MOUNTAINS

CONCEPT

Among the most striking of geologic features are mountains, created by several types of tectonic forces, including collisions between continental masses. Mountains have long had an impact on the human psyche, for instance by virtue of their association with the divine in the Greek myths, the Bible, and other religious or cultural traditions. One does not need to be a geologist to know what a mountain is; indeed there is no precise definition of mountain, though in most cases the distinction between a mountain and a hill is fairly obvious. On the other hand, the defining characteristics of a volcano are more apparent. Created by violent tectonic forces, a volcano usually is considered a mountain, and almost certainly is one after it erupts, pouring out molten rock and other substances from deep in the earth.

HOW IT WORKS

Plate Tectonics
Earth is constantly moving, driven by forces beneath its surface. The interior of Earth itself is divided into three major sections: the crust, mantle, and core. The lithosphere is the upper layer of Earth’s interior, including the crust and the brittle portion at the top of the mantle. Tectonism is the deformation of the lithosphere, and the term tectonics refers to the study of this deformation. Most notable among examples of tectonic deformation is mountain building, or orogenesis, discussed later in this essay.

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Northwest’s next big earthquake: Source mapped

This map shows the location of seawater samples taken by scientists and citizen scientists that were analyzed at the Woods Hole Oceanographic Institution for radioactive cesium as part of Our Radioactive Ocean. Cesium-137 is found throughout the Pacific Ocean and was detectable in all samples collected, while cesium-134 (yellow/orange dots), an indicator of contamination from Fukushima, has been observed offshore and in select coastal areas. Credit: Figure by Jessica Drysdale, Woods Hole Oceanographic Institution
This map shows the location of seawater samples taken by scientists and citizen scientists that were analyzed at the Woods Hole Oceanographic Institution for radioactive cesium as part of Our Radioactive Ocean. Cesium-137 is found throughout the Pacific Ocean and was detectable in all samples collected, while cesium-134 (yellow/orange dots), an indicator of contamination from Fukushima, has been observed offshore and in select coastal areas.
Credit: Figure by Jessica Drysdale, Woods Hole Oceanographic Institution

Scientists monitoring the spread of radiation in the ocean from the Fukushima nuclear accident report finding an increased number of sites off the US West Coast showing signs of contamination from Fukushima. This includes the highest detected level to date from a sample collected about 1,600 miles west of San Francisco. The level of radioactive cesium isotopes in the sample, 11 Becquerel’s per cubic meter of seawater (about 264 gallons), is 50 percent higher than other samples collected along the West Coast so far, but is still more than 500 times lower than US government safety limits for drinking water, and well below limits of concern for direct exposure while swimming, boating, or other recreational activities.

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Study undercuts idea that ‘Medieval Warm Period’ was global

Vikings may not have colonized Greenland in nice weather

Glaciers usually advance during cold times and recede during warm ones. These two in western Greenland are now retreating from where they may have been when the Vikings arrived. Credit: Jason Briner
Glaciers usually advance during cold times and recede during warm ones. These two in western Greenland are now retreating from where they may have been when the Vikings arrived.
Credit: Jason Briner

A new study questions the popular notion that 10th-century Norse people were able to colonize Greenland because of a period of unusually warm weather. Based upon signs left by old glaciers, researchers say the climate was already cold when the Norse arrived–and that climate thus probably played little role in their mysterious demise some 400 years later. On a larger scale, the study adds to building evidence that the so-called Medieval Warm Period, when Europe enjoyed exceptionally clement weather, did not necessarily extend to other parts of the world.

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Global human freshwater footprint surges

Global freshwater footprint Credit: Fernando Jaramillo, Navarino Environmental Observatory
Global freshwater footprint
Credit: Fernando Jaramillo, Navarino Environmental Observatory

The new study shows that dams and irrigation considerably raise the global human consumption of freshwater by increasing evapotranspiration. This effect increases the loss of freshwater to the atmosphere and thereby reduces the water available for humans, societies and ecosystems on land.

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Accidental discovery of how to stay young for longer

Scientists extend young adulthood in worms and discover new metric to track aging, stay young for longer.

