Tuesday 4 December 2018

Environment Health

What is water pollution?

Water pollution can be defined as the contamination of a stream, river, lake, ocean or any other stretch of water, depleting water quality and making it toxic for the environment and humans.
There are two types of water pollution:

  • 1.Organic pollution due to microorganisms - bacteria and viruses - present in the water, generated by excrement, animal and vegetable waste
  • 2.Chemical pollution generated by the nitrates and phosphates of pesticides, human and animal drugs, household products, heavy metals, acids and hydrocarbons used in industries

Water pollutioncauses

What are the sources of water pollution? Unsurprisingly, human activity is primarily responsible for water pollution, even if natural phenomenon - such as landslides and floods - can also contribute to degrade the water quality.
Photo by Erlend Ekseth on Unsplash
Water distribution pipe
SEWAGE AND WASTEWATER
Inadequate sewage collection and treatment are sources of water pollution. According to the United Nations, more than 80% of the worldwide wastewater goes back in the environment without being treated or reused.
Photo by markusspiske on Pixabay
Chainsaw
URBANIZATION AND DEFORESTATION
Even though it does not have a direct impact on water quality, urbanization and deforestation have a lot of indirect effects. For instance, cutting down trees and concreting over large areas generates an acceleration of flows which does not give enough time for water to infiltrate and be purified by the ground.
Photo by Ehrecke on Pixabay
Tractor ploughing
AGRICULTURE
Agriculture has an impact on water pollution due to the use of chemicals such as fertilizers, pesticides, fungicides, herbicides or insecticides running off in the water, as well as livestock excrement, manure and methane (greenhouse effect). Regarding aquaculture, pollution is directly in the water, as excess food and fertilizers are causing dystrophication.
Photo by Chris LeBoutillier on Pexels
Factories’ smokestacks by the sea
INDUSTRIES
Industries produce a lot of waste containing toxic chemicals and pollutants. A huge amount of the industrial waste is drained in the fresh water which then flows into canals, rivers and eventually in the sea. Another source of water pollution is the burning of fossil fuels, causing air pollution like acid rain which then flows to streams, lakes, and other stretches of water.
Photo by CC0 on Canva
Shard of glass on the beach
MARINE DUMPING
Everyday, garbage such as plastic, paper, aluminum, food, glass, or rubber are deposited into the sea. These items take weeks to hundreds of years to decompose, and thus they are a major cause for water pollution.
Photo by NeuPaddy on Pixabay
Toxic waste barrel
RADIOACTIVE WASTE
Generated - among others - by power plants and uranium mining, radioactive waste can linger in the environment for thousands of years. When these substances are released accidentally or disposed improperly, they threaten groundwater, surface water, as well as marine resources.

Water pollutioneffects

ON THE ENVIRONMENT
Water pollution truly harms biodiversity and aquatic ecosystems. The toxic chemicals can change the color of water and increase the amount of minerals - also known as eutrophication - which has a bad impact on life in water. Thermal pollution, defined by a rise in the temperature of water bodies, contributes to global warming and causes serious hazard to water organisms.
ON HUMAN HEALTH
Water pollution has very negative effects on public health. A lot of diseases result from drinking or being in contact with contaminated water, such as diarrhea, cholera, typhoid, dysentery or skin infections. In zones where there is no available drinking water, the main risk is dehydration obviously.

However, our purpose is not to dwell on problems,but rather to find solutions to fight water pollution!

Rhyth

Rhythm
Rhythm, in music, the placement of sounds in time. In its most general sense, rhythm (Greek rhythmos, derived from rhein, “to flow”) is an ordered alternation of contrasting elements. The notion of rhythm also occurs in other arts (e.g., poetrypaintingsculpture, and architecture) as well as in nature (e.g., biological rhythms).
Attempts to define rhythm in music have produced much disagreement, partly because rhythm has often been identified with one or more of its constituent, but not wholly separate, elements, such as accent, metre, and tempo. As in the closely related subjects of verse and metre, opinions differ widely, at least among poets and linguists, on the nature and movement of rhythm. Theories requiring “periodicity” as the sine qua non of rhythm are opposed by theories that include in it even nonrecurrent configurations of movement, as in prose or plainchant.

