Marijuana is the buds and leaves of the Cannabis sativa plant. This plant contains more than 400 chemicals, including delta-9-tetrahydrocannabinol (THC), the plant’s main psychoactive chemical. THC is known to affect our brain’s short-term memory. Additionally, marijuana affects motor coordination, increases your heart rate and raises levels of anxiety. Studies also show that marijuana contains cancer-causing chemicals typically associated with cigarettes.
The Asteroids in our Neighborhood
Check out this video from Scott Manley, tracing thirty years of asteroid discovery and the deployment of new and more sensitive instruments to find them. From the green main belt asteroids, to the yellow dots that cross Venus’ orbit, to the red that come near our own orbit … space has a lot of stuff in it. Nearly 600,000 objects known at the latest update.
But that doesn’t mean we’re in any special danger. As these objects, most very tiny, travel through their wonky, often angled orbits, they travel through a volume of 2,000,000,000,000,000,000,000,000 cubic km, or enough to fit a trillion Earths. Space may have a lot of stuff in it, but it’s also very big.
Rest easy. We’re watching the skies.
First algae powered building goes up in Hamburg
A 15-unit apartment building has been constructed in the German city of Hamburg that has 129 algae filled louvered tanks hanging over the exterior of the south-east and south-west sides of the building—making it the first in the world to be powered exclusively by algae. Designed by Arup, SSC Strategic Science Consultants and Splitterwerk Architects, and named the Bio Intelligent Quotient (BIQ) House, the building demonstrates the ability to use algae as a way to heat and cool large buildings.
Between fevers, congestion and diarrhea, there are numerous ways that microbes can make us feel sick. But just how do microorganisms cause these symptoms?
At any given time, the microbes inside of our bodies outnumber our own cells by at least 10 to 1. In general, these tiny organisms are harmless — and often beneficial — to us, but some bacteria, viruses, fungi and protozoan parasites cause nasty diseases. For example, Escherichia coli can cause diarrhea, rhinovirus is behind the common cold and the fungus Cryptococcus neoformans can bring about a severe form of meningitis.
As you’ve probably guessed, there is no singular way that microbes make us sick — different biological mechanisms underlie different disease symptoms. So let’s go over some of the ways that microbes cause different symptoms. (Note: This is a general guide and is in no way meant to be a comprehensive description of every symptom you could possibly get.)
Many disease symptoms that befall us are actually caused by the immune system’s response to invading pathogenic microbes, rather than something the microbes are doing, specifically. Take, for instance, the common cold.
When the rhinovirus gets into your upper respiratory tract and invades epithelial cells (those that line the cavities in the body), it triggers inflammatory and immune responses. Certain cells release histamines, which dilate your blood vessels and increase their permeability, allowing white blood cells and some proteins to get to the infected tissues.
You often experience nasal congestion because your inflamed blood vessels are now so large that they stuff you up. But histamines also affect the amount of mucus your body produces, as well as its viscosity — this altered mucus production, along with the increased fluid leakage from now-permeable capillaries, can cause a runny nose.
Similar immune system reactions take place when you develop pneumonia, which is most often caused by bacteria and viruses (especially the bacterium Streptococcus pneumonia). Your body has pretty decent defenses to keep microbes out of the lungs, including nose hairs that filter air and certain reflexes (coughing and sneezing) that shoot microorganisms that enter your body back out. But sometimes that’s just not enough.
If bacteria get inside the alveoli (tiny air sacs in the lungs), they can invade the spaces between cells and even travel to adjacent alveoli. Your immune system responds by once again inflaming your blood vessels and making them permeable, allowing white blood cells and proteins to come to the rescue. But this permeability allows fluids to seep into the alveoli, taking up space that’s needed for the oxygen-carbon dioxide exchange. You become somewhat oxygen deprived and exhibit the shortness of breath that’s a common symptom of pneumonia. Moreover, your respirations increase as you try to bring more oxygen in and blow more carbon dioxide out.
Pneumonia and the common cold are also marked by fever, something that also arises because of our immune system. When white blood cells called macrophages encounter bacteria or viruses in your system, they produce cell-signaling proteins called interleukin-1 (IL-1). These proteins do two things: They call in helper T-cells and they bind to certain hypothalamus receptors in your brain, causing a rise in your body temperature, which is thought to help kill some pathogenic microbes. Substances that induce fevers, such as IL-1, are called pyrogens; some bacteria can induce fevers with pyrogens, too.
