Sky High Cloud Formations By Khaty Panambo

Cloud formations has fascinated the young and old worldwide. Being the subject of too many photographs and children's poems, it is safe to say that people spend their time staring up the sky and trying to determine cloud formations. Cloud watching is perfect for long and lazy afternoons. But its purpose does not only serve the aesthetic value but also other effects such as trying to determine the weather.

There are different types of cloud formations. Each formation of clouds lend different shapes and appear differently as well as signal different types of weather. Nimbus clouds, stratus clouds, cumulus clouds all mean different types of weather all ranging from sunny days to dark and ominous rains.

Since time in memoriam, meteorologists observe clouds and cloud formation when trying to predict the weather. True that today's weather men have sophisticated equipment but they still rely on clouds and cloud formations to tell them the indication of rain or snow or sunny days. Clouds are located in different parts of the atmosphere, their shape, appearance and position in the atmosphere could tell the meteorologist and even the laymen some weather predictions.

The next time you look up the sky, remember that clouds do more than just form shapes of bunnies and wizards, they also signal rain or a bright day ahead.

Clouds are a mass of visible water formed in the sky. Clouds form because of the expansion of rising air mass. When dust, ice, salt and water condense, they form clouds. The process is, theoretically, simple. Air contains water vapor. This vapor is cooled below the dew point. This causes moisture which condenses in the atmosphere.

Formation of Clouds
http://formationofclouds.com/

Larvivorous Fishes - A Measure For Mosquito Control! By Navodita Maurice

Nature is magnificent, full of diverse, bizarre flora as well as fauna. Some creatures are useful for us while some create hindrance for our healthy living. These disturbing elements "mosquitoes" play a very crucial role in making our life unhealthy. Mosquitoes are vectors of several diseases and carry parasites of malaria, filaria, yellow fever etc. They breed in all sorts of stagnant water and shallow weed infested ponds, swamps, pits, gutters and all other kinds of inland water bodies. Different species of mosquitoes prefer different places for breeding. During last few years DDT and other insecticides have been used for controlling mosquito menace but these chemicals caused many ill-effects on the human health.

Fish are a natural enemy of mosquito larvae and eggs hence, is a good ecological means of bilogical control practiced since olden times. Sveral species of fresh water fishes have been used for controlling the population of mosquitoes. These fishes are termed as "LARVIVOROUS FISHES". For a fish to be used as a larvivorous fish it must contain following characters:

1. It much be of small size so as to move freely,
2. It should be hardy fish,surviving in deep as well as in shallow water,
3. It should breed freely in confined waters,
4. It should be a surface feeder and carnivorous in habit,
5. It should have no food value.

The eggs, larvae and adults of mosquitoes form excellent food for the fishes. Some fishes feed on mosquitoes throughout their life while others prefer to feed on them for only a particular period of their life. The fishes that feed on mosquitoes throughout their life are basically used for larvicidal purposes of bilogical control. There are several exotic as well as indigenous species of fishes that are good biocontrol agents.

Exotic Species

Caraassius auratus, Lebistes sp., Gambusia offinis.

Indigenous Species

Notopterus, Oxygaster, Danio, Anabas, Mugil etc.

Biological control with the help of fishes is the most practical and cheap method. Fishes belonging to the family Cyprinodontidae are most efficient larvivorous fishes and satisfy all the characters that are needed for effective mosquito control. This practice of effective biocontrol needs much more efforts to be used on mass scale.

Navodita Maurice

Long-Necked Dinosaurs - Did Sauropods Hold Their Heads Up High? The Debate Continues By Mike Walley

The debate over the posture of the Sauropodomorphs has been opened up again with a new research paper published by a team of scientists from the University of Portsmouth, England. Sauropodomorpha is the correct taxonomic name for a Sub-Order of the Superorder Dinosauria. It contains the long-necked herbivores with lizard-like feet such as the Diplodocids and Brachiosaurs. It was one of two general clades from the Order Saurischia (lizard-hipped dinosaurs). This particular group of dinosaurs includes some very well known genera such as Diplodocus, Apatosaurus, and Barosaurus. Most young children will be familiar with these elephantine creatures, with their long necks and long tails. These animals (also termed Sauropods) are believed by scientists to be the largest land animals in the fossil record. Once again, most young children can tell you at least one or two items of information about these particular dinosaurs. For example, when we visit schools the enormous dimensions of some of these animals are frequently recited to us by enthusiastic dinosaur fans.

It is true that many of these Mesozoic monsters could have reached lengths in excess of 30 metres and weighed upwards of fifty tonnes or more, but despite their fossilised bones dominating the vestibules and grand halls of many a museum, palaeontologists know surprisingly little about their posture.

In the late 1980s and 1990s many a large Sauropod exhibit was re-mounted in a different pose as scientists concluded that in most case the tails of these animals did not drag on the ground. The accepted consensus at present is that most of the Sauropods held their tails straight out behind them, this explains why the Diplodocus (Diplodocus carnegiei) that dominates the entrance to the Natural History Museum in London had to be reassembled in 1994.

However, the debate over the posture and head position of the Sauropodomorphs has been opened up again with the new paper from the University of Portsmouth team. Just when we thought the back ends were sorted so differing opinions as to the flexibility and natural position of Sauropod necks have risen up again (no pun intended).

The University of Portsmouth team, led by Dr. Mike Taylor compared the cervical vertebrae (neck bones) of a number of Sauropods with mammals and birds that are alive today (extant species). By examining the skeletons and muscle structure of living animals which share the dinosaur's upright stance (mammals and birds), the researchers have concluded that the long-necked dinosaurs may have held their heads higher than previously thought, for much of the time.

This study is in contrast to earlier work (published this year), from the University of Adelaide, led by evolutionary biologist Dr. Roger Seymour. In this research paper, the swan-like neck pose of Sauropods was refuted. It was calculated that these reptiles were not capable of maintaining a high enough blood pressure to permit blood circulation from the heart to the brain. The pressure required to drive blood fifteen of so metres vertically upwards to reach the heads of the largest Sauropods would, it was calculated, be nearly fatal.

The accepted doctrine is that Sauropods held their heads relatively in line with their shoulders and they were unable to maintain a head held in a more vertical position. The range of movement in the neck of a dinosaur such as an Apatosaurus was believed to be quite constrained permitting the lifting of the neck only a few tens of degrees from the horizontal.

Dr. Taylor and his team used X-rays and other sophisticated techniques to plot the movement range capabilities of the necks of several Sauropods. Based on this study, the team concluded that Sauropods could have held their heads in a more vertically inclined position, similar to the way that mammals such as ourselves do.

The problem is, with the lack of preserved soft-tissue such as tendons and muscle in the Sauropod fossil record it is difficult to interpret the articulation and movement of the fossilised bones in isolation. The public can be lulled into a sense of thinking that scientists know all there is to know about dinosaurs, this is far from the truth. Even some of the best known dinosaurs, the ones generated by CGI for the movies, still refuse to yield their secrets and the debate over the posture of these huge dinosaurs is set to continue.

One of the drawbacks of using extant species to study dinosaurs, is that no animals today are really comparable with these leviathans from the Age of Reptiles. Perhaps a more complete specimen will be found soon, one that has elements of soft tissue preservation that may shed more light on the mystery of how Sauropods held their heads.

The history of palaeontology shows that a number of contrasting theories regarding the posture of Sauropods have held sway in the past, it looks like that for the immediate future the debate over the position of the heads of long-necked dinosaurs is set to continue.

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