Elements Of Rhythm

Unlike a painting or a piece of sculpture, which are compositions in space, a musical work is a composition dependent upon time. Rhythm is music’s pattern in time. Whatever other elements a given piece of music may have (e.g., patterns in pitch or timbre), rhythm is the one indispensable element of all music. Rhythm can exist without melody, as in the drumbeats of so-called primitive music, but melody cannot exist without rhythm. In music that has both harmony and melody, the rhythmic structure cannot be separated from them. Plato’s observation that rhythm is “an order of movement” provides a convenient analyticalstarting point.

Beat

The unit division of musical time is called a beat. Just as one is aware of the body’s steady pulse, or heartbeat, so in composing, performing, or listening to music one is aware of a periodic succession of beats.

Tempo

The pace of the fundamental beat is called tempo (Italian: “time”). The expressions slow tempo and quick tempo suggest the existence of a tempo that is neither slow nor fast but rather “moderate.” A moderate tempo is assumed to be that of a natural walking pace (76 to 80 paces per minute) or of a heartbeat (72 per minute). The tempo of a piece of music indicated by a composer is, however, neither absolute nor final. In performance it is likely to vary according to the performer’s interpretative ideas or to such considerations as the size and reverberation of the hall, the size of the ensemble, and, to a lesser extent, the sonority of the instruments. A change within such limits does not affect the rhythmic structure of a work.

Rubato

The tempo of a work is never inflexibly mathematical. It is impossible to adhere in a musical manner to the metronomic beat for any length of time. In a loosely knit passage a tautening of tempo may be required; in a crowded passage a slackening may be needed. Such modifications of tempo, known as tempo rubato—i.e., “robbed time”—are part of the music’s character. Rubato needs the framework of an inflexible beat from which it can depart and to which it must return.

Time

The mind apparently seeks some organizing principle in the perceptionof music, and if a grouping of sounds is not objectively present it imposes one of its own. Experiments show that the mind instinctively groups regular and identical sounds into twos and threes, stressingevery second or third beat, and thus creates from an otherwise monotonous series a succession of strong and weak beats.
In music such grouping is achieved by actual stress—i.e., by periodically making one note stronger than the others. When the stress occurs at regular intervals, the beats fall into natural time measures. Although in European music the concept of time measures reaches back to a remote age, only since the 15th century have they been indicated by means of bar lines. Thus, the terms measure and bar are often used interchangeably.
The time measure is indicated at the opening of a piece by a time signature—e.g., 2/44/83/46/8. The length of each beat in a measure may be a time unit of short or long duration:
Time measures (embedded)
The signature 4/1 (above) means that the whole note (1) is the unit in each measure, and there are four (4) of them to each measure. In the second illustration, 4/2, the half note (2) is the unit of measurement, with four of them (4) to each measure, and so on.
The two basic types of time measure have either two or three beats and admit of many different notations.
two basic types of time measurement (inline)
“Four time,” or “common time,” is really a species of duple time allied to “two time,” as it can hardly be thought of without a subsidiary stress at the half measure—i.e., on the third beat—thus:
on the third beat (inline)
Duple, triple, and quadruple time measures—i.e., those in which there are two, three, and four beats to a measure—are known as simple time. The division of each of the component beats into three produces compound time:
compound time (inline)
More-complex times, such as the quintuple, 5/4, usually fall into groups of 3 + 2, as in “Mars” from Gustav Holst’s suite The Planets and in the second movement of Tchaikovsky’s Sixth SymphonyRimsky-Korsakov, in Sadko, and Stravinsky, in Le Sacre du printemps, use 11 as a unit. Ravel’s piano trio opens with a signature of 8/8 with the internal organization 3 + 2 + 3. Folk song and folk dance, particularly from eastern Europe, influenced the use of asymmetrical time measures, as in the “Bulgarian Rhythm” pieces in 7/8 and 5/8 in Bartók’s Mikrokosmos.

Metre

The combinations of long (—) and short ([breve]) syllables are known in prosody as feet. The system of notating the musical equivalents of feet derives from the application of prosody to music. The foundations for European music were laid in ancient Greece, where classical music and poetry were regarded as parts of a single art. These principles were adopted by the Romans and were transmitted, by way of Latin poetry, to medieval Europe. The feet of classical poetry and their equivalents in music are shown in the Table. And in late antiquity St. Augustine (354–430), in De musica, added more.