Bacteria are divided into two major groups based on the structure of their cell wall: Gram-negative and Gram-positive bacteria. The outer membrane of Gram-negative bacteria, such as E. coli and Salmonella, contains large molecules called lipopolysaccharides, which are made up of lipids and polysaccharide (sugar) chains.
These molecules are also called endotoxins (pdf), and they can act as pyrogens. When certain cells called phagocytes engulf the bacteria, lipopolysaccharides get released, which in turn causes macrophages to release IL-1. These proteins, as you know, cause fever.
But endotoxins can do a lot more than cause fever. For instance, if the bacteria Neisseria meningitides reaches the brain from the bloodstream, it can cause bacterial meningitis (Meningococcal meningitis). Endotoxins stimulate the synthesis of pro-inflammatory molecules called cytokines. So when the bacteria reaches the blood-brain barrier, a sharp inflammatory response ensues, causing cerebral blood vessels to leak protein and fluid, and swelling to develop in the membrane between the brain and skull.
These changes lead to an increase in intracranial pressure, resulting in the common meningitis symptoms of headache, stiff neck and sensitivity to bright lights. The pressure on nerves and decreased blood flow starves the brain of oxygen, leading to permanent brain damage and sometimes death.
The bacteria are more deadly if they stick to the bloodstream, where they can cause a blood infection called sepsis. This ability is partly due to the fact that N. meningitides’s endotoxin concentration is up to a 1,000 times greater than that other Gram-negative bacteria. The toxins target the heart and reduce its ability to pump blood, while also causing blood vessels throughout the body to rupture (more specifically, white blood vessels cause the breaks with the chemicals they release in response to the endotoxin).
As the vessels throughout the body leak, blood pressure drops and blood flow slows, leading to the failure of some major body organs and systems, including the kidneys, liver and central nervous system. The disease can manifest a number of conspicuous symptoms, such as fever, light-headedness, rapid heartbeat and skin rash (from the blood leaking under the skin).
While only Gram-negative bacteria use endotoxins, both Gram-negative and Gram-positive bacteria can cause disease symptoms using exotoxins, a type of protein toxin. Exotoxins are grouped into categories based on their biologic effect on cells: Cytotoxins kill or damage cells, neurotoxins interfere with nerve impulses and enterotoxins affect the intestines.
Many well-known disease symptoms are traced back to exotoxins secreted by various bacteria. For example, the Gram-positive bacterium Streptococcus pyogenes releases three cytotoxins — one of its toxins damages blood capillaries, causing the infamous red rash of scarlet fever. Clostridium perfringens releases a toxin that disrupts normal cellular function and leads to the mass tissue necrosis commonly known as gangrene.
And when Corynebacterium diphtheriae is infected by a certain bacteriophage (bacteria-infecting virus), it can release the diphtheria toxin, which inhibits protein synthesis in cells and eventually causes their death. The cytotoxin can affect a wide range of tissues, and at high concentrations will produce diphtheria’s characteristic swollen neck, often called “bull neck.”
Bacterial neurotoxins are equally well known and scary. The uncontrollable spasms and convulsions of tetanus are all thanks to Clostridium tetani’s neurotoxin, which blocks the relaxation of skeletal muscles. Clostridium tetani’s relative, Clostridium botulinum, excretes a very potent neurotoxin that inhibits the release of the neurotransmitter acetylcholine — this inhibition prevents the transmission of nerve impulses to muscles, resulting in paralysis.
Now, let’s not forget about the wonderful enterotoxins that screw up our intestines. Vibrio cholerae’s cholera toxin (pdf) affects the ion transport and water balance in the intestines, causing epithelial cells to discharge large amounts of fluids and electrolytes. Some toxins produced by E. coli work in a similar way to the cholera toxin, while others are known to affect the intestinal blood vessels, causing bloody diarrhea.
Though we’ve covered quite a bit already, we’ve really only brushed the surface of how microbes bring about disease symptoms. Diarrhea, for example, can also come about when the single-celled parasite Giardia lamblia coats the intestines and prevents nutrient absorption. And the pain and frequent urination associated with urinary tract infections result from inflammation (pain from inflammation occurs only when the appropriate sensory nerve endings are in the inflamed area).
In addition, boils and other abscesses (such as those from a staph infection) can develop after bacteria populate a cut or break in the skin. Neutrophils, which are a type of white blood cells, rush to the infection, leading to inflammation. Eventually, pus forms from the mixture of old white blood cells, dead skin cells and bacteria.
