Geographic zonality and vertical explanation. Geographic shell
The region in a broad sense, as already noted, is a complex territorial complex that is rewarded by the specific uniformity of various conditions, including natural, geographical. This means that there is a regional differentiation of nature. The processes of spatial differentiation of the natural medium have a huge effect of such a phenomenon as the zonality and the abonality of the geographical shell of the Earth.
According to modern ideas, under the geographic zonality, it means a natural change in physico-geographical processes, complexes, components as they move from the equator to poles. That is, the zonality on land is a sequential change of geographical belts from the equator to the poles and the natural distribution of natural zones within these belts (equatorial, subevatorial, tropical, subtropical, moderate, subanctic, subanctic).
The causes of zonality are the shape of the Earth and its position relative to the Sun. The zonal distribution of radiant energy determines the zonality of temperature, evaporation and clouds, salinity of the surface layers of sea water, the level of saturation of its gases, climates, process of weathering and soil formation, vegetable and animal world, hydraulic, etc. Thus, the most important factors determining geographic zonality are the uneven distribution of solar radiation over latitude and climate.
The most clearly geographical zonality is expressed on the plains, since it is when moving along them from the north to the south there is a climate change.
Zonalness is also manifested in the World Ocean, and not only in surface layers, but also on the oceanic bed.
The doctrine of geographic (natural) zonality is hardly designed in geographic science. This is explained by the fact that it reflects the earliest of the laws open by geographers, and the fact that this theory forms the core of physical geography.
It is known that the hypothesis of latitudinal thermal belts arose in the ancient time. But in the scientific direction, it began to transform only at the end of the XVIII century, when naturalists became part of the circulatoons. Then, in the XIX century, A. Humboldt was made of a great contribution to the development of this teaching, who traced the zonality of vegetation and the animal world due to the climate and discovered the phenomenon of the altitude.
Nevertheless, the doctrine of geographical zones in its modern form originated only at the turn of the XIX-XX centuries. As a result of research V.V. Dokuchaev. He, as admitted, is the founder of the theory of geographic zonality.
V.V. Dokuchaev substantiated zonality as a universal nature of nature, manifested equally on land, sea, in the mountains.
To understand this law, he came from the study of soil. His classic work "Russian Chernozem" (1883) laid the foundations of genetic soil. Considering the soil "Mirror of the Landscape", V.V. Dokuchaev and during the isolating natural zones called soils characteristic of them.
Each zone, according to a scientist, is a comprehensive education, all the components of which (climate, water, soil, soil, vegetable and animal world) are in close relationship.
In the development of the teaching on geographic zonality, a notable contribution was made by L.S. Berg, A.A. Grigoriev, M.I. Budyko, S.V. Caustry, K.K. Markov, A.G. Isachenko and others.
The total number of zones is determined in different ways. V.V. Dokuchaev highlighted 7 zones. L.S. Berg in the middle of the XX century. Already 12, A.G. Isachenko - 17. In modern physico-geographical atlas of the world, their amount, taking into account the subband, sometimes exceed 50. As a rule, this is not a consequence of any errors, but the result of hobbies too detailed classifications.
Regardless of the degree of fragility, in all versions the following natural zones are presented: Arctic and subarctic desert, tundra, timber, forests of moderate belt, taiga, mixed forests of moderate belt, cooler forests of moderate climate, steppes, semi-edge and deserts of moderate belt, desert and subtropical semi-desert and tropical belts, monsoon forests of subtropical forest, forests of tropical and subequatorial belts, savanna, wet equatorial forests.
Natural (landscaped) zones are not perfectly correct aroles coinciding with certain parallels (nature is not mathematics). They do not cover our planet with solid stripes, often open.
In addition to zonal, avisonal patterns are revealed. An example of it is the high-rise explanancy (vertical zonality), depending on the height of sushi and changes with the height of the heat balance.
In the mountains, the natural change of natural conditions and natural-territorial complexes is called high-altitude. It is also explained mainly by climate change with a height: 1 km of lifting the air temperature decreases by 6 degrees C, the air pressure decreases, its dustiness, cloudy and the amount of precipitation increases. A single system of high-altitude belts is formed. The above the mountains, the most fully expressed high-rise lower. Landscapes of high-altitude explanation are mainly similar to landscapes of natural zones on the plains and follow each other in the same order, and the same belt is located higher, the closer the mining system to the equator.
