Contexts, Charlie Lake Cave, British Columbia." American Antiquity 64, no. 2 (1999): 289–98. http://dx.doi.org/10.2307/2694279.
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Two raven skeletons were excavated from Charlie Lake Cave, British Columbia, in association with Paleoindian occupations dated at about 10,500 and 9500 B.P. The distribution and condition of the bones, the association with artifacts, the configuration and location of the site, and data from ethnographic and historic sources contribute to the argument that the two ravens were deposited deliberately by people.
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Oates, Nathan. "In the Ravine." Antioch Review 70, no. 3 (2012): 459. http://dx.doi.org/10.7723/antioch.70.3.0459.
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Nathan Oates. "In the Ravine." Antioch Review 70, no. 3 (2012): 459. http://dx.doi.org/10.7723/antiochreview.70.3.0459.
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George and Eva Klein. "Bridge or ravine?" Nature 413, no. 6854 (2001): 365. http://dx.doi.org/10.1038/35096653.
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Demske, Nick. "Ravine (A Necropastoral)." Colorado Review 39, no. 2 (2012): 108–9. http://dx.doi.org/10.1353/col.2012.0053.
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Eschtruth, Anne K., Natalie L. Cleavitt, John J. Battles, Richard A. Evans, and Timothy J. Fahey. "Vegetation dynamics in declining eastern hemlock stands: 9 years of forest response to hemlock woolly adelgid infestation." Canadian Journal of Forest Research 36, no. 6 (2006): 1435–50. http://dx.doi.org/10.1139/x06-050.
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Hemlock woolly adelgid (HWA; Adelges tsugae Annand) infestations have resulted in the continuing decline of eastern hemlock (Tsuga canadensis (L.) Carrière) throughout much of the eastern United States. In 1994 and 2003, we quantified the vegetation composition and structure of two hemlock ravines in the Delaware Water Gap National Recreation Area. This is the first study to use pre-adelgid disturbance data, annual monitoring of infestation severity, and annual records of hemlock health to assess forest response to HWA infestation. In 2003, 25% of monitored hemlock trees were either dead or in severe decline. Measures of hemlock decline (crown vigor, transparency, density, and dieback) were correlated with HWA infestation severity and changes in light availability over the study period. Average percent total transmitted radiation more than doubled at these sites from 5.0% in 1994 to 11.7% in 2003. The total percent cover of vascular plants increased from 3.1% in 1994 to 11.3% in 2003. Species richness increased significantly, and more species were gained (53) than lost (19) from both ravine floras over the 9-year study period. Though exotic invasive plants were absent from these ravines in 1994, our 2003 resurvey found invasive plants in 35% of the permanent vegetation plots.
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Policht, Richard, Vlastimil Hart, Denis Goncharov, et al. "Vocal recognition of a nest-predator in black grouse." PeerJ 7 (March 15, 2019): e6533. http://dx.doi.org/10.7717/peerj.6533.
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Corvids count among the important predators of bird nests. They are vocal animals and one can expect that birds threatened by their predation, such as black grouse, are sensitive to and recognize their calls. Within the framework of field studies, we noticed that adult black grouse were alerted by raven calls during periods outside the breeding season. Since black grouse are large, extremely precocial birds, this reaction can hardly be explained by sensitization specifically to the threat of nest predation by ravens. This surprising observation prompted us to study the phenomenon more systematically. According to our knowledge, the response of birds to corvid vocalization has been studied in altricial birds only. We tested whether the black grouse distinguishes and responds specifically to playback calls of the common raven. Black grouse recognized raven calls and were alerted, displaying typical neck stretching, followed by head scanning, and eventual escape. Surprisingly, males tended to react faster and exhibited a longer duration of vigilance behavior compared to females. Although raven calls are recognized by adult black grouse out of the nesting period, they are not directly endangered by the raven. We speculate that the responsiveness of adult grouse to raven calls might be explained as a learned response in juveniles from nesting hens that is then preserved in adults, or by a known association between the raven and the red fox. In that case, calls of the raven would be rather interpreted as a warning signal of probable proximity of the red fox.
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Kulahci, Ipek G., Daniel I. Rubenstein, Thomas Bugnyar, William Hoppitt, Nace Mikus, and Christine Schwab. "Social networks predict selective observation and information spread in ravens." Royal Society Open Science 3, no. 7 (2016): 160256. http://dx.doi.org/10.1098/rsos.160256.