And let’s not even get into viruses, which produce symptoms by triggering immune responses (like the rhinovirus), interfering with cells’ normal processes or destroying cells by exploding out of them.
The ways in which microbes produce disease symptoms are about as varied as the microbes themselves. Some microorganisms mess with our bodily functions, while others are satisfied with just destroying our cells. And, of course, there are all of those pathogens that turn our own immune system against us. Evil buggers.
for years I thought I was the only one having this happen! I am so glad that I am not going insane/being possessed by a demon.
Introduction to How Marijuana Works
Marijuana plants contain more than 400 chemicals, 60 of which fit into a category called cannabinoids. THC is just one of these cannabinoids, but it’s the chemical most often associated with the effects that marijuana has on the brain. Cannabis plants also contain choline, eugenol, guaicacol and piperidine. The concentration of THC and other cannabinoids varies depending on growing conditions, plant genetics and processing after harvest.
Every time a user smokes a marijuana cigarette or ingests marijuana in some other form, THC and other chemicals enter the user’s body. The chemicals make their way through the bloodstream to the brain and then to the rest of the body. The most powerful chemical in marijuana is THC (delta-9-tetrahydrocannabinol), which is primarily responsible for the “high” associated with the drug.
The most common way of using marijuana is smoking. Smoking is also the most expedient way to get the THC and other chemicals into the bloodstream. When the smoke from marijuana is inhaled, the THC goes directly to the lungs. Your lungs are lined with millions of alveoli, the tiny air sacs where gas exchange occurs. These alveoli have an enormous surface area — 90 times greater than that of your skin — so they make it easy for THC and other compounds to enter the body. The smoke is absorbed by the lungs just seconds after inhaling.
You can also eat marijuana. In this case, the marijuana enters the stomach and the blood absorbs it there. The blood then carries it to the liver and the rest of the body. The stomach absorbs THC more slowly than the lungs. When marijuana is eaten, the levels of THC in the body are lower, but the effects last longer
Marijuana and the Brain
THC is a very potent chemical compared to other psychoactive drugs. An intravenous (IV) dose of only 1 milligram can produce serious mental and psychological effects. Once in your bloodstream, THC typically reaches the brain within seconds after it is inhaled and begins to go to work.
Marijuana users often describe the experience of smoking marijuana as initially relaxing and mellow, creating a feeling of haziness and light-headedness. The user’s eyes may dilate, causing colors to appear more intense, and other senses may be enhanced. Later, feelings of a paranoia and panic may be felt by the user. The interaction of the THC with the brain is what causes these feelings. To understand how marijuana affects the brain, you need to know about the parts of the brain that are affected by THC. Here are the basics:
- Neurons are the cells that process information in the brain. Chemicals called neurotransmitters allow neurons to communicate with each other.
- Neurotransmitters fill the gap, or synapse, between two neurons and bind to protein receptors, which enable various functions and allow the brain and body to be turned on and off.
- Some neurons have thousands of receptors that are specific to particular neurotransmitters.
- Foreign chemicals, like THC, can mimic or block actions of neurotransmitters and interfere with normal functions.
In your brain, there are groups of cannabinoid receptors concentrated in several different places. These cannabinoid receptors have an effect on several mental and physical activities, including:
- Short-term memory
- Problem solving
Cannabinoid receptors are activated by a neurotransmitter called anandamide. Anandamide belongs to a group of chemicals called cannabinoids. THC is also a cannabinoid chemical. THC mimics the actions of anandamide, meaning that THC binds with cannabinoid receptors and activates neurons, which causes adverse effects on the mind and body.
High concentrations of cannabinoid receptors exist in the hippocampus, cerebellum and basal ganglia. The hippocampus is located within the temporal lobe and is important for short-term memory. When the THC binds with the cannabinoid receptors inside the hippocampus, it interferes with the recollection of recent events. THC also affects coordination, which is controlled by the cerebellum. The basal ganglia controls unconscious muscle movements, which is another reason why motor coordination is impaired when under the influence of marijuana.
One peculiar phenomenon associated with marijuana use is the increased hunger that users feel, often called the “munchies.” Research shows that marijuana increases food enjoyment and the number of times a person eats each day.