There is no complete similarity of natural zones on the plains and vertical explanation, since the vertically landscape complexes are changing with different rates than horizontally, and often in a different direction.
In recent years, as the humanization and sociologization of geography, geographic zones begin to call natural and anthropogenic geographical zones more often. The teaching on geographic zonality is of great importance for regional and country analysis. First of all, it allows you to reveal the natural prerequisites of specialization and management of the economy. And in the context of modern RTR, with a partial weakening of the dependence of the farm from natural conditions and natural resources, its close relations with nature continue to be maintained, and in some cases, dependence on it. The obvious and continuing important role of the natural component in the development and functioning of the Company is observed in its territorial organization. Differences in the spiritual culture of the population, also can not be understood without applying to natural regionalization. It also forms the skills of human adaptation to the territory, determines the nature of environmental management.
Geographical zonality actively affects the rank differences in the life of society, being an important factor in the zoning, and, therefore, regional policies.
The teaching on geographic zonality gives a huge material for country and regional comparisons and thereby contributes to clarifying country and regional specifics, its reasons are that, ultimately, is the main task of regions and country studies. For example, the taiga zone in the form of a loop crosses the territory of Russia, Canada, Fennoscandia. But the degree of population, economic development, living conditions in the taiga zones of the countries listed above have significant differences. In the regions, civil analysis may not be covered by the attention of the nature of these differences, nor the question of their sources.
In a word, the task of regional and country analysis is not only the characteristics of the peculiarities of the natural component of a territory (the theoretical basis of it and is the doctrine of geographical zonality), but also to identify the nature of the relationship of natural regionalism with the regionalization of the world on economic, geopolitical, cultural and civilization nym, etc. grounds.
Many physico-geographical phenomena in the geographic shell are distributed in the form of strips elongated along the parallels, or at some angle to them. This property of geographic phenomena is called zonality (geographic zonality law).
The ideas about natural zonality arose from ancient Greek scientists. So, in V c. BC. And Heponix celebrated five zones of the Earth: tropical, two moderate and two polar. A great contribution to the doctrine of natural zonality was made by a German geographer, which established the climatic and vegetable zones of the Earth ("Geography of Plants", 1836). In Russia, the ideas about geographic zonality were expressed in 1899 in the book "The Doctrine of Nature Zones. Horizontal and vertical soil zones. Professor owns research on causes and factors of zonality. He came to the conclusion about the big role of the ratio of radiation balance and the number of annual precipitation (1966).
Currently it is believed that natural zonality is represented
- component zonality;
- landscape zonality.
All components geographic shell Subordinates to the global law of zonality. Zonality is noted for climatic indicators, plant groups and soil types. It also manifests itself in hydrological and geochemical phenomena, as a derivative of climatic and soil and plant conditions.
The basis of the zonality of physico-geographical phenomena is the regularity of the flow of solar radiation, the arrival of which decreases from the equator to the poles. However, the distribution of solar radiation is superimposed by the transparency factor of the atmosphere, which is azeralSince it is not associated with the form of the Earth. From solar radiation, the air temperature depends on the distribution of which another avison factor affects - the properties of the earth's surface is its heat capacity and thermal conductivity. This factor leads to an even greater impaired zonality. Oceanic and air flows, forming heat transfer systems, also have a large influence on the distribution of heat on the surface of the Earth.
It is even more difficult to distribute atmospheric precipitation on our planet. They have, on the one hand, zonal character, and on the other - are associated with the position of the territory in the western or eastern part of the continents and the height of the earth's surface.
The joint impact of heat and moisture is a major factor that determines most of the physico-geographical phenomena. Since in the distribution of moisture and heat, the orientation of latitude is maintained, then all the phenomena associated with the climate are oriented to sewn. As a result, a sewn structure is formed on Earth, called geographic explanation.
Explanation is manifested in the distribution of the main climatic characteristics: solar radiation, temperature and atmospheric pressure, which leads to the formation of a system of 13 climatic belts. Plant groups on Earth also form elongated stripes, but more complex configuration than climatic belts. They are called vegetation zones. Soil cover is closely connected with vegetation, climate and the nature of the relief, which allowed V.V. Dokuchaev allocate the genetic types of soil.