Laboratory microscope (stock image). Credit: © 18percentgrey / Fotolia
Laboratory microscope (stock image).
Credit: © 18percentgrey / Fotolia

Living longer usually means a longer dotage, but wouldn’t it be enticing to extend young adulthood instead? It’s such an appealing prospect that scientists who are announcing success with roundworms are keen to be clear they are a long way from achieving it in humans.

„We don’t want people to get the impression they can take the drug we used in our study to extend their own teens or early twenties,“ says lead author Michael Petrascheck from The Scripps Research Institute (TSRI), California.

„We may have done this in worms, but there are millions of years of evolution between worms and humans.

„We think it is exciting to see that extending lifespan by extending young adulthood can be done at all,“ he says.

In the study to be published in the journal eLife, the TSRI-led team administered an antidepressant called mianserin to Caenorhabditis elegans, a type of roundworm used frequently in research. In 2007, they discovered that the drug increases the lifespan of roundworms by 30-40 per cent. Their new goal was to investigate how.

The team treated thousands of worms with either water or mianserin and looked at the activity of genes as the worms aged. First, they measured the activity of genes in young adults as a reference point against which to monitor the aging process. Reproductive maturity begins in day-old roundworms and they live for 2-3 weeks on average.

As the worms aged, the team observed dramatic changes in gene expression. However, the changes occurred in a way that came as a complete surprise. Groups of genes that together play a role in the same function were found to change expression in opposing directions.

They have called this newly-discovered phenomenon ‘transcriptional drift’. By examining data from mice and from 32 human brains aged 26 to 106 years, they confirmed that it also occurs in mammals.

„The orchestration of gene expression no longer seemed coordinated as the organism aged and the results were confusing because genes related to the same function were going up and down at the same time,“ says Petrascheck.

„Transcriptional drift can be used as a new metric for measuring age-associated changes that start in young adulthood,“ says first author Sunitha Rangaraju.

„Until now we have been dependent on measuring death rates, which are too low in young adults to provide much data. Having a new tool to study aging could help us make new discoveries, for example to treat genetic predispositions where aging starts earlier, such as Hutchinson-Gilford progeria syndrome,“ she says.

Using this new metric revealed that treatment with mianserin can suppress transcriptional drift, but only when administered at the right time of life. By 10 days old, treated worms still had the gene expression characteristics of a three-day-old – physiologically they were seven days younger. But by 12 days, the physiological changes required to extend lifespan were complete and lifelong exposure to the drug had no additional effect. Mortality rates were shifted parallel by 7-8 days across the treated worms’ lifespan, confirming the finding.

Mianserin blocked signals related to the regulation of serotonin and this delayed physiological changes associated with age, including the newly-identified transcriptional drift and degenerative processes that lead to death. The effect only occurred during young adulthood and the duration of this period of life was significantly extended.

„How much of our findings with regards to lifespan extension will spill over to mammals is anyone’s guess, for example the extension of lifespan might not be as dramatic,“ says Petrascheck.

„However, we are already excited about the fact that we observed the phenomenon of transcriptional drift in species ranging from worms, mice to humans.“

The findings have opened up many new avenues of research for the team and are likely to spawn a wealth of research by others. For example, a significant next step for the team will be to test the effect in mice and to investigate whether there are any side effects. Different environments could produce different results and this will need to be explored. They would also like to test whether the impact is different for different organs in the body.

The discovery of ‘transcriptional drift’ raises the prospect of the phenomenon providing a new general metric for aging, but again this requires further research.

In terms of extending teenage and young adult life in humans, just the idea invites a wealth of questions about the potential social implications and whether this would be as desirable as it first seems.


Story Source:

The above post is reprinted from materials provided by eLife. Note: Materials may be edited for content and length.


Journal Reference:

  1. Sunitha Rangaraju, Gregory M Solis, Ryan C Thompson, Rafael L Gomez-Amaro, Leo Kurian, Sandra E Encalada, Alexander B Niculescu, Daniel R Salomon, Michael Petrascheck. Suppression of transcriptional drift extends C. elegans lifespan by postponing the onset of mortality.eLife, 2015; 4 DOI: 10.7554/eLife.08833

http://www.sciencedaily.com/

Faintest galaxy from the early universe, 400 million years after the big bang

 

 

 

 

Hubble Space

This is a Hubble Space Telescope view of a very massive cluster of galaxies, MACS J0416.1-2403, located roughly 4 billion light-years away and weighing as much as a million billion suns. The cluster’s immense gravitational field magnifies the image of galaxies far behind it, in a phenomenon called gravitational lensing. The inset is an image of an extremely faint and distant galaxy that existed only 400 million years after the big bang.