Until recently, the munchies were a relative mystery. However, a recent study by Italian scientists may explain what happens to increase appetite in marijuana users. Molecules called endocannabinoids bind with receptors in the brain and activate hunger.
This research indicates that endocannabinoids in the hypothalamus of the brain activate cannabinoid receptors that are responsible for maintaining food intake.
Other Physiological Effects of Marijuana
In addition to the brain, the side effects of marijuana reach many other parts of the body, which include:
- Problems with memory and learning
- Distorted perception
- Difficulty with thinking and problem solving
- Loss of coordination
- Increased heart rate
- Anxiety, paranoia and panic attacks
The initial effects created by the THC in marijuana wear off after an hour or two, but the chemicals stay in your body for much longer. The terminal half-life of THC is from about 20 hours to 10 days, depending on the amount and potency of the marijuana used. This means that if you take one milligram of THC that has a half-life of 20 hours, you will still have 0.031 mg of THC in your body more than four days later. The longer the half-life, the longer the THC lingers in your body.
The debate over the addictive capacity of marijuana continues. Ongoing studies now show a number of possible symptoms associated with the cessation of marijuana use. These symptoms most commonly include irritability, nervousness, depression, anxiety and even anger. Other symptoms are restlessness, severe changes in appetite, violent outbursts, interrupted sleep or insomnia. In addition to these possible physical effects, psychological dependence usually develops because a person’s mind craves the high that it gets when using the drug.
Beyond these effects that marijuana has, marijuana smokers are susceptible to the same health problems as tobacco smokers, such as bronchitis, emphysema and bronchial asthma. Other effects include dry mouth, red eyes, impaired motor skills and impaired concentration. Long-term use of the drug can increase the risk of damaging the lungs and reproductive system, according to the U.S. Drug Enforcement Agency (DEA). It has also been linked to heart attacks.
Although marijuana is known to have negative effects on the human body, there is a raging debate over the use of medicinal marijuana. Some say that marijuana should be legalized for medical use because it has been known to suppress nausea, relieve eye pressure, decrease muscle spasms, stimulate appetite, stop convulsions and eliminate menstrual pain. Because of its therapeutic nature, marijuana has been used in the treatment of several conditions including: cancer and AIDS (to supress nausea and stimulate appetite), glaucoma (to alleviate eye pressure), epilepsy (to stop convulsions) and multiple sclerosis (to decrease muscle spasms).
Web Star Physics Professor to Teach Millions
EdX, the not-for-profit online learning initiative founded by Harvard Univ. and the Massachusetts Institute of Technology (MIT), announced today a new course from the legendary professor Walter Lewin who, for 47 years, has provided generations of MIT students – and millions watching online – with his inspiring and unconventional lectures. Now, with this edX version of Lewin’s famous course Electricity and Magnetism (Physics), people around the world can experience it just like his students on the MIT campus. MITx 8.02x Electricity and Magnetism is now open for enrollment and classes will begin on February 18, 2013.
Read more: http://www.laboratoryequipment.com/news/2013/01/web-star-physics-professor-teach-millions
presence of mucus cocoons in parrotfish
several species of parrotfish are known to secrete a protective mucus cocoon around themselves before they go to sleep. This cocoon provides several benefits for the fish as it hides its scent from predators, and acts as an early warning system giving the fish a few precious seconds to escape from a preadator. This membrane also keeps the fish clean as parasites and UV light cannot penetrate the membrane. The skin of the membrane may have antioxidant properites in it which could help the fish repair any damage done to it.
Picture of the Big Bang (a.k.a. Oldest Light in the Universe)
Absolute zero, the temperature at which atoms completely cease motion was once a goal of physicists. But now, physicists have now somehow managed to take atoms colder than infinite zero that loops back around into weird negative temperature realm that can only be described as infinite hot.
I can’t stop loving how much Carl still inspires people to this day.
Evidence for the importance of physical activity in keeping and potentially improving cognitive function throughout life was found in a literature review in Psychonomic Bulletin & Review by Hayley Guiney and Liana Machado from the University of Otago, New Zealand.
- Cognitive functions such as task switching, selective attention, and working memory appear to benefit from aerobic exercise. Studies in older adults reviewed by the authors consistently found that fitter individuals scored better in mental tests than their unfit peers.
- Scores in mental tests improved in participants who were assigned to an aerobic exercise regimen compared to those assigned to stretch and tone classes.
- Exercise has been found to positively affect mental tasks relating to activities such as driving, an activity where age is often seen as a limiting factor.