In the 50s of the 20th century, Geographers of Grigoriev and Budyko developed the law of the Docoyev zonality and formulated periodic law of geographic zonality. This law establishes the repetition of the same type of geographic zones inside the belts - depending on the ratio of heat and moisture. Thus, forest zones are available in equatorial, subequatorial, tropical and moderate belts. The steppes and deserts are also found in different geographic belts. The presence of one-type zones in different belts is due to the repetition of the same heat and moisture ratios.
In this way, zone- This is the large part of the geographical belt, which is characterized by the same rates of radiation balance, the annual amount of precipitation and evaporation. At the beginning of the last century, Vysotsky proposed the coefficient of moisture, equal to the ratio of precipitation to evaporates. Later, Budyko introduced the indicator - the radiation index of dryness, which is the attitude of the incoming amount of solar energy to the cost of heat to the evaporation of atmospheric precipitation. As established, there is a close relationship of geographic zones from the value of the flow of solar heat and the radiation index of dryness.
Geographical belts are internally inhomogeneous, which is primarily due to the avison circulation of the atmosphere and the transfer of moisture. Taking into account this sectors stand out. As a rule, their three: two oceanic (Western and oriental) and one continental. Secto – this is a geographical zonality that is expressed in the change of the main natural indicators in longitude, that is, from the oceans deep into the mainland.
Landscape zonality is determined by the fact that the geographical shell in the process of its development acquired a "mosaic" structure and consists of a variety of natural complexes of unequal values \u200b\u200band complexity. By definition F.N. Milkova PTK is a self-regulating system of interrelated components, functioning under the influence of one or more components acting as a leading factor.
As a result of the study of the material of this chapter, the student must:
- know determination of the law of geographic zonality; titles and placement of the geographical zones of Russia;
- be able to characterize each geographical area in Russia; explain the specifics of the configuration of the geographical zones of Russia;
- own Representation of zonality as a natural cultural phenomenon.
Geographic zonality as a natural cultural phenomenon
Medieval travelers, overcoming large spaces and watching landscapes, have already noted a lawsuit, not accidental nature of changes in nature and culture in space. Thus, the famous Arabic geographer al-Idrisi was a map of the Earth, where she showed seven climatic latitudinal zones in the form of strips - from the equatorial strip to the zone of the North Snow desert.
Naturalists of the second half of the XIX century. They tried to explain the phenomenon of geographical zonality from the system positions.
First, they found out that the main reason for the occurrence of this phenomenon is a spherical form of the Earth, with which the uneven flow of heat on different geographic latitudes is connected. On the material of field studies, made mainly in the Russian plain, an outstanding domestic scientist V. V. Dokuchaev (he belongs to the honor of the opening of the law of geographic zonality) showed that not only climate, but also other elements of nature (natural water, soil, vegetation, animal The world) is distributed over the earth's surface in a certain pattern. The scientist noted that "thanks to the famous position of our planet regarding the Sun, thanks to the rotation of the Earth, its shag-formation, climate, vegetation and animals are distributed over the earth's surface in the direction from the north to south, in a strictly defined manner, with a correctness that allows the division of the globe to the belt - polar, moderate, tatropical, equatorial, etc. » .
Secondly, scientists explained why geographic zones do not always have a latitudinal stretch: if there were no oceans on Earth and the whole surface would be even, then the zones would be squeezed all the earth in the form of parallel stripes. But the presence, on the one hand, the oceans, and on the other - the irregularities (mountains, elevations) distorts the perfect picture. Geographic zonality is better expressed on the plains in the form of certain strips, belts or zones. It is not by chance that the landscapes of water-regulating plains and lowlands in geography are called zonal.TO azeralbelieve the landscapes that differ sharply from typical zonal landscapes. Recall, for example, the landscapes of the Valley of the River Nile, very unlike the zonal landscapes of surrounding tropical deserts. The most common abonal landscapes are landscapes of river valleys and mountain landscapes.
However, the most important discovery, made by V. V. Dokuchaev, is that geographic zonalityrepresents naturally cultural phenomenon.It affects not only in nature, but also to culture and human activity. According to the expression of Dokuchaev, a man of zonalin in all manifestations of his life:"In customs, religion (especially in non-Christian religions), in beauty, even sexual activity, in clothing, in the whole everyday situation; Zonalny - domestic livestock ... Cultural vegetation, construction, food and drink. That ... who had to travel from Arkhangelsk to Tiflis, could easily be convinced how buildings, dress, morals, customs of the population and their beauty, depending on climate, animals, plants, soils, characteristic of one or another area are strongly changing.