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Animals are predicted to selectively observe and learn from the conspecifics with whom they share social connections. Yet, hardly anything is known about the role of different connections in observation and learning. To address the relationships between social connections, observation and learning, we investigated transmission of information in two raven ( Corvus corax ) groups. First, we quantified social connections in each group by constructing networks on affiliative interactions, aggressive interactions and proximity. We then seeded novel information by training one group member on a novel task and allowing others to observe. In each group, an observation network based on who observed whose task-solving behaviour was strongly correlated with networks based on affiliative interactions and proximity. Ravens with high social centrality (strength, eigenvector, information centrality) in the affiliative interaction network were also central in the observation network, possibly as a result of solving the task sooner. Network-based diffusion analysis revealed that the order that ravens first solved the task was best predicted by connections in the affiliative interaction network in a group of subadult ravens, and by social rank and kinship (which influenced affiliative interactions) in a group of juvenile ravens. Our results demonstrate that not all social connections are equally effective at predicting the patterns of selective observation and information transmission.
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Yanyuk, Vyacheslav Mikhailovich, Petr Vladimirovich Tarasenko, Vladimir Aleksandrovich Tarbaev, et al. "MONITORING THE STATUS OF RECLAIMED LAND DISTURBED BY THE CON-STRUCTION OF LINEAR FACILITIES IN THE SARATOV REGION." Agrarian Scientific Journal, no. 6 (June 19, 2020): 43–49. http://dx.doi.org/10.28983/asj.y2020i6pp43-49.
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The results of using the methodology for monitoring the condition of reclaimed lands disturbed by the construction of the main gas pipeline in the Saratov region are presented. On the basis of a digital elevation model, the lost and renewed volumes of soil were determined, which made it possible to quantify the development of erosion processes at the beginning of construction and installation works and after reclamation. The reason for the intensive development of erosion is revealed - non-compliance with the regulations of departmental rules for laying a gas pipeline through weakly stable soils of underlying rocks. Effective anti-erosion measures (plowing across the slope, installation of drainage shafts and drainage structures at the top of ravines) and a set of remediation work (planning, flattening, fixing the slopes of the ravine with polymer-honeycomb coatings, backfilling them with sand and gravel mixture, sowing perennial grasses) were determined.
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Bollhagen, Andrew. "Hempel’s Raven Revisited." Journal of Philosophy 118, no. 3 (2021): 113–37. http://dx.doi.org/10.5840/jphil2021118310.
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The paper takes a novel approach to a classic problem—Hempel’s Raven Paradox. A standard approach to it supposes the solution to consist in bringing our inductive logic into “reflective equilibrium” with our intuitive judgements about which inductive inferences we should license. This approach leaves the intuitions as a kind of black box and takes it on faith that, whatever the structure of the intuitions inside that box might be, it is one for which we can construct an isomorphic formal edifice, a system of inductive logic. By popping open the box we can see whether that faith is misplaced. I aim, therefore, to characterize our pre-theoretical, intuitive understanding of generalizations like “ravens are black” and argue that, intuitively, we take them to mean, for instance: “ravens are black by some indeterminate yet characteristic means.” I motivate and explicate this formulation and bring it to bear on Hempel’s Problem.
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Yakovenko, V. M., and N. A. Bilova. "Morphology of forest ravined soil formation on deluvial loams." Fundamental and Applied Soil Science 16, no. 3-4 (2015): 5–17. http://dx.doi.org/10.15421/041512.
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The paper establishes the general features of the soil morphogenesis in ravined forests of Dnieper Prysamaria and genetic relationships of forest soils with zonal chernozem under herbaceous associations based on the detection of morphological properties that are «lithogenic», that is inherited from deluvial material and «pedogenic» features formed directly in the forest soil. The study area is located on the Dnieper Prysamaria (Dnipropetrovsk region) within the area of the steppes. The trial areas are incorporated in the upper Deep ravine, located in the upland part of watershed landscape. Catena is represented by five typical sections – between edging of the ravined forest and the field in the middle thirds of the slopes of the northern and southern exposures and in the thalweg of the ravine. Samples for meso-morphological studies were selected by genetic horizons, samples for soil horizons were selected using a soil drill. Basic morphological characteristics were determined in the laboratory (except for the hardness index). The mathematical processing of the results was carried out by methods of nonparametric statistics (method K-means). It was found that, despite the temporal and spatial disorder of deluvial material deposition processes and the differences of the water regime in the thalweg on the slopes, in the ravined biogeocenoses the forest soils are formed with common features of morphological organization of the genetic profile of the individual and morphological properties. The uniformity of the general structure is shown in a set sequence and the power of the genetic horizons, polycyclic and texture eluvial-illuvial differentiation of the genetic profile. The uniformity of the changes in the profile of the individual morphological properties is shown in the form of colour options of genetic horizons (due to humus content talus deposits), changing the particle size distribution of horizons in accordance with the general differentiation profile on eluvial and illuvial (due lessivage) part, changes in the morphology and dimensions of structural units related to changes in the structure of hardness horizons intensive leaching of carbonates from the profile of forest soils. The necessity of research processes clayization profile in situ, their role in the morphogenesis of compacted horizons are noted. There are two groups of properties that make it possible to analyze the micromorphology level communication between the soils in the catena. The first – a lithogenic conditionally or diluvial material properties, which persist for a long time in a forest soil – granulometry and less coloration horizons. The second – a pathogenic properties, sharply differing in the studied soils associated with the peculiarities of morphogenesis of a particular genetic profile and specific genetic horizon. These include the level of occurrence of carbonates in the profile and intensity of effervescence, the morphology of the structural units, the hardness of the genetic horizons, the level of spot colour. Cluster analysis identified a statistically illustrates the differences between the morphological structure of the soil catena, combining in one cluster the ravined soils on deluvial deposits under forest vegetation, and in the other – the soils on the loess under herbaceous vegetation. The contrast of differences increases down the profile.