Rhythmic metre

Until the 12th centurychurch music was virtually limited to unadorned plainchant. The early composers found that polyphony required a rhythmical organization to keep the parts together, so rhythmic metre was adopted (see Table). Compared with a hypothetical flow of beats equal in stress, metre adds significance to what was merely a forward flow in time—though the continuation of a metrical pattern may itself become monotonous. Thus, metre, though “rhythmic” by comparison with pulse, is not the whole of rhythm. The 13th-century musicians often varied the rhythmic modes by combining several of them simultaneously in different parts of polyphonic composition.

Polyphonic metre

Theoretically, metre appears to be without stress accent, and certainly much polyphonic music of a later period, such as the masses of Giovanni Pierluigi da Palestrina, has an almost stressless flow. Yet these works reveal a subtle rhythmical organization. At a later period metre and time measure cannot be wholly separated. In their “purest” forms they may be extremes, but in music predominantly of one type, the other element is rarely wholly absent, though on an instrument such as the organ, actual dynamic stress is impossible. After all, metres like the spondee, ♩♩, and the dispondee, ♩♩♩♩, need an accent on the first beat to keep their identity. Notwithstanding the opposite tendencies of metrical organization and stress accent, however, some metre is obviously subject to stress, so that metre and time measure become very closely linked, as in the scherzo of Beethoven’s Ninth Symphony, where a measure has a strong first beat and at the same time follows a metre.

Organic Rhythm

In broad terms, the time framework of music is composed of tempo, time measure, metre, and period; and its rhythmical life hangs on rubato, musical motif (which may already include cross accent), and metrical variation, as well as on asymmetry and balance of phrase. Whereas the former are more or less measured and rational, the latter are organically inspired and numerically irrational—the very life of the music.

Prose rhythms and plainsong

Rhythm is, therefore, not any one of these rational or formal features, nor is it composed solely of a combination of these factors. Yet rhythm requires the background of a rational framework in order that it may be fully perceived, but this framework need not embrace all the rational factors described above.
Thus, plainchant, as it is known in modern times, makes no use at all of measure or of regular metre but is supremely rhythmical in conception; its “free” rhythms are felt. Whereas so much music has for its framework a regular repetition of underlying accent, whether stress or durational, the framework of plainchant is irregular. Its rhythm belongs to the Latin tongue and springs from the correct accentuation of the text and the dynamic quality inherent in the word grouping.

Rhythm, melody, and harmony

Thus far, music’s structure in time has been examined separately from its structure in tone, but no such separation is really possible. Melody and rhythm are intimately connected. Moreover, various styles of music tend to standardize their melodic cadences and, with them, their time divisions (e.g., Mozart’s melodic rhythm is much more regular than Prokofiev’s).
In music employing harmony, the rhythmic structure is inseparable from harmonic considerations. The time pattern controlling the change of harmonies is called harmonic rhythm. In 17th- and 18th-century music, harmony tends to limit rhythmic subtleties and flexibility of the melodic elements (as well as determining the basic type of melody) in regard to stress accents. It is, therefore, no accident that the polyphonic music of Indonesia and Southeast Asia, like much European music, exhibits certain four-square melodic tendencies. By contrast, the music of India and the Perso-Arab world employs a melody instrument or voice performing in a given metre offset by a drum playing cross rhythms or (in the Arab world) a quite different metre. With no harmony (except a drone) to impede its flow, the rhythm can reach a structure of great subtlety and complexity.

Rhythm, structure, and style

In European music the great variety of styles derives its relation to melody from different concepts of rhythm. They include the strict rhythmic modes of the 13th century, the free oratorical speech-rhythms of the Renaissance, the almost stressless flow of Renaissance polyphony, the strong body rhythms of the Baroque, the freedom of the late Romantics, and the primitivistic rhythms of the 20th century with composite and ever-changing time signatures.
Thus, study of musical history shows a varying attitude toward rhythm, sometimes closer to strict rule, sometimes to “freedom,” as the temper of the times and the relative influence of poetry, dance, and folk musicdecree. Plato’s definition of rhythm as “an order of movement” might, therefore, be expanded. As a determining factor in the vitality of music, rhythm may be described as “an inspired organic order of movement” communicating intelligibly to the senses. From the analytical viewpoint, it operates in the rational framework described, which it varies in terms of rubato, motif, and so on. Ultimately, rhythm is the organic process of music in time; it is music’s direction in time. The quality of rhythm is the quality of life; however vitally composers conceive their music, they must depend upon performers to recreate it rhythmically.