Under geographic areaV. V. Dokuchaev understood such a system in which nature (climate, water, vegetation, animal peace) and a person, his activities are interrelated, "configured" to each other.
Obviously, the relationship between human communities and the surrounding landscapes was closer to the industrial revolution, when human technical capabilities were modest, he lived closer to nature, and people were significantly less. Nevertheless, everyone, even the most "technical", the people persists the memory of the "maternal" (well-defined zonal or abonal) landscape, forest or wall, about the associated landscape images of the motherland, not only visual, but also cultural and linguistic . The language retains the memory of the mastered landscapes and contains their characteristic.
Zonality geographic
Zonality geographic
(the zonality of physico-geographical), a change in the natural conditions from the poles to the equator, due to the latitudinal differences in the flow of solar radiation on the surface. Max. Energy gets the surface perpendicular to the solar rays (equatorial latitudes); The more tilt, the smaller the heating (polar latitude). Geographical zonality is one of the most universal geographical patterns that has the status of the law. In accordance with this law, the landscape membrane of the Earth is divided into natural zones repeated in North. and south. Hemispheres (eg, forest zones and moderate belts, tropical deserts, etc.).
The idea of \u200b\u200bthe geographical zonality began to form still in the ancient time (Herodotus, Eucdonis, Posyondos); The foundations of the teachings on bioclimatic zonality were laid by A. Humboldt. In Russia, the greatest contribution to the doctrine of geographical zonality was made by V. V. Dokuchaev, Hp Berg, A. A. Grigoriev, M. I. Budyko, I. P. Gerasimov, E. N. Lukasheva, A. G. Isachenko and others.
Geographic zonality law:I R - radiation index of dryness; diameters of circles are proportional to the biological productivity of landscapes
The zonality is distinguished by a latitudinal, component (climate, soil, vegetation), the zonality of sedimentogenesis, exogenous geomorphological processes, hydrological (zonality of the characteristics of the flow of rivers), hydrogeological and complex, or landscape. The differentiation of the geographic shell on natural (landscaped) zones is the ratio of heat and moisture. The latitudinal zonality is most clearly manifested in the plains having a huge stretching with S. on Yu. (Russian and West Siberian plains). OSN. The form of procurement in the mountains - high-rise explanancy. The traits of the latitudinal zonality are peculiar to the surface aqueous mass of the ocean, which is manifested in the seawater, saltness, oxygen content, bioproductivity, in the vertical and horizontal speed of movement.
Geography. Modern illustrated encyclopedia. - M.: Rosman. Edited by prof. A. P. Gorkina. 2006 .
Watch what is "zonality geographical" in other dictionaries:
The main pattern of differentiation of the geographic shell of the Earth, manifested in a sequential and definite change of geographic belts and zones due to mainly the nature of the distribution of the radiant energy of the Sun in the latitudes ... ... Ecological Dictionary
The main pattern of the distribution of landscapes on the surface of the Earth, consisting in a sequential change of natural zones, due to the nature of the distribution of the radiant energy of the Sun in the latitude and uneven moisture. Geographic ... ... Financial vocabulary
Differentiation of the earth's surface on climatic, biogeographic zones and other features due to mostly latitudinal distribution of solar heat. Ecological encyclopedic dictionary. Chisinau: Home Editorial Moldavian ... ... Ecological Dictionary
See zonality geographical. Geography. Modern illustrated encyclopedia. M.: Rosman. Edited by prof. A. P. Gorkina. 2006 ... Geographic Encyclopedia
The pattern of differentiation of the geographic shell of the Earth; It is manifested in a sequential and definite change of geographic belts and zones, due, mainly, the nature of the distribution of the radiant energy of the Sun in the latitudes (decreases ... Ecological Dictionary
geographic zonality - the latitudinal differentiation of the geographical shell of the Earth, manifested in a consistent change of geographic belts, zones and a sub-diabetes caused by a change in the arrival of the radiant energy of the Sun in the latitude and uneven moisturizing. → Fig. 367, p. ... ... Dictionary on geography
The geographical, pattern of differentiation of geographic (landscape) shell of the Earth, manifested in a consistent and definite change of geographic belts and zones (see the physicome geographical zones), due to the first place ... Great Soviet Encyclopedia
geographic zonality - Geografinė Zona Statusas T Sritis Ekologija Ir Aplinkotyra apribėžtis Geografinės Juostos žemyninė Dalis, Kurią Lemia Tam Tikras Šilumos Ir Drėgmės Derinys. Atitikmenys: Angl. Geographical Zone Vok. geografische zonierung, f; GLOBALE ZONIERUNG, ... ... Ekologijos Terminų aiškinamasis žodynas
Uneven distribution of solar heat On the surface of the Earth, due to its shag-formation and rotation around its axis, it forms, as we have already spoken, climatic belts (p. 54). For each of them, a certain orientation and rhythm of natural phenomena are characterized (biomaste accumulation, the intensity of the soil formation and the formation of the relief under the influence of external factors and others). Therefore, on the basis of climatic belts, geographic belts can be distinguished.