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Lofgren, Erik R., Furui Yoshikichi, and Meredith McKinney. "Ravine and Other Stories." World Literature Today 72, no. 1 (1998): 211. http://dx.doi.org/10.2307/40153729.
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Coats, Karen. "Into the Ravine (review)." Bulletin of the Center for Children's Books 61, no. 4 (2007): 188. http://dx.doi.org/10.1353/bcc.2007.0820.
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Vasilyev, O. A. "THE MAIN RAVINE SOILS IN THE RAVINE SYSTEM «VEERNYI», CHEBOKSARY, CHUVASH REPUBLIC." VESTNIK OF THE BASHKIR STATE AGRARIAN UNIVERSITY 48, no. 4 (2018): 7–12. http://dx.doi.org/10.31563/1684-7628-2018-48-4-7-12.
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Urbančič, Mojca, Peter Korošec, Matjaž Fležar, and Mojca Globočnik Petrovič. "Diabetična retinopatija kot subklinično vnetje: Analiza citokinov v steklovini in serumu." Slovenian Medical Journal 89, no. 5-6 (2020): 243–54. http://dx.doi.org/10.6016/zdravvestn.2972.
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Izhodišče: Diabetično retinopatijo lahko opredelimo kot kronično subklinično vnetje. Želeli smo ugotoviti razlike v ravneh vnetnih citokinov med steklovino in serumom pri bolnikih s proliferativno diabetično retinopatijo (PDR) pri kontrolni skupini ter primerjati ravni citokinov v steklovini glede na aktivnost PDR. Boljše poznavanje vnetnega dogajanja v očesu bolnikov s PDR bi lahko prispevalo k razvoju novih načinov zdravljenja teh bolnikov.Metode: V raziskavo smo vključili 37 bolnikov (37 oči) s PDR, pri katerih je bila potrebna vitrektomija, ter 20 bolnikov (20 oči) z idiopatskim foramnom makule (FM), ki so predstavljali kontrolno skupino. Glede na pregled pred operacijo in oceno očesnega ozadja med samim posegom smo opredelili aktivnost PDR. V steklovini in serumu smo s citometrično metodo CBA (angl. Cytometric Bead Array) analizirali citokine interlevkin 1β (IL-1β), dejavnik tumorske nekroze α (TNF-α), makrofagni vnetni protein 1α (MIP-1α), makrofagni vnetni protein 1β (MIP-1β), monocitni kemotaktični protein 1 (MCP-1), žilni endotelni rastni dejavnik (VEGF), interlevkin 6 (IL-6), interlevkin 8 (IL-8), interlevkin 10 (IL-10) in interlevkin 12 (IL-12).Rezultati: Ravni vseh citokinov so se v steklovini pomembno razlikovale od ravni v serumu. Raven MCP-1, VEGF, IL-6, IL-8 v steklovini bolnikov s PDR je bila statistično pomembno višja v primerjavi z ravnijo v steklovini pri bolnikih v kontrolni skupini, raven MIP-1α, IL-10 in IL-12 v steklovini bolnikov s PDR je bila statistično pomembno nižja v primerjavi z bolniki v kontrolni skupini (p < 0,05). Ravni citokinov v serumu bolnikov s PDR se niso pomembno razlikovale od ravni citokinov pri kontrolni skupini. Bolniki z aktivno PDR so imeli v steklovini višjo raven MCP-1, VEGF, IL-6 in IL-8 kot bolniki z inaktivno PDR, a razlike niso bile statistično značilne.Zaključek: Z našo analizo smo potrdili pomembne razlike v ravneh citokinov med steklovino in serumom pri bolnikih s PDR, kar kaže na pomen lokalnega vnetnega dogajanja v očesu pri PDR. Višje ravni MCP-1, VEGF, IL-6 in IL-8 nakazujejo aktivnost PDR.
