Plants couldn’t run away from Chernobyl—but that’s what saved them

https://www.popsci.com/chernobyl-plants-radiation-cancer/

An abandoned hotel building in Pripyat, a few miles from Chernobyl.

An abandoned hotel building in Pripyat, a few miles from Chernobyl. (Fotokon/Shutterstock/)

Chernobyl has become a byword for catastrophe. The 1986 nuclear disaster, recently brought back into the public eye by the hugely popular TV show of the same name, caused thousands of cancers, turned a once populous area into a ghost city, and resulted in the setting up of an exclusion zone 1,000 mi² in size.

But Chernobyl’s exclusion zone isn’t devoid of life. Wolves, boars and bears have returned to the lush forests surrounding the old nuclear plant. And when it comes to vegetation, all but the most vulnerable and exposed plant life never died in the first place, and even in the most radioactive areas of the zone, vegetation was recovering within three years.

Humans and other mammals and birds would have been killed many times over by the radiation that plants in the most contaminated areas received. So why is plant life so resilient to radiation and nuclear disaster?

To answer this question, we first need to understand how radiation from nuclear reactors affects living cells. Chernobyl’s radioactive material is "unstable" because it is constantly firing out high energy particles and waves that smash cellular structures or produce reactive chemicals which attack the cells’ machinery.

Most parts of the cell are replaceable if damaged, but DNA is a crucial exception. At higher radiation doses, DNA becomes garbled and cells die quickly. Lower doses can cause subtler damage in the form of mutations altering the way that the cell functions—for example, causing it to become cancerous, multiply uncontrollably, and spread to other parts of the body.

In animals, this is often fatal, because their cells and systems are highly specialized and inflexible. Think of animal biology as an intricate machine in which each cell and organ has a place and purpose, and all parts must work and cooperate for the individual to survive. A human cannot manage without a brain, heart, or lungs.

Plants, however, develop in a much more flexible and organic way. Because they can’t move, they have no choice but to adapt to the circumstances in which they find themselves. Rather than having a defined structure as an animal does, plants make it up as they go along. Whether they grow deeper roots or a taller stem depends on the balance of chemical signals from other parts of the plant and the "wood wide web," as well as light, temperature, water, and nutrient conditions.

Trees have reclaimed the area surrounding the old nuclear power station.

Trees have reclaimed the area surrounding the old nuclear power station. (Fotokon/Shutterstock/)

Critically, unlike animal cells, almost all plant cells are able to create new cells of whatever type the plant needs. This is why a gardener can grow new plants from cuttings, with roots sprouting from what was once a stem or leaf.

All of this means that plants can replace dead cells or tissues much more easily than animals, whether the damage is due to being attacked by an animal or to radiation.

And while radiation and other types of DNA damage can cause tumors in plants, mutated cells are generally not able to spread from one part of the plant to another as cancers do, thanks to the rigid, interconnecting walls surrounding plant cells. Nor are such tumors fatal in the vast majority of cases, because the plant can find ways to work around the malfunctioning tissue.

The rigid and interconnecting walls of plant cells make them resistant to cancer.

The rigid and interconnecting walls of plant cells make them resistant to cancer. (Rattiya Thongdumhyu/Shutterstock/)

Interestingly, in addition to this innate resilience to radiation, some plants in the Chernobyl exclusion zone seem to be using extra mechanisms to protect their DNA, changing its chemistry to make it more resistant to damage, and turning on systems to repair it if this doesn’t work. Levels of natural radiation on the Earth’s surface were much higher in the distant past when early plants were evolving, so plants in the exclusion zone may be drawing upon adaptations dating back to this time in order to survive.

A new lease of life

Life is now thriving around Chernobyl. Populations of many plant and animal species are actually greater than they were before the disaster.

Given the tragic loss and shortening of human lives associated with Chernobyl, this resurgence of nature may surprise you. Radiation does have demonstrably harmful effects on plant life, and may shorten the lives of individual plants and animals. But if life-sustaining resources are in abundant enough supply and burdens are not fatal, then life will flourish.