Total allocated 13. geographic belts: one equatorial, two subequatorial (in the northern and southern hemispheres), two tropical, two subtropical, two moderate, two subolar (subaarctic and subnatrotic) and two polar (arctic and antarctic).
The list of names already indicates the symmetric location of the belts relative to the equator. In each of them, certain air masses are dominated. For belts wearing the names without a console "" are characterized by their own air masses (Equatorial, tropical, moderate, arctic). On the contrary, in three pairs having a prefix "sub", alternately dominate the neighboring geographical belts: in the summer half of the year in the northern hemisphere - more southern (and in South, on the contrary, - Northern), in the winter half of the year - more northern (and in southern Hemisphere - South).
Largely elongated sushi geographic belts are heterogeneous. This is determined primarily by the position of one or another of them in the co-economy or continental districts. The prieuchechnic is better moisturized, and continental, internal, on the contrary, more dry: the effect of oceans no longer applies. On this basis, the belts are divided into sectors - propeanic and continental.
Especially well, the sectoral is expressed in the moderate and subtropical belts of Eurasia, where the land reaches maximum sizes. Here, the wet forest landscapes of the coequicanic colors (two coeches) as the mainland is deeply replaced by dry steppe, and then semi-desert and deserted landscapes of the continental sector.
The least clearly sectorate is manifested in tropical, subequatorial and equatorial belts. In the tropics bring sediments only on the eastern periphery of the belts. Here and wet wet. As for the inner and western regions, they differ in dry, hot climate, and the deserts on the west coasts go to the Ocean itself. Therefore, only two sectors are allocated in the tropics.
Two sectors are also highlighted in equatorial and subequatorial belts. In the subequatorial - it is a constantly wet sector () with forest landscapes and seasonally wet sector (includes the rest of the rest), occupied by gentlemen and savannahs. In the equatorial belt, some of the territory refers to a constantly wet sector with wet "rain" forests (gilas) and only the eastern - to seasonally wet, where predominantly deciduous.
The sharpest "sector border" happens where it goes through mountain barriers (for example, in Cordillera North America and Andes - South). Here, the Western co-roester sectors occupy a narrow coastal lane of plains and adjacent mountain slopes.
Large components of belts - sectors are divided into smaller units - natural zones. The basis of such a unit is the differences in humiliation of the territory. However, it would be incorrectly measured only by the number of drop-down precipitation. Here is the ratio of moisture and heat, since the same amount of precipitation, for example less than 150-200 mm per year. It can also lead to the development of swamps (in the tundra), and to the formation of the desert (in the tropics).
To characterize moisture, there are many quantitative indicators, more than two dozen coefficients or indexes (dryness or humidity). However, all of them are not perfect. For our topic - to clarify the influence of the ratio of heat and moisture on the differentiation of natural zones - it is better to consider not the full amount of precipitation for the year. And only the so-called gross moisturizing (drainage) and its radiation balance, since in biological processes is practically not involved. This indicator is called the "hydrothermal coefficient" (GTC). It is fuller than others expresses the main zonal patterns. If it has a value greater than 10, the landscapes are developed (mainly forest), if less than 7 - herbal-shrub, and in the range from 7 to 10 - transition types; With a GTK smaller 2 - desert.