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Ekanayake, Kasun B., Duncan R. Sutherland, Peter Dann, and Michael A. Weston. "Out of sight but not out of mind: corvids prey extensively on eggs of burrow-nesting penguins." Wildlife Research 42, no. 6 (2015): 509. http://dx.doi.org/10.1071/wr15108.
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Context Egg depredation is a major cause of reproductive failure among birds and can drive population declines. In this study we investigate predatory behaviour of a corvid (little raven; Corvus mellori) that has only recently emerged, leading to widespread and intense depredation of eggs of a burrow-nesting seabird (little penguin; Eudyptula minor). Aims The main objective of this study was to measure the rate of penguin egg depredation by ravens to determine potential threat severity. We also examined whether penguin burrow characteristics were associated with the risk of egg depredation. Ravens generally employ two modes of predatory behaviour when attacking penguin nests; thus we examined whether burrow characteristics were associated with these modes of attack. Methods Remote-sensing cameras were deployed on penguin burrows to determine egg predation rates. Burrow measurements, including burrow entrance and tunnel characteristics, were measured at the time of camera deployment. Key results Overall, clutches in 61% of monitored burrows (n = 203) were depredated by ravens, the only predator detected by camera traps. Analysis of burrow characteristics revealed two distinct types of burrows, only one of which was associated with egg depredation by ravens. Clutches depredated by ravens had burrows with wider and higher entrances, thinner soil or vegetation layer above the egg chamber, shorter and curved tunnels and greater areas of bare ground and whitewash near entrances. In addition, 86% were covered by bower spinach (Tetragonia implexicoma), through which ravens could excavate. Ravens used two modes to access the eggs: they attacked through the entrance (25% of burrow attacks, n = 124); or dug a hole through the burrow roof (75% of attacks, n = 124). Burrows that were subject to attack through the entrance had significantly shorter tunnels than burrows accessed through the roof. Conclusions The high rates of clutch loss recorded here highlight the need for population viability analysis of penguins to assess the effect of egg predation on population growth rates. Implications The subterranean foraging niche of a corvid described here may have implications for burrow-nesting species worldwide because many corvid populations are increasing, and they exhibit great capacity to adopt new foraging strategies to exploit novel prey.
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Moreau, J. J. "Hommage à Robert Ravon." Neurochirurgie 65, no. 6 (2019): 347. http://dx.doi.org/10.1016/j.neuchi.2019.10.005.
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Tarasov, V. "Ravine denudation on hollow downslopes." Visnyk agrarnoi nauky 95, no. 9 (2017): 53–57. http://dx.doi.org/10.31073/agrovisnyk201709-10.
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Lu, Chenguang. "Channels’ Confirmation and Predictions’ Confirmation: From the Medical Test to the Raven Paradox." Entropy 22, no. 4 (2020): 384. http://dx.doi.org/10.3390/e22040384.
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After long arguments between positivism and falsificationism, the verification of universal hypotheses was replaced with the confirmation of uncertain major premises. Unfortunately, Hemple proposed the Raven Paradox. Then, Carnap used the increment of logical probability as the confirmation measure. So far, many confirmation measures have been proposed. Measure F proposed by Kemeny and Oppenheim among them possesses symmetries and asymmetries proposed by Elles and Fitelson, monotonicity proposed by Greco et al., and normalizing property suggested by many researchers. Based on the semantic information theory, a measure b* similar to F is derived from the medical test. Like the likelihood ratio, measures b* and F can only indicate the quality of channels or the testing means instead of the quality of probability predictions. Furthermore, it is still not easy to use b*, F, or another measure to clarify the Raven Paradox. For this reason, measure c* similar to the correct rate is derived. Measure c* supports the Nicod Criterion and undermines the Equivalence Condition, and hence, can be used to eliminate the Raven Paradox. An example indicates that measures F and b* are helpful for diagnosing the infection of Novel Coronavirus, whereas most popular confirmation measures are not. Another example reveals that all popular confirmation measures cannot be used to explain that a black raven can confirm “Ravens are black” more strongly than a piece of chalk. Measures F, b*, and c* indicate that the existence of fewer counterexamples is more important than more positive examples’ existence, and hence, are compatible with Popper’s falsification thought.