Credit: NASA, ESA, and L. Infante (Pontificia Universidad Católica de Chile)

Astronomers harnessing the combined power of NASA’s Hubble and Spitzer space telescopes have found the faintest object ever seen in the early universe. It existed about 400 million years after the big bang, 13.8 billion years ago.

The team has nicknamed the object Tayna, which means „first-born“ in Aymara, a language spoken in the Andes and Altiplano regions of South America.

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Колко вида мълнии има – от вулканична до космическа.

Снимката изобразява буря над южната част на Мексико Сити на 10 август 2015. Снимката показва стандартна гръмотевична буря и голяма ярка червена светкавица - това е червен спрайт. Той се среща в района на мълнии с висока мощност на височина от около 90 километра над повърхността. Снимка: Space.com
Снимката изобразява буря над южната част на Мексико Сити на 10 август 2015. Снимката показва стандартна гръмотевична буря и голяма ярка червена светкавица – това е червен спрайт. Той се среща в района на мълнии с висока мощност на височина от около 90 километра над повърхността. Снимка: Space.com

Колко вида мълнии има – от вулканична до космическа?

Гръмотевичните бури бяха особено активни, а и опасни тези дни в нашата страна.  В същото време от борда на Международната космическа станция са успели да заснемат т. нар. червени спрайтове – огромни по размер светкавици, срещащи се високо над повърхността на планетата.

Свикнали сме да наблюдаваме само един вид мълнии, но се оказа че са поне 7 вида, а от космоса се виждат още повече.

Хората отдавна са разбрали как се случват мълниите:

В буреносните облаци се генерират мощни електрически полета с отрицателен заряд в долния слой и положителен – в горния. Мълнията е канал, провеждащ електричество, който се появява за кратко и възстановява частично баланса на електрическите заряди между отделните слоеве на облаците или между облаците и Земята.

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Проблемът с „мъртвите делфинчета“ през погледа на един специалист

мъртвите делфинчета
“A deaf dolphin or whale is a dead dolphin or dead whale.”
Michael Jasny

По данни на РИОСВ – Бургас от началото на сезона до 05.08. в района от с. Бяла до с. Резово са намерени 22 броя мъртви китоподобни бозайника, като три от случаите са били със съмнения за насилствена смърт. За тях са сигнализирани съответно органите на МВР. От началото на тази година до 3.08. във Варненската екоинспекция са получени 15 сигнала за изхвърлени от морето делфини, 6 от тях – неоснователни.

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Менопаузата се появява, за да намали конфликтите

Менопаузата се появява, за да намали конфликтите между поколенията жени
Съществува ли генетичен конфликт между майки и свекърви? Снимка: Parents United Kingdom

Защо фертилността (възможността за зачеване) на жените рязко спада на средна възраст (около 38 г), а окончателно губят способността си да имат деца само 10 години по-късно, по време на т.нар. менопауза

Двама учени са разработили нов модел, според който загубата на фертилност помага за намаляване на конфликтите между различните поколения жени.

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Итън Сийгъл отговаря: Защо съществува животът?

С две думи мога да изразя всичко, което съм научил за живота: той продължава.

– Робърт Фрост

Итън Сийгъл отговаря: Защо съществува животът?
Итън Сийгъл отговаря: Защо съществува животът?

Итън Сийгъл (Ethan Siegel), доктор по астрофизика и професор по физика и астрономия в Lewis & Clark College в Портланд отговаря на въпроса на свой читател:

„Бих искал да знам вашето мнение относно прилагането на втория закон на термодинамиката да произхода на живота.“

Добре известно е, че в началото във Вселената не е имало нищо наподобяващо живот. Не само сложни многоклетъчни форми на живот като бозайници или насекоми, веднага след Големия взрив не е бил дори атоми! Но от тази много гореща и плътна супа от доисторическа материя и лъчения постепенно започва всичко. А някои от тези стъпки са известни напълно.

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