Crucially, the burden brought by radiation at Chernobyl is less severe than the benefits reaped from humans leaving the area. Now essentially one of Europe’s largest nature preserves, the ecosystem supports more life than before, even if each individual cycle of that life lasts a little less.

In a way, the Chernobyl disaster reveals the true extent of our environmental impact on the planet. Harmful as it was, the nuclear accident was far less destructive to the local ecosystem than we were. In driving ourselves away from the area, we have created space for nature to return.

Stuart Thompson is a Senior Lecturer in Plant Biochemistry, University of Westminster. This article was originally featured on The Conversation.

The Conversation

via Popular Science – New Technology, Science News, The Future Now https://www.popsci.com

June 25, 2019 at 11:17AM

Raspberry Pi 4 Launched: Quad Cortex-A72 Single-Board Computer For $35

https://www.anandtech.com/show/14581/raspberry-pi-4-launched-quad-cortex-a72-project-board-for-35-dollars

This morning the Raspberry Pi Foundation took the wraps off of their next generation hobbyist project computer, the Raspberry Pi 4. The eagerly anticipated update to the Raspberry Pi lineup – which is actually arriving a bit ahead of schedule due to some good fortunes in SoC development – offers a significant upgrade to the family thanks to its new 28nm Broadcom SoC, which among other things incorporates a more powerful quad Arm Cortex-A72 CPU cluster. The single-board computer is available now, and like its predecessors, prices start at $35.

Long a favorite for tinkers, makers, and anyone else looking for a project board or a simple computer, the Raspberry Pi family has been around since 2012. Its last full update was in 2016, when the Foundation released the Raspberry Pi 3. In the intervening three years the technology landscape has changed a fair bit, and so has the underlying hardware of the Pi. While still based on Broadcom SoCs, the new Pi incorporates Broadcom’s BCM2711, a 28nm SoC with a quad Cortex-A72 setup along with the company’s VideoCore VI GPU. While the GPU remains nothing to write home about – the Raspberry Pi Foundation prioritizes an open GPU first and foremost – the CPU upgrade is far more interesting. This update replaces the old Cortex-A53 CPU cores with cores from Arm’s much faster high-performance line of out-of-order execution cores. As a result, even with a clockspeed of just 1.5GHz, the Pi 4 is a good deal faster than the Pi 3, not to mention faster than even some mid-range smartphones.

Raspberry Pi
  Raspberry Pi 4
SoC Broadcom BCM2711

4x Cortex-A72
@ 1.5GHz

VideoCore VI
@ 500Mhz

DRAM 1/2/4GB LPDDR4
Storage microSD
Networking 1x Gigabit Ethernet
802.11ac
BT 5.0
USB 2x USB-A 3.0
2x USB-A 2.0
Video Output 2x HDMI 2.0 Type-D
GPIO 17 Pins
Power USB-C (Suggested: 15W, 5.1V/3A)
Dimensions 85.6mm x 56.5mm x 17mm
Price 1GB: $35
2GB: $45
4GB: $55

I/O has also received a much-needed upgrade for the latest Pi. The new SoC brings with it USB 3 support, giving the platform access to SuperSpeed USB data rates for the first time. HDMI support has been similarly bumped to 2.0 (meaning 4K output support), and fittingly, the board can now decode H.264 and H.265 video (another first) at resolutions up to 4K. Networking performance has been upgraded as well with the addition of a full-speed Gigabit Ethernet port, and joining the 802.11ac radio is support for Bluetooth 5.0.

All told, the Foundation is selling 3 different versions of the Raspberry Pi 4, depending on the memory configuration. The $35 model comes with 1GB of LPDDR4, while 2GB and 4GB models are available for $45 and $55 respectively. Which in the case of the latter two models is a significant shot in the arm for the board, as now they have two to four times the memory to play with.

Meanwhile, our sister site Tom’s Hardware already has an early review out, confirming much of what you’d expect from the Raspberry Pi 4 based on the specifications. CPU, memory, and storage performance are all greatly improved over past models, though power consumption has gone up a bit in the process.

via AnandTech http://bit.ly/phao0v

June 24, 2019 at 06:25PM