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Ekanayake, Kasun B., Desley A. Whisson, Laura X. L. Tan, and Michael A. Weston. "Intense predation of non-colonial, ground-nesting bird eggs by corvid and mammalian predators." Wildlife Research 42, no. 6 (2015): 518. http://dx.doi.org/10.1071/wr15080.
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Context Loss of eggs to predators is a major cause of reproductive failure among birds. It is especially pronounced among ground-nesting birds because their eggs are accessible to a wide range of predators. Few studies document the main causes of clutch fate of ground-nesting birds. Aims The main objective of the present study was to identify the major egg predator of red-capped plovers (Charadrius ruficapillus). We also investigated the effectiveness of the following two primary strategies available to the plovers to avoid egg predation: (1) the placement of clutches under vegetative cover and (2) avoiding predators by nesting outside the peak season of predator occurrence. Methods Remote-sensing cameras were deployed on plover nests to identify egg predators and nests were monitored over four breeding seasons to document reproductive success and fate. An experiment using false clutches with model eggs investigated the influence of nest cover on the risk of egg predation throughout the year. Line-transect surveys were conducted to estimate the abundance of egg predators in and around the wetlands. Key results The little raven (Corvus mellori) was the major egg predator identified in 78.6% of red-capped plover clutches and in 92.4% of false clutches that were camera-monitored. The hatching success of plover eggs was not influenced by nest cover (P = 0.36), but model egg survival in false clutches improved significantly with the presence of nest cover (P = 0.02). The abundance of little ravens increased during the plover breeding season and was highly negatively correlated with false clutch survival (rpearson = –0.768, P = 0.005). Conclusions Little ravens were the major predator of red-capped plover eggs and their abundance increased significantly during the plover breeding season. Any influence of nest cover on hatching success of eggs may have been masked by the extremely high rate of egg loss associated with the increased little raven abundance during the plover breeding season. Implications The high rate of egg predation is likely to have negative consequences on the local red-capped plover population, suggesting management is warranted. Little raven populations have expanded and, thus, their impact as egg predators needs to be investigated especially on threatened species.
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Bower, Shannon Stunden. "The Affordances of MacKinnon Ravine: Fighting Freeways and Pursuing Government Reform in Edmonton, Alberta." Feature Article 44, no. 1-2 (2016): 59–72. http://dx.doi.org/10.7202/1037237ar.
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This article examines the disputes that erupted in the second half of the twentieth century over the proposal to build a freeway through Edmonton’s MacKinnon Ravine, a landscape some saw as fundamental to the city’s network of recreational lands along the North Saskatchewan River and its extensive ravine system. MacKinnon Ravine, as a possibility-rich landscape, helped successive waves of urban activists articulate opposition to freeway development by serving as the keystone in a multi-decadal arc of civic activism. An orientation to the ravine allowed a series of distinct advocacy efforts to build on each other both in methods and in goals. These successive waves of activism not only altered MacKinnon Ravine’s future but also helped reshape civic governance in Edmonton.
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Adriaense, Jessie E. C., Jordan S. Martin, Martina Schiestl, Claus Lamm, and Thomas Bugnyar. "Negative emotional contagion and cognitive bias in common ravens (Corvus corax)." Proceedings of the National Academy of Sciences 116, no. 23 (2019): 11547–52. http://dx.doi.org/10.1073/pnas.1817066116.
Full textAbstract:
Emotional contagion is described as an emotional state matching between subjects, and has been suggested to facilitate communication and coordination in complex social groups. Empirical studies typically focus on the measurement of behavioral contagion and emotional arousal, yet, while highly important, such an approach often disregards an additional evaluation of the underlying emotional valence. Here, we studied emotional contagion in ravens by applying a judgment bias paradigm to assess emotional valence. We experimentally manipulated positive and negative affective states in demonstrator ravens, to which they responded with increased attention and interest in the positive condition, as well as increased redirected behavior and a left-eye lateralization in the negative condition. During this emotion manipulation, another raven observed the demonstrator’s behavior, and we used a bias paradigm to assess the emotional valence of the observer to determine whether emotional contagion had occurred. Observers showed a pessimism bias toward the presented ambiguous stimuli after perceiving demonstrators in a negative state, indicating emotional state matching based on the demonstrators’ behavioral cues and confirming our prediction of negative emotional contagion. We did not find any judgment bias in the positive condition. This result critically expands upon observational studies of contagious play in ravens, providing experimental evidence that emotional contagion is present not only in mammalian but also in avian species. Importantly, this finding also acts as a stepping stone toward understanding the evolution of empathy, as this essential social skill may have emerged across these taxa in response to similar socioecological challenges.