You can build the ratio of heat and moisture in the main natural zones of land on the plains (see p. 54). The space exposed inside the curve is an isna of the development of natural landscapes.
Especially great variety of landscapes in a hot climatic belt. This is the result of large differences here under humidification at high temperatures. Scientists have long appreciated the conditions of moisture with the productivity of vegetable mass: above all it is in the delta areas of the sub-zknatorial belt - up to 3 thousand cm of dry substance with 1 hectare per year; The delta, located at the junction of sushi and the sea, are most provided with moisture and necessary chemical elements in the soil, and in high temperatures, it continues round here. The names of natural zones are given by the nature of vegetation, as it most clearly reflects the zonal features of nature. In the same natural zones on different continents, plant covers have similar features. However, the distribution of vegetation is influenced not only by the zonal characteristics of the climate, but also other factors: the evolution of the continents, the features of rocks, alkalizing surface horizons, human influence. A significant role in the distribution of modern vegetation is also played by the location of the mainland. Thus, the territorial proximity between Eurasia and North America, especially in the Pacific areas, led to the obvious relationship of vegetation in the polar areas of both continents. On the contrary, the vegetation cover is more distant from each other in the mainland, located in the southern hemisphere, is significantly different in the viewing composition. Especially many endemics, i.e., species common in a limited territory in Australia is its long-term isolation.
The main barriers on the paths of plants migration were not only oceans, but also the mountain ranges, although it happened that they served as the routes of plant resettlement.
All these factors led to a variety of roast cover of the globe. In the following section, when describing natural zones, we will give a characteristic of the zonal type of vegetation, the properties of which most correspond to the climatic conditions of certain zones. However, according to the specified composition, the vegetation of the same natural zones on different continents is characterized by significant differences.
Natural zones of arctic, subarctic, moderate and subtropical belts are most pronounced in Eurasia and North America. This is due to the large sizes of sushi in these latitudes and the vastness of the plain territories, as the high mountains and violate how we will see below, the general features of zonality. Most of the mainlands of South America, Africa, as well as the southern part of Asia are located in the ecu-torient, subequatorial and tropical belts.
The belts and natural zones are complicated as moving from the Arctic regions to the equator. In this direction, against the background of an increasing amount of heat, regional differences are increasing in humidification. Hence the significantly more motley nature of landscapes in tropical latitudes.
Along with the zonality of natural processes, there is a phenomenon called intrasonality. Intrazoneal soils, vegetation cover, various natural processes may occur in specific conditions and are found in separate territories in different natural zones. Moreover, the ingrazal phenomena usually carry the imprint of the corresponding zone; We will see it below on specific examples.
Natural zones are divided into smaller units landscapes which serve as the main cells of the geographic shell.
In landscapes, all natural components are closely interrelated and interdepended, as if "fitted" to each other, that is, the forming! Pretty. The variety of landscapes is determined by many factors: real composition and other features of the lithosphere, the peculiarities of surface and groundwater, the climate, the nature of the soil and vegetation cover, as well as inherited, "yesterday" features.
Currently, when direct impacts on the nature of man's economic activity are increasing, and "virgin" landscapes in "Anthropogenic" occurs.
In turn, the landscapes due to the differences in the microclimate, microrelief, soil subtypes can be divided into smaller territorial areas of the lower rank - arugating and facies - a specific OBPAI or and their slopes, etc. Homogeneous landscapes are composed of the same set and naturally repeated combinations of facies and a tract. However, landscapes, of course, are not isolated and affecting each other due to the circulation of the atmosphere, the migration of organisms, etc.
Local traits of landscapes are individual and unique. But landscapes also have common zonal features that can be repeated even on different continents. For example, the Great Plains in North America resemble the steppe territories of the moderately continental parts of Eurasia. By Lomu, with some abstraction, land landscapes can be generalized, to type, which allows you to trace the natural placement of zonal types of landscapes not only on each mainland separately, but also on a planetary scale.
To make it easier to understand the location of geographic belts and zones on our land, imagine hypothetical uniformly plain mainland with an area equal to half of Sushi Square (let the other sushi part of the Sushi are located in another hemisphere, overseas). The outline of this mainland in the northern hemisphere can resemble something among North America and Eurasia, and in South - something average between South America, Africa and Australia. Then the generalized () contours on the plains of real continents are applied to the boundaries of geographical belts and zones.