- MRI studies of aging have shown that, as compared with unfit, highly fit older adults exhibit less age-related atrophy in the prefrontal and temporal cortices; preserved neural tracts connecting the prefrontal cortex to other regions of the brain; superior white matter integrity in the corpus callosum; greater gray matter density in the frontal, temporal, and parietal cortices; and greater hippocampal volumes.
- Physically active older adults have both higher circulating neurotrophin levels and gray matter volumes in the prefrontal and cingulate cortex.
- These results were not replicated in children or young adults, except for memory tasks. Both the updating of working memory and the volume of information which could be held was also better in young fitter individuals or those put on an aerobic exercise regime. “Although the evidence to date supports a wider range of executive functions benefiting from regular exercise in older adults, the relative lack of supportive evidence in young adults and children may, in part, reflect a poverty of studies, especially controlled trials, in these age groups,” the authors suggest.
There is nothing that cannot be ultimately explicated & understood via the use of scientific analysis. It is the limitations of our brains — so large-seeming in those cozy alien cannisters, but so minute swimming in this vast black universe — that all but require an author to explore the supernatural. It’s supremely ironic that the natural world is too enormous and too fearful for the human mind to properly correlate all its contents & so we appeal to the supposedly inexplicable supernatural world to explicate the ultimately apprehendable natural world.
Remarkable interview with H. P. Lovecraft, conducted in handwriting on a single postcard, which Nick Mamatas accidentally discovered in a used book.
Complement with Lovecraft’s timeless advice to young writers.
The Scientific Power of Thought - How Imagining Makes It So
Disgusting, shocking expose by Agence France-Presse. Hong-Kong. After people complained, tens of thousands of shark fins were brought to the roof tops to dry. The article says they did this to hide the fins from the public because of increased awareness of animal cruelty.
Shark fin traders in Hong Kong have taken to drying freshly sliced fins on rooftops since a public outcry over them drying the fins on public sidewalks forced them to move the trade out of sight.
Activists have raised concerns that the over-harvesting of fins is causing an environmental calamity. Although sales have fallen in recent years Hong Kong remains one of the world’s biggest markets for shark fins, which are used to make soup that is an expensive staple at Chinese banquets. NBC
I can’t stomach watching the process of shark finning (more videos here). Basically, they catch the shark, cut off its fins, and throw the shark back into the ocean - alive and awake. The sharks bleed to death and/or suffocate since they can’t swim.
But saying “gross” or “I’m sad” is not enough. There are a variety of ways you can help stop finning.
Sharks are threatened by climate change. Increased temperatures are affecting their habitat and food supplies around the globe. Changes to their habitat threaten their survival.
Last year, Discovery reported the world’s first hybrid shark and speculated it had adapted to climate change. They speculated that two separate shark species paired as a result of climate change. It was the first time a shark hybrid has been found and scientists speculated they were evolving, e.g., they adapted to increased temperatures.
The Australian black-tip is slightly smaller than its common cousin and can only live in tropical waters, but its hybrid offspring have been found 2,000 kilometers (1,243 miles) down the coast, in cooler seas.
It means the Australian black-tip could be adapting to ensure its survival as sea temperatures change because of global warming.
“If it hybridizes with the common species it can effectively shift its range further south into cooler waters, so the effect of this hybridizing is a range expansion,” Morgan said.
“It’s enabled a species restricted to the tropics to move into temperate waters.” Via Discovery
Adaptation is not fast enough. Habitat and food supplies are quickly being destroyed, not to mention ocean currents are shifting, adding additional pressure on marine life. Most importantly, the incredible increases wealth in China and Asia generally has increased demand for shark fin soup, which is considered a delicacy.
Gordan Ramsay, an A-list celebrity chef, was doused with gasoline and held at gun-point while exposing shark finning on his TV show last year. He tried the soup and deemed it unremarkable and bland, comparing the soup to eating salted potatoes.
He was horrified and sickened at the process (warning: very tough to watch. Several sharks are hacked live). Chef Ramsay subsequently advocated for the finning of these amazing animals to stop. He helped contribute to the passage of a bill banning shark fin soup in the U.S.
There are several ways to stop finning: Pressuring grocery stores and Asian markets, writing congress (it works, I swear), contributing cash and volunteer time to anti-finning campaigns, passing the word around to educate others, and signing petitions.
- And thanks for reading my post. m